Inger-Britt Falk-Petersen

Lipid class and fatty acid composition of eggs from the Atlantic halibut (Hippoglossus hippoglossus)

Abstract Lipid class and fatty acid analyses were carried out on ripe roe of halibut caught in North Norway. The percentage of neutral lipids was c. 30% while the main polar lipids were phosphatidylcholine (62%) and phosphatidylethanolamine (7%). The phospholipids were very unsaturated, with high concentrations of ( n −3) polyunsaturated fatty acids (PUFA), especially 20:5 ( n −3) and 22:6 ( n −3).

Lipids in atlantic halibut (Hippoglossus hippoglossus) eggs from planktonic samples in Northern Norway

Fertilized Atlantic halibut (Hippoglossus hippoglossus L.) eggs in different developmental stages (Days 0 to 18) were sampled from plankton in North Norway in February 1986 and analysed for lipid classes and fatty acid content. In unfertilized ovulated eggs taken from ripe fish caught in 1983/1984, polar and neutral lipids comprised ca. 71 and 30% of the total lipids, respectively, decreasing and increasing to 67 and 33%, respectively, in Stage III (11 to 18 d old) fertilized eggs. Of the polar lipids, phosphatidylcholine decreased markedly from 62% in unfertilized ovulated eggs to ca. 40% in Stage I (0 to 3 d old) fertilized eggs, while phosphatidylethanolamine increased from ca. 7 to 33%. Triacylglycerols, the major neutral lipids, increased from ca. 13% in unfertilized ovulated eggs to 16% in Stage III fertilized eggs. The total lipid in Stage I fertilized eggs had relatively low levels of polyunsaturated fatty acids (PUFA), with (n-3) PUFA accounting for only ca. 25% of the total fatty acids. The (n-3) PUFA increased to ca. 40% of the total fatty acids in Stage III, while the (n-3): (n-6) ratio increased from 4.1 to 7.0.

Occurrence and size/age relations of polar cod, Boreogadus Saida (Lepechin), in Spitsbergen coastal waters

Abstract The polar cod were common in catches with bottom and pelagic trawl in Spitsbergen coastal waters. O-group polar cod were found in the upper echo-layers (15–80 m), while adults were confined to the deeper layers. A size/depth segregation was noted in the bottom layers with smaller individuals occurring mostly in the shallower areas and larger ones at greater depths. In general, pelagic hauls were dominated by fish smaller than 10 cm. Polar cod from Spitsbergen coastal waters were generally smaller and apparently grew more slowly than their counterparts in the central and eastern Barents Sea.

A review of the culture potential of spotted wolffish Anarhichas minor Olafsen

The first articially fertilized spotted wolffish eggs hatched only 10 years ago, and today the species is considered a very promising candidate species for cold water aquaculture in the North Atlantic. Recent research has focused on identifying key biological parameters in spotted wolffish aquaculture in order to establish a full production line for the species, and basic aspects of reproduction and larval development are now understood, controlled, and no longer limiting production. Spotted wolffish eggs (5–6 mm) have a protracted incubation period (800–1000 D°) and newly hatched individuals (20–25 mm) are well developed, with the only larval characteristic remaining being a relatively small yolk sac which is completely resorbed after 3–4 weeks. The species can be weaned directly on formulated feed, and high specific growth rates have been obtained in land-based culture facilities using shallow raceways. Adaptive immune responses are present early after hatching and few potential disease problems have been identified. Only one bacterial disease, atypical furunculosis, has been reported in farmed fish, but oil-emulsified vaccines have displayed efficient protection both in juvenile and adult fish. Ectoparasites may, however, constitute a problem during parts of the year when sea-water temperature increases.Optimal temperature for growth decreases with increasing fish size and is 10–12 °C for early juveniles and 4–6 °C for adult fish and broodstock. Spotted wolffish is a very robust species, and juveniles thrive at high densities and may be reared at a wide range of salinity levels. The species has further displayed a high tolerance to environmental changes in water quality parameters such as oxygen, carbon dioxide and un-ionized ammonia. Currently, the possibility of rearing spotted wolffish in flat-bottom net cages with shelves in the sea is being investigated. Preliminary results suggest that sea-based production may be a viable alternative to land-based rearing of the species in certain areas.

