ALBERT

Description: Single grains of detrital white mica from two different synorogenic sediments in the Southern Urals were analysed using the in situ ultraviolet laser ablation Ar–Ar dating technique to discriminate between age signatures associated with a high-pressure signal (phengites) from those related to muscovite only. Two disparately aged sandstone formations of Neoproterozoic (Upper Vendian) and Upper Devonian (Famennian) age were formed by the erosion of high-relief source areas with contemporaneously exhumed high-pressure rocks. A bimodal distribution of ages and chemical compositions can be detected in the two detrital populations. There is no age overlap between the two populations, reflecting completely different source areas containing high-pressure rocks of different ages.Within the Upper Vendian sandstones, detrital white mica from a 571–609 Ma age group is phengitic in composition (Si 3.3–3.41 per formula unit), while an older 645–732 Ma age group is comprised of muscovite composition grains only. The first group is compatible with the time of late exhumation and emplacement of a source area containing high-pressure rocks, the Neoproterozoic Beloretzk terrane. The older age range is compatible with a long history of cooling and the allochthonous nature of this terrane. Detrital white mica from the Famennian sandstones(Zilair Formation) comprises one age group (342–421 Ma) containing phengite (Si 3.21–3.39 per formula unit) and muscovite, and a second group (446–496 Ma) containing muscovite only. While the derivation of the second group cannot be correlated with any as yet known regional data, the first age group indicates the earliest arrival of high-pressure rocks at the surface along the suture zone after Late Devonian arc–continent collision.

Description: Oithona similis is an abundant but poorly studied cyclopoid copepod in the brackish Central Baltic Sea. We describe the spatio-temporal distribution of O. similis in a Central Baltic deep basin (Bornholm Basin) during spring and summer 1999. Using vertically resolving sampling in parallel with hydrographic measurements, we found the copepod to dwell in the permanent halocline characteristic of a Central Baltic deep basin. The habitat of O. similis is thus limited from above by low salinity and from below by low oxygen conditions, both characteristic for the area. Horizontally resolving sampling yielded abundance surfaces which were compared by analysis of variance showing similar patterns among sampling dates. Comparison with flow fields from a three-dimensional hydrodynamic model suggests that the horizontal distribution is primarily the result of circulation in the dwelling depth. The study shows how the physical environment in the area determines the spatial distribution which might affect abundance and production of this copepod.

Description: The seasonal development of bacteria was studied in the hypertrophic coastal lagoon Ciénaga Grande de Santa Marta (Caribbean coast of Colombia). This large but only 1.5 m deep lagoon is subject to strong seasonal variations of salinity from almost fully marine (April/May) to brackish conditions in October/November. Chlorophyll ranged from 6 to 182 μg L−1, and gross primary production amounted to 1690 g C m−2 per year. Total bacterial number (TBN) ranged from 6.5 to 90.5 × 109 cells L−1 and bacterial biomass (BBM) from 77 to 1542 μg C L−1, which are among the highest ever reported for natural coastal waters. Neither TBN nor BBM varied significantly with salinity, phytoplankton or seston concentrations. Only the bacterial mean cell volume showed a significant relation to salinity, being highest (0.066 μm3) during the period of increasing and lowest (0.032 μm3) during decreasing salinity. Bacterial protein accounted for 24% (19–26%) and phytoplankton protein for 57% (53–71%) of total seston protein. The ratio (annual mean) of bacterial carbon to phytoplankton carbon was 0.44 (range 0.04–1.43). At low phytoplankton abundance [chlorophyll a (Chl a) 〈 25 μg L−1], bacterial carbon was almost equal to phytoplankton biomass (i.e. the mean ratio was 1.04). In contrast, at Chl a 〉 100 μg L−1, BBM was low compared to phytoplankton biomass (the mean ratio was 0.16). In general, BBM varied less than phytoplankton biomass. Most probably, the missing correlation between bacterial and phytoplankton variables was due to (i) organic material partly derived from allochthonous sources serving as food resource for bacteria and (ii) a strong resuspension of bacteria from the sediment caused by frequent wind-induced mixing of the very shallow lagoon.

Description: The so-called ‘turbulence incubator’ overcomes an essential disadvantage of static in situ incubations where at high irradiances an artificial photoinhibition is caused by neglecting turbulent mixing in the upper water column. It is operated on deck and simulates the changing light conditions for vertically mixed phytoplankton cells by moving the sample bottles horizontally through a circular water bath covered by a glass lid of neutral optical density filters. In this way the exponentially decreasing irradiance within the euphotic zone is simulated and photoinhibition near the surface is avoided. A crucial point is the choice of revolution rate for simulating turbulent mixing under natural conditions. The incubator is characterized by its handy size, a relatively simple and inexpensive construction and a battery-driven motor. It can thus even be operated on small vessels without an electric generator. The incubator is especially suited for vertically mixed waters such as shallow bays, tidal estuaries and rivers. Its reliability was successfully tested by a simultaneous comparison with in situ measurements at various stations representing different water types and environmental conditions, ranging from the turbid River Elbe to the clear open Baltic Sea. In 9 out of 11 experiments, higher primary production rates were obtained in the turbulence incubator than in static in situ incubations. The majority of the latter were characterized by a pronounced photoinhibition in the upper two incubation depths representing the 100 and 50% light levels. The average rate increase amounted to 22%, with a range between 11 and 53% depending on light attenuation and irradiance.

Description: The vertical distribution patterns of paralarvae from several abundant cephalopod taxa were examined from depth-stratified tows in the northeast Pacific (44–56°N, 145–165°W) during three summer surveys in 1999–2001. A total of 309 cephalopods representing 10 taxa in three families were collected. Gonatid squids composed 97% of the total catch, and the most numerous taxa were Berryteuthis anonychus (59% of the total catch), Gonatus spp. (21%) and Gonatopsis borealis (17%). B. anonychus and Gonatus spp. were both most abundant in the upper 20 m; catches of both taxa varied significantly with depth and were significantly higher above the thermocline than in and below the thermocline. Gonatopsis borealis was collected mostly between 20 and 50 m, and catches were significantly higher in the thermocline than above and below the thermocline. Paralarvae of the three major taxa showed no evidence of diel vertical migration. Mantle lengths of Gonatus spp. and G. borealis each varied significantly with depth, and Gonatus spp. showed a strong positive correlation between mantle length and depth.

Description: Age and growth of Todarodes sagittatus were estimated based on statolith analysis from individuals (N=352; 81–418 mm mantle length) caught by bottom trawlers during a year of sampling in the western Mediterranean. The daily nature of statolith increments was indirectly validated comparing the mean age of consecutive monthly modes (identified on the monthly length–frequency distributions) with the corresponding increase of 30 days. In agreement with other ommastrephids, results confirmed the following points: (1) lifespan lasts nearly a year; (2) growth rates decrease with age; (3) when adult, females have higher growth rates than males; and (4) females mature about a month later than males. Significant correlation was found between hatching (which occurred throughout the year but with a peak in November) and temperature at 50 m depth (where it is thought that hatchlings inhabit). Age and growth results were compared with those obtained in a similar work carried out in north-west Africa (Arkhipkin et al., 1999). Comparisons suggested that due to higher growth rates in juveniles, southern populations reach maturity and consequently decrease somatic growth at younger ages and smaller sizes than northern squid, which attain larger sizes as a result of maintaining fast growth and delaying maturation. Greater growth rates in juveniles from west Sahara could be explained by higher temperatures in this area than in the Mediterranean.

Description: Selectivity-size spectra, clearance and ingestion rates and assimilation efficiencies of Acartia clausi (Copepoda), Penilia avirostris (Cladocera) and Doliolum denticulatum (Doliolida) from Blanes Bay (Catalan Sea, NW Mediterranean) were evaluated in grazing experiments over a wide range of food concentrations (0.02–8.8 mm3 L−1 plankton assemblages from Blanes Bay, grown in mesocosms at different nutrient levels). Acartia clausi reached the highest grazing coefficients for large algae 〉70 μm (longest linear extension), P. avirostris for intermediate food sizes between 15 and 70 μm, and D. denticulatum for small sizes from 2.5 to 15 μm. Penilia avirostris and D. denticulatum acted as passive filter-feeders. Acartia clausi gave some evidence for a supplementary raptorial feeding mode. Effective food concentration (EFC) decreased linearly with increasing nutrient enrichment for D. denticulatum and followed domed curves for A. clausi and for P. avirostris with maximum values at intermediate and high enrichment levels, respectively. Clearance rates of crustacean species showed curvilinear responses with narrow modal ranges to increasing food concentration. Clearance rates of D. denticulatum increased abruptly and levelled into a plateau at low food concentrations. Mean clearance rates were 13.9, 25.5 and 64.1 mL ind.−1 day−1, respectively. No clearance could be detected for A. clausi at food concentrations 〈0.1 mm3 L−1 and for P. avirostris at food concentrations ≤0.02 mm3 L−1. Ingestion rates indicate a rectilinear functional response for A. clausi and for P. avirostris and showed a sigmoidal curve for D. denticulatum. Mean ingestion rates were 1.3, 2.8 and 7.7 μg C μg Cind.−1 day−1, respectively. Conversion of ingested carbon to tissue was 30–80% for the investigated crustaceans and 20–50% for doliolids. Food niche calculations suggest that food niche separation may explain the coexistence of the three species in summer in Blanes Bay.

Description: The δ15N of marine mesozooplankton species was measured on four occasions. Significant differences were found between copepods and meroplanktonic larvae, yet not between holoplanktonic species. On average, mesozooplankton was enriched by 3.4 ± 0.9‰ relative to selected seston size fractions. Despite suggesting small differences (∼0.5 to 1‰) in the δ15N of different phytoplankton taxa on one occasion, the size fractionation procedure generally proved inadequate in separating major taxonomic groups composing seston. This circumstance, and phase-shifts in the transmission of rapid changes (〉2‰) in seston δ15N to mesozooplankton complicate the calculation of mesozooplankton trophic levels.

Description: Markedly different cooling histories for the hanging- and footwall of theVari detachment on Syros and Tinos islands, Greece, are revealed by zircon and apatite fission-track data. The Vari/Akrotiri unit in the hangingwall cooled slowly at rates of 5–15 ◦CMyr−1 since Late Cretaceous times. Samples from the Cycladic blueschist unit in the footwall of the detachment on Tinos Island have a mean zircon fission-track age of 10.0±1.0 Ma, which together with a published mean apatite fission-track age of 9.4±0.5 Ma indicates rapid cooling at rates of at least ∼60 ◦CMyr−1. We derive a minimum slip rate of ∼6.5 kmMyr−1 and a displacement of 〉∼20 km and propose that the development of the detachment in the thermally softened magmatic arc aided fast displacement. Intra-arc extension accomplished the final ∼6–9 km of exhumation of the Cycladic blueschists from ∼60 km depth. The fast-slipping intra-arc detachments did not cause much exhumation, but were important for regionalscale extension and the formation of the Aegean Sea.

Description: In a mesocosm study, the appendicularian Oikopleura dioica bloomed after the reduction of copepod abundance, and in a second treatment showed a significantly negative correlation with copepod densities. Calculations, together with field data from the Baltic Sea, suggest that common calanoid copepods may control appendicularian population dynamics.

