Marine Anomurans (Decapoda) from the Non-Consolidated Sublittoral Bottom at the Southeastern Coast of Brazil

Abstract

The present study assessed the composition and abundance of species of Anomura at the southeastern coast of Brazil. Sampling was carried out monthly from January 1998 to December 1999, in three regions of Ubatuba: Ubatumirim Bay, Ubatuba Bay and Mar Virado Bay, using a fishing boat equipped with two double-rigged nets. Four transects were defined at depths of 5, 10, 15, and 20 meters in each bay. Two additional transects were defined perpendicular to the beach: one in a sheltered area and the other in an area exposed to wave action. A total of 6356 specimens of anomurans representing 15 species and 9 genera of 3 superfamilies (11 Paguroidea, 1 Hippoidea, and 3 Galatheoidea) was recorded. Paguristes robustus was recorded for the first time from the São Paulo State coast. Dardanus insignis was the most abundant species, followed by Loxopagurus loxochelis and Porcellana sayana. The high abundance of P. sayana may be related to the presence of D. insignis and Petrochirus diogenes, because this porcellanid crab lives inside the shells occupied by these hermit crabs. Species richness varied among the bays and transects, but the highest values were observed at the exposed and sheltered areas. The highest abundance of anomurans was recorded at a depth of 20 m during winter in the bays Mar Virado and Ubatuba. The anomuran species comprised 75% of the total number previously recorded from coastal non-consolidated bottoms of São Paulo. We therefore infer that this region affords favourable biotic and abiotic conditions for the settlement and maintenance of a large number of species of Anomura. RESUMO

Effect of environmental factors on the abundance of decapod crustaceans from soft bottoms off southeastern Brazil

“…Shrimp fisheries along the southeastern Brazilian coast have targeted the most profitable species, environmental factors. The association of some individual decapods with environmental factors was examined by Fransozo et al (1992Fransozo et al ( , 1998Fransozo et al ( , 2002Fransozo et al ( , 2008Fransozo et al ( , 2011, Negreiros-Fransozo et al (1997), Mantelatto and Fransozo (2000), , Castilho et al (2008) and Bertini et al (2010). The objective of the present study was to comprehend how variations in environmental factors (bottom temperature and salinity, sediment texture and organic-matter content) affect the abundance of decapod crustaceans inhabiting the Ubatuba region, by means of a multivariate analysis.…”

Shell occupation by the hermit crab Dardanus insignis (Decapoda, Diogenidae) from the north Coast of São Paulo state, Brazil

“…Hahn (1998) suggested that the occupation of the same shell species (in this case, O. urceus) decreases intraspecific competition, which has a positive influence at the population level. This fact might be associated with the competitive dominance of D. insignis in the sub-littoral region (see Fransozo et al, 2008Fransozo et al, , 2011Ayres-Peres et al, 2008). Hazlett et al (2005) suggests that male hermit crabs that use for the most part a given species of shell are considered specialists and allow for a higher effectiveness in the mating process in comparison to hermit crabs with generalist occupation patterns, occupying shells of different species according to their availability in the environment.…”

Comparative analysis of populational structure of the Hermit Crab Dardanus insignis (Anomura: Diogenidae) in a Subtropical Area of the Brazilian Coast

“…Several studies with old information was recently published with this purpose (Fransozo et al, 2011;2012;Andrade et al, 2013a, b, c;Baeza et al, 2013;Furlan et al, 2013;herein). In this study, it was found that the environmental factors showed distinct variations for both sampled sites, being the SACW evidenced by means the decrease in the water surface temperature values at the Couves Island during spring and summer (Mantelatto & Fransozo, 1999;Negreiros-Fransozo et al, 1991).…”

“…The hermit crab Dardanus insignis (Saussure, 1858) is the most abundant hermit crab of soft bottom littoral at Southeastern Brazil (Fransozo et al, 2011;2012), being classified as one of the species that structuring the benthic mega fauna, from shallow regions to depths greater than 100 meters at southeastern of Brazilian coast (Pires, 1992). One of the main factors in the success of the hermit crabs is the flexibility of the feeding behavior (omnivorousdetritivorous) that characterizes them as opportunistic feeders, allied to the gastropod shell utilization, which promote their adaptation to any environment (Hazlett, 1981).…”