This chapter provides a general overview of the Barents Sea demersal trawl fishery. First, it reviews historical catch levels and current biomass status of four commercially important demersal species (cod, haddock, Greenland halibut, and redfish) and includes an overview of their management plan that has been carried out by the Joint Norwegian–Russian commission. Then, it presents the evolutio...

Survival during the larval and juvenile stages of marine fishes is highly variable and plays a critical role in determining recruitment potential (Cushing, 1975; Houde, 1987). Early life survival is a function of both growth and mortality, and it is clear that these mechanisms act in concert to determine an individual’s probability of survival (Houde, 1996). Individuals experiencing rapid growt...

RNA:DNA ratios of larval and juvenile red drum (Sciaenops ocellatus) collected from nursery habitats in the Aransas Estuary, Texas, in 1994 were quantified using a highly sensitive ethidium-bromide fluorometric technique. RNA:DNA ratios of wild red drum were evaluated by comparing individual values to a linear regression model derived for starved laboratoryreared red drum. Wild red drum were in...

The study presents fine structure data on the ovipositor of four bitterling species (Rhodeus ocellatus, Rhodeus amarus, Paratanakia himantegus and Acheilognathus barbatulus). In A. barbatulus P. himantegus, has never been studied. Novel were collected using two complementary methods, light- transmission electron microscopy. new findings relate to covering lining epithelia, basal laminae, cell j...

Herbicide pollution is persistent, which not only has a negative impact on individual organisms, but also may alter population dynamics and stability of interspecific relationships. Cladocerans, an important part zooplankton, are often simultaneously exposed to environmental pollutants predation risk in the aquatic environment. To evaluate combined effects atrazine fish traits cladocerans, we D...

We found that vitamin C is an essential nutrient for an Amazonian ornamental fish, the oscar (Astronotus ocellatus). This was demonstrated by the absence of L-gulonolactone oxidase activity, the enzyme responsible for the biosynthesis of vitamin C, in liver or kidney of oscars and by a feeding trial in which oscars without vitamin C dietary supplementation developed clinical deficiency signs. F...