Grenadiers (Pisces, Macrouridae) of the Southwest Atlantic Ocean: biologic and fishery aspects

Abstract

Several grenadier species distribute in the Southwest Atlantic Ocean. Macrourus carinatus and Caelorinchus fasciatus are more frequently identified in commercial catches and during research cruises. Those benthopelagic fishes, related to subantarctic waters, inhabit at depths beyond 200 m and in high seas, between 36° S-59° S. During the surveys carried out on board of Argentinean research vessels, M. carinatus was present in 4% of the trawls performed. The highest densities (>17 t nm^-2), obtained between 360-380 m depth, at 39° S, decreased significantly southwards. C. fasciatus was caught in 6% of the total trawls and the highest densities (15-35 t nm^-2) were found at depths beyond 200 m, south of 52° S. Due to the difficulty encountered to identify them, in fishing statistics they are grouped as “Grenadiers”. Nevertheless, in many cases, the correct identification by scientific observers on board of commercial vessels provides useful information to support the data gathered. Grenadiers are caught as by-catch in important fisheries that have the main fishing grounds south of 52° S. Historically, different countries participated in the fishery that shows two evolution periods. In the first, exploitation carried out mainly by vessels from the former USSR reached a maximum of 31,000 t in 1984. In the second, the Argentine fleet caught up to 10,000 t in 2000. At present, freezer and factory trawlers obtain 88% of the catches and longliners 10% of the total.