Long term fish assemblages as units of management in a temperate estuary (Rio de La Plata - SW Atlantic Ocean)

  • María Inés Lorenzo Dirección Nacional de Recursos Acuáticos; Departamento de Biología Poblacional
  • Juan M. Díaz de Astarloa Universidad Nacional de Mar del Plata; Facultad de Ciencias Exactas y Naturales; Departamento de Ciencias Marinas
  • Walter Norbis Dirección Nacional de Recursos Acuáticos; Departamento de Biología Poblacional
  • María B Cousseau Universidad Nacional de Mar del Plata; Facultad de Ciencias Exactas y Naturales; Departamento de Ciencias Marinas
Keywords: Persistence, Fisheries, Demersal fish assemblages, Uruguay, Multivariate analysis

Abstract

Demersal fish assemblages from trawl surveys in the Rio de la Plata estuary and its inner continental shelf were analyzed from 1975 to 1995. The first two factors of Principal Component Analysis explained 48% of the variance in species distribution, and they are consistent with the results of a cluster analysis. The analysis indicated the existence of three spatially and temporally distinct fish assemblages: internal and external estuarine and inner continental shelf (Uruguayan coastal assemblages). These assemblages were persistent considering the environmental characteristics and their species composition. Despite the changes registered in the species density during the period surveyed, the fish assemblages tend to persist over time. It was demonstrated that the assemblages can be considered as open systems and that there exists a reciprocal flow of organisms between adjacent associations. However, each assemblage showed high spatial and temporal persistence in accordance with the environmental characteristics of the system analyzed. Therefore, and according to the multispecies fisheries operating in the system, each assemblage defined could be considered a unit of management.

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Published
2011-03-01
How to Cite
Lorenzo, M., Astarloa, J., Norbis, W., & Cousseau, M. (2011). Long term fish assemblages as units of management in a temperate estuary (Rio de La Plata - SW Atlantic Ocean). Brazilian Journal of Oceanography, 59(1), 43-59. https://doi.org/10.1590/S1679-87592011000100004
Section
naodefinida