We evaluated the condition factor (K ), an index of weight per unit length, in a sample of 49 761 longline-caught specimens of Antarctic toothfish, Dissostichus mawsoni, from the Ross Sea. Our sample consisted of specimens from northern (60–708S) and southern (70–788S) regions. Fifty percent of the northern sample and 4.9% of the southern sample were large individuals with a low condition facto...

One of the mysteries of the animal kingdom is the long-distance migration (5000-6000 km) of the European eel Anguilla anguilla L. from the coasts of Europe to its spawning grounds in the Sargasso Sea. The only evidence for the location of the spawning site of the European eel in the Sargasso Sea is the discovery by Johannes Schmidt at the beginning of the previous century of the smallest eel la...

While the ecology and evolution of partial migratory systems (defined broadly to include skip spawning) have been well studied, we are only beginning to understand how partial migratory populations are responding to ongoing environmental change. Environmental change can lead to differences in the fitness of residents and migrants, which could eventually lead to changes in the frequency of the s...

The management of Atlantic herring in the Bay Fundy/Gulf Maine/Scotian Shelf region Northwest (NAFO areas 4WX5YZ) assumes separate stocks Canadian and US waters; however, landed weir fishery southwest New Brunswick (SWNB) are assumed to be origin for purposes. present study is a review tagging studies that have been conducted on since 1950s NAFO 4WX5YZ. data show consistent patterns over time. ...

The European eel Anguilla anguilla (L.) is a catadromous fish: individuals grow and feed in brackish and fresh waters as yellow eels until sexual maturation, when they metamorphose to the silver stage and leave continental waters to reach their spawning grounds in the Sargasso Sea. Sexual maturation of European eels, as well as sex differentiation, depend upon body size rather than age, with fa...

Synchronous variations in the abundance of geographically distinct marine fish populations are known to occur across spatial scales on the order of 1,000 km and greater. The prevailing assumption is that this large-scale coherent variability is a response to coupled atmosphere-ocean dynamics, commonly represented by climate indexes, such as the Atlantic Multidecadal Oscillation and North Atlant...

The cues triggering large-scale broadcast-spawning events in marine invertebrates are not fully understood. Using the sea urchin Lytechinus variegatus, we tested the effectiveness of a variety of potential spawning cues in eliciting a spawning response. In the laboratory, during two consecutive spawning seasons, about 400 isolated sea urchins were exposed to phytoplankton, sperm, or eggs, singl...

The aim of this study was to establish an experimental protocol for the artificial reproduction royal carp ‘Cyprinus carpio’ with hormonal induction spawning. For purpose, we conducted at aquaculture farm in Khemis Meliana (Ain Defla, Algeria). included six broodstock, 4 females and 2 males. Hormone injection performed dorsal muscle under fin. done successively by GnRH a dose 3 mg/kg males hCG ...

During the mid-1990s, anglers reported large numbers of walleye (Stizostedion vitreum) in spawning condition concentrated on shallow points adjacent to the Maumee River channel during spring. These fish had flowing eggs and semen and were suspected to be actively spawning in Maumee Bay. To investigate the potential of walleye spawning, we used a benthic pump to sample for eggs at five sites adj...