RECRUITMENT IN THE HOLOTHURIAN CUCUMARIA-FRONDOSA IN THE GULF OF MAINE

The sea cucumber Cucumaria frondosa spawns in the spring, in the Gulf of Maine, USA. The larvae remain pelagic for several weeks prior to re cruitment to the benthos. In the western Gulf of Maine, a previous stu dy showed that juvenile C. frondosa occur exclusively inside mussel be ds; adults are absent from the region. In the present investigation, r ecruitment and juvenile abundances in the field were examined from 199 3-1995. A study conducted in the spring of 1993 in the Maine-New Hamps hire coastal waters indicated that recruitment of C. frondosa to musse l beds was high. In the fall of 1994, no recruits were present on the benthos; juveniles were more abundant in coralline algae than in musse l beds or kelp holdfasts. In 1995, recruitment and juvenile abundance monitored over the recruitment season revealed that recruitment was hi ghest in June. Toward the end of June and during early July, recruitme nt was significantly higher in mussel beds than in coralline algae and kelp holdfasts. In June, a a-day intensive field study indicated that recruits were significantly more abundant in mussel beds than in kelp holdfasts or coralline algae, while juveniles were significantly more abundant in the mussel beds than coralline algae. Mussel beds may enh ance early survival by providing a refuge from predation. A potential predator on new recruits are large nereid worms.