Reproductive cycle, development and recruitment of two geographically separated populations of the dendrochirote holothurian Aslia lefevrei

摘要: The boreo-mediterranean holothurian Aslia lefevrei (Barrois) occupies cryptic habitats from low-water mark to ca. 20 m. During the present work specimens were collected west coast of Ireland (February 1979 August 1980), where A. lefevreiis a prominent element in two discrete epibenthic assemblages, and north-west Spain (September 1981 1982), this is densely aggregated association with raft cultivation mussel Mytilus edulis. Its reproductive cycle, spawning process, embryological development, settlement, early growth rates have been documented by means laboratory field studies. Depending on geographic location, wild occurs between January May. Development gastrula takes some 3 4 d. Uniformly ciliated dipleurula/auricularia hatch 12 24 h after gastrulation. pentactula stage attained approximately 7 d fertilization, following which larva settles. Newly settled individuals utilize five primary tentacles for both feeding locomotion. With advent small numbers podia ambulacral regions, prolong their locomotory anchorage capabilities while remaining develop adult characteristics function solely feeding. Growth was followed an estimated 30 mo period using length-frequency analyses. In first year life, attain average length 3.4 cm; sea floor can up 18 cm, indicating possible life expectancy 10 yr or more.