The toxic dinoflagellate Alexandrium minutum impairs the performance of oyster embryos and larvae

Publication date: February 2020Source: Harmful Algae, Volume 92Author(s): Justine Castrec, Hélène Hégaret, Matthias Huber, Jacqueline Le Grand, Arnaud Huvet, Kevin Tallec, Myrina Boulais, Philippe Soudant, Caroline FabiouxAbstractThe dinoflagellate genus Alexandrium comprises species that produce highly potent neurotoxins known as paralytic shellfish toxins (PST), and bioactive extracellular compounds (BEC) of unknown structure and ecological significance. The toxic bloom-forming species, Alexandrium minutum, is distributed worldwide and adversely affects many bivalves including the commercially and ecologically important Pacific oyster, Crassostrea gigas. In France, recurrent A. minutum blooms can co-occur with C. gigas spawning and larval development, and may endanger recruitment and population renewal. The present study explores how A. minutum affects oyster early development by exposing embryos and larvae, under controlled laboratory conditions, to two strains of A. minutum, producing only BEC or both PST and BEC. Results highlight the major role of BEC in A. minutum toxicity upon oyster development. The BEC strain caused lysis of embryos, the most sensitive stage to A. minutum toxicity among planktonic life stages. In addition, the non-PST-producing A. minutum strain inhibited hatching, disrupted larval swimming behavior, feeding, growth, and induced drastic decreases in survival and settlement of umbonate and eyed larvae (9 and 68 %, respectively). The findings indic...
Source: Harmful Algae - Category: Environmental Health Source Type: research