Welsh Journals

ON THE FOOD OF THREE SPECIES OF LITTORAL FISH FROM THE GOWER PENINSULA BRIAN W. COAD INTRODUCTION The ecology of rocky shore fishes is a somewhat neglected field of study in comparison with the work which has been carried out on other littoral organisms. Their size and abundance alone would seem to indicate that they play a major role in the ecology of the littoral environment. One major facet of their interaction with other littoral organisms is their status as predators. However, analyses of diet have been few and have not to my knowledge been applied to common South Wales species. Collections of rocky shore fishes made around the Gower Peninsula during September 1969 were found to consist mainly of three species namely the Rock Goby (Gobius paganellus (L.)); the Five-bearded Rockling (Ciliata mustela (L.)); and the Worm Pipefish (Nerophis lumbriciformis (Jenyns)). The diet of these three species was examined and compared with published accounts. It is hoped that the present study will stimulate further research into the ecology of rocky shore fishes. MATERIALS AND METHODS Samples were collected by hand from rock pools or from under rocks isolated at the time of low water. The numbers and location of collections are given in Table 1. Specimens were preserved in 70% alcohol until examination. Each specimen was measured to the nearest millimetre from snout to base of caudal fin (standard length), and the stomach with intestine removed. Each gut was split mid-dorsally under a binocular microscope and the contents removed and examined in 70% alcohol, after the degree of fulness of each stomach was estimated. The contents were identified as far as their state of digestion allowed using the keys in Barrett and Yonge (1958), Eales (1967), Mortensen (1927) and Reid (1944). TABLE 1. Numbers and location of specimens from the Gower Peninsula, September 1969. Mumbles Oxwich Port Eynon Pwll Du 21-22 Sept. Bay 24 Sept. Bay 23, 25, 25 Sept. 26 Sept. Gobius paganellus 24 83 3 Ciliata mustela 5 45 13 9 Nerophis 11 5 3 lumbriciformis