Morphometric model and laboratory analysis of intracohort cannibalism in giant grouper Epinephelus lanceolatus fry

Abstract

During larviculture of giant grouper, Epinephelus lanceolatus , intracohort cannibalism usually results in mass mortality. Thus, in the present study, we attempted to develop a cannibalprey length relationship from morphometric measurements for giant grouper fry and to verify it with pairwise predation experiments. Based on measurements of morphometric characteristics (i.e. mouth width, body depth, and total length), a model of prey length (mm) to cannibal length was constructed: TL prey = 0.83 TL cannibal -2.48. According to the equation, approximately 30% is a threshold in total length differences to use for grading giant grouper fry. The threshold was supported by our pairwise experiments using 136 pairs; we found that 33 out of 36 cannibalism incidents occurred only when the prey was of equal or smaller size than that predicted by the equation. In aquaculture practice of this species, we thus suggest that when the length of larger fry exceeded that of smaller fry by more than 30%, the potential cannibals should be removed.

How many meals a day to minimize cannibalism when rearing larvae of the Amazonian catfishPseudoplatystoma punctifer? The cannibal’s point of view

“…These scores compare to those of highly cannibalistic species such as barramundi Lates calcarifer (Parazo et al 1991), northern pike Esox lucius (Bry et al 1992;Ziliukiene and Ziliukas 2006), tunas (Sawada et al 2005) and groupers Epinephelus spp. (Hseu et al 2003(Hseu et al , 2004(Hseu et al , 2007. Cannibals of P. punctifer in the present study never consumed prey as large as allowed by their mouth dimensions, possibly because stomach capacity was limiting.…”

“…Living Resour. 24, 379-390 (2011) Sogard and Olla 1994;Hseu et al 2003Hseu et al , 2004. In general, during the larval and juvenile stages there is a positive allometric growth of body depth (or width) and a negative allometric growth of mouth dimensions, which altogether force cannibals to select prey that are increasingly smaller relative to their own size (Hecht and Pienaar 1993;Baras and Jobling 2002).…”

Do cannibalistic fish forage optimally? An experimental study of prey size preference, bioenergetics of cannibalism and their ontogenetic variations in the African catfishHeterobranchus longifilis

“…In larger fish, the victims are swallowed whole and cannibalism is governed by specific morphological restrictions (reviews in Hecht and Pienaar 1993;Folkvord 1997;Baras and Jobling 2002;Baras 2013). Information on the allometric variations of mouth and body dimensions has been used often to predict the occurrence or risk of cannibalism (Hecht and Appelbaum 1988;Brabrand 1995;Hseu et al 2003Hseu et al , 2004Hseu et al , 2007Hseu and Huang 2014). In some cases, cannibalistic fishes have been found to ingest siblings near the maximal possible size (e.g., largemouth bass Micropterus salmoides, Johnson and Post 1996; redtail catfish Hemibagrus nemurus, Baras et al 2013), whereas this "maximalistic" behaviour is infrequent with other types of piscivory (Juanes 1994(Juanes , 2003Juanes et al 2002).…”

Molecular Electrophoretic Technique for Authentication of the Fish Genetic Diversity

“…It is one of the two largest species of groupers in the world. Due to its fast growth and high price, giant grouper currently is regarded as a favorite species for marine culture in Taiwan (Hseu, et al, 2004).…”