The food of Raja clavata Linnaeus 1758, Raja montagui Fowler 1910, Raja naevus Müller and Henle 1841 and Raja brachyura Lafont 1873 in British waters

Abstract

The occurrence of food items in the stomachs of 545 Raja clavata, 340 R. montagui, 174 R. naevus and 33 R.brachyura caught in British waters, mainly in the Irish Sea and the Bristol Channel, is described by size categories, except for the last species. In all four species the stomach contents consisted of a wide range of Crustacea, nereids and fish, in that order of importance. Mollusca formed a relatively small proportion of the stomach contents. In small rays, amphipods and Crangon vulgaris were the most frequently occurring food items, diversity of stomach contents increasing with size, with fish occurring most frequently in the largest rays, although being found more frequently and at a smaller size in R. naevus than in either R. clavata or R. montagui, in which latter species it was of least importance. In general the more active prey species occurred in the larger rays. After reviewing the work of other authors, it is concluded that all four species of rays are indiscriminate feeders whose selection of food items is limited by the availability of potential prey species, their speeds relative to that of their prey and the structure of their mouth parts.