Multiple New Paralytic Shellfish Toxin Vectors in Offshore North Sea Benthos, a Deep Secret Exposed

Abstract

In early 2018, a large easterly storm hit the East Anglian coast of the UK, colloquially known as the ‘Beast from the East’, which also resulted in mass strandings of benthic organisms. There were subsequent instances of dogs consuming such organisms, leading to illness and, in some cases, fatalities. Epidemiological investigations identified paralytic shellfish toxins (PSTs) as the cause, with toxins present in a range of species and concentrations exceeding 14,000 µg STX eq./kg in the sunstar Crossaster papposus. This study sought to better elucidate the geographic spread of any toxicity and identify any key organisms of concern. During the summers of 2018 and 2019, various species of benthic invertebrates were collected from demersal trawl surveys conducted across a variety of locations in the North Sea. An analysis of the benthic epifauna using two independent PST testing methods identified a ‘hot spot’ of toxic organisms in the Southern Bight, with a mean toxicity of 449 µg STX eq./kg. PSTs were quantified in sea chervil (Alcyonidium diaphanum), the first known detection in the phylum bryozoan, as well as eleven other new vectors (>50 µg STX eq./kg), namely the opisthobranch Scaphander lignarius, the starfish Anseropoda placenta, Asterias rubens, Luidia ciliaris, Astropecten irregularis and Stichastrella rosea, the brittlestar Ophiura ophiura, the crustaceans Atelecyclus rotundatus and Munida rugosa, the sea mouse Aphrodita aculeata, and the sea urchin Psammechinus miliaris. The two species that showed consistently high PST concentrations were C. papposus and A. diaphanum. Two toxic profiles were identified, with one dominated by dcSTX (decarbamoylsaxitoxin) associated with the majority of samples across the whole sampling region. The second profile occurred only in North-Eastern England and consisted of mostly STX (Saxitoxin) and GTX2 (gonyautoxin 2). Consequently, this study highlights widespread and variable levels of PSTs in the marine benthos, together with the first evidence for toxicity in a large number of new species. These findings highlight impacts to ‘One Health’, with the unexpected sources of toxins potentially creating risks to animal, human and environmental health, with further work required to assess the severity and geographical/temporal extent of these impacts.

First Report of Paralytic Shellfish Toxins in Marine Invertebrates and Fish in Spain

“…However, to the best of our knowledge, there are no previous reports of ascidians, starfish or squids contaminated with PSTs in Spain. None of the recent articles [ 11 , 12 , 13 ] about PSTs in non-traditional vectors from European waters report the presence of PSTs in fish. Moreover, we could only find a Canadian paper reporting the presence of PSTs in the Humboldt squid ( Dosidicus gigas ) [ 28 ].…”

“…This is the case of the EU where Regulation (EC) No 853/2004 sets the maximum PSTs concentrations in bivalve mollusks, echinoderms, tunicates and marine gastropods [ 10 ]. In recent years, several papers reported, for the first time, the presence of PSTs in non-traditional vectors in different European countries [ 11 , 12 , 13 ]. However, to our knowledge, studies describing the presence of PSTs on several non-bivalve mollusk marine invertebrate vectors have not been conducted in Spain.…”

Paralytic and Amnesic Shellfish Toxins Impacts on Seabirds, Analyses and Management

“…), to a variety of suspension and filter-feeding shellfish, cephalopods, crabs, echinoderms, snails, bryozoans, etc., as well as planktivorous fish (herring, mackerel, sardine, anchovies, etc. ), they can all consume and retain toxic microalgae, incorporating and potentially transferring their toxins in the food chain [ 22 , 23 , 71 , 72 , 73 , 74 , 75 , 76 , 77 ]. With regard to ASTs and PSTs, as well as for other biotoxins, some of these vectors convert the original compounds from the microalgae to other congeners, to eliminate them and detoxify their tissues [ 18 , 35 , 78 , 79 ].…”

“…Other species produce potent toxins during blooming, which can be accumulated by filter feeders [ 19 ]. Within marine ecosystems, harmful algal toxins can be transmitted through the food web from zooplankton to different fish, marine invertebrates (gastropods, crustaceans, equinoderms, tunicates), seabirds, marine mammals, and people [ 20 , 21 , 22 , 23 ]. Marine biotoxins pose a serious threat to human health.…”

Effects of long-term low dose saxitoxin exposure on nerve damage in mice

“…A survey conducted in the North Yellow Sea of China from 2011 to 2012 found the concentration of STX in the range of 30 to 788μg/kg [ 7 ]. In the summers of 2018 and 2019, high concentrations of PST were detected in the Southern Bight of the UK, with mean toxicity of 449 μg STX eq./kg [ 8 ]. Recently, the concentrations of STX in freshwater reservoirs in Brazil have reached as high as 0.05μM [ 9 ].…”