Dinoflagellate Crop in the North Sea: Biological Observations associated with the Toxic Phytoplankton Bloom off the East Coast

Marine zooplankton can accumulate and retain dinoflagellate toxins and cause fish kills

“…Adams et al (1968) first suggested that planktonic herbivores may play a role in fish kills by acting as vectors of dinoflagellate toxins. In the 1976 herring kill in the Bay of Fundy, G. excavata toxins were measured in the stomachs of dead fish, and later experiments showed that these levels of toxins (21 Fg STX equiv.…”

“…The probability that the toxins were transmitted by pteropods (Limacina retroversa) after feeding on the dinoflagellates raised major questions concerning the role of herbivorous zooplankton as vectors of dinoflagellate toxins, the fate of the toxins in planktonic food chains, and the consequences to higher marine organisms, especially fish. About 10 years earlier, Adams et al (1968) had suggested that planktonic herbivores acted as intermediaries in a kill of sand lance (Ammodytes sp.) following a G. tamarensis bloom off the northeast coast of the United Kingdom.…”

Toxic dinoflagellates and marine mammal mortalities : proceedings of an expert consultation held at the Woods Hole Oceanographic Institution

“…In 1976 and 1979, massive kills of adult herring occurred in the Bay of Fundy during Alexandrium blooms as a result of toxin transfer through zooplankton (White, 1980). Similar events, involving Alexandrium toxins, zooplankton and kills of sand lance occurred in England in 1968 (Adams et al, 1968) and off Cape Cod in 1978 (Nisbet, 1983 for a 100-g fish (White, 1981b). Experimental studies show that ingestion of zooplankton containing much less toxin than this cause mortality of marine fish larvae (White et al, 1989).…”

“…Toxin levels as high as 1400 pg toxins/lOOg viscera have been reported (White, 1984). Past experience has shown that toxin levels in the viscera can be high enough so that ingestion of whole fish can cause kills of seabirds (Adams, 1968;Nisbet, 1983), carnivorous fish (Nisbet, 1983) and humans (Adnan, 1984). During a Pyrodiniwn red tide in Indonesia in 1983,4 people were killed and 191 became ill from "paralytic shellfish poisoning" after eating whole planktivorous (clupeoid) fish taken alive from the red tide area.…”

Gymnodinium blooms in the Helgoland bight (North Sea) during August, 1968

“…They started in April and May and caused extensive mortality of fish, shellfish and seabirds (ROBINSON 1968, ADAMS et al 1968, INCHAM et al 1968, CLARK 1968, McCoLLuM et al 1968, COULSON et al 1968.…”