ALBERT

Notes: Abstract Dry body weights, lipid levels and lipid compositions were measured in I-and II-group Thysanoessa raschi (M. Sars) and T. inermis (Krøyer) collected in April-May, 1980 in Balsfjorden, north Norway. Dry body weights were mininal in late April but had doubled by mid-May for I-group T. raschi and for I- and II-group T. inermis. II-group T. raschi had increased its dry weight by less than 50% by mid-May. Lipid accounted for approximately 10% of the dry body weight throughout the period, with free fatty acids and phospholipids being the dominant classes. An exception occurred for II-group T. inermis in mid-May, when wax esters were present in substantial amounts. Wax esters were present only in small amounts at other times and triacylglycerols were negligible. The free fatty acids in I-group T. raschi and I-group T. inermis in late April were deficient in polyunsaturates; by mid-May the free fatty acids were rich in polyunsaturates. II-group T. raschi and II-group T. inermis had free fatty acids rich in polyunsaturates throughout the period of study. The wax esters present in II-group T. inermis in mid-May consisted mainly of 16:0 and 14:0 alcohols esterified to 18:1 fatty acid. The traces of wax esters present in T. raschi did not contain significant amounts of phytol. Results are discossed with respect to the metabolic activities of the two euphausiids and their trophic positions in terms of different dietary inputs.

Notes: Abstract Surface sediments from the Svartnes basin (195 m deep) in Balsfjorden, northern Norway (ca. 70°N), were partially characterized to assess the nature and origin of the organic material present and its potential nutritive value for sediment-ingesting animals. Seasonal analyses were carried out on material collected between May 1979 and August 1980 for total organic matter, organic C and N, acid-extractable amino acids and lipids extractable with chloroform:methanol. Little or no seasonal variation was seen in any of the parameters analysed. The mean apparent organic content was 9.3% of sediment dry weight, the organic C content was 2.38%, the organic N content was 0.26% and the C:N ratio was 9.1:1. Acid hydrolysis of sediment yielded 575 mg of amino acids and 41 mg of NH3 per 100 g sediment dry weight, the composition of the amino acids being similar to that of nutritionally highquality animal or microbial protein. Glucoseamine was not detected in acid hydrolysates of sediment, consistent with the absence of chitin. Chloroform:methanol extraction yielded 133 mg of material per 100 g sediment dry weight, 62% of which was accounted for by saponifiable lipids (fatty acids) and non-saponifiable lipids present in approximately equal amounts. Fatty alcohols accounted for 30% of the non-saponifiable lipids and phytol accounted for 40% of the fatty alcohols. Small amounts of very long-chain fatty alcohols characteristic of terrestrial plants were present, but long-chain monounsaturated fatty alcohols characteristic of marine zooplankton were essentially absent. Very small quantities of long-chain ketones characteristic of marine coccolithophores were detected. The major fatty acids present in sediments were 16:0, 14:0, 16:1 (n-7) and 18:1 (n-9), and 11% of the total fatty acids were comprised of a mixture of odd-numbered straight-chain and branched-chain moieties characteristic of micro-organisms. The data point to small amounts of material characteristic of marine and terrestrial photosynthetic organisms being present in sediments at any given time, whereas material characteristic of marine zooplankton is not present. The presence of material characteristic of micro-organisms is consistent with conversion of sedimenting material into a pool of sediment micro-organisms. Although the biological availability to sediment-ingesting organisms of the esterified fatty acids and the acid-extractable amino acids in sediments remains to be assessed, the maximum amounts available are equivalent to approximately 60 mg of polar lipid and 575 mg of protein per 100 g sediment dry weight. These amounts are small in relation to the production rates in the photic zone of the fjord, implying that the bulk of the energy flow in Balsfjorden occurs in its relatively short pelagic food chains.

