Population dynamics of Pinnixa patagoniensis RATHBUN, 1918 (Brachyura : Pinnotheridae) a symbiotic crab of Sergio mirim (Thalassinidea : Callianassidae) in Cassino Beach, Southern Brazil

Pinnotherid crabs are typically found associated with many benthic invertebrates. On sandy beaches of southern Brazil, Pinnixa patagoniensis RATHBUN, 1918 inhabits burrows of the ghost shrimp Sergio mirim (RODRIGUES, 1971). The population dynamics of this crab were studied from monthly samples taken...

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Bibliographic Details
Published in:Marine ecology (Berlin, West) West), 1998-03, Vol.19 (1), p.37-51
Main Authors: DOS SANTOS ALVES, E, PEZZUTO, P. R
Format: Article
Language:English
Subjects:
Animal and plant ecology
Animal, plant and microbial ecology
Animals
Biological and medical sciences
Brachyura
Callianassidae
Demecology
Fundamental and applied biological sciences. Psychology
Marine
Pinnixa patagoniensis
Pinnotheridae
Protozoa. Invertebrata
Sergio mirim
Thalassinidae
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Summary:Pinnotherid crabs are typically found associated with many benthic invertebrates. On sandy beaches of southern Brazil, Pinnixa patagoniensis RATHBUN, 1918 inhabits burrows of the ghost shrimp Sergio mirim (RODRIGUES, 1971). The population dynamics of this crab were studied from monthly samples taken between March 1989 and November 1991 near the Patos Lagoon outlet, southern Brazil (ca. 32 degree 13'S; 52 degree 15'W). There was no correlation between the number and size of the crabs and the size of their respective hosts. Mean densities and incidence reached 3.1 indiv. opening super(-1) (range: 0 to 29) and 83.9%, respectively. Sex-ratios were not significantly different from 1: 1 for the different size classes and sampling dates. Ovigerous females were found between October and March, showing an average fecundity of 1529 eggs per female. The annual recruitment pattern was bimodal, with a minor peak in summer and a fall peak that accounted for almost 70% of the population maintenance. Males and females both reached a maximum carapace width of 11.5 mm and had a life span of nearly two years as estimated from fitted VON BERTALANFFY growth curve parameters.
ISSN:0173-9565
1439-0485
DOI:10.1111/j.1439-0485.1998.tb00452.x