Induction of settlement and metamorphosis of the scallop <i>Argopecten purpuratus</i> Lamarck by excess K<SUP>+</SUP> and epinephrine
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1999
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Abstract
Settlement and metamorphosis of marine invertebrate larvae is known to be triggered by specific environmental cues. Neuroactive compounds, particularly some monoamines, have been implicated in this process, and depolarization of receptor cell membranes has been suggested to occur as a response to them. An increase of extracellular K+ in seawater has been used as an effective inducer of these processes for some species. This study describes work designed to assay effects of epinephrine and excess K+ as inducers of settlement and metamorphosis of larvae of the scallop Argopecten purpuratus. Epinephrine and excess K+ increased the percentages of settlement, metamorphosis, and survival of these larvae. Responses were dose-dependent, with a maxima under 10(-5) M (epinephrine) and 10 mM (K+). In the case of epinephrine, the responses did not vary significantly with the time of exposure. An analysis of size and energy content of larvae induced to metamorphosis by the different methods showed that larvae induced with epinephrine produced postlarvae that were significantly smaller in size and energetically weaker than postlarvae produced using excess K+ or no added exogenous inducer.
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Argopecten purpuratus larvae, metamorphosis, scallops, settlement