Nassarius vibex (Gastropoda, Nassariidae): crescimento e reprodução em bancos de mitilídeos de substrato areno-lamoso na costa sudeste do Brasil / Nassarius vibex (Gastropoda, Nassariidae): growth and reproduction on soft bottom mitilids beds in the Southeast coast of Brazil

AUTOR(ES)
DATA DE PUBLICAÇÃO

2010

RESUMO

The present study analyzed the characteristics and the associated fauna of two beds of the mitilid Mytella charruana, located on Camaroeiro and Cidade beaches on the northern coast of the state of São Paulo. It also assessed the egg-capsule developmental stages, growth, allometry, reproduction, and recruitment of the gastropod Nassarius vibex, which occurred associated with the mitilid beds. In total, 32,639 invertebrates were sampled, 14,432 on Camaroeiro Beach and 18,207 at Cidade, belonging to Polychaeta (64.90 and 63.13% of the individuals of Camaroeiro and Cidade, respectively), Crustacea (18.36 and 17.05% of the individuals of Camaroeiro and Cidade, respectively), Mollusca, and Nematoda. Of the 1,558 egg capsules, 859 were collected at Camaroeiro and 699 at Cidade, with similar deposition periods of the populations. In the Camaroeiro bed, capsules were first recorded in May 2006, with a peak in July and a subsequent reduction in December 2006. In the Cidade bed, the capsules were observed between July and December 2006, with a peak of abundance in August 2006. In the same area, a second group of capsules was recorded from January to April 2007. The population structure of N. vibex was characterized by the presence of 4 adult age classes and three juvenile cohorts, with two annual recruitment periods. The growth pattern was similar to other subtropical and temperate species, with slow growth and a long life span. Juveniles were not common in either population, indicating a high mortality in the first year of life. The allometric growth of the two populations showed variations in the development of the individuals, and may be related to the different growth and oscillation rates. The reproductive cycle of N. vibex was biannual, with two maturation and spawning events during the year. Mature individuals were normally restricted to summer and winter, and spawning occurred in autumn and spring.

ASSUNTO(S)

nassarius vibex growth and reproduction crescimento e reprodução nassarius vibex

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