ALBERT

Description: An abrupt lithofacies change between calcareous shale and noncalcareous shale occurs in strata deposited in the mid-Cretaceous Greenhorn Seaway in the southeastern corner of Montana. The facies were correlated lithostratigraphically using bentonites and calcarenites. The lithocorrelations were then refined using ammonites, foraminifera, and calcareous nannofossils. Twenty-five time slices were defined within the upper middle and lower upper Cenomanian strata. Biofacies analysis indicate that lithofacies changes record the boundary or oceanic front between two water masses with distinctly different paleoceanographic conditions. One water mass entered the seaway from the Arctic and the other from the Gulf of Mexico/Tethys. The microfauna and microflora permit interpretation of the environmental conditions in each water mass. At times when the front was near vertical, the two water masses were of the same density but of different temperatures and salinities.

Description: We present ΔA14C and 39Ar data collected in the Nansen, Amundsen and Makarov basins during two expeditions to the central Arctic Ocean (RV Polarstern cruises ARK IV/3, 1987 and ARK VIII/3, 1991). The data are used, together with published Δ14C values, to describe the distribution of Δ14C in all major basins of the Arctic Ocean (Nansen, Amundsen, Makarov and Canada Basins), as well as the 39Ar distribution in the Nansen Basin and the deep waters of the Amundsen and Makarov Basins. From the combined Δ14C and 39Ar distributions, we derive information on the mean “isolation ages” of the deep and bottom waters of the Arctic Ocean. The data point toward mean ages of the bottom waters in the Eurasian Basin (Nansen and Amundsen Basins) of ca. 250-300 yr. The deep waters of the Amundsen Basin show slightly higher 3H concentrations than those in the Nansen Basin, indicating the addition of a higher fraction of water that has been at the sea surface during the past few decades. Correction for the bomb 14C added to the deep waters along with bomb 3H yields isolation ages for the bulk of the deep and bottom waters of the Amundsen Basin similar to those estimated for the Nansen Basin. This finding agrees well with the 39Ar data. Deep and bottom waters in the Canadian Basin (Makarov and Canada Basins) are very homogeneous, with an isolation age of ca. 450 yr. Δ14C and 39Ar data and a simple inverse model treating the Canadian Basin Deep Water (CBDW) as one well-mixed reservoir renewed by a mixture of Atlantic Water (29%), Eurasian Basin Deep Water (69%) and brine-enriched shelf water (2%) yield a mean residence time of CBDW of ca. 300 yr.

Description: The foraging ecology of free—living King Penguins (Aptenodytes patagonicus) was studied during October and November 1991 on Possession Island (46°25' S, 51°45'E), Crozet Archipelago. Feeding was detected with stomach temperature sensors, which logged feeding activity as indicated by temperature drops. The penguins fed mainly on myctophid fish. Stomach temperature of 16 birds at sea was recorded for a total of 146 d. During 125 d a total of 16 474 food ingestion events was recorded, a mean of 132 events per day. Here, calculated food intake averaged 2320 g/d (range 11—12 889 g) with 〉80% (range 71—95%) of prey caught during daylight. During the remaining 21 d stomach temperature dropped below the detection limit of 20°C, which made determination of the number of ingestion events impossible and mass ingested determination inaccurate. We propose that there is selection pressure for King Penguins to ingest and digest large quantities of food quickly because these birds alternate fasting periods on land, during which time they care for their chicks, with foraging trips, during which time they must feed on patchily distributed prey.

Description: The proximate (protein, lipid, carbohydrate and ash) and elemental (C, H, N and P) composition of the major tissues were measured for 18 male and 51 female Illex argentinus sampled from the feeding grounds over the Patagonian Shelf. In most tissues the chemical composition did not vary with sexual maturity, although the mass of the tissue increased significantly because sexual maturation and growth were proceeding simultaneously. The composition of the ovary and associated tissues (nidamental gland, oviducal gland) did change significantly during sexual maturation. Several tissues contained significant amounts of one or more unknown components. The nitrogen content of an unknown component in the testis was similar to that of DNA. In the spermatophoric complex the nitrogen content suggested the unknown fraction may be an amino acid or short peptide, whereas in the nidamental gland the nitrogen content suggested an amino-sugar or polysaccharide derivative. The digestive gland was rich in lipid and continued to accumulate substantial reserves of energy throughout the period of sexual maturation on the feeding grounds. During this period there was no evidence for the utilization of either digestive gland or mantle tissues to supply energy for gonads. Accumulation of carbon and energy (estimated stoichiometrically from carbon) during the final 50 days on the feeding grounds indicated that energy demands for tissue synthesis in females were almost twice those of the smaller males, and that a relatively small fraction of the demands were for reproductive tissues (5% in males, 15% in females). Most energy intake in this period was directed to the digestive gland (40% in males, 47% in females) and other somatic growth (54% in males, 38% in females). A preliminary power budget suggested that during the final days of feeding before migrating to the spawning grounds, energy intake of Illex argentinus is 4-5% body energy content per day, growth efficiencies are low (17-22%) and that energy reserves in the digestive gland would fuel migration in the absence of feeding for 14 days in males and 21 days in females.

