Intracohort cannibalism in European catfish (Silurus glanis L.) larvae under controlled rearing conditions at different stocking densities

Vasilka Krasteva and Maria Yankova
Agricultural Academy, Institute of Fisheries and Aquaculture, 4003 Plovdiv, Bulgaria

Abstract

Krasteva, V. & Yankova, M. (2021). Intracohort cannibalism in European catfish (Silurus glanis L.) larvae under controlled rearing conditions at different stocking densities. Bulg. J. Agric. Sci., 27 (2), 379–384

Under controlled conditions intracohort cannibalism is one of the main factors that affect the growth performance and survival of fish, especially during the early life stages of carnivorous species. The present study investigated the influence of different stocking densities on the frequency of occurrence of intracohort cannibalism, as an opportunity to study and mitigate the negative effects of this common behavior. The research was carried out at the Institute of Fisheries and Aquaculture, Plovdiv in two consecutive phases (Phase I and Phase II) with an overall period of 32 days. During Phase I three variants of stocking densities were evaluated: variant A - 10 ind.l-1, variant B - 20 ind.l-1 and variant C - 40 ind.l-1, whereas in Phase II the stocking densities were reduced (A-5 ind.l-1, B-10 ind.l-1, C-15 ind.l-1, D-28 ind.l-1). During Phase I of the experiment, only cannibalism type I was observed with a significant effect of the stocking density on the index of cannibalism (%) (P<0.05). At the beginning of Phase II cannibalism type II was observed, as its frequency increased with the increasing of the stocking density (P<0.05).

Keywords: European catfish; larvae; indexes of cannibalism; stocking densities

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