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Marine Ecology Progress Series

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MEPS 118:167-177 (1995)  -  doi:10.3354/meps118167

Prey preferences of blue crabs Callinectes sapidus feeding on three bivalve species

Ebersole, E. L., Kennedy, V. S.

Individual blue crabs Callinectes sapidus were allowed to forage on 3 bivalve species (soft clam Mya arenaria; Atlantic rangia clam Rangia cuneata; hooked mussel Ischadium recurvum), with 2 of the 3 species made available together at one time in 220 l aquaria. In 3 separate sets of experiments, we examined the blue crab's consumption and preferences between 2 bivalve species of different profitabilities [(net energy intake)/(handling time); J s-1]: M. arenaria and R. cuneata, M. arenaria and I. recurvum, and R. cuneata and I. recurvum. These experiments also examined the effects of 3 additional factors on prey consumption and prey preference: prey location (near to or distant from point of introduction of crab), prey refuge availability (shallow or deep sand for the clams; detached or clustered for the hooked mussel), and prey density (high or low numbers). Profitability curves correctly predicted that the blue crab preferred the highly profitable soft clam over the less energetically profitable Atlantic rangia clam. When the difference between prey profitabilities was not as great (i.e. between the soft clam and the hooked mussel, and between the Atlantic rangia clam and the hooked mussel) profitability alone was not a clear predictor of blue crab preference. Prey refuge availability significantly affected prey preference; deep sand provided (1) a greater refuge for the soft clam than for the Atlantic rangia clam and (2) a greater refuge for the soft clam than clustering provided for the hooked mussel. Prey location and refuge availability interacted to affect prey preference, in that prey location significantly affected prey consumption in shallow sand (more near prey than distant prey were eaten), but not in deep sand. Prey density generally affected total prey consumption, but not prey preference.

Foraging . Prey preferences . Blue crabs . Bivalves . Callinectes . Mya . Rangia . Ischadium

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