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

DEGRATI, MARIANA; KROCK, BERND; HOFFMEYER, MÓNICA S.; D'AGOSTINO, VALERIA C.; SANTINELLI, NORMA; DANS, SILVANA L.; SASTRE, VIVIANA; KROHN, TORBEN

HARMFUL ALGAE

ELSEVIER SCIENCE BV

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

1568-9883

The gulfs that surround Península Valdés (PV), Golfo Nuevo and Golfo San José in Argentina, areimportant calving grounds for the southern right whale Eubalaena australis. However, high calf mortalityevents in recent years could be associated with phycotoxin exposure. The present study evaluated thetransfer of domoic acid (DA) from Pseudo-nitzschia spp., potential producers of DA, to living and deadright whales via zooplanktonic vectors, while the whales are on their calving ground at PV.Phytoplankton and mesozooplankton (primary prey of the right whales at PV and potential grazersof Pseudo-nitzschia cells) were collected during the 2015 whale season and analyzed for speciescomposition and abundance. DA was measured in plankton and fecal whale samples (collected duringwhale seasons 2013, 2014 and 2015) using liquid chromatography coupled to tandem mass spectrometry(LC?MS/MS). The genus Pseudo-nitzschia was present in both gulfs with abundances ranging from4.4 102 and 4.56 105 cell l1. Pseudo-nitzschia australis had the highest abundance with up to4.56 105 cell l1. DA in phytoplankton was generally low, with the exception of samples collected duringa P. australis bloom. No clear correlation was found between DA in phytoplankton and mesozooplanktonsamples. The predominance of copepods in mesozooplankton samples indicates that they were theprimary vector for the transfer of DA from Pseudo-nitzschia spp. to higher trophic levels. High levels of DAwere detected in four whale fecal samples (ranging from 0.30 to 710 mg g1 dry weight of fecal sample orfrom 0.05 and 113.6 mg g1wet weight assuming a mean water content of 84%). The maximum level of DAdetected in fecal samples (710 mg DA g1 dry weight of fecal sample) is the highest reported in southernright whales to date. The current findings demonstrate for the first time that southern right whales, E.australis, are exposed to DA via copepods as vectors during their calving season in the gulfs of PV.