Domoic acid in a marine pelagic food web: Exposure of southern right whales Eubalaena australis to domoic acid on the Península Valdés calving ground, Argentina

D´AGOSTINO VALERIA; DEGRATI MARIANA; SASTRE VIVIANA; SANTINELLI NORMA; KROCK BERND; KROHN TORBEN; DANS SILVANA; HOFFMEYER MÓNICA

HARMFUL ALGAE

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2017 vol. 68 p. 248 - 257

1568-9883

The gulfs that surround Península Valdés, Golfo Nuevo and Golfo San José in Argentina, are important calving grounds for the southern right whales Eubalaena australis. However, a high mortality of calves has been observed in the last years, which could be associated with phycotoxin exposure. The present study evaluated the transfer of domoic acid (DA) from Pseudo-nitzschia spp., potentially producers of DA, to live and dead individuals of E. australis through of zooplanktonic vectors, while whales stay on their calving ground of Península Valdés. Both phytoplankton (in microplankton samples) and mesozooplankton (mostly prey of whales and potential predators of Pseudo-nitzschia cells) collected during whale season 2015 were qualitative and quantitatively examined. DA was measured in plankton and fecal whale samples (collected during whale seasons 2013, 2014 and 2015) by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The genus Pseudo-nitzschia was present in both gulfs during the considered whale season. Pseudo-nitzschia spp. cell abundances ranged between 440 and 4.56 x 105 cell l-1. The species found at highest abundances was P. australis up to 4.56 x 105 cell l-1. DA in phytoplankton was generally low, with the exception of samples collected during the P. australis bloom. No clear correspondence was found between DA in phytoplankton and mesozooplankton samples. The dominance of copepods in mesozooplankton indicated that copepods were the main vector for the transfer of DA from Pseudo-nitzschia spp. to highest trophic levels including the southern right whales. High levels of DA were detected in four whale fecal samples (ranging from 0.30 to 710 μg g-1). The maximum level of DA detected in fecal samples (710 μg DA g-1) is the highest reported in marine mammal fecal samples to date including those reported during marine mammal mortality events. Our findings demonstrated for the first time that live individuals of southern right whales Eubalaena australis are exposed to DA via copepods as vector during their reproductive stay in the gulfs of Península Valdés.