Prediction of cannibalism in juvenile black rockfish, Sebastes schlegelii (Hilgendorf, 1880), based on morphometric characteristics and paired trials

To predict the occurrence of cannibalism in the culture of larval black rockfish, Sebastes schlegelii, we developed a regression model based on morphometric measurements. First, 156 black rockfish were measured to obtain a theoretical model, that is L-T (prey) = 0.624 L-T cannibal (+) 0.835. Then, 202 trials of paired fish, together with 31 pairs of cannibalistic fish, were used to revise this model, and the practical model was constructed: L-T (prey) = 0.522 L-T cannibal + 4.908 (R-2 = 0.99). According to this equation, the threshold of size ratio was deduced, that is 1.30-1.69, which could be used to grade black rockfish by size and remove potential cannibals.