Exposure of the North Atlantic right whale Eubalaena glacialis to the marine algal biotoxin, domoic acid

Abstract

In addition to ship collisions and fishing gear entanglements, recovery of the highly endangered North Atlantic right whale Eubalaena glacialis has been challenged by reproductive abnormalities and compromised health. Of the factors hypothesized as contributing to the observed reproductive dysfunction in right whales, exposure to marine biotoxins such as domoic acid (DA) has received comparatively little consideration. The present study assessed the occurrence of DA in right whale feces, copepods, and krill collected from April through September of 2005 and 2006 on the whales' feeding grounds along the northeastern USA and eastern Canada. DA was detected by surface plasmon resonance (SPR) in 69 right whale fecal samples, 6 krill samples, and 32 copepod samples. Many of the latter were dominated largely by Stage V Calanus finmarchicus copepodites. DA detection by SPR in fecal and zooplankton collections was verified by receptor binding assay and confirmed using liquid chromatography -tandem mass spectrometry (LC-MS/MS). Moreover, LC-MS/MS determined the presence of a putative methylated DA metabolite in all fecal and zooplankton samples analyzed. Frustules of several potentially toxic Pseudo-nitzschia spp. were identified in whale feces and phytoplankton samples by light and electron microscopy. Electron microscopy also revealed an abundance of C. finmarchicus mandibles in right whale feces. These findings confirm that E. glacialis was exposed to DA for several months, likely through ingestion of a DAcontaminated copepod vector. The extent to which this algal biotoxin may contribute to the failed recovery of the E. glacialis population warrants further investigation. KEY WORDS: Domoic acid · Eubalaena glacialis · Right whale · Pseudo-nitzschia · Calanus finmarchicus · Copepod · Biotoxin trophic transfer · Harmful algal blooms Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 398: 287-303, 2010 (Clapham et al. 1999, Knowlton & Kraus 2001). An overall low reproductive rate coupled with highly variable annual calving numbers represent further impediments to the recovery of this species (Kraus et al. 2001(Kraus et al. , 2007. Reproductive abnormalities were especially pronounced during the 1990s when the interval between calving for mature females increased from about 3.5 to almost 6 yr, and the age of first parturition also increased. Although causes of the apparent reproductive dysfunction in E. glacialis are not clear, reproductive success may be affected by habitat loss or degradation, nutritional stress, low genetic variability, disease, and sublethal exposure to pollutants as well as natural toxins such as paralytic shellfish poisoning (PSP) and amnesic shellfish poisoning (ASP) toxins produced by marine microalgae (Reeves et al. 2001).ASP is a syndrome resulting from human ingestion of seafood, primarily shellfish, contaminated with domoic acid (DA), a potent water-soluble neurotoxin produced by certain species of the diatom genus Pseudonitzschia. DA bi...

Potentially toxic Pseudo-nitzschia species in plankton and fecal samples of Eubalaena australis from Península Valdés calving ground, Argentina

“…DA levels in zooplankton samples (mostly copepods) collected during their study ranged from 0.02 to 0.17μg DA g -1 . In parallel, the presence of remains of the copepod Calanus finmarchicus in all whale feces led to the conclusion that E. glacialis was exposed to DA by ingestion of contaminated copepods (Leandro et al, 2010). Similarly, trace levels of saxitoxin and DA were detected in samples of feces, urine and tissues collected from dead individuals of E. australis in PV (Uhart et al, 2009;Rowntree et al, 2013).…”

“…in fecal samples of stranded and live individuals of the North Atlantic right whales (Eubalaena glacialis) that had been feeding in their feeding grounds in spring and summer (Leandro et al, 2010). DA levels in zooplankton samples (mostly copepods) collected during their study ranged from 0.02 to 0.17μg DA g -1 .…”

“…identification following Leandro et al (2010) with slight modifications. One mL of each fecal sample was pipetted onto 3 µm pore, 47 mm diameter polycarbonate filter and rinsed under low vacuum with 10 mL of distilled water.…”

Pseudo-nitzschia physiological ecology, phylogeny, toxicity, monitoring and impacts on ecosystem health

“…North Atlantic DA present in body and feces, frustules in feces Bates and Trainer (2006), and Leandro et al (2010b) California sea lion…”

“…comm.). Later, DA was detected in fecal samples of the highly endangered North Atlantic right whale (Eubalaena glacialis) in the Gulf of Maine and Georges Bank, and in its food source (krill and copepods), from April to September of 2005and 2006(Leandro et al, 2010b Bates et al, 1998). It is also the first time that a diatom produced a phycotoxin.…”