ABUNDANCE AND CONDITION OF LARVAL COD (GADUS-MORHUA) AT A CONVERGENT FRONT ON WESTERN BANK, SCOTIAN SHELF

Citation
Se. Lochmann et al., ABUNDANCE AND CONDITION OF LARVAL COD (GADUS-MORHUA) AT A CONVERGENT FRONT ON WESTERN BANK, SCOTIAN SHELF, Canadian journal of fisheries and aquatic sciences, 54(7), 1997, pp. 1461-1479
Citations number
43
Categorie Soggetti
Marine & Freshwater Biology",Fisheries
ISSN journal
0706652X
Volume
54
Issue
7
Year of publication
1997
Pages
1461 - 1479
Database
ISI
SICI code
0706-652X(1997)54:7<1461:AACOLC>2.0.ZU;2-7
Abstract
In November and December 1992, Atlantic cod (Gadus morhua) larvae were most abundant at a convergent front located at the periphery of a wel l-mixed gyrelike water mass rotating near the crest of Western Bank (o uter Scotian Shelf). Zooplankton wet biomass and plankton abundance (2 72 and 529 mu m size-classes) were also higher in the frontal region r elative to the adjacent water masses. We used the frontal feature to t est the hypothesis that larvae in frontal regions are in better condit ion than larvae elsewhere. No significant differences in triacylglycer ol content (an index of nutritional condition), Fulton's K condition i ndex, nor in the daylight feeding ratio were found between larvae in t he frontal region and those in the adjacent waters. The convergent fro nt acted as a larval collector, but exchange with other water masses e liminated measurable differences in larval condition. Our observations indicate that physically driven retention, not differential mortality (approximated by condition), was responsible for high abundances of c od larvae at this front.