METAMORPHOSIS OF CONCHOLEPAS-CONCHOLEPAS (BRUGUIERE, 1789) INDUCED BY EXCESS POTASSIUM
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1993
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Abstract
Planktonic larvae of Concholepas concholepas Bruguiere underwent complete metamorphosis in response to excess K+. The effect was dose-dependent and optimal at approximately double the normal concentration of K+ in 0.45 um membrane-filtered seawater. Increasing concentration over 25 mM K+ produced a decline in survival, suggesting toxicity. Metamorphosis began with propodium attachment to the substratum and subsequent deciliation and destruction of the velum, followed by the emergence of cephalic tentacles from the larval shell margin. Velar loss, induced by K+, began with the detachment of large ciliated cells at the velar margin. Field-collected larvae, from different localities along the Chilean coast, presented a positive response to excess K+, and almost 80% of the larvae metamorphosed in 1 to 2 days. The induction of metamorphosis of Concholepas concholepas larvae by K+, provides a useful biotechnological tool for the cultivation of this socio-economically important marine resource of the southeastern Pacific Ocean.
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MOLLUSKS, CONCHOLEPAS-CONCHOLEPAS, PLANKTONIC LARVAE, SETTLEMENT, METAMORPHOSIS, POTASSIUM (IONS)