Description: The development and application of a dilution method for measuring primary production in coastal waters is described.

Description: We used otolith microstructure analysis to reconstruct the growth histories of larval radiated shanny ( Ulvaria subbifurcata ) collected over a 2-week period in Trinity Bay, Newfoundland. A dynamic 3-dimensional, eddy-resolving circulation model of the region provided larval drift patterns, which were combined with measurements of temperature and zooplankton abundance to assess the environmental history of the larvae. The abundance of juvenile and adult capelin ( Mallotus villosus ), the dominant planktivorous fish in this area, was monitored using five hydroacoustic surveys. The goal was to determine whether environmental histories are helpful in explaining spatial and temporal differences in larval shanny growth, measured as cumulative distribution functions (CDF) of growth rates. We found evidence for a selective loss of slower growing individuals and recognized considerable spatial differences in the CDF of larval growth rates. Consistent patterns in capelin abundance suggested that faster growing survivors, sampled at the end of the 2-week period, developed in areas of low predator densities. A dome-shaped relationship between temperature and larval growth was observed, explaining a significant but small amount of the overall variability (14%). Effects of experienced prey concentrations on larval growth rates could not be demonstrated.

Description: The effect of boundary conditions on the ‘critical dynamics’ at the onset of Taylor vortices is investigated in a combined numerical and experimental study. Numerical calculations of Navier–Stokes equations with ‘stress-free’ boundary conditions show that the Landau amplitude equation provides a good model of the transient dynamics. However, this rapidly breaks down when the ‘no-slip’ condition is approached. Apparent ‘critical’ behaviour observed in experiments is shown to have a surprising dependence on the length of the system.

Description: Specimens of the onychoteuthid squid Moroteuthis ingens were collected from four sites in the Southern Ocean: Macquarie Island, the Falkland Islands, the Chatham Rise (New Zealand) and the Campbell Plateau (New Zealand). Spatial variations in diet among these areas were investigated using stomach contents and lipid and fatty acid profiles. Myctophid fish were prominent prey items at all sites, and the diet at New Zealand sites contained temperate myctophid species that were not identified at other sites. The diet at the Falkland Islands differed considerably from other sites due to the large proportion of cephalopod prey that had been consumed by M. ingens . This is likely to be due to the absence of key myctophids, such as Electrona carlsbergi , and the abundance of smaller squid such as Loligo gahi and juvenile M. ingens over the Patagonian Shelf. Stomach contents data could not be used effectively to determine dietary differences between the Chatham Rise and Campbell Plateau, largely due to differences in sample sizes between these sites. Lipid class and fatty acid profiles of the digestive gland indicated that the diet of M. ingens differed significantly between the Chatham Rise and Campbell Plateau, despite the relative proximity of these sites. We conclude from total lipid content that this was due to a reduction in food availability to M. ingens at the Campbell Plateau. The highly productive waters of the Subtropical Front pass over the Chatham Rise, whereas the Campbell Plateau is situated in less productive sub-Antarctic water. Differences in oceanographic conditions are likely to have driven dietary variations between these two sites.

Description: The syntypes of the endemic Southern Ocean octopodid Pareledone polymorpha (Robson, 1930) were re-examined and measurements, counts and indices are presented. The two forms described by Robson, namely oblonga and affinis , are determined to have no taxonomic validity. The species polymorpha shows morphological similarities with Pareledone adelieana (Berry, 1917) but differs in relative arm lengths, sucker counts, external colouration and size at maturity. Both species are transferred to the new genus Adelieledone , which is separated from the genus Pareledone s.s. by the transverse ridges in the ligula groove of the hectocotylus, the sharp tip of the lower beak, the enlarged posterior salivary glands, the absence of stylets and by skin sculpture, especially by the presence of two longitudinal integumentary ridges on the dorsal mantle. A new species, Adelieledone piatkowski , is described from the Antarctic Peninsula. Beak morphology can discriminate the genera in predator studies.

Description: This paper examines the relationship between simulation and experiment. Many discussions of simulation, and indeed the term “numerical experiments,” invoke a strong metaphor of experimentation. On the other hand, many simulations begin as attempts to apply scientific theories. This has lead many to characterize simulation as lying between theory and experiment. The aim of the paper is to try to reconcile these two points of view—to understand what methodological and epistemological features simulation has in common with experimentation, while at the same time keeping a keen eye on simulation's ancestry as a form of scientific theorizing. In so doing, it seeks to apply some of the insights of recent work on the philosophy of experiment to an aspect of theorizing that is of growing philosophical interest: the construction of local models.

Description: Possible effects of ‘El Niño’ Southern Oscillation (ENSO) components ‘El Niño’ and ‘La Niña’ on populations of southern elephant seals, Mirounga leonina, were analysed. Changes in the cephalopod diet composition of moulting females at King George Island, Antarctic Peninsula were considered. The diet of female elephant seals sampled in 1991–1992 and 1992–1993 (El Niño years) were compared with those taken in 1995–1996 (La Niña year) at the same site and employing the same methodology. The squid Psychroteuthis glacialis constituted the main cephalopod prey of the seals. A reduction in the ‘Index of Biomass Ingested’ by female elephant seals (IBIF) of this prey species was observed in ‘El Niño’ years (1992, 1993) compared with the ‘La Niña’ year (1996). This reduction in biomass applied to all squid species in the seals' prey with the exception of Galiteuthis glacialis, which occurred in low numbers, but was more abundant during El Niño years than in the La Niña year.

Description: Miocene Ignimbrite ‘A’ on Gran Canaria contains three compositional endmember fiamme types(two rhyolites and one trachyte) each of which crystallized distinct feldspar. Various textural and compositional criteria are interpreted as reflecting a complex scenario within the magma chamber in which the crystals formed. About 25–30% of the feldspar phenocrysts contain evidence for magma mixing in the form of (1) partial to severe dissolution–resorption rims, (2) distinct zones of drastically different compositions and (3) overgrowth textures on formerly resorbed crystals. Four major types of zoning in the oligoclase to anorthoclase feldspars of ignimbrite ‘A’ include a normal and a reversely zoned type and two complexly zoned types. The feldspars with normal and reverse zonation show only minor compositional amplitudes between individual zones (ΔAb, Or ∼4%), whereas the complexly zoned types show compositional differences between zones of up to 18 mol % Ab and 20 mol % Or and are commonly associated with an internal dissolution surface. Complex zoning with large compositional amplitudes and dissolution textures is taken as evidence of crystal movements within the magma and across compositional boundaries between magma batches. A multiple ‘step-cycle’ model, involving growth and transport of a crystal into another magma batch and its return to the original host magma, is suggested by the data. Moreover, feldspars from one rhyolite compositional group are found to be substantially elevated in δ18O, suggesting an input of a high δ18O component to this rhyolite. The other endmember rhyolite appears to be related to the endmember trachyte by mainly crystal fractionation of anorthoclase feldspar. This observation is consistent with trace element and rare earth element concentrations for the magma endmembers and their feldspars, where contamination led to a depletion in incompatible trace elements and light rare earth elements in the contaminated rhyolite and its feldspar phenocrysts. We suggest that the combination of textural and compositional variation in ternary feldspar of peralkaline rhyolitic systems is well suited to reconstruct dynamic processes such as magma mixing and contamination in evolving rhyolitic magma chambers.

Description: Incubation experiments with natural phytoplankton revealed a relationship between CO2 concentration and the production of transparent exopolymer particles (TEP), with TEP production being linearly related to theoretical CO2 uptake rates.

Description: Lipid content, lipid class and fatty acid composition of four Southern Ocean cephalopod species – the myopsid Sepioteuthis australis and three oegopsids, Gonatus antarcticus , Moroteuthis robsoni and Todarodes spp. – were analysed. The lipid content of the digestive gland was consistently greater than that of the mantle, and was an order of magnitude greater in oegopsid species. The lipid class and fatty acid composition of the mantle and digestive gland also differed markedly in each species. Digestive gland lipid is likely to be of dietary origin, and large amounts of lipid in the digestive gland of oegopsids may accumulate over time. Thus the digestive gland is a rich source of fatty acid dietary tracers and may provide a history of dietary intake. However, the absolute amount of dietary lipid in the digestive gland of oegopsid species exceeds the absolute lipid content of mantle tissue. Therefore the overall lipid “signature” of an oegopsid may more closely resemble its prey species rather than its mantle tissue. When lipid techniques are used in dietary analysis of teuthophagous predators, squid may not be represented by a unique signature in analyses and their importance in the diets of predators may be underestimated.

Description: Uplift of the Rhenish Massif can be demonstrated by means of the stream-made river terrace system that accompanies the Rhine river and its tributaries along their way through or within this part of the Variscan fold and thrust belt. The height difference between a former valley floor, especially that of the Younger ‘Hauptterrasse’ (Main Terrace), and the recent one allows to quantify the uplift by the amount of downcutting erosion. The uplift velocity increased just after the BRUNHES / MATUYAMA boundary, i.e. about 0.8 Ma B.R Since that time, a domal uplift of more than 250 m is documented in the eastern Hunsriick and in the south-eastern Eifel. The area of this maximum height anomaly is situated just between the East-and West-Eifel Quaternary volcanic districts. Thus, causal connections are supposed. The domai uplift is affected by normal faulting partly inherited since Tertiary rifting.

Description: Squid of the genus Alloteuthis from the Aegean Sea and eastern Mediterranean were identified as A. media. It is not possible to distinguish A. media from A. subulata by relative fin length. Both ‘species’ are probably intraspecific forms. Egg size varied from 1·5 to 2·3 mm. Oocyte maturation in the ovary occurs in batches. The potential fecundity is some 1000–4000 eggs, most of these being released during continuous spawning accompanied by female growth.

Description: Population dynamics of major Baltic calanoid copepod species in the Gotland Basin during the last two decades were characterized by a decline of Pseudocalanus elongatus associated with declining salinities, and an increase of Temora longicornis and Acartia spp. potentially due to warmer conditions. Additionally this study investigated the effect of predation by the major planktivorous fish species herring (Clupea harengus) and sprat (Sprattus sprattus) for the period 1977–1996 in the Gotland Basin (Central Baltic Sea). Examination of consumption by these fish species in relation to copepod production estimates showed a switch by herring from consuming mainly CV/VI of P. elongatus and T. longicornis, to preying on CII of the latter copepod. This switch was potentially due to increased competition with the drastically increased sprat stock since the late 1980s. Further, an increased predation pressure by sprat on CV/CVI of both copepod species in spring resulted in higher copepod mortality rates. In consequence, based on these results we suggest that the increase in the sprat stock since the late 1980s contributed to a decline of P. elongatus, and additionally prevented an even more pronounced temperature-driven increase in the T. longicornis stock, as was observed for Acartia spp., which was not significantly consumed.

