Fisheries Behavioral Ecology - Abstracts
Stoner, A.W. 2004. Effects of environmental variables on fish feeding
ecology: implications for the performance of baited
fishing gear and stock assessment. Journal of Fish Biology 65:1445-1471.
Abstract
The effectiveness of baited fishing gear ultimately depends upon behaviour of the target species –
activity rhythms, feeding motivation, and sensory and locomotory abilities. While any environmental
parameter that mediates feeding or locomotion can have an important influence on the
active space presented by the bait and fish catchability, few biologists have considered how such variation in behaviour might affect catch per unit effort (CPUE) and the resultant stock
abundance estimates or population parameters. This review reveals that environment-related
variation in feeding behaviour can act through four different mechanisms: metabolic processes,
sensory limitations, social interactions and direct impacts. Water temperature, light level, current
velocity and ambient prey density are likely to have largest effects on fish catchability, potentially
affecting variation in CPUE by a factor of ten. Feeding behaviour is also density-dependent, with
both positive and negative effects. Over time and geographic space a target species can occupy
wide ranges of environmental conditions, and in certain cases, spatial and temporal variation in
feeding biology could have a larger impact on CPUE than patterns of abundance. Temperature,
light and current can be measured with relative facility and corrections to stock assessment
models are feasible. Making corrections for biological variables such as prey density and bait competitors will be more difficult because the measurements are often not practical and relationships
to feeding catchability are more complex and poorly understood. There is a critical need for
greater understanding of how environmental variables affect feeding-related performance of
baited fishing gear. A combination of field observations and laboratory experiments will be
necessary to parameterize stock assessment models that are improved to accommodate variation
in fish behaviour. Otherwise, survey data could reveal more about variation in behaviour than
abundance trends.
Last updated
27 April, 2007
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