Ortega Ileana, Martín Alberto, Díaz Yusbelly
Universidad Simón Bolívar, Departamento de Estudios Ambientales, Centro de Biodiversidad Marina, Laboratorio de Crustáceos Peracáridos, Apdo. 89000, Caracas 1086-A, Venezuela.
Rev Biol Trop. 2011 Mar;59(1):53-69.
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 +/- 0.022 ind/m2 in dry season and 0.014 +/- 0.06 ind/m2 in rainy season) and in the CFI project the densities in "Golfo de Paria" section were 0.705 +/- 0.829 ind/m2 in rainy season and 1.027 +/- 1.107 ind/m2 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 +/- 0.018 mg/m2 in dry season and 0.005 +/- 6.542 x 10(-06) mg/m2 in rainy season for 2004-2005 and 3.979 +/- 4.024 mg/m2 in dry season; and 3.117 +/- 3.137 mg/m2 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.
缘边 Astropecten marginatus 是一种广泛分布于南美洲北部和东部的海星，在浅水区和深水区的沙质和泥质海底均有发现。为描述其一些生态特征，我们计算了它在奥里诺科河三角洲生态区（委内瑞拉）的时空分布、种群参数（基于大小和重量）以及食性。该生态区分为三个部分：帕里亚湾、蛇嘴湾和三角洲平台。雨季和旱季的样本来自“三角洲平台环境基线（LBAPD）”和“科罗科罗一期（CFI）”项目的大型底栖生物调查。收集到的海星进行测量、称重，并从口侧解剖以取出其胃部，识别所摄食的猎物。LBAPD项目共收集到570只海星，CFI项目收集到306只。几乎在所有区域，旱季的密度最高。在LBAPD项目中，最高密度出现在“三角洲平台”区域（旱季为0.007±0.022只/平方米，雨季为0.014±0.06只/平方米）；在CFI项目中，“帕里亚湾”区域的密度在雨季为0.705±0.829只/平方米，旱季为1.027±1.107只/平方米。最常见的大小范围是3.1 - 4.6厘米。最高生物量出现在“帕里亚湾”区域（200年 - 2005年旱季为7.581±0.018毫克/平方米，雨季为0.005±6.542×10⁻⁶毫克/平方米；2006年旱季为3.979±4.024毫克/平方米，雨季为3.117±3.137毫克/平方米）。发现海星大小与其重量之间存在线性关系，但未观察到其大小与采集深度之间的关系。软体动物在海星的食物中占主导地位（丰度为47.4%）。使用多变量排序（MDS）和相似性百分比分析（SIMPER）发现，任何区域、季节、项目或大小类别之间的食物组成都是异质的，并且海星能摄食的猎物数量或食物元素没有差异。尽管缘边 Astropecten marginatus 被描述为一种捕食者，但在本研究中也推断出其具有清道夫和食碎屑习性。
