Fisheries Behavioral Ecology - Abstracts
Stoner, A.W. 2003. Hunger and light level alter response to bait by Pacific halibut: laboratory analysis of detection, location and attack. Journal of Fish Biology 62:1176-1193.
Abstract
Laboratory experiments with Pacific halibut Hippoglossus stenolepis revealed that hunger level
had a significant effect on the first detection of bait, the number of baits located and attacked,
the time required to locate and attack baits and handling times. In all cases, feeding motivation
and efficiency increased with hunger. Light level influenced general locomotory
activity and location and attacks on baits, but not detection or handling times. The effect of
light was interactive with fish hunger level. Hungry fish could locate and consume baits in all
light levels, ranging from daylight conditions to near darkness (10-8 µmoles photons m-2 s-1),
but location, attack and handling times were all significantly elevated in low light conditions,
and attack rates were significantly reduced. In the dark, only 50% of the baits were located
and only 17% were attacked. Performance metrics were relatively similar among three higher light treatments (10-5, 10-3 and 10-1 µmoles photons m-2 s-1) where bait location and attack
were more efficient. Active space and effective area associated with baited fishing gear will
vary because hunger and light levels affect variation in bait detection, locomotion and
feeding behaviour. Consequently, fishing activity and stock assessments that depend upon
bait may be compromised by spatial and temporal variation in prey abundance, time of
day, season, depth and other environmental variables that influence feeding motivation and
efficiency.
Last updated
27 April, 2007
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