Article Title

Succession and the Role of Ophiuroids as it Applies to the Marine Infaunal Associations off Palos Verdes, California


Thomas Scanland





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Based on literature and data from monitoring surveys throughout the Southern Cahfomia Bight and especially off Palos Verdes, the pattern and rate of succession of ophiuroid populations of a previously perturbed (ocean outfall) area is assessed. Pre-discharge population levels of ophiroids off Palos Verdes were generally low, and between the early 1950's and 1970's densities were near zero. From 1972 to 1992 the number of ophiuroid species and densities have increased towards the center of the shelf and the zone of initial dilution (ZID), previously impacted by the effects of outfall. Even after natural mass mortalities, resettlement of ophiuroid populations is very slow, mainly due to adult migration rather than larval recruitment. In turn, the presence of high densities of adult populations favors settlement and metamorphosis of larvae. Conditions suitable for promoting and maintaining critical levels of adults represent the Catch-22 of larval recruit- ment, and hence successful resettlement of a previously perturbed area. Regard- less, conditions for infaunal benthos in general, and ophiuroids in particular, continue to improve off the Palos Verdes outfall as resettlement progresses.