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

Abstract

The gulfs that surround Península Valdés (PV), Golfo Nuevo and Golfo San José in Argentina, are important calving grounds for the southern right whale Eubalaena australis. However, high calf mortality events in recent years could be associated with phycotoxin exposure. The present study evaluated the transfer of domoic acid (DA) from Pseudo-nitzschia spp., potential producers of DA, to living and dead right 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 grazers of Pseudo-nitzschia cells) were collected during the 2015 whale season and analyzed for species composition and abundance. DA was measured in plankton and fecal whale samples (collected during whale 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 from 4.4×10 and 4.56×10 cell l. Pseudo-nitzschia australis had the highest abundance with up to 4.56×10 cell l. DA in phytoplankton was generally low, with the exception of samples collected during a P. australis bloom. No clear correlation was found between DA in phytoplankton and mesozooplankton samples. The predominance of copepods in mesozooplankton samples indicates that they were the primary vector for the transfer of DA from Pseudo-nitzschia spp. to higher trophic levels. High levels of DA were detected in four whale fecal samples (ranging from 0.30 to 710μgg dry weight of fecal sample or from 0.05 and 113.6μgg wet weight assuming a mean water content of 84%). The maximum level of DA detected in fecal samples (710μg DA g dry weight of fecal sample) is the highest reported in southern right 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.

Occurrence of Toxigenic Microalgal Species and Phycotoxin Accumulation in Mesozooplankton in Northern Patagonian Gulfs, Argentina

“…In contrast, harvests have not been closed due to domoic acid, a neurotoxin produced by species of the diatom genus Pseudo‐nitzschia (the regulatory limit for domoic acid being 20 μg g –1 of mussel tissue). Although no cases of ASP events have been documented to date either in wildlife or in humans in the Northern Patagonian gulfs, previous research carried out in Golfo Nuevo and Golfo San José showed the presence of domoic acid in samples of phytoplankton and mesozooplankton (mostly calanoid copepods), as well as in fecal samples of whales ( Eubalaena australis ) collected at similar sites and on similar dates to those of the present study (D'Agostino et al ). These findings indicate that southern right whales are exposed to domoic acid through the ingestion of contaminated zooplankton, mainly copepods, while they remain in their calving grounds in these gulfs.…”

“…Abundance (ind m –3 ) of potential vectors of phycotoxin and phycotoxin levels present in mezooplankton samples from Golfo Nuevo ( A ) and Golfo San José ( B ). Domoic acid (DA) data from June to December 2015 in Golfo Nuevo and July to November 2015 in Golfo San José were taken from D'Agostino et al (). C = N ‐sulfocarbamoyl toxins; GTX = gonyautoxins; PTX = pectenotoxins; SPX = spirolides; DTX = dinophysistoxins.…”

First Evidence of the Toxin Domoic Acid in Antarctic Diatom Species

“…The area is especially important to the humpback whale (Megaptera novaeangliae) and the southern right whale (Eubalena australis). Both are dependent on the Antarctic region to feed on krill before the long fasting periods, which they spend calving at lower latitudes [34,35]. However, krill is an important vector for DA [15], and DA can cross the placental barrier of pregnant marine mammals [15].…”

“…However, krill is an important vector for DA [15], and DA can cross the placental barrier of pregnant marine mammals [15]. This raises concern for the accumulation of DA in marine mammals in the Antarctic region [4,34,35]. Thus, toxigenic blooms of DA-producing diatoms have the potential to disturb a marine ecosystem, which is already susceptible to the effects of climate change.…”

Can domoic acid affect escape response in copepods?

“…Diatoms of the genera Nitzschia and Pseudo-nitzschia produce a neurotoxin, domoic acid (DA), which can be transferred via copepods to higher food web levels (Leandro et al, 2010a;Tammilehto et al, 2012;D'Agostino et al, 2017) and intoxicate organisms such as seabirds, whales and seals (Fritz et al, 1992;Leandro et al, 2010b;Jensen et al, 2015). Domoic acid can also cause amnesic shellfish poisoning in humans (Quilliam and Wright, 1989;Landsberg, 2002).…”