Description: To test the effects of diatom production on larval fish growth and condition, laboratory experiments were performed with larval North Sea cod reared on different algal food chains. These food chains were based on cultures of (a) the diatoms Skeletonema costatum and Thalassiosira weissflogii; (b) the dinoflagellate Heterocapsa triquetra; (c) the flagellate Rhodomonas baltica; (d) a diet composed of both Skeletonema and Heterocapsa food chains (1:1), and (e) a starvation group. These algae were fed to cultures of adult Acartia tonsa. Copepod eggs were collected, hatched, and the N1 nauplii (200l−1) were fed to post-yolk-sac larval cod. Results indicate that larval growth rates are significantly influenced by the content of essential fatty acids of the algal food source: growth rates were positively correlated with the content of DHA (C22:6ω3) and negatively with EPA (C20:5ω3). The ratio of ω3/ω6 fatty acids in the algal source had no significant effect. The highest and lowest growth rates were observed in food chains based on H. triquetra and T. weissflogii, respectively (means for days 14–16 of 4.0 and −4.7). The mixed diatom/dinoflagellate diet resulted in intermediate growth rates and condition. Regressions of growth rates against EPA and DHA content indicated no inhibitory effect of diatom production on growth in larval cod.

Description: Retention or dispersion of larvae from the spawning grounds has been identified as one of the key processes influencing recruitment success in fish stocks. To examine the potential effects of transport on recruitment, numerical simulations were performed utilizing a three-dimensional physical oceanographic model of the Baltic Sea. Cod larvae were represented as Lagrangian drifters released in the deepwater region of the Bornholm Basin, the main spawning ground for Baltic cod. Simulations were performed for the major spawning seasons of 1993 and 1994, when annual and interannual variability of meteorological forcing was large. The principal goals of the modelling exercise were first to identify the physical processes influencing the demersal distribution of the early life stages and second to describe the transport of the pelagic stages in response to variations in windstress, thereby identifying the meteorological and hydrodynamic mechanisms influencing retention and/or dispersal. The results suggest that periods of low wind, especially from northern and eastern directions, retain early life stages of cod within the deepwater region of the Bornholm Basin. Periods of higher windstress and duration from the west and south resulted in a rapid transport of larvae into shallow coastal regions. Based on the results obtained from these drift experiments and a wind data time series from the meteorological station Christiansoe, a transport index has been developed, variations in annual retention/ dispersal have been identified, and comparisons with variations in recruitment success are presented.

Description: Todarodes sagittatus (N=1131) were opportunistically sampled from commercial and research trawling in Irish and Scottish waters between 1993 and 1998. The results suggest that the species is common in deep waters (〉200 m) to the west of Ireland and Scotland, particularly in late summer and autumn. The size of squid caught was related to depth, with larger squid caught deeper, and is indicative of an ontogenetic, bathymetric migration. Females were more common (sex ratio 1·00:0·46), and attained a larger maximum size (520 mm mantle length (ML)) than males (426 mm ML). Mature females (360–520 mm ML) were caught in deep water (〉500 m), between March and November, with a large catch of mature females taken off the west coast of Ireland in August 1996. Mature males (300–426 mm) were found from August to November. Potential fecundity was estimated to range from 205,000–523,500 eggs female −1 . Putative daily increments in statoliths indicated a life cycle of slightly over a year, with rapid growth of approximately 1·8 mm d −1 during subadult and adult life. Fish were the most important prey of T. sagittatus and 17 fish prey taxa were identified, of which pelagic species were the most important.

Description: Four Benthoctopus species are recognized in the waters of the Falkland Islands: B. eureka , B. magellanicus, Benthoctopus sp. A , and Benthoctopus sp. B . Initial oocyte reserve of B. eureka is 250–535 eggs, the actual fecundity is 75–234 eggs while the rest of the oocytes degenerate at maturation. Larger females have higher fecundity. Gonad maturation of Benthoctopus sp. A and Benthoctopus sp. B follows a similar pattern. The Benthoctopus egg masses contained 170–190 eggs. The hatchlings possess arms that are much longer than mantle length with a large number of suckers, and do not have discernible chromatophores.

Description: A large, mature, female cirrate octopod, Cirroteuthis magna , was caught in a research trawl at 3200-m depth on the Cape Verde Terrace off the west African coast in November 1999. It is only the fourth recorded specimen of this species and the largest specimen (1,700 mm TL; 330 mm ML) of cirrate octopod ever caught. Detailed measurements were taken of the fresh and preserved specimen and indicated considerable shrinkage (17–32%) during formalin preservation. Careful dissection revealed large mature eggs (12·5–14 mm long) in the proximal oviduct, and a wide range of egg sizes and development stages in the ovary. The taxonomy and ecology of the species is briefly discussed.

Description: Two taxa of commercially exploited cuttlefish, Sepia officinalis and S. hierredda , are compared for the first time on the bases of quantitative morphology and allozyme polymorphisms. Morphometric measurements and meristic counts of selected soft and hard (cuttlebone) body characters, with allozyme electrophoretic analysis are used. Samples were obtained from north-west Iberian Peninsula and Senegalese waters (West Africa). Significant differences in mantle width, arm and hectocotylus length, numbers of rows of reduced suckers on the hectocotylus and in most cuttlebone measurements were found. Canonical discriminant functions of cuttlebone measurements for males and females were calculated. Allozyme electrophoresis for 33 presumptive loci showed low levels of genetic variability and 13 diagnostic loci between the two Sepia taxa. The genetic identities ( I ) in pairwise comparisons of populations of both taxa were I =0·582–0·596, which are typical values for congeneric species. These congruent morphological and genetic results strongly suggest that S. officinalis and S. hierredda are different species.

Description: Biological data are presented on two specimens of Taningia danae , an adult female caught by a trawler in Galician waters (north-west Spain) and a juvenile caught in a deep-water research trawl in Scottish waters (UK). The species has not previously been recorded in either area, although its presence has been inferred from beaks found in sperm whale stomach contents.

Description: Published information on the diet of Cuvier's beaked whales Ziphius cavirostris (Odontoceti: Ziphiidae) is reviewed and new information on the stomach contents of three animals: two stranded in Galicia (north-west Spain) in February 1990 at A Lanzada, and in February 1995 at Portonovo; and the third stranded in February 1999 in North Uist (Scotland), is presented. The whale stranded in 1990 was a male; the other two were adult females. All animals were 〉5 m long. The limited published information on the diet of this species indicates that it feeds primarily on oceanic cephalopods although some authors also found remains of oceanic fish and crustaceans. Food remains from the three new samples consisted entirely of cephalopod beaks. The Scottish sample set is the largest recorded to date for this species. The prey identified consisted of oceanic cephalopods, mainly squid (Cephalopoda: Teuthoidea). The most frequently occurring species were the squid Teuthowenia megalops , Mastigoteuthis schmidti and Taonius pavo (for the Galician whale stranded in 1990), Teuthowenia megalops and Histioteuthis reversa (for the second Galician whale) and T. megalops , Gonatus sp. and Taonius pavo (for the Scottish whale). Other prey included the squid Histioteuthis bonnellii , Histioteuthis arcturi and Todarodes sagittatus as well as Vampiroteuthis infernalis (Cephalopoda: Vampyromorpha), Stauroteuthis syrtensis and Japetella diaphana (Cephalopoda: Octopoda). The squid eaten (estimated from the measurement of the lower beaks) included juvenile and mature individuals of the most important species ( Teuthowenia megalops , Gonatus sp.). The range of species found in the diet of Z. cavirostris is greater than that reported for sperm whales and bottlenosed whales in the north-east Atlantic.

Description: The relationship between sperm reservoir and total spermatophore length among 168 spermatophores from 44 species in 11 genera has been considered. Bivariate plots show that four Atlantic species of the genus Eledone produce spermatophores with relatively large sperm reservoirs that differ from all others. Measurements of the remaining spermatophores are so tightly correlated that a single equation explains over 96% of the variation. Functional constraints on gross spermatophore morphology may be so strong that males cannot manipulate sperm reservoir size independently of spermatophore size to maximize the sperm delivered at a single copulation. Alternate means to assure male paternity may have evolved in the group as a result. Despite the overall uniformity of the relationship among all species other than those of Eledone in the Atlantic, these measurements distinguish the overtly similar species Octopus bimaculatus – Octopus bimaculoides and separate Benthoctopus januarii from all others.

Description: This study provides a description of the Mediterranean monk seal ( Monachus monachus ) diet from the Aegean Sea coast of Turkey. A total of 23 prey items belonging to five species were identified from the two stomachs examined. Cephalopods constitute the dominant prey group by weight (94·01%). Sarcotragus sp. (Porifera) and Posidonia oceanica (Magnoliophyta) are assumed to be incidental prey. Of the cephalopods identified, Eledone moschata and Bathypolypus sponsalis were encountered for the first time in a monk seal stomach.

Description: Possible effects of “El Niño” Southern Oscillation (ENSO) components “El Niño”and “La Niña“ on populations of southern elephant seals, Mirounga leonina L., are considered in this study. Information on pup weaning mass, collected at King George Island, South Shetland Islands, over a ten-year period (1985–94) was analysed with respect to the occurrence of ENSO and recent research in feeding ecology of this population in the Bellinghausen Sea. Weaning mass of elephant seals was found to be higher during “La Niña” and a lower during “El Niño”. Differences in weaning mass between sexes varied in different proportions during El Niño and La Niña. The teleconnection between tropical Pacific anomalies and the Bellinghausen Sea deserves further research, and our results suggest a way to study this phenomenon using data of elephant seal pups weaning mass as indicators of changes in food availability.

Description: A female Octopus macropus , the first ever observed spawning, attached eggs (4·0×1·2 mm, with a chorion stalk 4 mm in length) individually or in clusters to a hard substrate, and brooded them till hatching. Hatchlings measured 4·0 mm in dorsal mantle length, 5·5 mm in total length and were planktonic; their short arms had seven suckers each, the outer demi-branch of each gill had ten lamellae. The chromatophore pattern confirmed an earlier identification of young individuals from the plankton (Naef, 1923).

Description: Diatoms exude considerable quantities of polymers, mainly polysaccharides, that play an important role in the process of sestonic particle aggregation in the sea. We investigated the impact of copepods on transparent exopolymeric particles (TEP) generated by the diatom Thalassiosira weissflogii. Grazing experiments with 14C-labelled algae exudates demonstrated that copepods typical of the Baltic Sea were not actively filtering TEP. Control experiments showed that ‘uptake’ of radioactivity could be ascribed to passive uptake, such as adsorption of radioactively-labelled particles to the body surface. Furthermore, we tested the effect of copepods on TEP size spectra. The abundance and size distribution of TEP (from 1.4 to 180 μm of Equivalent Spherical Diameter) were analysed in a 4 h incubation experiment. In the presence of copepods, the proportion of larger TEP was higher. An increase in total volume of TEP in jars containing copepods (~2 × 107 μm ml–1) compared with control jars without copepods (~0.5 × 107 μm3 ml–1) was also observed. The process of aggregation of TEP demonstrated in this work, whereby copepods increase downward particle flux without consuming carbon, can have far-reaching consequences for carbon fluxes along the water column and for copepods feeding dynamics.

Description: A new species of terebellid polychaete, Lanice arakani sp. nov., is described from two specimens collected in deep water at seamounts of the west Pacific by the submersible `JAGO', and comparisons are made with the established species of the genus. Special reference is given to the morphology of the worm's sediment tube and in situ observations.

