Reproductive cycle and feeding periodicity in the starfishAstropecten brasiliensisin the Cabo Frio upwelling ecosystem (Brazil)

Abstract

Monthly collections ofAstropecten brasiliensis were made at depths of 30 and 45 m. The highest number of prey in the stomach occured in summer in both 1987 and 1988. Specimens larger than 4 cm in radius had mature gonads. The reproductive cycle was determined by gonad indices and histological analysis of gonads. In 1988, the species exhibited an annual reproductive cycle with spawning in December. The pyloric caecum indices showed the highest values between April and July. The relationship between gonad index and pyloric caecum index was inverse. The pyloric caecum peak occurred during the downwelling period (fall and winter) when warm tropical waters (Brazil Current) were inshore. The reproductive peak coincided with the upwelling period (during spring and summer) enabling the larvae to benefit fiom the richer water condition when phytoplankton are more abundant.

Spatial distribution of bivalve mollusc assemblages in the upwelling ecosystem of the continental shelf of Cabo Frio, Rio de Janeiro, Brazil

“…The ecology of benthic invertebrates of the Cabo Frio upwelling system is poorly studied, similar to other Brazilian continental margin benthic habitats. A multidisciplinary oceanographic project carried out by the Admiral Paulo Moreira Sea Studies Institute generated some results about the local benthic invertebrates, but only data on echinoderms and anomuran crustaceans were published until now (VENTURA & FERNANDES 1995, VENTURA et al 1997, DA GAMA & FERNANDES 1994. This work describes the distribution of the bivalve mollusc assemblages on the inner shelf and aims to contribute to the knowledge of the local ecosystem, as these invertebrates could represent an important link in the food chain from primary producers, such as phytoplancton and microphytobenthos, to predators, such as fishes (KAMERMANS 1992).…”

Efficiency of starfish mopping in reducing predation on cultivated benthic mussels ( Mytilus edulis Linnaeus)

“…Such seasonal variation in food seeking and feeding behaviour may, therefore, influence the temporal movements of starfish on mussel beds in Belfast Lough. In addition, a reduction in feeding activity prior to spawning and a resumption of feeding following spawning, to replenish depleted energy reserves, has been identified in a number of starfish species (Hancock, 1955;Ventura et al, 1997). As such the reproductive cycle of starfish in Belfast lough could influence starfish movements and feeding behaviour.…”

“…Interestingly mopping efficiencies were lowest between May and July, which coincides with a fall in the gonad index and rise in the pyloric caeca index of starfish. Following spawning, starfish often resume feeding at an increased rate to replenish energy stores (Hancock, 1955;Ventura et al, 1997). If increased feeding activity was occurring during these months a greater proportion of starfish might be engaged in active feeding and be attached to prey items using their tube feet (Hancock, 1955).…”

“…To assess the population structure of the starfish on mussel beds the abundance and size of starfish collected by mops was recorded from a total of 81 tows, including the additional tows where recorded video footage was not suitable for analysis (Table 1). The reproductive condition of starfish was also assessed to examine possible relationships between spawning periods, the movement of starfish and the potential variability in feeding rate experienced during the reproductive cycle (Gallagher et al, 2008;Hancock, 1955;Ventura et al, 1997). Twenty starfish were selected randomly from mop tows at each sampling date and the longest arm length (precision 0.1 mm) and biomass (precision 0.01g) of each starfish was recorded.…”

Reproductive biology of Palythoa caribaeorum and Protopalythoa variabilis (Cnidaria, Anthozoa, Zoanthidea) from the southeastern coast of Brazil

“…Fadlallah et al (1984) suggested that repeated exposure to air during low tide, and consequent exposure of the colonies of P. caribaeorum and Z. sociatus to high temperatures, might be a cue to spawning. In the case of spawning in marine invertebrates, food availability, which in the rich upwelling waters near Cabo Frio, Brazil, favors just-released planktotrophic larvae, must also be taken into account (Ventura et al, 1997). Temperature seems to be the ultimate factor influencing the reproduction of Protopalythoa sp.…”