Fisheries Behavioral Ecology - Abstracts
Hurst, T.P. 2004. Temperature and state-dependence of feeding and
gastric evacuation in juvenile Pacific halibut. Journal of Fish Biology 65:157–169.
Abstract
Relationships between nutritional state, behavioural response to prey and gastric evacuation
rates were examined in juvenile Pacific halibut Hippoglossus stenolepis feeding on squid. Pacific
halibut reared at 2, 6 and 10° C were fasted for 1 or 7 days to generate variation in energetic
state. The 7 day fast resulted in measurable declines in condition indices at 10 and 6° C but not
at 2° C. At 10° C, all Pacific halibut consumed the first meal offered, but fish previously fasted
for 7 days took significantly longer to locate and consume the meal than fish fasted for only 1
day. At 2° C, Pacific halibut fasted for 7 days did not generally consume the first meal offered,
but resumed feeding 2.1 days sooner, on average, than fish fasted for only 1 day. The gastric
evacuation rate of the squid meal was best described by a power model with near-exponential
curvature (a = 1.011). The evacuation rate was strongly temperature-dependent (Q10 = 3.65) but
displayed the same degree of variability at each temperature. The evacuation rate in Pacific halibut was not affected by feeding history, body size or energetic state. Furthermore, individual
variation in gastric evacuation rate was not correlated with feeding responsiveness at any
temperature. These results indicate a general plasticity in the behavioural but not physiological
aspects of energy acquisition.
Last updated
26 April, 2007
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