Parasites of Cynoscion guatucupa along South American Atlantic coasts: evidence for stock discrimination.

TIMI, J.T.; LUQUE, J.L.; SARDELLA, N.H.

JOURNAL OF FISH BIOLOGY

Blackwell Publishing

Año: 2005 vol. 67 p. 1603 - 1618

0022-1112

Two stocks of striped weakfish, Cynoscion guatucupa (Cuvier, 1830), in the Southwest Atlantic, were identified using parasites as biological tags. A total of 297 fish caught at Brazil, Uruguay and Argentina, contained 29 species of metazoan parasites. Univariate analysis on parasite populations, as well as multivariate discriminant analysis, calculated for juvenile and adult fish separately, allowed the identification of the two stocks, one from Argentina and Uruguay and other from Brazil. Southern samples were characterised by higher prevalences and abundance of larval endohelminths, whereas in the northern stock, gastrointestinal and ectoparasitic species were common. Discriminant analyses on parasite infracommunities of Brazilian fish showed notable differences between juvenile and adult hosts; no such trend was observed in fish from Argentina and Uruguay, despite differences between juvenile and adult at population level. Differential oceanographic conditions and their influence on the distribution of parasites as well as of other hosts involved in their life-cycles could be key factors for the differences observed among stocks of C. guatucupa.