Volume 7, Issue 2, June 2003
Volume 7, Issue 2 – June 2003
Alexei M. Orlov: Diets, feeding habits, and trophic relations of six deep-benthic skates (Rajidae) in the western Bering Sea, pp. 45-60
The diets of six species of skates inhabiting the western Bering Sea were examined: Aleutian skate, Bathyraja aleutica, Alaska skate B. parmifera, Matsubara skate B. matsubarai, white-blotched skate B. maculata, white-brow skate B. minispinosa, and Bering skate Rhinoraja iterrupta. The diets of predatory skates (Alaska, Aleutia, white-blotched, Matsubaa, and white-brow skates) consisted of large crustaceans, cephalopods and fishes. Benthophagic Bering skates consumed mainly Tanner crabs, gammarid amphipods, and shrimps. The consumption of worms and crustaceans by predatory skates declined with increasing skate size, whereas consumption of fishes increased. The consumption of worms and small crustaceans by benthophagic Bering skates declined with increasing skate size while consumption of crabs and squid increased. Diets of male and female skates differed, probably due mostly to the effect of size. Among the species examined, three skate pairs had a medium level of dietary similarity: Aleutian and Alaska skates, Alaska and white-brow skates, and white-brow and Bering skates.
Aleutian skate (Bathyraja aleutica) caught in the western Bering Sea. Photo by Alexei M. Orlov
Bertran M. Feitoza, Luiz A. Rocha, Osmar J. Luiz-Junior, Sergio R. Floeter and João L. Gasparini: Reef fishes of St. Paul’s Rocks: new records and notes on biology and zoogeography, pp. 61-82
St. Paul’s Rocks is a very small group of rocky islands located on the mid-Atlantic ridge just north of the Equator, about 1000 km from the Brazilian coast. The aim of this work is to add new information on the abudance, biology, zoogeography and taxonomy of its reef fishes. In the course of four expeditions the fish fauna was surveyed in tide pools and over reefs at depths down to 62 m using a number of different methodologies. Seventy-five fish species (25 new records) were recorded, of which 58 are reef inhabitants and 17 are pelagic. The most speciose families were Muraenidae (seven species), Carangidae (five), Pomacentridae (five), Labridae (four), Serranidae (three), and Scaridae (three). Stegaster sanctipauli (Pomacentrdae), Chromis multilineata (Pomacentridae), Melichthys niger (Balistidae) and Caranx lugubris (Caranagidae) were the most visually abundant fishes. Depsite being recorded in prior surveys, Carcharhinus galapagensis and Anthias salmopunctatus were not observed by our team. It was observed that 60.3% of the reef fish species are carnivores, 15.5% planktivores, 8.6% omnivores, 8.6% territorial herbivores, and 6.9% non-territorial herbivores. Of the 58 reef fishes recorded, four are endemic to St. Paul’s Rocks and about 80% also occur off the coast of Brazil. It is thought therefore that St. Paul’s Rocks should be regarded as an impoverished outost of the Brazilian province.
Normal colour and morphological pattern of Holacanthus ciliaris from Rio Grande do Norte coast, north-eastern Brazil. Photo by B. M. Feitoza
Alexei M. Tokranov and Alexei M. Orlov: Some biological characteristics of the rare, little-studies gloved snailfish Palmoliparis beckeri Balushkin, 1996 (Liparidae, Teleostei), in the Pacific off the northern Kuril Islands, pp. 83-88
The sptial and bathymetric distribution, size, weight composition, age, fecundity, and diet composition of the rare, little-studied gloved snailfish Palmoliparis beckeri Balushkin, 1996 (Liparidae) are considered, based on data obtained during expeditions between 1995 and 2001 in the Pacific, off the northern Kuril Islands, Russia.
The gloved snailfish Palmoliparis beckeri caught off the northern Kuril Islands. Photo by A. M. Orlov