Population Biology of the Mole Crab Emerita brasiliensis (Decapoda: Hippidae) at Fora Beach, Brazil

Abstract

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. The Crustacean Society is collaborating with JSTOR to digitize, preserve and extend access to Journal of Crustacean Biology. ABSTRACTThe population biology of Emerita brasiliensis (Decapoda: Hippidae) was studied by means of biweekly sampling from October 1990 through March 1993 at Praia da Fora Beach, Rio de Janeiro, Brazil (22?57'S, 43?10'W). Two transects were established in the swash zone, and divided into 4 strata parallel to the waterline. From each stratum, 4 replicates were taken with a 0.04-m2 sampler. Highest population densities were observed at the end of spring and during summer. The presence of ovigerous females and juveniles during the entire sampling period indicated continuous reproduction of the population. The sex ratio was 1.82 for males : 1.00 for females. Batch size varied from 610-1,093 eggs, for females 10-23 mm long, respectively. Growth and mortality rates were higher for females than for males. Longevity for 99% of the population varied approximately from 6-10 months.

Testing the swash exclusion hypothesis in sandy beach populations: the mole crab Emerita brasiliensis in Uruguay

“…These animals are found at lower fringes of the intertidal or even in the subtidal, at 30 cm deep. Thus, they are not exposed at the same degree as smaller males (Lercari & Defeo 1999, Veloso & Cardoso 1999. These differential zonation patterns have been described for the sympatric yellow clam Mesodesma mactroides and wedge clam Donax hanleyanus (Defeo et al 1986, de Alava 1993, Defeo 1993.…”

“…***p << 0.001, **p < 0.01 and *p < 0.05 for the regressions and parameter estimates. ANCOVA results (logtransformed data) are also shown reproductive output and fitness in the harsh surf zone of high energy reflective beaches (Veloso & Cardoso 1999). On the other hand, lower growth rhythms in males at Barra del Chuy could be explained by alternative mechanisms to environmental forcing.…”

“…Megalops were those with an undeveloped ocular peduncle and presence of plumose pleopods (Veloso & Cardoso 1999). The sex of each adult was determined and sorted into males with and without spermatophores, females without eggs (hereafter females) and ovigerous females.…”

Patterns, processes and regulatory mechanisms in sandy beach macrofauna: a multi-scale analysis

“…Smaller individual sizes tend to remain in the swash zone close to the substratum surface and are more dependent on passive transport by waves, whereas large adults regulate their position on the beach by greater mobility and behavioural adaptations, including rapid burrowing (Trueman 1970, McLachlan & Young 1982, Defeo et al 1986, Veloso & Cardoso 1999. Patchy distribution may also be related to made of locomotion, particularly in supralittoral species (Scapini et al 1995, Brown 1996, Giménez & Yannicelli 1997.…”

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“…The mole crab Emerita brasiliensis (Crustacea: Anomura: Hippidae), belongs to an intertidal faunal, presenting differentiated responses concurrent with the environmental variability in the spatial and temporal scales (Contreras et al, 1999;Lercari and Defeo, 1999). The mole crab can be found in several localities along the South Atlantic American coast, from Espírito Santo, Brazil, to the Uruguayan shore (Veloso and Cardoso, 1999).…”