Benthic and Semidemersal Fish associations in the Argentine Sea

Abstract

Abstract During a fishery research cruise aboard the R/V “Orient Maru I”;, the authors identified 65 species of benthic and semidemersal fishes captured in 96 stations between the southern part of Buenos Aires province and Magellan Strait. Data were analyzed with a combination of similarity coefficients and cluster analysis as used in numerical taxonomy. The matrix obtained by using the Jaccard coefficient was used as input in the calculation of phenograms by unweighted pair groups using arithmetic averages (UPGMA). Phenograms were calculated for both the species (R mode) and the stations (Q mode). Four associations were found, three of them consistent with known zoogeographical and ecological interpretations of the considered area, and another, unexpected one, which proved the heuristic value of the employed methodology. Each association was found within a given area with particular temperature (specially) and depth ranges. The permanence of the associations in space and time was checked against a similar analysis made with the data from the R/V “Kaiyo Maru”; cruise in 1969–70. Together with the large coincidence of most groups resolved independently from those cruises, the patterns of distribution obtained provide a new scheme to consider the results of other studies.