Feeding Ecology of Juvenile Kelp Bass (Paralabrax clathratus) and Barred Sand Bass (P. nebulifer) in Punta Banda Estuary, Baja California, Mexico

Abstract

Kelp bass {Paralabrax clathratus) and barred sand bass (P. nebulifer) diets are analyzed between seasons at Punta Banda estuary, Baja California, Mexico (1992-1993). Beam-trawl and otter-trawl tows (5m depth) collected kelp bass of 40-1 10mm SL range, and P. nebulifer of 30-230mm; overall, gammarid amphipods dominated their diets in index of relative importance, (IRI; 79.4% and 50.9%, respectively). In kelp bass, gammarids had highest IRI in summer (89.3%) and winter (74.9%), with a fish occurrence of 1.6-12.2%, and eelgrass remains of 0.8-7.1%. In P. nebulifer, summer to winter IRI of gammarids were 40.0- 88.4%, and occurrence (43.8-65.6%), numeric (65.2-95.0%), and weight (2.5- 49.8%). Kelp bass and barred sand bass numeric diet breadth in summer were 0.038 and 0.12, respectively, and 0.031 and 0.013 in winter; for kelp bass, weight diet breadth were 0.031-0.27, and for barred sand bass 0.18-0.26. Dietary overlap between basses was low (