Contrasting diet of two temperate reef fish species (Notolabrus tetricus and meuschenia hippocrepis) as determined from commercial rock lobster bycatch samples

The commercial rock Lobster Fishery is South australia’s most valuable wild fishery. its bycatch is primarily composed of finfish that includes wrasses, leatherjackets, and bearded rock cods. This study used bycatch samples to broaden the biological understanding of two such species, namely the bluethroat wrasse Notolabrus tetricus and the horseshoe leatherjacket Meuschenia hippocrepis. Specifically, we examined the diets of each species through stomach content analyses, which were then compared to gape morphology. PErManoVa analyses indicated a highly significant difference in diet between bycatch species. For M. hippocrepis, sponges, and red and brown algae were important dietary components, while molluscan prey species were more prevalent in N. tetricus. Morphometric analyses indicated that gape morphology was adapted to dietary items consumed. Mouth parts of M. hippocrepis were beak-like and highly suited for algal grazing. in contrast, mouth parts of N. tetricus consisted of a masticating plate combined with sharp, conical teeth that allowed for consumption of hard-shelled molluscan prey species.