Contents of Vanadium and Sulphur in the Blood Cells of Ascidia Mentula and Ascidiella Aspersa

Henze (1911) was the first to discover large amounts of vanadium and sulphuric acid in the blood of certain species of tunicates. Webb (1939) established that both the sulphuric acid and the vanadium were present in blood in the same cell type, termed a vanadocyte. Since then much further work (reviewed by Goodbody, 1974) has been done on these highly unusual cells. Some species of tunicates accumulate other metals, including iron, titanium, niobium and tantalum (Carlisle, 1968) but the role(s) of these metals and indeed of vanadium itself remains unclear. The vanadium is present in vanadocytes in a reduced cationic form largely as vanadium(III) (Carlson, 1975; Tullius et al. 1980) which is complexed with a chromagen of as yet undefined structure and with sulphate as the counter anion (Bielig et al. 1966). The blood of Ascidia nigra is not capable of reversible oxygen binding (Macara, McLeod & Kustin, 1979), and there has been speculation that the reduced vanadium is involved in the synthesis of the tunic material (see Goodbody, 1974). The tunic of ascidians also contains cells rich in vanadium and sulphuric acid and roles for them in anti-fouling and anti-predation have been considered (Stoecker, 1980 a, b ).

Reproductive cycles of two closely related sea urchin species, Strongylocentrotus droebachiensis (O.F. Müller) and Strongylocentrotus pallidus (G.O. Sars)

Strongylocentrotus droebachiensis and S. pallidus, from c. 70° N in the north east Atlantic, have different spawning times. The main breeding season of S. droebachiensis was found to be late winter, while S. pallidus spawned during spring or early summer. This difference in spawning time may explain why hybridization is rare at these latitudes. Both species initiated rapid oocyte growth during autumn. Maturing and mature specimens of S. pallidus were found during a longer period than those of S. droebachiensis. Ovaries did not display a resting phase. Oocyte proliferation and differentiation was initiated during winter and spring while the previous generation of mature eggs was still present. Gonad indices and gonad weights of maturing and mature S. pallidus were always lower than those of S. droebachiensis, which may suggest a lower fecundity in the former.

Breeding season and egg morphology of echinoderms in Balsfjorden, northern Norway

Abstract Reproduction has been investigated in echinoderms from selected localities in an arctic-boreal fjord (c. 70° N). Three echinoids (Strongylocentrotus droebachiensis, S. pallidus, and Echinus esculentus) and three ophiuroids (Ophiopholis aculeata, O. sarsi, and O. albida) all produce large numbers of small eggs that develop plankto-trophically in the pelagic zone during spring and summer. So does one of the six asteroids examined, Asterias rubens. Five other asteroids (Leptasterias muelleri, Asterias lincki, Ctenodiscus crispatus, Pteraster militaris, and Solaster endeca) and the one holo-thurioid examined (Cucumaria frondosa) all produce fewer numbers of large eggs. A. lincki, C. crispatus, S. endeca, and C. frondosa develop lecithotrophically in the pelagic zone. S. endeca and C. frondosa reproduce during spring whereas A. lincki and C. crispatus have main reproductive peaks in mid-winter. L. muelleri and P. militaris develop by brood protection; the former reproduces in winter, the latter in spr...

Structure and function Of an unusal lipid storage organ in the Arctic fish Lumpenus maculatus Fries

Abstract Juvenile Lumpenus maculatus have a special oil sac composed of large polygonal units situated on the ventral part of the fish from the pectoral fins to the anus. The sac consists of pure triacylglycerols, whose major fatty acids are 20:1 (n-9) and 22:1 (n-11). The fish flesh is also rich in lipid (c. 40 % of dry weight), of which 50 % are triacylglycerols and 35 % wax esters. Both the fatty alcohols and fatty acids are dominated by 20:1 (n-9) and 22:1 (n-11) moities. The results are discussed in relation to current knowledge of the role of lipids in marine pelagic animals at high latitudes.

First feeding of common wolffish on formulated dry feed diets in a low water-level raceway system

Wolffish (Anarhichos lupus) larvae were first fed in a low water-level raceway system, with two new types of formulated dry feed diets. Water level in the rearing tank was 1.5 cm. The fish showed a high preference for feeding from the surface. During the first week the fish experienced a drop in dry weights. The highest SGR of 5.8% was obtained between day 35–60. The best feeding regime gave a survival rate of 82 (2.5)%. Results indicate failure to initiate feeding as a main cause of mortality in the fed groups. Death by starvation occurred after 30–40 days. It is speculated whether the large difference in growth rates between the two feeding regimens is due to differences in carbohydrate levels between the two feed types. The rearing tank technology proved, with minor adjustments, to be self-cleaning and well suited for first feeding of wolffish.

Ecological investigations on the zooplankton community of Balsfjorden, northern Norway: Planktonic eggs and larvae from March 1978 to February 1980

Eggs and larvae of benthic and pelagic marine organisms were present in zooplankton hauls during all months of the year. The diversity and quantity of larvae were low during the winter months. Increasing numbers of species were noted during early spring and through summer, consistent with the fact that most planktonic larvae are dependent on the phytoplankton production as a food source. Winter-breeding species developed via relatively large, lecithotrophic eggs.