Abstract:
A central tenet of fisheries oceanography is that the growth rate of
the planktonic larvae determines cumulative predation mortality during the
first year of life and ultimately, year class strength. Recent studies by our
group indicate that significant interannual differences in the early growth of
Atlantic cod, pollock, yellowtail and witch flounders on Western Bank (Scotian
Shelf) are
... correlated with interannual differences in feeding success (number
of prey per gut at capture). Temperature, rather than feeding success,
explained interannual differences in the somatic growth of haddock larvae, a
species that hatches at very low temperature (1-3 degrees C)in late winter.
These results lead to testable predictions of the relative strength of the two
year classes studied. Most importantly, they indicate a direct link between
climate and zooplankton dynamics and recruitment to commercial stocks. The same
approach applied to the study of interannual differences in the early growth of
fish over several years (5-10) would yield: 1)a robust test of the
match/mismatch and growth-predation hypotheses 2)a potentially useful tool for
the prediction of year class strength. This work will add several years to the
data base already available for Western Bank (1991 & 1992), by acquiring
additional data on interannual differences in the growth of larval fish in
relation to feeding success and temperature. The data set contains weekly field
temperature (minilog) and zooplankton abundance (plankton nets, horizontal
tows), biological data (age, size, stomach contents) from June to September
1997-2000. The data was collected by the Magdalen Islands and the Southern Gulf
of St. Lawrence (47 28N, 61 40W). 
