Argentina is one of the countries with the largest overall landings of skates and rays(24 000 t/year). As a consequence of high levels of exploitation and deficient managementtools, many of these species are threatened with extinction. In the bottom trawl fisheryof San Matías Gulf, northern Patagonia, skates and rays are caught as bycatch and all havehistorically been recorded in the fishery logbook under the category “rays”. Therefore,species composition and their characteristics were unknown. The aim of this study was tocharacterize the commercial exploitation of batoid species in this fishery. Our resultsindicate that commercial landings include nine species of skate, six of which are common.Among these, Atlantoraja platana, Sympterygia bonapartiiand Dipturus chilensis were considered the main species of thisfishery. Their combined relative abundance and weight made up about 90% of the batoidcatch throughout the year. Sexual segregation was detected in four species in whichindividuals of one sex dominated commercial landings. The commercial fraction was composedof individuals with a wide range of sizes. Immature individuals could represent 90% of theindividuals landed for some species. At present, lack of data prevents us from quantifyingthe impact that this fishery is having on these species, but our findings highlight theimportance of conducting research surveys to assess the abundance and geographic extent ofthese populations. The information presented here provided the basis for the proposal of anew logbook format incorporating species-level identification. The new logbook wasimplemented on 1 January 2010.

The reproductive biology of Psammobatis lentiginosa was studied in San Matías Gulf (Patagonia, south-west Atlantic). A total of 1033 skates was analysed, total length ranged from 17 to 52 cm for females and from 13 to 55 cm for males. Total length–total weights relationships differed between sexes, with TW = 0.005 × TL3.02 for females and TW = 0.005 × TL2.97 for males. The overall sex-ratio was 1:1. In females, the L50% was 41.06 cm, in males the L50% was 41.38 cm. The mean number of yolked oocytes per skate was 4.22 (±2.41). The mean number of yolked oocytes and the length of the female were linearly related. The diameter maximum of yolked oocytes was 24 mm. The species exhibited a continuous reproductive cycle throughout the year, with a peak of egg-case production during autumn that was synchronous with maximum values of the epididymis and uterus indices. This is the first record of a reproductive aggregation for P. lentiginosa in San Matías Gulf, North Patagonia. This finding together with its continuous presence around the year, suggest that this area is the main distribution area of P. lentiginosa in the south-west Atlantic.