Population dynamics of the seabob shrimp Xiphopenaeus kroyeri (Dendrobranchiata, Penaeidae) in south-eastern Brazil

  • GS Heckler
  • SM Simões
  • APF Santos
  • A Fransozo
  • RC Costa

Abstract

The population dynamics, including the sex ratio, reproductive period, individual growth and longevity, and population structure of the shrimp Xiphopenaeus kroyeri, are described. The shrimps were collected monthly from July 2005 to June 2007 at four sites in Ubatuba Bay, Brazil. The salinity, temperature, depth, organic matter content and sediment grain size were measured at each site. Specimens were quantified and sexed, their carapace length measured and their gonads were classified according to the stage of maturation. A von Bertalanffy model was used to estimate the individual growth, and longevity was calculated using its inverted formula. In total, 6 470 individuals were examined and the number of males and females differed significantly in favour of females. During some periods, the segregation could be related to the reproductive period. Reproductive females were captured throughout the sampled period, and there were biannual peaks that were followed by peaks of juveniles. Carapace growth was less for males than for females, which is likely related to oocyte production and the higher fecundity of the females. The higher probability of female capture can be related to their longer foraging to sustain the enhanced food requirement during the ovarian maturation period.

Keywords: closed season, growth, longevity, recruitment, reproductive period, sex ratio

African Journal of Marine Science 2013, 35(1): 17–24

Author Biographies

GS Heckler
Departamento de Ecologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, Travessa 14, nº 321, Cidade Universitária, São Paulo, SP, CEP: 05508-090, Brazil
SM Simões
LABCAM (Laboratório de Biologia de Camarões Marinhos e de Água Doce), Departamento de Ciências Biológicas, Faculdade de Ciências, Universidade Estadual Paulista, Avenida Luiz Edmundo Carrijo Coube, 14-01, Bauru, São Paulo, 17033-360, Brazil
APF Santos
LABCAM (Laboratório de Biologia de Camarões Marinhos e de Água Doce), Departamento de Ciências Biológicas, Faculdade de Ciências, Universidade Estadual Paulista, Avenida Luiz Edmundo Carrijo Coube, 14-01, Bauru, São Paulo, 17033-360, Brazil
A Fransozo
Departamento de Zoologia, Instituto de Biociências, Universidade Estadual Paulista, Distrito de Rubião Junior, s/n, Botucatu, São Paulo, 18618-000, Brazil
RC Costa
LABCAM (Laboratório de Biologia de Camarões Marinhos e de Água Doce), Departamento de Ciências Biológicas, Faculdade de Ciências, Universidade Estadual Paulista, Avenida Luiz Edmundo Carrijo Coube, 14-01, Bauru, São Paulo, 17033-360, Brazil
Published
2013-05-03
Section
Articles

Journal Identifiers


eISSN: 1814-2338
print ISSN: 1814-232X