Population structure of the swimming crab Achelous spinicarpus (Crustacea, Portunoidea) in São Paulo northern coast, Brazil

Authors

  • Thiago Elias Silva Núcleo de Estudo em Biologia, Ecologia e Cultivo de Crustáceos - NEBECC Universidade Estadual Paulista "Júlio de Mesquita Filho" - UNESP, Instituto de Biociências de Botucatu - IB Botucatu.
  • Fabiano Gazzi Taddei Laboratório de Estudos de Crustáceos Amazônicos - LECAM Universidade do Estado do Amazonas/ Centro de Estudos Superiores de Parintins – UEA/CESP,
  • Giovana Bertini Núcleo de Estudos em Biologia, Ecologia e Cultivo de Crustáceos - NEBECC. Universidade Estadual Paulista "Júlio de Mesquita Filho" - UNESP, Campus de Registro.
  • Luciana Segura Andrade Núcleo de Estudos em Biologia, Ecologia e Cultivo de Crustáceos - NEBECC. Universidade Federal do Triângulo Mineiro - UFTM - Campus de Iturama.
  • Gustavo Monteiro Teixeira Núcleo de Estudos em Biologia, Ecologia e Cultivo de Crustáceos - NEBECC. Universidade Estadual de Londrina - UEL
  • Adilson Fransozo Núcleo de Estudo em Biologia, Ecologia e Cultivo de Crustáceos - NEBECC. Universidade Estadual Paulista "Júlio de Mesquita Filho" - UNESP, Instituto de Biociências de Botucatu - IB Botucatu.

DOI:

https://doi.org/10.4013/nbc.2017.123.01

Abstract

The swimming crab Achelous spinicarpus is commonly captured as a “by catch” of the shrimp fishery. This study evaluated some aspects of the population structure of A. spinicarpus, such as sex-ratio and size classes’ frequency distribution. A shrimp trawler equipped with double-rig nets was used to capture the swimming crabs at Ubatuba and Caraguatatuba areas, northern coast of São Paulo state, Brazil. A total of 1,057 individuals were collected in Ubatuba, including 598 males (525 juveniles and 73 adults) and 459 females (379 juveniles and 80 adults, including 15 ovigerous crabs). In Caraguatatuba 5,112 individuals were collected, of which 3,138 males (2,638 juveniles and 500 adults) and 1,974 females (1,746 juveniles and 228 adults, including 29 ovigerous crabs). The sex-ratio favors the number of males in both regions, probably because females have the habit of occupying deeper regions. The size classes’ frequency distribution shows polymodality for both sexes, except for males in Ubatuba. This is the result of some age groups among the juveniles, which migrate to shallower areas, being affected by the fishing activity. Adults have the habit of staying in deeper areas characterized by colder waters.

Keywords: Brachyura, sex-ratio, Decapoda, bycatch, size distribution.

Author Biographies

Thiago Elias Silva, Núcleo de Estudo em Biologia, Ecologia e Cultivo de Crustáceos - NEBECC Universidade Estadual Paulista "Júlio de Mesquita Filho" - UNESP, Instituto de Biociências de Botucatu - IB Botucatu.

Departamento de zoologia

Adilson Fransozo, Núcleo de Estudo em Biologia, Ecologia e Cultivo de Crustáceos - NEBECC. Universidade Estadual Paulista "Júlio de Mesquita Filho" - UNESP, Instituto de Biociências de Botucatu - IB Botucatu.

Departamento de zoologia

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Published

2017-08-31

Issue

Vol. 12 No. 3 (2017): September/December

Section

Articles

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