TY - JOUR
T1 - The impact of environmental gradients on the early life inshore migration of the short-finned squid Illex illecebrosus
AU - Perez, J. A.A.
AU - O'Dor, R. K.
PY - 1998
Y1 - 1998
N2 - Recruitment of the short-finned squid Illex illecebrosus to adult feeding grounds on the shelf off eastern Canada constitutes an important transition from warm food-limited Gulf Stream waters to cold and productive slope and coastal waters. The impact of such gradients was addressed by analyzing the gladius growth of 1585 juvenile squid collected across the Gulf Stream and shelf/slope fronts during research cruises conducted between 1979 and 1989. Temperature- and size-specific growth potential, as estimated by a bioenergetics model, were compared to measured gladius growth rates and revealed that young Tilex were energetically expensive and food-limited in Gulf Stream waters (their hatching environment). Growth condition improved inshore, where metabolic costs decreased and more food became available. Similar patterns were observed when size-specific growth rates of squid caught across the temperature and food gradients were directly compared. In addition, transport processes in the Gulf Stream and slope water played an important role in providing access and retention in favourable areas. Juvenile onshore migration seems to be driven by elevated food requirements and involves physiological adaptations to compensate for decreasing temperatures. The individual 'success' in terms of growth and survival may depend, however, on access to concentrated patches of food which, in turn, will be determined by timing and the transport dynamics of the main water masses.
AB - Recruitment of the short-finned squid Illex illecebrosus to adult feeding grounds on the shelf off eastern Canada constitutes an important transition from warm food-limited Gulf Stream waters to cold and productive slope and coastal waters. The impact of such gradients was addressed by analyzing the gladius growth of 1585 juvenile squid collected across the Gulf Stream and shelf/slope fronts during research cruises conducted between 1979 and 1989. Temperature- and size-specific growth potential, as estimated by a bioenergetics model, were compared to measured gladius growth rates and revealed that young Tilex were energetically expensive and food-limited in Gulf Stream waters (their hatching environment). Growth condition improved inshore, where metabolic costs decreased and more food became available. Similar patterns were observed when size-specific growth rates of squid caught across the temperature and food gradients were directly compared. In addition, transport processes in the Gulf Stream and slope water played an important role in providing access and retention in favourable areas. Juvenile onshore migration seems to be driven by elevated food requirements and involves physiological adaptations to compensate for decreasing temperatures. The individual 'success' in terms of growth and survival may depend, however, on access to concentrated patches of food which, in turn, will be determined by timing and the transport dynamics of the main water masses.
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U2 - 10.2989/025776198784126359
DO - 10.2989/025776198784126359
M3 - Article
AN - SCOPUS:0032467968
SN - 0257-7615
SP - 293
EP - 303
JO - South African Journal of Marine Science
JF - South African Journal of Marine Science
IS - 20
ER -