Notes: Abstract The structure of the reproductive system in Copepodite Stages IV and V of the marine copepod Calanus finmarchicus (Gunnerus) is described, together with seasonal variations in gonad development and sex ratio, from Balsfjorden (69°21′N; 19°06′E), a subarctic fjord in northern Norway. The genital system in Copepodite Stage IV consists of a small gonad with two genital ducts. The gonad of Copepodite Stage V in its most immature condition resembles that seen in Copepodite Stage IV, whereas the sex of Stage V copepodites with mature gonads can be easily and reliably determined. The genital ducts are the key characters for separating males and females in Copepodite Stage V; potential males have one and potential females two genital ducts connecting the gonad to the genital opening on the first urosome segment. Adults males were rare compared to females, and were only in the majority at the end of January and beginning of February. The sex-ratio also favoured females in Copepodite Stage V. Seasonal peaks in the proportion of adult males reflected peaks of males in Copepodite Stage V, suggesting that seasonal variations in the adult sex-ratio are a direct result of a situation which has already been determined in Copepodite Stage V. The seasonal variation in gonad development in Copepodite Stages IV and V of C. finmarchicus reveals that the size of maturity of the gonad varies throughout the year. This study indicates that visible sex-differentiation in Stage V and moulting into adults occurs in Balsfjorden at least 2 months before spawning in April. Phytoplankton levels are immeasurable before the spring diatom increase starts at the end of March, implying that development and maturation of gonads are dependent upon internal energy resources, whereas the final act of spawning seems to require energy input from phytoplankton.

Notes: Abstract Changes in the wet weights and lipid contents of muscle, liver and gonad were determined in male and female Mallotus villosus in Balsfjorden, northern Norway, in 1981, from January, when gonadal development becomes noticeable, until May when the fish are spawning. Fatty acid compositions of tissue lipids were also determined. Over 4 mo prior to spawning, the weight of muscle in female capelin decreased by 32% while the weight of the ovary increased exponentially by 830%. In males the weight of the muscle remained constant and that of the testis decreased slightly. The lipid contents of the muscle of both males and females decreased by 76% over the period and an inverse relationship existed between the water and lipid contents of muscle in both sexes. Male liver weight remained constant over the period of study whereas female liver weight increased transiently by 300% between January and March. 38% of the lipid lost from female muscle was accounted for by lipid deposited in ovary whereas negligible amounts of the lipid lost from male muscle was accounted for by lipid in the testis. Gonadal lipid was always richer in polyunsaturated fatty acids than muscle lipid and, immediately prior to spawning, 42% of the fatty acids in ovarian lipid were polyunsaturated. Muscle lipid of males and females showed a progressive increase in the percentage of the long-chain monoenes 20:1 and 22:1 between January and May. It is concluded that male capelin catabolise more of their muscle lipid reserves than females in the 4 mo prior to spawning and that most of the lipid catabolism in males is associated with physical activity. Conversely, females deposit much more of their muscle lipid in gonads than males, although considerable selectivity occurs in the mobilisation of fatty acids from muscle lipid into ovarian lipid. Additionally, biosynthesis of gonadal constituents accounts for a considerable proportion of the lipid catabolised in females.

Notes: The Barents Sea capelin is a major forage species for many apex predators, for example, fish, marine mammals, sea birds, and man. The fishery for Barents Sea capelin increased exponentially in the early 1970s with the demise of the Atlanto-Scandian herring fishery along the Norwegian coast. The collapse of the herring spawning-stock resulted in the disappearance of young herring from the southern Barents Sea and the diet of the larger (ca. 3+ ages), piscivorous cod. Since then the only major dietary alternative for these larger cod has been capelin. The over-all trend in the biomass of the Barents Sea cod. however, has been one of decline since the late 1940s. As there was a marked decrease in the biomass of the 3+ ages of cod from ca. 3 • 106 tonnes to ca. 1 • 106 tonnes from 1974 to 1983, this would have simultaneously caused a great reduction in the predation pressure from cod on the capelin.The Barents Sea capelin is an r-strategist. Its weight-at-age is inversely related to population size, and thus the number of cohorts and subsequently age-at-maturity are positively related to population size. Principal components analysis (PCA) indicates that the biomass of 2+ ages of capelin and population characteristics already exhibited a declining trend from about 1975, despite a declining cod stock. Coupling of independent Russian and Norwegian data clearly shows that the percentage occurrence of prawns in the stomach of 3+ cod increased disproportionately from the mid-1970s despite a decrease in the cod biomass, probably indicating a lack of capelin as primary-choice prey. The nominal capelin catch between 1978 and 1983 is probably an unreliable estimate of fishing mortality. A drastic decline in the capelin stock occurred after 1983/1984, with marked predation from the potentially strong 1983 cod year-class.The capelin, as an r-strategist, is very difficult to manage in the fluctuating biological and climatic environment of the Barents Sea. Fisheries for capelin should be limited within the framework of multispecies perspectives, with much of its production being primarily used to sustain an elevated long-term yield of cod.

