The biology of Echinocardium cordatum [Echinodermata: Spatangoidea] from different habitats
The biology of Echinocardium cordatum [Echinodermata: Spatangoidea] from different habitats
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来自不同生境的 Echinocardium cordatum [Echinodermata: Spatangoidea] 的生物学
DOI：
10.1017/s0025315400017574
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发表时间：
1966
影响因子：
1.2
通讯作者：
J. Buchanan
中科院分区：
文献类型：
--
作者：
J. Buchanan
从它们的幼虫同时定居和建立起，观察了7年的时间，从近海和沿海的棘球绦虫种群开始。滨海种群分布在有机含量较低的清洁沙地中。个体埋深15 cm，能以6~8 cm/h的速度在沙地上移动，试验长度平均每年增加8 mm。第一次繁殖发生在第三年，之后每年都会继续繁殖。离岸种群是在30-40米深的粉砂中发现的。在这里，个体挖到了非常浅的深度，2厘米。或更少，在沉积物中移动非常缓慢。试种生长量年生长量仅为3 mm左右。估计显示，沿海人口的生产率是近海人口的四倍。在观察期间，离岸种群没有达到性成熟。在观察期间，该地区任何地方都没有观察到新的沉降。近海种群出现在大的离散斑块中，每个斑块都显示出数量上的同心图案，中心区域密度高。在斑块内的单个站点采集的样本显示，在一年中的大部分时间里，这种分布是随机的，但在6、7和8月形成了聚集。这两个种群的死亡率稳定在每年15%左右，寿命估计在15岁左右。根据水族馆对摄食行为的长期观察，给出了认为前游动肌毛状管足的表面收集活动应被认为是真正的摄食机制的理由。
An offshore and a littoral population of Echinocardium cordatum have been observed for a period of 7 years, starting from the time of their simultaneous larval settlement and establishment. The littoral population was found in clean sand of low organic content. Individuals burrowed to a depth of 15 cm and could move through the sand at a speed of 6–8 cm/h. The test length increased at an average increment of 8 mm/annum. Breeding first took place in the third year and continued each year after. The offshore population was found in very silty sand at depths of 30–40 m. Here individuals burrowed to a very shallow depth, 2 cm. or less, and moved very slowly through the sediment. The annual increment of test growth was only about 3 mm. Estimations showed that the littoral population had a production rate four times greater than the offshore. The offshore population did not reach sexual maturity during the period of observation. No new settlement was observed anywhere in the area during the period of observation. The offshore population occurred in large discrete patches, each displaying a quantitatively concentric pattern with a central area of high density. Samples taken at single stations within the patch showed that the distribution was random for most of the year but that aggregations formed in June, July and August. Both populations showed a steady mortality rate of about 15 % per annum and the longevity was estimated to be in the region of 15 years. Based on prolonged aquarium observations of the feeding behaviour, reasons are given for believing that the surface collecting activities of the penicillate tube-feet of the anterior ambulacrum should be considered as a true feeding mechanism.