Description: Long-term dynamics (1959–1997) of the copepod species Pseudocalanus elongatus, Temora longicornis, Acartia spp. and Centropages hamatus, as well as the taxonomic group of cladocerans, are described for the open sea areas of the central Baltic Sea. Differences between areas, i.e. Bornholm Basin, Gdansk Deep and Gotland Basin, as well as between 5 year periods, were investigated by means of Analysis of Variance (ANOVA). No significant differences in mesozooplankton biomass between areas were found. On the other hand, clear time-trends could be demonstrated and related to salinity and temperature, with P.elongatus biomass mainly dependent on salinity and T.longicornis, Acartia spp. and cladocerans biomasses dependent, to a large extent, on thermal conditions. Decreasing salinities since the early 1980s due to a lack of major inflows of highly saline water from the North Sea and increased river run-off, both triggered by meteorological conditions, obviously caused a decrease in biomass of P.elongatus. Contrarily, the standing stocks of the other abundant copepod species and cladocerans followed, to a large degree, the temperature development and showed, in general, an increase. The shift in species composition during this period is considered to be a reason for decreasing growth rates of Baltic herring (Clupea harengus) since the early 1980s, and for sprat (Sprattus sprattus) since the early 1990s. Generally, it is suggested that low mesozooplankton biomasses in the 1990s were caused, at least partially, by amplified predation by clupeid fish stocks.

Description: Qualitative historical benthos data (1902–1912) were compared with recent data (1986) to find long-term trends in epifauna species composition in the southern North Sea that may be attributed to fishery-induced changes. In general, the frequency of occurrence of bivalve species declined, whereas scavenger and predator species (crustaceans, gastropods, and sea stars) were observed more frequently in 1986. We suggest that these shifts can be attributed not only to the physical fishery impact, but also to the additional potential food for scavenging and predator species provided by the large amounts of discards and moribund benthos. Our findings are put into the perspective of the general development of the demersal fishery in the southern North Sea. Despite the problems with the historical data set, the comparison presented may be the best illustration achievable of the changes in the benthos from a near-pristine situation to the present conditions after long-term disturbance.

Description: Throughout the 1980s, reproductive success of the top-predator cod declined and stock sizes of the main prey species herring and especially sprat, important planktivorous predators in the system, increased substantially. Although the hydrographic conditions conducive for survival of early life stages improved during the 1990s, recruitment success of cod remained far below average. As clupeids have been identified as major predators on cod eggs and larvae in the Baltic, increased predation may be an important factor hampering stock recovery. Results from stomach content analysis of herring and sprat during the spawning season of 1988–1995 and ichthyoplankton surveys in the Bornholm Basin (the only important spawning area of cod in the Central Baltic in this period) allow a comparison of estimated consumption rates by the predator populations with standing stocks and production rates of cod eggs and larvae. Despite uncertainties in the estimation procedure, the findings confirm substantial predation on cod eggs by both clupeid species. Especially at the beginning of the cod-spawning season, characterized by low zooplankton availability, sprat consumed a considerable proportion of the eggs produced. In 1993, the relative importance of zooplankton as prey increased, while fish eggs were encountered more rarely. In contrast, predation by herring remained on the same level or even increased, especially late in the spawning season. The larval stage of cod is not substantially affected by predation owing to limited spatial overlap between prey and predator.

Description: Birds are the most conspicuous, wide-ranging, and easily studied organisms in the marine environment. They can be both predators and scavengers, and they can be harmed by and can benefit from fishing activities. The effects of fishing on birds may be direct or indirect. Most direct effects involve killing by fishing gear, although on a lesser scale some fishing activities also disturb birds. Net fisheries and hook fisheries have both had serious negative effects at the population level. Currently, a major negative impact comes from the by-catch of albatrosses and petrels in long-lines in the North Pacific and in the Southern Ocean. High seas drift nets have had, prior to the banning of their use, a considerable impact on seabirds in the northern Pacific, as have gillnets in south-west Greenland, eastern Canada, and elsewhere. Indirect effects mostly work through the alteration in food supplies. Many activities increase the food supply by providing large quantities of discarded fish and wastes, particularly those from large, demersal species that are inaccessible to seabirds, from fishing vessels to scavengers. Also, fishing has changed the structure of marine communities. Fishing activities have led to depletion of some fish species fed upon by seabirds, but may also lead to an increase in small fish prey by reducing numbers of larger fish that may compete with birds. Both direct and indirect effects are likely to have operated at the global population level on some species. Proving the scale of fisheries effects can be difficult because of confounding and interacting combinations with other anthropogenic effects (pollution, hunting, disturbance) and oceanographic factors. Effects of aquaculture have not been included in the review

Description: Population structure of the short-finned squid Illex illecebrosus (Ommastrephidae) was studied on the Nova Scotian shelf between July–September 1984. It was characterized by a prevalence of winter-hatched squid in summer–early autumn, their short (three months of the summer) occurrence on the shelf, and a predominance of females in sex ratios during the feeding period. Ages of squid were estimated by statolith increment counts and ranged from 128 to 201 d. Growth in length was described by linear model with daily growth rates of 0.99 mm/d −1 . Adding the length-at-age data from juveniles caught in 1979 to the 1984 data set enabled to construct an ontogenetic growth curve for the winter-hatched squid which was best approximated by the Gompertz growth function.

Description: Annual catches of Todarodes pacificus in Japan have gradually increased since the late 1980s. Paralarval abundances have also been higher since the late 1980s compared to the late 1970s and mid-1980s. Here is proposed a possible scenario for the recent stock increase based on changing environmental conditions. Based on trends in annual variations in stock and in larval abundances, catches are reviewed and potential spawning areas inferred, assuming that egg masses and hatchlings occur over the continental shelf at temperatures between 15 and 23°C. Changes are then inferred in the spawning areas during 1984–1995, based on GIS data. Since the late 1980s, the autumn and winter spawning areas in the Tsushima Strait and near the Goto Islands appear to have overlapped, and winter spawning sites seem to have expanded over the continental shelf and slope in the East China Sea.

Description: Length composition, maturation and growth of the ommastrephid squid Todaropsis eblanae were studied using length–frequency distributions (LFDs) and statoliths of squid caught off the north-west African coast. Length–frequency distributions were quite similar in all seasons studied, indicating all year round spawning. However, both high proportions of mature squid in the winter and the hatching peak of squid from our sample in spring suggested the winter–spring peak of spawning. Immature and maturing squid had rather high growth rates, attaining 140—150 mm of dorsal mantle length (ML) by the age of 160—170 d. Todaropsis eblanae is likely to have an annual life cycle on the north-west African shelf.

Description: Aspartate transcarbamylase (ATCase) activity was used to estimate instantaneous growth in young cuttlefish (Sepia officinalis) reared under different diet conditions, and compared with estimation obtained by RNA concentration. During the first month of life, the changes in ATCase activity and RNA content of muscle are related to growth. ATCase appears to be a good index of growth during the first stage of intense cell multiplication. ATCase activity is correlated to food intake up to a maximum ration, but decreases when animals are more than 40 days old. The approach of using ATCase activity as a biochemical index for estimating short-term change in growth rates of young cuttlefish in experimental rearing could be extended to young cephalopods collected in the field, and used to predict the effect of biotic factors in recruitment.

Description: A new octopod species, Graneledone gonzalezi sp. nov., is described from 19 specimens collected off the northern Îles Kerguelen. This is a bathyal octopus which is characterized by: the absence of supra-ocular papillae, short arms, a long ligula without copulatory ridges, a narrow head, six filaments per outer demibranch and radula exhibiting no archaic traits, medium size oocytes and a low number of very long spermatophores. Graneledone gonzalezi is compared with its other congeneric species and found most closely resemble G. antarctica . The geographic and bathymetric distribution of G. gonzalezi is also discussed.

Description: The stranding of a female specimen of the genus Architeuthis , a species not previously recorded in the Mediterranean Sea, is reported from the southern Spanish coast (Alboran Sea, western Mediterranean). The geographical distribution of the species is discussed.

Description: A new species of eledonid octopus is described from the southwestern Atlantic Ocean from depths between 90 and 1000 m off the coasts of southern Brazil, Uruguay, and Argentina. This species, Graneledone yamana is characterized by having a papillose skin, two well developed 'horns' above the eyes, small gills with 5-7 lamellae on the outer demibranch, arms with uniserial suckers, 35-80 on females and 26-70 on males. The third right arm is hectocotylized, the ligula is small, the calamus is large and well differentiated. Ink sac absent. These characters differ from all other known Graneledone species from the southern oceans.

Description: Phylogenetic analysis conducted on a 784-bp fragment of 82 actin gene sequences of 44 coleoid cephalopod taxa, along with results obtained from genomic Southern blot analysis, confirmed the presence of at least three distinct actin loci in coleoids. Actin isoforms were characteri zed through phylogenetic analysis of representative cephalopod sequences from each of the three isoforms, along with translated actin cDNA sequences from a diverse array of metazoan taxa downloaded from GenBank. One of the three isoforms found in cephalopods was closely related to actin sequences expressed in the muscular tissues of other molluscs. A second isoform was most similar to cytoplasmic-specific actin amino acid sequences. The muscle type actins of molluscs were found to be distinct from those of arthropods, suggesting at least two independent derivations of muscle actins in the protostome lineage, although statistical support for this conclusion was lacking. Parsimony and maximum-likelihood analyses of two of the isoforms from which 〉30 orthologous coleoid sequences had been obtained (one of the cytoplasmic actins and the muscle actin) supported the monophyly of several higher-level coleoid taxa. These included the superorders Octopodiformes and Decapodiformes, the order Octopoda, the octopod suborder Incirrata, and the teuthoid suborder Myopsida. The monophyly of several taxonomic groups within the Decapodiformes was not supported, including the orders Teuthoidea and Sepioidea and the teuthoid suborder Oegopsida. Parametric bootstrap analysis conducted on the simulated cytoplasmic actin data set provided statistical support to reject the monophyly of the Sepioidea. Although parametric bootstrap analysis of the muscle actin isoform did not reject sepioid monophyly at the 5% level, the results (rejection at P = 0.068) were certainly suggestive of sepioid nonmonophyly.

Description: Cod is the top piscivore predator in the Baltic Sea ecosystem. Based on stomach content data from 62 427 cod collected during 1977–1994 and food consumption rates, cannibalism in the Eastern and Western Baltic cod stocks has been quantified using multispecies virtual population analysis. In the Eastern Baltic stock, depending on model assumptions, an average of 25–38% of the 0-group and 11–17% of the 1-group were removed by predation by adults. Thus, between age 0 and age 2 a year class may lose on average about 31% and 44% of the initial number as a result of cannibalism. Cannibalism is lower in the Western Baltic. On average, 19% of the 0-group and 9% of the 1-group are consumed per year, i.e. 24% of the initial cohort is eaten before reaching age 2. Predation was most intense in 1978–1984, a period with high juvenile abundance and large adult stock sizes in both areas. Subsequently, stock, recruitment, and cannibalism declined steadily until the early 1990s and then increased again. Problems identified in relation to data compilation and estimation procedure are discussed with respect to their impact on estimates of cannibalism and stock– recruitment relationships

Description: In an assessment of non-indigenous species transported by international ship traffic to German waters, commissioned by the German Federal Environmental Agency, the survival of tropical plankton organisms in ballast water was studied by accompanying a container vessel on its 23-day voyage from Singapore to Bremerhaven in Germany. Two tanks, one filled off Singapore and the other off Colombo, Sri Lanka, were monitored for their phyto- and zooplankton content by daily sampling. As already reported in previous studies, species abundance and diversity, especially of zooplankton, decreased sharply during the first days, and only a few specimens survived the whole cruise. The contents of the Colombo tank, however, changed dramatically during the last week. The harpacticoid copepod, Tisbe graciloides, increased its abundance by a factor of 100 from 0.1 to 10ind. l–1 within a few days. This is the first time that a ballast water organism has been found to multiply at such a high rate. Opportunistic species such as Tisbe are apparently able to thrive and propagate in ballast water tanks under certain conditions. Ballast water tanks may thus serve as incubators for certain species depending on their characteristics.

