New records of the Pacific sleeper shark, Somniosus pacificus (Chondrichthyes: Squalidae), from the southwest Atlantic

• Published in: Ichthyological research Vol. 46; no. 3; pp. 303 - 308
• Main Authors: de Astarloa, J.M.D. (Universidad Nacional de Mar del Plata (Argentina)), Figueroa, D.E, Lucifora, L, Menni, R.C, Prenski, B.L, Chiaramonte, G
• Format: Journal Article
• Language: English
• Published: Tokyo Springer Nature B.V 25.08.1999
• Subjects: ATLANTICO SUDOCCIDENTAL; ATLANTIQUE SUD OUEST; BATHYAL ZONE; DISTRIBUCION GEOGRAFICA; DISTRIBUTION GEOGRAPHIQUE; GEOGRAPHICAL DISTRIBUTION; IDENTIFICACION; IDENTIFICATION; Marine; MILIEU BATHYAL; Somniosus microcephalus; Somniosus pacificus; Somniosus rostratus; SOUTHWEST ATLANTIC; SQUALIFORMES; ZONA BATIAL
• ISSN: 1341-8998; 1616-3915
• DOI: 10.1007/BF02678517

The genus Somniosus Lesueur, 1818, is represented worldwide by three species: the Greenland shark (S. microcephalus (Bloch and Schneider, 1801)), the Pacific sleeper shark (S. pacificus Bigelow and Schroeder, 1944) and the little sleeper shark (S. rostratus (Risso, 1826) (Compagno, 1984; Francis et al., 1988)). There are few records of Somniosus from the South Atlantic. A female about 440 cm TL was caught in a depth of 677 m off Cape Columbine, South Africa (Bass et al., 1976), and Gushchin et al. (1986) reported a male 416 cm TL from 42 degree 24'S, 58 degree 19'W, off Patagonia, Argentina, at 800 m depth. These specimens, at first tentatively identified as S. microcephalus, were subsequently referred to S. pacificus by Francis et al. (1988). A brief reference without data (Soto et al., 1995) refers to S. microcephalus off Rio Grande do Sul, Brazil, and an identified Somniosus was sighted by Diaz de Astarloa (unpubl.) near the South Georgia Islands. The last-mentioned specimen was collected incidentally during a commercial catch of Patagonian toothfish (Dissostichus eleginoides) and returned immediately to the sea, before any detailed information could be obtained. Recent exploratory cruises aboard the R/V Azuchi Maru to investigate potential fisheries resources off the South American continental shelf, such as the toothfish (Dissostichus eleginoides), facilitated the gathering of new information on the occurrence of sleeper sharks in the region. The present paper reports new records of Somniosus pacificus from the southwest Atlantic.