Feeding ecology of the Mediterranean spiderfish, Bathypterois mediterraneus (Pisces: Chlorophthalmidae), on the western Mediterranean slope

The feeding habits of the Mediterranean spiderfish, Bathypterois mediterraneus, the most abundant fish below 1000 m on the deep slope of the Catalan Sea (western Mediterranean), were studied. Samples were obtained at depths between 1000 and 2250 m. Diet was analyzed for two different size classes (immature and mature specimens) and three different bathymetric strata. The most important food items found were benthopelagic planktonic calanoid copepods. In juveniles from 1800 to 2250 m, benthic tanaidaceans were secondary, whereas in the adults, mysids were secondary. At other depths, there were no secondary prey: calanoid copepods were consumed almost exclusively; other items were very scarce. Adults ingest larger amounts and sizes of prey than juveniles. The scarcity of resources below 1200-1400 m diversified the diet, although it still primarily consisted of elements from the benthopelagic plankton.