Description: The termination of diatom spring blooms in temperate waters has been connected with the formation and subsequent rapid sedimentation of aggregates. According to coagulation theory, the rate of aggregate formation depends on the probability of particle collision and on the efficiency with which two particles adhere once they have collided (stickiness). During this study, the variation in particle stickiness was determined over the decline of a diatom bloom using the Couette Chamber assay with low shear (G = 0.86 s–1). A mixed diatom population, dominated by Skeletonema costatum, was sampled during the spring bloom in the Baltic Sea and incubated in the laboratory for 18 days. Measurements of diatom species composition, transparent exopolymer particles (TEP) and bulk particle abundance, as well as chemical and biological variables, were conducted in order to reveal the determinants of coagulation efficiency. The investigation showed that an increase in TEP concentration relative to conventional particles at the decline of the bloom significantly enhanced apparent coagulation efficiencies. High proportions of TEP led to apparent values of stickiness 〉1, which indicates that collision rates can be substantially underestimated when the stickiness parameter α is calculated on the basis of conventional particle counting only, e.g. with the Coulter Counter. A new stickiness parameter, α′, was therefore estimated based on the combined volume fractions of TEP and conventional particles. The problems of stickiness measurements are discussed and the role of TEP in coagulation processes is emphasized.

Description: Artificial selection processes associated with harvesting may operate over relatively short time scales in short-lived semelparous species. The ommastrephid squid Illex argentinus on the Patagonian Shelf is the target of a major fishery. Recent work has provided new information on the biological characteristics of squid in this fishery. That information has been utilized in the development of a model of the cohort dynamics and some of the within-seasons selective effects considered. The model results are consistent with earlier data from the shelf fisheries, supporting suggestions that the males nature and migrate earlier towards the spawning grounds than the females. Earlier maturation results in a smaller mean size in the spawning stock, while later maturation results in greater exposure to the fishery and a reduced numbers of individuals surviving to spawn. Under the current fishing regime greater egg production and a larger spermatophoric complex mass for the whole cohort is achieved by relatively late maturation. In general, however, the earlier maturation occurs, the earlier is the peak in total egg production. The within-season pattern of effort expenditure in the fishery can affect not only yield from the fishery but also the reproductive potential of the spawning stock. The management policy adopted for this fishery is likely to be conservative in terms of maintenance of a spawning stock, however, the potential for selective effects is larger and this may affect both yield and reproductive potential. The results are discussed in relation to short- and long-term effects in the fishery and the implications for future research requirements.

Description: The data presented provides new information on the distribution of Antarctic squids and on the summer diet of the emperor penguins. The diet of 58 adult emperor penguins (Aptenodytes forsteri) on the fast ice of the Drescher Inlet, Vestkapp Ice Shelf (72°52′S, 19°25′W) in the eastern Weddell Sea was investigated. Prey consisted principally of squid, fish, krill, amphipods and isopods. Squids were identified by the lower beaks and allometric equations were used to estimate the squid biomass represented. Beaks occurred in 93% of the stomach samples. Each sample contained a mean of 27 beaks (range 1–206). Ninety-two percent of the squids could be identified by the lower beaks and belonged to four families (Onychoteuthidae, Psychroteuthidae, Neoteuthidae and Gonatidae). The most abundant squid was Psychroteuthis glacialis which occurred in 52 samples with lower rostral lengths (LRL) ranging from 1.4–7.2 mm. Forty-five samples contained Alluroteuthis antarcticus (LRL range 1.8–5.8 mm), 17 Kondakovia longimana (LRL range 4–12.1 mm), and four Gonatus antarcticus (LRL range 4.1–6.1 mm). In terms of biomass K. longimana was the most important species taken by the penguins comprising 50% of total estimated squid wet mass (245348 g) in 1990 and 48% in 1992 (154873 g). However, if only fresh beaks were considered for estimations of squid consumption, i.e. beaks that have been accumulated for not longer than 5–6 days in the stomachs, squid diet was of minor importance. Then total squid wet mass accounted for only 4809 g in 1990 and 5445 g in 1992 which implies that one penguin took c.30 g squid d−1 with P. glacialis and A. antarcticus being the most important by mass. The prey composition suggests that emperor penguins take squid at the steep slope regions of the eastern Weddell Sea.

Description: During a study based on catches taken in the northern North Sea by selected Scottish fishing boats during 1985–1992, large numbers of the normally rare short-fin squid, Todaropsis eblanae (Cephalopoda: Ommastrephidae), were recorded in 1987 and 1990. Our findings, supported by data obtained from plankton/young fish surveys in 1988 and 1989, suggest that in northern waters Todaropsis eblanae generally mates and spawns during late summer and early autumn (June-November). Successful hatching events appear to occur during October-March, producing juvenile (stage I) squid in the early part of the year (January-June). Estimations of maximum male reproductive output and female fecundity were up to 130 spermatophores and ~28,000 eggs per individual, respectively.

Description: Vesteris Seamount is a solitary alkaline volcano in the Greenland Basin some 280 km NW of Jan Mayen. Topographic and geophysical studies have shown no sign of an associated plume trace. Evidence from ash layers in sediment cores around the volcano and dating of dredged samples show that it has been active in Quaternary times. The lavas from Vesteris studied here consist of basanites, tephrites, mugearite, and alkali basalts. Crystal fractionation models are consistent with the generation of the tephrites and mugearite from a basanitic parent. Extensive kaersutite fractionation is required late in the fractionation sequence to produce the extreme mugearite composition. Na-Al-Fe-rich green cores to many clinopyroxene phenocrysts at Vesteris suggest a fractionation history beginning at high pressure in the mantle. Differences between Vesteris and Jan Mayen in the ratios of highly incompatible trace elements such as Ce/Pb and Rb/Cs, which will not normally be fractionated from one another during mantle melting, suggest that the two are not derived from the same source. Relatively unradiogenic Sr isotope ratios (compared with Bulk Earth), and highly incompatible trace element patterns similar to those for St. Helena, suggest that Vesteris magmas are derived from a depleted, asthenospheric source. We propose that the Vesteris basanites are very low degree partial melts (˜1%) of this source, most probably those which give rise to the seismic low-velocity zone (LVZ). Such small-degree melts may preferentially tap small-scale heterogeneities in the asthenosphere. Vesteris lies at the intersection of two major structural trends in the Greenland Basin—(1) a zone of major reorientation of spreading direction on the Mohns Ridge north of Jan Mayen and (2) the extension of the Kolbeinsey Ridge axis. We propose that a combination of the extensional stress fields related to these two lineaments produces sufficient dilation of the lithosphere at Vesteris to allow magmas from the LVZ to reach the surface.

Description: The functional morphology of the buccal mass of 23 species of cephalopod (Octopoda, 4 species; Teuthoidea, 17; Sepioidea, 2) was investigated by gross dissection, histology and observations on fresh preparations. Cephalopod beaks lack a joint or articulation point. The jaws slide and rotate around an area rather than a fixed point. During closing the superior mandibular muscle (SMM) provides the force of a bite and the largest movement vector, whilst the inferior mandibular muscle (IMM) acts to retract the upper beak, causing shearing action. Dorsal portions of the lateral mandibular muscles (LMM) flex the upper beak walls outwards, probably to accomodate the backwards sweep of the radula and buccal palps during closing. To open the beaks, the ventral portions to the lateral mandibular muscles pull the rear lateral walls of the two beaks towards each other, moving the lower beak back relative to the upper. The buccal mass weighs more in decapods (0.65-4.34% of body weight) than octopods (0.49-0.77%). The weight difference is mainly accounted for by the size of the superior mandibular muscle. Beak shape and muscle volume are related. Increasing the size of the upper beak hood and lateral wall area results in larger SMM and LMM respectively Increasing hood size in the lower beak increases IMM size, and altering the angle by which the wings meet the lateral wall changes the volume of the SMM and LMM. To accomodate the decapod pointed upper rostrum, the lateral walls of the lower beak have shortened in length, whilst increasing in breadth and surface relief to maintain the area available for muscle insertion. In species with a lateral wall ridge or fold (e.g. Onychoteuthis) this may mark the insertion point of the LMM.

Description: Arm autotomy was induced in a living specimen of Metacrinus rotundus (Echinodermata: Crinoidea). An arm was autotomized at a ligamentary articulation known as a cryptosyzygy, following incision by scissors distal to the break point. Although sessile stalked crinoids cannot entirely escape from a predatory attack by arm autotomy and they do not have an active defense, arm autotomy at cryptosyzygies reduces damage and arm loss by effective distribution, and by minimizing trauma and facilitating subsequent regeneration. The paradigmatic distribution of cryptosyzygies in which arm loss is set at a minimum, compared with the actual distribution, shows that these two patterns are similar and that actual specimens successfully reduce arm loss by the effective distribution of cryptosyzygies. The crinoid branching pattern also affects arm loss, and two different paradigms are discussed: anti-predatory and harvesting. Arm branching patterns of various isocrinids have tended toward the anti-predatory configuration from the Jurassic to the Recent, suggesting that the isocrinids have coped with increased predation. Shallow-water comatulids generally adopt the anti-predatory paradigm in their branching pattern, whereas many deep-water, stalked crinoids adopt a harvesting paradigm, reflecting that shallow-water comatulids receive more predatory attacks than do deep-water crinoids.

Description: The population dynamics and the trophic role of Aurelia aurita medusae in the Kiel Bight/western Baltic are described from nine years of investigation between 1978 and 1993. There is considerable yearly variation in standing stock with summer median abundance ranging from 0.2 to 16 ind. 100 m−3 and biomass from 0.2 to 4.4 g C 100 m−3. The lower variation is due to marked differences in size of adult medusae between years. In years of low abundance medusae exhibit an average dise diameter of about 30 cm and weight about 1 kg. In bloom years, however, adult size is only about 20 cm and weight ranges between 200 and 400 g. Estimates of feeding are somewhat contradictory, but feeding rates of 40–80 mg C ind.−1 day−1 seem probable. It can be concluded that Aurelia medusae consume about 2/3 of daily secondary production in years of high abundance, and are thus responsible for a decline of mesozooplankton in these years.

Description: An investigation was carried out on larvae of the oceanic tropical squid Sthenoteuthis pteropus in the equatorial Atlantic (2°30′N–7°S;12°W –8°30′E) The age of the larvae was calculated from the statolith microstructure of 20 larvae; mortality was estimated from the size structure of 1128 larvae. The larval stage lasts 32–38 days. At ages ranging from 14 to 38 days. the daily relative growth rates of mantle length decrease from 7.5 to 2.8% day −1 and from 14–16 to 5.8% of body weight day −1 At age 12–24 days, mortality rates were estimated using both raw catch data and corrected data accounting for net avoidance. The mean value of raw mortality rates was 0.189, the corrected value was 0.158. During the proboscis division (transformation of the larva into juvenile) at age 25–35 days, a sharp decrease in larval growth rates and a simultaneous increase in mortality rates (raw 0.443, corrected 0.379) were observed.

