The toxic dinoflagellate Alexandrium catenella adversely affects early life stages of tehuelche scallop

GRACIA VILLALOBOS, LEILÉN L.; GETINO MAMET, LEANDRO N.; VÁZQUEZ, NURIA; SORIA, GASPAR; GONÇALVES, RODRIGO J.

MARINE ENVIRONMENTAL RESEARCH

ELSEVIER SCI LTD

Año: 2023 vol. 192

0141-1136

The effects of the toxic dinoflagellate Alexandrium catenella were investigated on growth, survival, and histo-pathology in larvae and spat of the Tehuelche scallop Aequipecten tehuelchus from Patagonia, Argentina. Thestudy consisted of laboratory incubations of scallop larvae/spat with A. catenella, using environmentally realisticabundances of the dinoflagellate. Survival, growth, and histopathological effects were documented for scalloplarvae/spat before, during, and after 7-day-long exposure to A. catenella. The scallops were grouped in flaskscontaining 0 (control), 20, 200, and 2000 cells mL 1 of A. catenella. The presence of A. catenella induced reducedlarvae survival after 24 h, whereas a clear effect was observed after 3 days (survival of control larvae 95%, 72,and 79% for 20 and 200 cells mL 1, respectively, and 43% for 2000 cells mL 1). The growth rates of the controllarvae and those exposed to 20 mL 1 cells were significantly different from zero. Histopathological effects(melanization, loss of connective tissue, necrosis, and inflammatory responses) were observed in spat exposed toA. catenella. These effects were more pronounced at the highest dinoflagellate concentration. Blooms ofA. catenella frequently coincide with the reproductive season of A. tehuelchus, thus there is a need to further studythe relationship between harmful algal blooms and the effect on scallops’ natural populations in the region.