Short-term dynamics in fish assemblage structure on a sheltered sandy beach in Guanabara Bay, Southeastern Brazil

Authors

  • Ruan Managna Vasconcellos,

    1.  Programa de Pós Graduação em Biologia Animal – PPGBA, Universidade Federal Rural do Rio de Janeiro, Laboratório de Ecologia de Peixes,  Seropédica, Rio de Janeiro, Brazil
    Search for more papers by this author
  • Francisco Gerson Araújo,

    1.  Programa de Pós Graduação em Biologia Animal – PPGBA, Universidade Federal Rural do Rio de Janeiro, Laboratório de Ecologia de Peixes,  Seropédica, Rio de Janeiro, Brazil
    Search for more papers by this author
  • Joaquim Neto De Sousa Santos,

    1.  Programa de Pós Graduação em Biologia Animal – PPGBA, Universidade Federal Rural do Rio de Janeiro, Laboratório de Ecologia de Peixes,  Seropédica, Rio de Janeiro, Brazil
    Search for more papers by this author
  • Márcio De Araújo Silva

    1.  Agência Nacional de Águas – ANA, Setor Policial, Brasilia, Distrito Federal, Brazil
    Search for more papers by this author

Francisco Gerson Araújo, Programa de Pós Graduação em Biologia Animal – PPGBA, Universidade Federal Rural do Rio de Janeiro, Laboratório de Ecologia de Peixes, IB/DBA, BR 465, Km 7, 23.851-970 Seropédica, Rio de Janeiro, Brazil.E-mail: gerson@ufrrj.br

Abstract

Short-term dynamics in juvenile fish assemblage structure were studied to test whether the most abundant species show temporal segregation, in order to assess whether selected environmental variables could predict species groupings, and to examine the stability of sunset–day–sunrise–night differences. Samplings were collected at 3-h intervals over 48 h on a seasonal basis between spring 2005 and winter 2006. Fish species richness and abundance were higher in spring, and the lowest values occurred in winter. Harengula clupeola occurred mainly in spring, whereas Atherinella brasiliensis peaked in summer and autumn. On the other hand, Trachinotus carolinus, Umbrina coroides and Mugil liza were abundant in winter. Although temperature, salinity and dissolved oxygen were not found to have a strong effect on the abundance patterns of most species, they did appear to have a significant influence on assemblage groupings, according to canonical correspondence analysis and Spearman rank correlation. There is no consistency of diel usage patterns by a given species across seasons. The relative abundance differed between the time of day, which differed among the seasons; this further complicates an understanding of the dynamics of an assemblage. Studies of diel changes that pooled the sampling period as day or night can miss important changes that occur in a short time scale, such as a 3-h period.

Ancillary