Description: The stomachsof 23 striped dolphins (Stenella coeruleoalba Meyen, 1833, Cetacea), stranded along the Ligurian coast (western Mediterranean Sea), contained 32 species of cephalopods, crustaceans and fishes, totalling an estimated 2,723 prey specimens representing about 36 kg in weight. Cephalopods and bony fishes were equally important in the diet (50%). Todarodes sagittatus (34.5%) and Micromesistius poutassou (25.9%) were found to be the most important food species. Other species belonging to six cephalopod families, three crustacean families and nine bony fish families, contributed to the diet with variable numbers, weights, and occurrences, demonstrating the opportunistic character of striped dolphin feeding.

Description: Samples of two loliginid squids Alloteuthis africana and A. subulata were collected from the continental shelf off the west Sahara in August-September 1987. Statoliths were taken from 124 specimens and processed using statolith ageing techniques. Statoliths of both species were very similar in shape. In the ground statolith, growth increments were examined and grouped into four growth zones distinguished mainly by the width of the increments. Age of adult mature males of both species did not exceed eight months, that of females six months. Alloteuthis africana grew faster than A. subulata in weight and, particularly, in length. At age 180 d the mantle of A. africana was twice as long and the body weight 1·2–1·5 times as large. Both species matured over a wide range of sizes and ages (from 120 to 180 d). The life span of A. africana and A. subulata hatching between January and May on the west Saharan shelf is about six months, much shorter than that of A. subulata in its northern temperate range.

Description: Mortality of two dogs, after exposure to water of a brackish lake on the German North Sea coast in 1990, is considered to be caused by a toxic Nodularia spumigena Mertens bloom.

Description: Statoliths of Loligo gahi were sampled in the fishery region 45–47°S on the Patagonian shelf during September 1989. Peculiarities of the growth zones in the ground statoliths of adults are described. Maximum age of large maturing and mature females (130–160 mm of mantle length, ML) was estimated to be 325–345 d, that of large mature males (250–290 mm ML) ranged from 360 to 396 d. The squid Loligo gahi d'Orbigny, 1835, occurs in temperate shelf and upper slope waters of the Atlantic and Pacific coasts of South America and is caught commercially by the international fleet in the southern part of the Patagonian shelf within the Falkland Islands Interim Conservation Zone (FICZ) (Roper et al., 1984; Csirke, 1987). Occasionally, dense shoals of L. gahi appear in the fishery region 45–47°S off the Exclusive Economic Zone of Argentina (EEZA) and have been caught in significant numbers by trawlers at depths of 120–150 m in September-October (Chesheva, 1990). Loligo gahi is a medium sized loliginid; in Falkland waters males attain 350 mm ML, females 210 mm ML (Hatfield, 1991), while in the fishery region 45–47°S maximum size is 260 mm and 160 mm, respectively (Chesheva, 1990). Patterson (1988) revealed two Falkland spawning stocks of L. gahi of unclear status, spring-spawners and autumn-spawners (austral seasons) and pointed out that the life span of squid of each stock lasted ~1 y. Recently Hatfield (1991) used statoliths to elucidate Patterson's (1988) estimations of age and growth of Falkland stocks of L. gahi and confirmed the 1-y duration of L. gahi's life span.

Description: Ripe egg dimensions in the squid genus Illex are close to the minimum for cephalopods. The average diameter varies significantly depending on species (0.77–0.82 mm in I. coindeti , 0.75–0.88 mm in I. illecebrosus , and 0.96–1.04 mm in I. argentinus ), on geographical distribution intraspecifically, e.g. I. argentinus (0.96–0.97 mm in the shelf groups and 1.04 mm in the slope oceanic group), and between pre-spawning and spawning females of the summer-spawning shelf group of I. argentinus (0.97 and 0.92 mm, respectively). The potential fecundity (PF), defined as total oocyte stock both in the ovary and oviducts, depends on mantle length (ML in each species. It varies from 90 000 (ML = 150–160 mm) to 800 000 (ML = 230–250 mm) in I. coindeti , from 200 000 to 630 000 (ML = 220–280 mm) in I. illecebrosus , and from 75 000 (ML = 150–170 mm) to 1 200 000 (ML = 360–380 mm) in I. argentinus . It is possible to estimate the actual value of PF shortly before vitellogenesis begins and up to a start of spawning, when the diameter of the smallest oocytes exceeds 0.05 mm. The summer-spawning shelf females of I. argentinus release about of 70% of PF. Their spawning is intermittent and ripe egg production decreases over time with only a 50% replacement of the initial stock of vitelline oocytes and a decreasing volume of eggs at each release. Feeding activity decreases and the mantle wall and internal organs shrink once spawning commences. In spent animals, a degeneration of both vitelline and protoplasmic oocytes occurs. The squids genus Illex is one of typical r-strategists among the cephalopods.

Description: Outer membrane (OM), cytoplasmic membrane (CM) and intracytoplasmic membranes (ICM) from the halophilic phototrophic purple sulphur bacterium Ectothiorhodospira mobilis 9903 were purified and characterized. The three membrane fractions were significantly different in regard to protein profiles on SDS-PAGE, and to the composition of amino acids, fatty acids and lipids. The presence of lipoproteins, the occurrence of lyso-phosphatidyl-ethanolamine and an increased content of saturated and short-chain fatty acids are characteristic properties of the OM. CM and ICM fractions are different on the basis of buoyant density, of protein profiles and amino acid composition, and due to the presence of succinate dehydrogenase activity in CM. In addition, CM and ICM showed significant differences in pigment content and absorption spectra.

Description: The abundance and sedimentation of acantharia and their cysts was recorded in the water column and sediment traps in the East Greenland Sea in August-September 1990. Although acantharia constituted 〈1% of total suspended particulate organic carbon (POC) in the water column, up to 90% (average 55%) of the POC sedimenting in 100 m was present in the form of acantharian cysts during a 9 day drift experiment. Rapid dissolution of strontium sulphate, of which their shells and spines are constructed, was evidenced by their disappearance with depth in the water column, maximum dissolution occurring between 500 and 1000 m water depth. Mass encystment and sedimentation of this single group of sarcodine protozoa can have dramatic effects on, the measurement of particulate fluxes in the open ocean, and may be a recurrent phenomenon in the eastern North Atlantic.

Description: The plankton multiplier is a positive feedback mechanism linking the greenhouse effect and biological pump (Woods.J.D., Royal Commission on Environmental Pollution, 1990). As pollution increases the atmospheric concentration of carbon dioxide, the enhanced greenhouse effect induces radiative forcing of the ocean, which diminishes the depth of winter convection, reducing the annual resupply of nutrients to the euphotic zone and therefore the annual primary production. That weakens the biological pump, which contributes to oceanic uptake of CO2,. As the ocean takes up less CO2, more remains in the atmosphere, accelerating the rise in radiative forcing. We have used a mathematical model of the upper ocean ecosystem, based on the Lagrangian Ensemble method, to estimate the sensitivity of the biological pump to radiative forcing, which lies at the heart of the plankton multiplier. We conclude that increasing radiative forcing by 5 W m− (equivalent to doubling atmospheric CO2) reduces the deep flux of paniculate carbon by 10%. That sensitivity is sufficient to produce significant positive feedback in the greenhouse. It means that the plankton multiplier will increase the rate of climate change in the 21st century. It also suggests that the plankton multiplier is the mechanism linking the Milankovich effect to the enhanced greenhouse effect that produces global warming at the end of ice ages.

Description: We report major and trace element X-ray fluorescence (XRF) data for mafic volcanics covering the 15-Ma evolution of Gran Canaria, Canary Islands. The Miocene (12-lS^Ma) and Pliocene-Quaternary (0-6 Ma) mafic volcanics on Gran Canaria include picrites, tholeiites, alkali basalts, basanites, nephelinites, and melilite nephelinites. Olivine±clinopyroxene are the major fractionating or accumulating phases in the basalts. Plagioclase, Fe-Ti oxide, and apatite fractionation or accumulation may play a minor role in the derivation of the most evolved mafic volcanics. The crystallization of clinopyroxene after olivine and the absence of phenocrystic plagioclase in the Miocene tholeiites and in the Pliocene and Quaternary alkali basalts and basanites with MgO〉6 suggests that fractionation occurred at moderate pressure, probably within the upper mantle. The presence of plagioclase phenocrysts and chemical evidence for plagioclase fractionation in the Miocene basalts with MgO〈6 and in the Pliocene tholeiites is consistent with cooling and fractionation at shallow depth, probably during storage in lower-crustal reservoirs. Magma generation at pressures in excess of 3-0-3-5 GPa is suggested by (a) the inferred presence of residual garnet and phlogopite and (b) comparison of FeO1 cation mole percentages and the CIPW normative compositions of the mafic volcanics with results from high-pressure melting experiments. The Gran Canaria mafic magmas were probably formed by decompression melting in an upwelling column of asthenospheric material, which encountered a mechanical boundary layer at ~ 100-km depth.

Description: The subaerial portion of Gran Canada, Canary Islands, was built by three cycles of volcanism: a Miocene Cycle (8-5—15 Ma), a Pliocene Cycle (1-8-60 Ma), and a Quaternary Cycle (1-8-0 Ma). Only the Pliocene Cycle is completely exposed on Gran Canaria; the early stages of the Miocene Cycle are submarine and the Quaternary Cycle is still in its initial stages. During the Miocene, SiO2 saturation of the mafic volcanics decreased systematically from tholeiite to nephelinite. For the Pliocene Cycle, SiO2 saturation increased and then decreased with decreasing age from nephelinite to tholeiite to nephelinite. SiO2 saturation increased from nephelinite to basanite and alkali basalt during the Quaternary. In each of these cycles, increasing melt production rates, SiO2 saturation, and concentrations of compatible elements, and decreasing concentrations of some incompatible elements are consistent with increasing degrees of partial melting in the sequence melilite nephelinite to tholeiite. The mafic volcanics from all three cycles were derived from CO2-rich garnet lherzolite sources. Phlogopite, ilmenite, sulfide, and a phase with high partition coefficients for the light rare earth elements (LREE), U, Th, Pb, Nb, and Zr, possibly zircon, were residual during melting to form the Miocene nephelinites through tholeiites; phlogopite, ilmenite, and sulfide were residual in the source of the Pliocene-Quaternary nephelinites through alkali basalts. Highly incompatible element ratios (e.g., Nb/U, Pb/Ce, K/U, Nb/Pb, Ba/Rb, Zr/Hf, La/Nb, Ba/Th, Rb/Nb, K/Nb, Zr/Nb, Th/Nb, Th/La, and Ba/La) exhibit extreme variations (in many cases larger than those reported for all other ocean island basalts), but these ratios correlate well with degree of melting. Survival of residual phases at higher degrees of melting during the Miocene Cycle and differences between major and trace element concentrations and melt production rates between the Miocene and Pliocene tholeiites suggest that the Miocene source was more fertile than the Pliocene-Quaternary source(s). We propose a blob model to explain the multi-cycle evolution of Canary volcanoes and the temporal variations in chemistry and melt production within cycles. Each cycle of volcanism represents decompression melting of a discrete blob of plume material. Small-degree nephelinitic and basanitic melts are derived from the cooler margins of the blobs, whereas the larger-degree tholeiitic and alkali basaltic melts are derived from the hotter centers of the blobs. The symmetrical sequence of mafic volcanism for a cycle, from highly undersaturated to saturated to highly undersaturated compositions, reflects melting of the blob during its ascent beneath an island in the sequence upper margin-corelower margin. Volcanic hiatuses between cycles and within cycles represent periods when residual blob or cooler entrained shallow mantle material fill the melting zone beneath an island.

