Spatial structure variation of the demersal ichthyofauna captured with botton trawl in the Pinheiros Bay, PR

Abstract

Spatial changes in the demersal ichthyofauna structure in the Pinheiros Bay, PR, were monitored between May 2003 and April 2004. Three bottom trawls were monthly performed at four points along an axis between the access inlet and inner areas of the Bay. The number of captured species, Shannon’s diversity index and Margalef’s Richness Index were significantly different between inner and outer areas of the Bay. Average capture, expressed by individual total catch, did not differ significantly among the four areas, but spatial separation patterns were observed for some species. The analysis of the spatial structure of species sizes revealed differences in individual total length average values among the studied areas. Some species presented spatial differences in number of individuals caught among the four areas. Cathorops spixii showed preference for more internal areas and Isopisthus parvipinnis, Stellifer rastrifer and Stellifer brasiliensis, for the most external area of the Pinheiros Bay.