Notes: Summary Chlorophyll a, phytoplankton species composition and carbon (PPC) estimated from cell-counts, were monitored together with hydrographic parameters and nutrients in the upper 50 m of Balsfjord (ca. 70° N), northern Norway between 08 February and 29 June 1982. Sediment traps were placed at 10, 50, 100, and 170 m (10 m above bottom) for intervals of 5–20 days during the study period. Trap contents were analyzed for phytoplankton as above; dry weight, particulate organic material (POM), particulate organic nitrogen and carbon (PON and POC), ash, and particulate phosphorus were also measured. The phytoplankton community exhibited three main phases: During the first (02–15 April, chiefly surface biomass) and the second (20 April–10 May, deep biomass-maximum and spring bloom peak) periods, Phaeocystis pouchetii dominated biomass (ca. 50% of PPC) followed by vegetative cells of Chaetoceros socialis. In the third period (10 May onwards, characterized by surface estuarinecir-culation), dino- and microflagellates dominated the low post-bloom biomass. Protozooplankton comprising tintinnids, other ciliates and heterotrophic dinoflagellates increased in abundance. Vegetative cells of phytoplankton were scarce in trap collections at 50 m or below; resting cells of Chaetoceros comprised nearly all the “intact” sedimenting phytoplankton. Krill faeces accounted for 〉90% by volume of the total faecal material trapped, despite a 〉2∶1 biomass dominance of copepods in the fjord. The greatest sedimentation rates of krill faeces were at 〉 100 m, reflecting the downward migration of krill during the day. In all, 2–3 g Cm−2 of krill faeces were collected, representing ca. twice that from intact phytoplankton cells. POC in the traps at ≥50 m was ca. 11 gm−2, accounting for ca. 17% of the estimated primary production during the study period. As the secondary production is high, a large proportion of the production of P. pouchetii must be grazed by herbivores. Copepod faeces are probably remineralized in the euphotic zone, while those of krill provide the major coupling between the pelagial and the benthos. The implications of such a sedimentation model for partitioning energy flow between the pelagial and the benthos is discussed.

Notes: Summary Correspondence analysis (CA) is used to examine the relationship between months, between selected body components/organs and between months and components/organs for male and female capelin from 12 to 37 months of age in Balsfijorden, northern Norway (69°21′N:19°06′E). The CA profiles have been used to quantify condition with regard to age and season. The major features determining the condition of fish depositing hyaline or opaque otolith zones are itemized using CA, and the data modelled by Multiple Regression (MR) using a cosine curve incorporating the chief mass variables with linear age-dependency. The highest proportion of fish having outer opaque zones are found from ca. June to October, whilst the highest proportion with exterior hyaline zones are found from ca. December to May. There is a clear annual cycle in the deposition of opaque and hyaline otolith zones in both sexes, but there is a significant difference in phase of ca. 12 days between the sexes. There is a significant trend for decreasing proportions of fish having outermost opaque otolith zones with increasing age; this trend is similar in both sexes. The mean level and amplitude of the cycles are similar in both sexes. On the other hand, CA shows a 12-month cycle of storage and utilization of body materials with obvious differences between sexes. In the female protein in the fillet plays a more dominant role than lipid in the fillet in accounting for anabolic and catabolic variations in mass, whereas in the male the opposite is true. Sexual maturation is negatively correlated with fillet (somatic) growth. Variations in stomach weight (with contents) and otolith zone deposition are not significantly correlated. Nevertheless, in both sexes there is a clear positive correlation between stomach weight and liver protein and lipid implying an association between stomach weight and feeding activity. In females, however, maximum liver condition is more positively correlated with exponential ovarian growth, probably through mobilization of lipoproteins for eggs. Qualitative (CA) and quantitative (MR) models have related changes in growth and condition to the type of otolith zone deposited. The fillet of capelin is the major somatic growth site. As CA indicates a negative correlation between fillet reserves and gonad maturation, and the best MR models describing the cycle of otolith zone deposition in males and females (accounting for 93% and 70% respectively of the variation) underlined and quantified the interplay between somatic and gonad growth, it is implicit that the energy balance of the fish will be an important determinant of otolith zone deposition in sexually maturing and mature capelin.