Description: Within the Western Ross Sea, there are six emperor penguin colonies of widely different size that occur exclusively on sea ice. In 1990 a survey of all six sites, two by close overflights and four from the ground, showed that the breeding habitats were highly variable. The most important physical characteristics of these habitats appear to be stable fast ice, nearby open water, access to fresh snow, and shelter from the wind.

Description: The groundmass of andesitic dykes at Sezaki, southwest Japan, has trachytic texture and contains microscopic shear zones. The shear zones comprise a conjugate pair formed by flattening of the solidifying dyke rock, probably caused by the magma pressure of the still molten part of the dyke. This pressure shortened the solidifying rock perpendicular to the dyke margins and caused it to extrude parallel to the magma flow direction. The groundmass shears indicate that locally the magma flowed 60° upward in the dykes. It is concluded that while groundmass shears are a useful indicator of flow direction in dykes, phenocryst alignment in dykes is strongly influenced by magma-pressure flattening and thus may be a poor indicator of flow direction.

Description: Age and growth were estimated in the European squid, Loligo vulgaris, by examining growth increments in the statoliths of 203 specimens collected from off the French Mediterranean coast. Length and increment data were analyzed assuming that the increments were formed daily. The relationships between age and length showed that: growth rate varied considerably among individuals; growth was double exponential; the squids grew on average to 240 mm ML at 240 d from hatching, with a maximum of 350 mm at 240 d; the life span is probably about one year.

Description: Some of the limits to the use of serology to identify prey species in the digestive tracts of cephalopods have been evaluated. Cuttlefish, Sepia officinalis, were given meals of krill slurry (Euphausia superba). Protein extracts of contents from four regions of the digestive tract, stomach, caecum, digestive gland and intestine, were tested for prey antigenicity. Digestion times (loss of antigenicity) ranged from 1 to 8 h depending on sampling site. Stomach and caecum emptied rapidly, but meal antigenicity persisted longer in the digestive gland. The Sepia experiments provide a basis for interpretation of results from natural predation by cephalopods).

Description: In 1988 and 1989 the occurrence of external diseases in fish from the German part of the Wadden Sea was quantified. Thirty-two stations, located along seven transects including four estuaries, were sampled monthly or at 3-month intervals with shrimp trawlers: more than 124 000 fish were studied. Six percent of the seven dominant fish species of 〉 12 cm length were diseased. In fish species which complete their life cycle in the Wadden Sea (gobies, hooknose, eelpout, sea scorpion) the total disease incidence was below 0.4%. In whiting, plaice and sole it was between 0.5 and 2.5%, while 6–8% of smelt, cod, eel, dab and flounder suffered from external lesions. The incidence of most diseases increased with increasing fish length. Similar geographical patterns in prevalence were observed for: (1) two types of skeletal deformities, (2) lymphocystis in dab and flounder, (3) papillomatosis in smelt and dab and (4) several infectious ulcerative diseases. Most of these ulcerative diseases of cod and flounder occurred on central estuarine stations, suggesting an impact of the relatively low, but greatly variable salinity on disease development. Buccal granulomatosis of smelt and papillomatosis of eels showed the highest incidence in the Elbe estuary as the most heavily polluted region of the Wadden Sea. A causal relationship between disease development and pollution, however, is not yet clear and requires experimental evidence. The disease types found are ranked into three priority groups regarding their indicator value for a pollution monitoring on the basis of fish diseases. There is evidence that the total disease load of fish in the Wadden Sea is higher than in other shallow coastal regions outside the North Sea. Little is known of the effects of these diseases on single fish and fish populations. “Yellow pest” of cod, which was recorded for the first time during this survey, and which occurred with an incidence of up to 14% in single estuarine samples, causes the most serious lesions and is supposed to be lethal. In total, however, the effects of a number of pathogenic parasites on fish survival is considered to be more serious than that of deformities and infectious diseases.

Description: Samples of female lllex argentinus were taken from the catch of a Japanese squid jigging vessel on the Patagonian Shelf during March 1986. Morphometrics of the somatic and reproductive organ systems and the histological structure of the mantle in relation to maturation were examined. The data suggest that growth and maturation occur simultaneously during most of the time that lllex argentinus females are on the feeding grounds. In a squid of a ‘standard’ mantle length the whole body mass increases relative to mantle length during maturation and growth of the reproductive organs. This is accompanied by a small but significant decrease in the relative mass of the mantle, head and viscera whilst the mass of the digestive gland remains constant. Although mantle mass of a ‘standard’ female squid decreases relative to mantle length with maturity this is not associated with degeneration of the mantle muscles. Energy and nutrient resources for maturation are apparently derived from the squid's food, not from reserves, and during the course of maturation there is an increasing shift of emphasis from somatic growth to production of gonad and accessory reproductive organs.

Description: The timing of spawning and recruitment in the squid Loligo forbesi in Scottish waters is described on the basis of data from three sources: monthly samples of squid caught by commercial trawls (1986–1988), egg masses found by fishermen (1987–1991), and statistical data on animals caught by research trawls (1978–1987). Spawning females were present in samples from December to June, with peak spawning occurring in March. Most records of egg masses were from these months, but eggs were also found in August and September. These results suggest that there is an extended spawning season. Small squid (≤100 mm dorsal mantle length) were rarely present in commercial samples, but were recorded in research samples almost all year round. Thus there appears to be more or less continuous recruitment into the catchable population. The results of the present study are consistent with published data from other parts of the geographic range in that there is a regular seasonal peak in spawning, and spawning adults disappear from the population in summer. Further interpretation of the life-cycle of this species is not justified on the basis of current knowledge, and more information is needed on migrations, geographical variation, and lifespan in Loligo forbesi.

Description: Cephalopod remains from the stomachs of a Risso's dolphin (Grampus griseus Cuvier, 1812, Cetacea) entangled in a fishing net off the Ligurian coast (central Mediterranean Sea) include squids Ancistroteuthis lichtensteini, Histioteuthis bonnellii, H. reversa and Todarodes sagittatus and the sepiolid Heteroteuthis dispar. All these cephalopods live in oceanic water including water over the steep continental slope where Risso's dolphin is frequently sighted. Histioteuthis reversa contributed 78% of the cephalopods by number, 81% of the wet weight and 73% of the dry weight and calorific value. The total calorific value of the cephalopods represented by lower beaks was 17,300 kj.

Description: The stomach contents of 235 specimens of the squid Sthenoteuthis oualaniensis (4·3–36·5 cm mantle length, ML) were examined. A detailed list of 60 species of prey, comprising young and adult squid, is given together with their frequency of occurrence and proportional contribution. The size and number of each food item was investigated. Three ontogenetic size-groups of S. oualaniensis were distinguished: I, fry and young (4–10 cm ML), micronektonic epipelagic plankton-eaters; II, transient critical size group (10–15 cm ML), converting from feeding on planktonic crustaceans and fish larvae to myctophid fishes; III, medium-sized (adult) nyctoepipelagic nektonic predators (15–36·5 cm ML), feeding primarily on myctophids and secondarily on squid. Myctophids (genera Symbolophorus, Myctophum and Hygophum) were the most abundant prey in the diet of adult S. oualaniensis from different parts of its distribution.

Description: Samples of male Illex argentinus were taken from the catch of a Japanese squid jigging vessel on the Patagonian Shelf during March 1986 and an analysis was carried out on the morphometrics of the somatic and reproductive organ systems in relation to maturation. The data show that growth and maturation occurred simultaneously during most of the time that Illex argentinus males were on the feeding grounds over the southern Patagonian Shelf. In a squid of a ‘standard’ mantle length the whole body mass increased relative to mantle length during maturation and this could be attributed to the increase in mass of the reproductive and accessory reproductive organs. During maturation the mantle and digestive gland mass showed no significant change relative to mantle length. The mass of the head increased and the mass of the viscera decreased relative to mantle length. In male Illex argentinus, as in the female, the energy and nutrient resources for maturation are derived from the squid's food and during the course of maturation there is an increasing shift of emphasis from somatic growth to production of gonad and accessory reproductive organs. The proportional investment of body mass in reproductive and accessory reproductive organs predicted for a fully mature male Illex argentinus was less than half that of the female.

Description: A joint research cruise (Japan-Argentina-Uruguay) was carried out in the South-western Atlantic during August-September 1989 in order to study the winter-spawning and hatchery areas of Illex argentinus, and also the migration pattern of the juveniles towards the continental shelf. A few Rhynchoteuthion larvae were found in subtropical waters of the Brazil Current, next to the Brazil-Malvinas confluence, and in the frontal zone with shelf water, but never at temperatures below 14°C. Large numbers of juveniles found in subantarctic waters (6–10°C) on the shelf were probably migrating southward from their hatchery grounds following the zooplankton concentrations on which they were feeding.

Description: Total biomass and biomass of large taxonomic groups (polychaetes, molluscs, crustaceans, echinoderms) and species diversity of the macrofauna were determined for almost 200 North Sea stations sampled synoptically by seven vessels during Spring 1986 and for 120 additional stations sampled in earlier years by the Marine Laboratory in Aberdeen. There exists a clear and significant decreasing trend in biomass with latitude, both in total biomass and for the different taxonomic groups. Apart from latitude, sediment composition and chlorophyll a content of the sediment also infuence total biomass and biomass of most groups significantly. Biomass increases consistently in finer sediments and sediments with a higher chlorophyll a content. The same trends are found for the results within laboratories. Some interaction exists, indicating weak laboratory and zonal effects. Diversity, as measured by Hill's diversity index N1 = (exp H′) shows a clear and significant trend with latitude. Towards the north of the North Sea diversity increases considerably. The trend is also found for laboratories separately and is everywhere equally strong. Also longitude and depth show an effect on diversity. Sediment variables have no clear influence on diversity. Other diversity measures show the same trend but are more variable than N1,. Total density tends to increase towards the north, but sediment related variables have a larger influence. Mean individual weight becomes considerably smaller towards the northern part of the North Sea.

Description: In 1986 participants of the Benthos Ecology Working Group of ICES conducted a synoptic mapping of the infauna of the southern and central North Sea. Together with a mapping of the infauna of the northern North Sea by Eleftheriou and Basford (1989) this provides the database for the description of the benthic infauna of the whole North Sea in this paper. Division of the infauna into assemblages by TWINSPAN analysis separated northern assemblages from southern assemblages along the 70 m depth contour. Assemblages were further separated by the 30, 50 m and 100 m depth contour as well as by the sediment type. In addition to widely distributed species, cold water species do not occur further south than the northern edge of the Dogger Bank, which corresponds to the 50 m depth contour. Warm water species were not found north of the 100 m depth contour. Some species occur on all types of sediment but most are restricted to a special sedimentand therefore these species are limited in their distribution. The factors structuring species distributions and assemblages seem to be temperature, the influence of different water masses, e.g. Atlantic water, the type of sediment and the food supply to the benthos. Eleftheriou, A. and Basford, D. J. Journal of the Marine Biological Association of the UK, 69: 123–143.

