Fisheries Behavioral Ecology - Abstracts
Davis, M.W. and S.J. Parker. 2004. Fish size and exposure to air: potential effects on behavioral
impairment and mortality rates in discarded sablefish. North American Journal of Fisheries Management 24:518–524.
Abstract
Fisheries models often assume that discarded undersized fish and target species will survive and contribute to future recruitment and yield. If smaller fish are more susceptible to
capture stressors than larger fish, then the assumption that smaller discards would contribute to
recruitment may not be true. We tested the hypothesis that small sablefish Anoplopoma fimbria show more behavioral impairment and mortality than large fish when exposed to air (10–60 min)
at various temperatures (10–18°C). Sablefish captured by trawl, longline, or trap are commonly
exposed to these conditions during warmer seasons when brought up on deck and sorted. Two
size-classes of fish (small: 32–49 cm total length [TL]; large: 50–67 cm TL) were used in the
experiments. Behavior was measured as upright orientation and startle responses to visual and
mechanical stimuli 1, 2, 3, and 24 h after air exposure; mortality was measured through 7 d after
air exposure. Small fish mortality increased as air time increased and was at higher levels than in
large fish. Only 10 min of air exposure caused behavioral impairment in small and large fish which
could lead to increased predation on discarded fish. At 24 h after air exposure, normal behavior
had not generally resumed and small fish had more behavioral impairment than large fish.
Last updated
26 April, 2007
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