Food habits of the Longnose Skate, Raja rhina (Jordan and Gilbert, 1880), in central California waters

Abstract

Feeding studies can provide researchers with important insights for understanding potential fishery impacts on marine systems. Knowing what a species eats can provide information about possible distribution and its position in food webs. Raja rhina is one of the most common elasmobranch species landed in central and northern California demersal fisheries, yet life history information is extremely limited for this species and aspects of its diet are unknown. Specimens of R. rhina were collected between September 2002 and August 2003 from fishery-independent trawl surveys. Values of Percent Index of Relative Importance (IRI) indicated that the most important prey items in 618 stomachs of R. rhina were unidentified teleosts (31.6% IRI), unidentified shrimps (19.6%IRI), unidentified euphausiids (10.9% IRI), Crangonidae (7.4% IRI), and Neocrangon resima (6.0% IRI). Smaller skates generally ate crustaceans and larger skates ate fishes and cephalopods. With increasing depths, diet included deeper-living fish species and more cephalopods and euphausiids. The findings of this study were consistent with previous researchers that reported similar diet shifts in skate species with size and depth