Reproductive cycle of the endemic cassiduloid Cassidulus mitis (Echinoidea : Cassiduloida) on the Brazilian coast

Cassidulus mitis Krau, 1954 is an endemic species from Rio de Janeiro, Brazil. To study the reproductive cycle of this species, samples were collected at Praia Vermelha, in Guanabara Bay, from Octo er 1998 to April 2000. The sex ratio for C. mitis was 1: 1, and reproduction occurred throughout the year. The gonadal index of males was greater than that of females. Five gametogenic stages were identified in males: early growth, premature, mature, partially spawned and early growth with a partially spawned stage. There were no spent or recovery stages such as those seen in females. Females had six gametogenic stages: recovery, early growth, premature, mature, partially spawned and spent stage; there was no early growth with a partially spawned stage as there was in males. The mean oocyte diameter was 382 mum (SD=49 mum), and the mean number of juveniles per female was 100 individuals (SD=108). The anterior gonads were frequently smaller than the posterior ones, and there were differences in the gametogenic stages between the anterior and posterior gonads. First sexual maturation occurred in individuals with a diameter of 17 mm. The intestinal wet weight was two- to threefold higher than the test wet weight. This may indicate that C. mitis uses its intestine as a "weight belt" to avoid displacement from the substratum.145360361

Dispersion in Populations of Tropiometra carinata (Crinoidea : Comatulida) in the Sao Sebastiao Channel, Sao Paulo State, Brazil

To understand the patterns of spatial distribution in populations of Tropimetra carinata (Lamarck), bi-monthly samples were collected in two areas of shallow water (Ponta do Baleeiro; PB, and Cabelo Gordo Beach; CG), in the Sao Sebastiao Channel, using a grid superimposed on the habitat. A pattern of clumped dispersion was observed, with values for Morisita's Index significantly different from those of a random pattern. The mean densities at PB and CG, from December 1997 to October 1998, were respectively 2.20 +/- 0.21 (SD) and 2.32 +/- 0.28 (SD) individuals m(-2). The length of the longest arm was used as an indicator of specimen size. The mean size at PB was 11.76 +/- 0.53 cm and at CG, 9.65 +/- 0.18 cm. The mean size of solitary individuals was greater than for clumped individuals in both areas. Small individuals tended to attach near clumps of greater individuals. The five principal microhabitats selected by these crinoids were lateral, upper and lower rock surfaces and lateral and upper rock crevices, with preferential attachment to lateral rock surfaces. The extent of substratum coverage by the zoanthid Palythoa caribaeorum varied between areas (74.1% at PB and 38.1% at CG), as did the association Tropimetra-Palythoa (81.4% at PB and 44.5% at CG). The clumped dispersion seen here optimizes filtration by enhancing the baffle effect. (C) 2002 Elsevier Science Ltd.54221922

The reproductive cycle of Scolelepis goodbodyi (Polychaeta, Spionidae)

The aim of this study was to examine the reproductive and gametogenic cycle of the spionid polychaete Scolelepis goodbodyi (Jones). Every 15 days, in the upper level of the intertidal zone on Barequecaba Beach in southeastern Brazil, a 100 m(2) area was delimited and within it three points were selected and sampled using a core sampler 0.01 m(2) in area x 0.2 m long. Each sample was divided into three sub-samples: surface (2 cm) and middle (8 cm), which were sieved through 0.5, 0.25 and 0.125 mm mesh sieves; and lower (10 cm), sieved through 1.0 and 0.5 mm mesh sieves. Males, females and undetermined individuals were separated, and the width of the third setiger was measured. The gonadal development of each individual was classified based on external features of the gametogenic setigers. Ten to 20 adults from each sampling period were classified according to their gonadal development stage and then analyzed histologically for gametogenic studies, for comparison with the former classification. Some of the ripe females were used for fecundity evaluation. The diameters of the oocytes were measured prior to spawning. Eight hundred and twenty-eight females (29.70%), 848 males (30.42%) and 1,112 undetermined individuals (39.89%) were analyzed. The sex ratio did not differ significantly from unity (chi(2) = 0.24; df = 1; P < 0.05). Males and females were more abundant in May 2002 (ca. 80%) and between November 2002 and May 2003 (between 77 and 90%); the proportion of undetermined individuals did not represent recruitment alone, but also a high incidence of adults with recovering gonads. Fecundity varied from 134 oocytes in a 0.54 mm W3 individual to 289 oocytes in a 0.4 mm W3 individual, with a mean of 220 (SD = 57) oocytes per female and 19 (SD = 5) oocytes per gametogenic setiger. Oocytes were ellipsoid, and ranged in size from 150 x 80 (to 220 x 120 mu m (mean +/- SD = 173 x 113 +/- 15 x 11 mu m). Neither a well-defined gametogenic cycle nor synchrony in the reproductive period was observed, because many gonadal development stages occurred in each month. Nevertheless, peaks of maturity were observed between October-December 2002 and April-May 2003.15131009102

Reproductive biology of Echinometra lucunter (Echinodermata: Echinoidea) in a northeast Brazilian sandstone reef

The edible sea urchin Echinometra lucunter (Linnaeus, 1758) is a very common species on the sublittoral-midlittoral in Brazilian rocky shores. The aim of this work was to describe the gametogenesis and reproductive strategy of the E. lucunter population at Muro Alto beach in the Northeast coast of Brazil from August 2004 to August 2005. A total of 240 specimens were collected on the sandstone reef flat from a tidepool during spring low tides. The overall sex ratio was1.12:1,withoutsignificanttemporalvariationexceptinOctober2004. Firsts sexual maturity ocurred in individuals from a diameter of 20.8 mm. There was not a significant difference in gonad index between females and males during the sampling period. The female's gonad index variation was associated with a well-defined spawning, corroborated by the histological analysis of the gonads, which demonstrates sex differences of the gamete production. By contrast, the males showed no clear pattern. It is suggested that continuous reproduction with seasonal peaks in the E. lucunter population occurs at Muro Alto beach.<br>O ouriço-do-mar comestível Echinometra lucunter (Linnaeus, 1758) é uma espécie muito comum no infralitoral e mediolitoral do Brasil. O objetivo deste trabalho foi descrever a gametogênese e a estratégia reprodutiva da população de E. lucunterna praia de Muro Alto entre agosto de 2004 e agosto de 2005. Um total de 240 espécimes foi capturado de uma poça de maré situada no topo recifal, durante as marés baixas de sizígia. A razão sexual total foi de 1,12:1 sem variação temporal significativa, exceto em outubro de 2004. A primeira maturidade sexual ocorreu em indivíduos a partir de 20,8 mm de diâmetro. Não houve nenhuma diferença significativa no índice gonadal entre fêmeas e machos durante o período de amostragem. A variação do índice gonadal das fêmeas foi associada a um período de desova bem definido, corroborado pela análise histológica das gônadas, que demonstra diferenças sexuais na produção de gametas. Ao contrário, os machos não apresentaram nenhum padrão. Sugere-se que a reprodução da população de E. lucunter na praia de Muro Alto é contínua, compicos sazonais