Phospholipid Composition of Fingerlings of Atlantic Salmon Salmo salar during Growth and Development in Aquaculture: The Effect of Different Lighting and Feeding Regimes.

The effect of different feeding and lighting regimes (natural and continuous) on the phospholipid composition of Atlantic salmon fingerlings reared in commercial aquaculture in the summer-autumn period in North Ossetia-Alania was studied. Qualitative and quantitative determination of phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, lysophosphatidylcholine, sphingomyelin was performed by high-performance liquid chromatography. A decrease (September-November) in the content of the studied phospholipids in fingerlings decreased, which should be considered primarily as a biochemical adaptation of development and preparation of juveniles for the upcoming smoltification.

Ontogenetic changes in the body structure of the Arctic fish Leptoclinus maculatus.

Histological studies of the ontogenetic changes in Arctic marine fishes are often fragmented and incomplete. Here we present a comprehensive histological ontogenetic analysis of the daubed shanny (Leptoclinus maculatus) from the Arctic, characterizing its development as it undergoes a series of changes in the organ and tissue organization, especially during the postlarvae transition from the pelagic to benthic lifestyle. The thyroid, heart, digestive tract, liver, gonads, blood, and the lipid sac of the postlarvae at different developmental stages (L1-L5) were studied for the first time.

Cortisol Level and Na/K-ATPase Activity during Growth and Development of Juvenile Daubed Shanny Leptoclinus maculatus (Fries, 1838) in the Arctic.

The dynamics of cortisol level and Na/K-ATPase activity that are associated with the maintenance of cell ion homeostasis was studied in skeletal muscles of juvenile circumpolar fish daubed shanny Leptoclinus maculatus (Fries, 1838), an ecologically significant representative of the ichthyofauna of the Arctic Svalbard Archipelago. It was established that the level of cortisol and Na/K-ATPase activity decrease during the development of daubed shanny juveniles from stage L2 pelagic juveniles to stage L5 juveniles, which are mainly demersal. The results obtained suggest that cortisol may be involved in the regulation of the activity of one of the main osmoregulatory factors, Na/K-ATPase.

Comparative Study of Lipid Content in Leptoclinus maculatus Postlarvae from Kongsfjord and Rjipfjord, Svalbard Archipelago.

A comparative study of lipid profile of the daubed shanny Leptoclinus maculatus postlarvae from fjords of different domains (arctic-boreal Kongsfjord and high-arctic Rjipfjord) of Svalbard Archipelago waters in summer was performed. A more efficient accumulation of lipids in the fishes from Kongsfjord compared to Rjipfjord due to triacylglycerols and wax esters was established. These differences may be related mainly to the trophic conditions of the habitat (species composition, abundance, and availability of food items).

Lipid Status of Gray Whales Eschrichtius robustus in the Piltun Feeding Area.

For the first time, the relationship of lipid and fatty acid composition with individual, gender and age characteristics of the gray whale Eschrichtius robustus in the Piltun feeding area is shown using the methods of biochemical analysis.