Description: Time series (1965-1985) of Illex illecebrosus catch and morphometric data from the Northwest Atlantic were analysed to describe geographic variability in population structure. The areas studied were NAFO sub-areas 3 to 6, which range from Newfoundland to the northeastern USA shelf. Population components, reflecting seasonal spawning groups, were identified based on analysis of length frequency data. Components 3 and 4 represent two prominent life cycles: the summer spawners and winter spawners respectively. Components 1, 2, and 5 do not represent different life cycles, but result from the capacity to shift between life cycles by prolonging (or shortening) the life span. The presence of up to five components in the southern area illustrates a life history strategy involving protracted spawning and complex population structure. There was clear geographic variability in annual catch, with fluctuations being most extreme in the most northern area. Annual catch levels in all areas were significantly correlated with the abundance of the winter-spawning component, as represented by the number of squid within samples which belong to component 4. Population structure in the most northem area was simplest and catch levels therefore were most dependent on the highly migratory winter-spawning component. This leads to greater catch variability in the most northern area than in the other areas. The advantages of good feeding conditions may compensate for the risks associated with long-range migrations, especially recruitment failure. Life history strategies involving migratory and non-migratory population components limit the risk of recruitment failure. The overall resultant life history strategy for Illex illecebrosus is one that ensures survival of the species by stabilizing recruitment in at least one (southern) area through protracted spawning, complex population structure and interaction of spawning components. Time series (1965-1985) of Illex illecebrosus catch and morphometric data from the Northwest Atlantic were analysed to describe geographic variability in population structure. The areas studied were NAFO sub-areas 3 to 6, which range from Newfoundland to the northeastern USA shelf. Population components, reflecting seasonal spawning groups, were identified based on analysis of length frequency data. Components 3 and 4 represent two prominent life cycles: the summer spawners and winter spawners respectively. Components 1, 2, and 5 do not represent different life cycles, but result from the capacity to shift between life cycles by prolonging (or shortening) the life span. The presence of up to five components in the southern area illustrates a life history strategy involving protracted spawning and complex population structure. There was clear geographic variability in annual catch, with fluctuations being most extreme in the most northern area. Annual catch levels in all areas were significantly correlated with the abundance of the winter-spawning component, as represented by the number of squid within samples which belong to component 4. Population structure in the most northem area was simplest and catch levels therefore were most dependent on the highly migratory winter-spawning component. This leads to greater catch variability in the most northern area than in the other areas. The advantages of good feeding conditions may compensate for the risks associated with long-range migrations, especially recruitment failure. Life history strategies involving migratory and non-migratory population components limit the risk of recruitment failure. The overall resultant life history strategy for Illex illecebrosus is one that ensures survival of the species by stabilizing recruitment in at least one (southern) area through protracted spawning, complex population structure and interaction of spawning components.

Description: Finding of some uncommon cephalopods, Ancistroteuthis lichtensteinii, Histioteuthis bonnellii, H. reversa and the first record of Chiroteuthis veranyi in the Ionian Sea are reported here. Data were collected during a trawl survey carried out on red shrimp grounds during August 1993.

Description: Four research surveys of Falkland Island waters were carried out to determine the distribution and abundance of the early life-history stages of Loligo gahi (d'Orbigny, 1835) in the austral winter of 1988 and the austral springs of 1990, 1991 and 1992. Juveniles were caught during three of the four surveys in both Bongo nets and an RMT8 net. In each case, greatest numbers were consistently caught in waters of ≤100 m to the south and east of East Falkland. The use of an opening/closing net in 1992 showed that most L. gahi juveniles aggregate close to the sea floor and are more available to the sampling gear by night than by day. Limited temperature data for the 1991 and 1992 surveys suggest that distribution on the coastal shelf may be associated with water-column structure. In 1992 when temperature data implied a mixed water column, juveniles were caught in deeper water than in 1991 when the water column was stratified. The results suggest that the spawning grounds of L. gahi are probably situated to the south and east of the Falkland Islands, at least for squid hatched in the austral winter/spring.