Características de algunas rayas de la región sudpatagónica | Biological characteristics of some rays from South Patagonian region

Data considered in this paper were obtained during a research cruise carried out on board of RV Dr. E.L. Holmberg from INIDEP (Instituto Nacional de Investigacion y Desarrollo Pesquero) during March-April 2000 in the area between 48°S and 55°S (S Patagonian) region, SW Atlantic. From 61 bottom trawls a total of 355 specimen belonging to 11 skate species were collected. This represents, in number, 1.8 of the total species biomass. All skate species were identified and some biological characteristics for each species analyzed. Abundance was estimated in tons and the distribution area of each species was determined. Total weight and morphometric data by sex were measured total length, disc width and clasper length. Stomach content and macroscopical reproductive conditions were checked in every individual gonads, epididymis, alar thorns, yolk oocytes, oviductal gland and eggs. The most abundant species were: Dipturus chilensis, Bathyraja macloviana, Psammobatis normani, Psammobatis rudis, and Bathyraja magellanica distributed in the whole study area. In lesser abundance Bathyraja brachyurops and Bathyraja albomaculata were present south of 51°S. The other skate species were occasional, with percentages of appearance lower than 1 Amblyraja doellojuradoi, Bathyraja griseocauda, Bathyraja multispinis and Sympterygia bonapartii. Food items in the stomach were identified and cluster analysis was used to characterize feeding preferences. Species were grouped according to feeding habits such as anelidophagous (P.normani, B.macloviana and B.albomaculata), mainly piscivorous (D.chilensis, B.griseocauda and B.brachiurops and to carcinophagous habits P.rudis, B.magellanica, A.doellojuradoi, B.multispinis and S.bonapartii.

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Rajidae, rayas