Distribución, parámetros poblacionales y dieta de Astropecten marginatus (Asteroidea: Astropectinidae) en el Atlántico venezolano

Abstract

Distribution, population parameters, and diet of Astropecten marginatus (Asteroidea: Astropectinidae) in the Venezuelan Atlantic coast. Astropecten marginatus is a sea star widely distributed in Northern and Eastern South America, found on sandy and muddy bottoms, in shallow and deep waters. To describe some of its ecological characteristics, we calculated it spatial-temporal distribution, population parameters (based on size and weight) and diet in the Orinoco Delta ecoregion (Venezuela). The ecoregion was divided in three sections: Golfo de Paria, Boca de Serpiente and Plataforma Deltana. Samples for the rainy and dry seasons came from megabenthos surveys of the "Línea Base Ambiental Plataforma Deltana (LBAPD)" and "Corocoro Fase I (CFI)" projects. The collected sea stars were measured, weighted and dissected by the oral side to extract their stomach and identify the preys consumed. A total of 570 sea stars were collected in LBAPD project and 306 in CFI one. The highest densities were found during the dry season in almost all sections. In LBAPD project the highest density was in "Plataforma Deltana" section (0.007±0.022ind/m 2 in dry season and 0.014±0.06ind/m 2 in rainy season) and in the CFI project the densities in "Golfo de Paria" section were 0.705±0.829ind/m 2 in rainy season and 1.027±1.107ind/m 2 in dry season. The most frequent size range was 3.1-4.6cm. The highest biomass was found in "Golfo de Paria" section (7.581±0.018mg/m 2 in dry season and 0.005±6.542x10 -06 mg/m 2 in rainy season for 2004-2005 and 3.979±4.024mg/m 2 in dry season; and 3.117±3.137mg/m 2 in rainy season for 2006). A linear relationship was found between the sea star size and its weight but no relationship was observed between its size and the depth where it was collected. Mollusks are dominant in the sea star diet (47.4% in abundance). The diet in any of the sections, seasons or between projects or size class was heterogeneous, using multivariate ordinations (MDS) and SIMPER analysis and there was no difference in the prey number or food elements that a sea star can eat. Although A. marginatus has been described as a predator, in this study were also inferred scavenger and detritivorous habits.

Variaciones estacionales en el tamaño corporal y dieta de la estrella de mar Astropecten marginatus (Paxillosida, Astropectinidae) frente a la costa de Paraná, sur de Brasil

“…The same feeding pattern has also been observed for A. marginatus inhabiting the Caribbean Sea (Soto, 1984;Ortega et al, 2011) and Brazil (Monteiro & Pardo, 1994). Furthermore, temporal differences in the amount of ingested items and in the food preferences have also been observed.…”

“…The most frequent length classes in this study (20.1-25mm) were lower than observed by Monteiro & Pardo (1994) for the population from state of São Paulo, Southeastern Brazil (40-50mm) or by Soto (1984) and Ortega et al, (2011) from the coast of Venezuela (30-34mm and 31-46mm, respectively). The maximum recorded length (56.2mm) are also lower than those observed for others Caribbean populations, where were recorded maximum sizes around 78mm (Roa, 1967;Walenkamp, 1976Walenkamp, , 1979Ortega et al, 2011).…”

“…Some biometric and ecological information about this species may be found in studies off the coast of Venezuela (Roa, 1967), Brazil (Tommasi, 1970;Monteiro & Pardo, 1994), and Suriname (Walenkamp, 1976(Walenkamp, , 1979. Furthermore, species feeding habits had only been studied for populations off Venezuelan (Soto, 1984;Ortega, Martín, & Díaz, 2011) and Southeastern Brazilian coasts (Monteiro & Pardo, 1994).…”

Un astropectínido (Echinodermata, Asteroidea) cretácico temprano de Patagonia (Argentina): Una nueva especie y el registro más antiguo de la familia para el Hemisferio Sur.

“…Astropectinids are voracious predators that feed on molluscs and echinoderms (including other astropectinids), amongst other invertebrates, but they may also consume algae and inorganic detritus (e.g., Ortega et al, 2011). They actively search for prey and are able to shallowly dig into the substrate to get it (see Ortega et al, 2011 and references therein).…”