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Effects of the gastropod, Ilyanassa obsoleta(Say) and the bivalve, Mercenaria mercenaria (L.), on larval settlement and juvenile recruitment of infauna

1987; Elsevier BV; Volume: 108; Issue: 3 Linguagem: Inglês

10.1016/0022-0981(87)90087-6

1879-1697

John H. Hunt, William G. Ambrose, Charles H. Peterson,

Marine Bivalve and Aquaculture Studies

Densities of a deposit-feeding gastropod, Ilyanassa obsoleta(Say) and a suspension-feeding bivalve, Mercenaria mercenaria (L.), were manipulated to test the importance of interactions between adults and settling larvae in affecting abundance patterns of infaunal invertebrates. Abundance of postlarvae and juveniles was significantly lower in the presence of Ilyanassa obsoleta than in snail-free controls. I. obsoleta caused a reduction in abundance of as much as 45%. Surface-dwelling tubiculous polychaetes, gastropods, harpacticoid copepods, and mobile subsurface-dwelling infauna all declined in abundance with increasing I. obsoleta density. Mercenaria mercenaria had little or no effect upon larval settlement. The effect of Ilyanassa obsoleta and Mercenaria mercenaria combined was equivalent to the sum of the effects of each species separately. Disturbance and ingestion of newly settled larvae by Ilyanassa obsoleta, larval settlement selectivity, and disturbance-induced emigration are probable mechanisms causing differences in abundance between I. obsoleta treatments.