Feeding habits of the ocean whitefish, Caulolatilus princeps Jenyns 1842 (Pisces: Branchiostegidae), in La Paz Bay, B.C.S., Mexico

Abstract

A total of 198 digestive tracts of ocean whitefish (Caulolatilus princeps, Jenyns, 1842) were examined from monthly catches, from February 1986 to January 1987. Using four indices (numeric, volumetric, frequency of occurrence and relative importance), the food components of the trophic spectrum were determined and categorized. This was made up of five major taxa: annelids, molluscs, crustaceans, echinoderms and fishes. The spectrum is dominated, most of the year, by the ostracod Conchoecia pacifìca, along with other secondary food items like hyperiid amphipods (Vibilia sp.), euphausiids (Nycthiphanes simplex), galatheids (Pleuroncodes planipes), pteropod molluscs (Hyaloselix striata, Clio piramidata), cephalopods (Loligo opalescens) and fishes, and with a range of incidental food items, like gammarids (Ampheliscidae), crab larvae (Callinectes sp.), isopods, penaeids, thalassinoideans, small gastropods, polychaetes and echinoderms. There are no significant differences in the spectra from males and females (Wilcoxon’s test, P = 0.05). The number of food components in the diet seems to increase with length. The most intensive feeding takes place between the end of the reproductive period and its start. In conclusion, the ocean whitefish is a passive predatory teleost, that feeds mainly during daylight hours upon organisms associated with the sea floor.