Partitioning of fish and diet selection as methods for the reduction of cannibalism in Paralichthys dentatus larviculture

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Partitioning of larvae and diet selection were examined as strategies to reduce cannibalism in summer flounder Paralichthys dentatus. Methods of partitioning included physical grading by size, baffle interference, and a control. The baffle consisted of a barrier with cells 14-mm square and walls 9-mm high. The barrier was positioned horizontally at a depth where it would divide the tank into two equal volumes of water. Factors which may characterize cannibalism were quantified, including: total length, developmental stage, pigmentation, wet weight, and biomass. Engineered to reduce cannibalism, the baffle instead contributed to a decrease in survival for at least one experiment (P < 0.05). Grading by size did not significantly increase survival over that of the untreated control (P > 0.05). Mean developmental stage of P. dentatus in the graded treatment was significantly less than fish in either the control or baffle treatments (P < 0.05). A factorial design of partition strategy and weaning diet did not demonstrate any difference in survival or measured character (P > 0.05). Finally, both inert feeds and live Artemia sp. nauplii were examined for their contribution to the occurrence of cannibalism. Predicted differences between live and artificial diets were not significant (P > 0.05). During experiments, cannibalism was principally observed in late larval and early juvenile stages and was not restricted to post-metamorphic juveniles feeding on premetamorphic larvae. Methods normally employed to reduce cannibalism (partitioning of larvae and diet selection) do not appear to be effective for P. dentatus.

Publication Title, e.g., Journal

Journal of the World Aquaculture Society