Description: The upper bathyal sea-pen Kophobelemnon stelliferum extends to depths of about 1600 m in the Porcupine Seabight, to the south-west of Ireland, but is rare below about 1150 m. Photographic data suggest that the species attains numerical abundances of more than 2 m−2and a wet weight biomass of at least 4 g m−2. The highest densities, however, do not necessarily correspond to the highest biomass values since there is a clear depth-related change in population structure. The largest sea-pens are restricted to the deeper parts of the bathymetric range of the species. There is also a marked change in the growth form at a total colony length of about 250 mm, with larger colonies having relatively more polyps than smaller ones. The sexes are separate in Kophobelemnon stelliferum and the sex ratio of colonies is about 1:1. The maximum oocyte diameter is about 800 μm, but there is no evidence of seasonal reproduction by this pennatulid in the Porcupine Seabight.

Description: Two biochemical methods for measuring larval fish condition – tryptic enzyme activity and RNA/DNA ratio measurement - were applied to laboratory-reared and wild-caught herring larvae. The comparison of both methods when applied to laboratory-reared herring larvae showed that tryptic enzyme activity and RNA/DNA ratio are linear and positively correlated under constant nutritional conditions. Wild-caught larvae were transferred to the laboratory and used to compare both indicators in relation to shortterm changes in food availability and long-term starvation periods (13 days). In the starvation experiments with the wild-caught larvae the lowest trypsin values were obtained after 3–4 days and a significant decrease in RNA/DNA ratios was obtained after 5–6 days. Prolongation of the starvation time did not result in a further significant change in either parameter. The results of the study demonstrate the usefulness of both methods in monitoring nutritional condition offish larvae in field samples.

Description: The presence of Stoloteuthis leucoptera in the Mediterranean is recorded on the basis of three specimens, including an adult male, caught by IKMT and by commercial otter-trawl in the Ligurian Sea. The hypothesis of a recent immigration is discussed. The list of Mediterranean cephalopods (Mangold Wirz, 1963; Torchio, 1968; Bello, 1986; Mangold & Boletzsky, 1987) includes the Sepiolidae of the subfamily Heteroteuthinae, whose members are supposed to be pelagic throughout their life cycle. Mangold Wirz (1963) recognizes in the Mediterranean fauna the unique species Heteroteuthis dispar, the other authors include H. atlantis Voss, which Voss himself (1955) reported at Messina. To this group may now be added Stoloteuthis leucoptera (Verrill, 1878) a species until now recorded in limited Atlantic areas. Verrill (1881) wrote “This species is an exceedingly beautiful one, when living, owing to the elegance and brilliancy of its colours and the gracefulness of its movements. In swimming it moves its fins in a manner analogous to the motion of the wings of a butterfly.”

Description: Earlier work by the second author on the growth of oceanic squids, based on sizefrequency distributions of beaks sampled from sperm whale stomachs and on structural marks on those beaks, showed that these squids apparently had growth rates far in excess of those reported for the fastest-growing fishes, e.g. bluefin tuna. The application of recently developed methods for analysis of length-frequency distributions to some of these earlier data, and new approaches for assessing and comparing the growth performance offish and aquatic invertebrates, suggest the need for a downward revision of these high growth estimates. This is illustrated here with data on Kondakovia longimana (Cephalopoda, Onychoteuthidae) sampled off Durban and Donkergat, South Africa, in the early to mid-1960s.

Description: A correlation of the Campanian–Maastrichtian boundary is attempted using foraminiferal and nannoplankton data from two areas: the eastern North Atlantic and northwestern Germany. The Boreal benthic and Tethyan planktonic foraminiferal zonation schemes are applied to Site 548A, where both foraminiferal groups occur frequently. A direct comparison of both biozonations reveals that the base of the Maastrichtian, according to planktonic foraminifers, has to be placed in the Upper Campanian of the Boreal benthic foraminiferal biozonation, which concurs with the nannoplankton results. The Tethyan Middle and Upper Maastrichtian are probably equivalent to the Upper Maastrichtian in the Boreal sense. The bases of the Maastrichtian substages are thus diachronous between the Boreal and Tethyan realms. Palaeotemperatures (which were estimated using the oxygen isotopic composition of the Goban Spur chalks) indicate, in combination with palaeowind directions, that the faunal and floral distribution pattern recorded is the result of a stable, warm water outflow from the northwest European epicontinental seas through the Channel area to the Celtic Shelf sea and Goban Spur. This mechanism appears to have been a dominant separating factor of the Boreal and Tethyan bioprovinces on the western European Shelf.

Description: The free-running locomotor activity rhythms of freshly-captured swimming crabs Liocarcinus holsatus and L. depurator have been studied in constant conditions in the laboratory. L. holsatus captured in the intertidal zone of sandy beaches showed strong circatidal activity rhythms with maximum activity at high tide. L. holsatus captured in the sublittoral zone had a clear tendency to show circadian activity rhythms with highest activity during day-time hours. L. depurator occurred only sublittorally and showed circadian activity patterns with highest activity during the night. Exposure to hydrostatic pressure cycles of tidal amplitude and periodicity, entrained strong circatidal activity rhythms in previously arhythmic L. holsatus. This activity pattern also showed a marked circadian component. Exposure to the same regime entrained a circadian rhythm, but not a circatidal rhythm in L. depurator. In the sublittoral zone L. depurator is active mainly during the night, whereas L. holsatus, is active mainly during the day. This may constitute a behavioural mechanism for minimizing competitive interactions between these two sympatric crabs

Description: The nutrient status of two common Antarctic diatoms (Corethron criophilum and Thalassiosira cf. antarctica) was analysed by studying the growth response in enrichment bioassays and by estimates of the cell quotas of Si, N and P after size-fractionation of net plankton samples Corethron had higher biomass-specific N-quotas; Si- and P-quotas were quite similar between both species. Corethron was Si-limited in five enrichment experiments and not nutrient limited in five experiments. Thalassiosira was not nutrient limited in six experiments, N-hmited in four experiments and Si-limited in one experiment Droop-kinetics of Si-limited growth of Corethron and of N-hmited growth of Thalassiosira were obtained by combining the growth rates in the bioassays and the cell quotas from the natural populations. The minimal Si-quota of Corethron was 0 041 mol Si/mol C, the saturating cell quota was 0.158 mol Si/mol C respectively The minimal N-quota of Thalassiosira was 0 0223 mol N/mol C, the saturating cell quota was 0.208 mol N/mol C Corethron was N-saturated at cell quotas of 〉0 106 mol N/mol C; Thalassiosira was Si-saturated at cell quotas of 〈0 132 mol Si/mol C. As the better competitor for N and the poorer one for Si, Corethron became more important with increasing Si N ratios, while Thalassiosira became more important with decreasing Si:N ratios in the water

Description: Serological methods for prey identification have been applied to detection of residues ofsandeel (Ammodytidae) protein in faeces of common seals (Phoca vitulina) and grey seals(Halichoerus grypus) from the Moray Firth, north-east Scotland. Antisera raised to muscleprotein from Ammodytes marinus were evaluated by testing their reactions with proteinextracts made from a range of North Sea fish species and protein residues in in vitro digestates,seal digestive tracts and seal faeces. It was concluded that, using fused rocketimmuno-electrophoresis, linkage of precipitin peaks from unknown samples with peaksfrom standard sandeel extract was a reliable indicator of the presence of sandeel in theunknown sample. Seasonal variation in the incidence of sandeels in common seal diet in theMoray Firth was examined by identifying otoliths, bones, and proteins, and all threemethods indicated that sandeels occurred in the majority of samples tested in the summer,but were less important during the winter. Proteins were detected in fewer samples thanotoliths, particularly in February and March. Possible reasons for this difference arediscussed. Serological identification of sandeel proteins is potentially applicable to dietarystudies on all marine predators.

Description: Thirty-four adult individuals of Loligo forbesi (males and females with dorsal mantle lengths from 27–77 cm) were observed in captivity in a 3 m diameter closed sea-water system on Faial Island, Azores. Squids were caught by jigging and were fed with horse mackerel (Trachurus picturatus) and chub mackerel (Scomber japonicus), either alive or dead. The maximum survival was 73 days. Feeding behaviour was dependent upon both the size of prey and its state of preservation;e.g. the squid would eat the head of small fish (〈 about 15 cm), reject the head of medium-sized fish (about 15–35 cm) and would eat only the dorsal part of a big fish (〉 about 35 cm) or a fish poorly preserved. Seventeen chromatic, 9 postural and 6 movement components of body patterns were observed and described. Conspecific interactions considered to be aggression and dominance were observed among males; no such interactions occurred when one male and two females were kept together. Body patterns in relation to relaxation, stress, shock, feeding, locomotion and aggression are also described.

Description: Gray whales (Eschrichtius robustus) feeding in the northern Bering Sea produce prey-rich mud plumes that provide ephemeral foraging opportunities for seabirds. Approximately 67% of all gray whales were attended by birds. In four whale-associating bird species (Northern Fulmar, Fulmarus glacialis; Red Phalarope, Phalaropus fulicaria; Black-legged Kitti-wake, Rissa tridactyla; and Thick-billed Murre, Uria lomvia), from 17 to 87% of all individuals that we observed on the water or foraging were in the whales' mud plumes. The combined density of these same four species was strongly correlated with whale density over a broad range of spatial scales. The whale-associating seabirds exhibited species-specific patterns of foraging behavior at plumes, including differences in mean group size, mean residence time, and patterns of movement between plumes. Birds tended to form larger groups and to form more mixed-species flocks in association with whales. The association of marine birds with gray whales in the Bering Sea provides a model system for examining seabird interactions at fine-scale oceanographic patches and demonstrates the importance of these patches in shaping patterns of seabird distribution and behavior.

Description: The Rhynchoteuthion larvae of Illex argentinus resulting from summer spawning in North Patagonic shelf waters, its distribution and abundance, are described in this paper. The material was collected in the Argentine Sea (35–55°S) by means of plankton nets. The research cruises were made by the R/V Shinkai Maru and the R/V Walther Herwig during the period April 1978 to April 1979. The most important spawning ground of the summer spawning subpopulation is found in continental-shelf waters (between 43 and 46°S) during the period December-February. This area was established on the basis of both ripe (December) and spent females (February). The larvae which were caught during the same period, especially in March, confirmed the spawning area of this demographic unit. The larvae showed the length of the mantle (ML) to be from 1.2 to 6.5 mm. Tentacles were splitting in specimens from 5.0 to 6.5 mm ML (transition stage). When 7.0 mm ML or more, all specimens were juveniles and had their tentacles completely separated. Larvae were characterized as type C, following the proposal of Sato (1973) and Sato and Sawada (1974) in the Bulletin of the Shizuoka Prefectural Fisheries Experimental Station.