Three phytoplankton species blooms which have been reported harmful to fisheries in UK waters are discussed:
(1) The armoured dinoflagellate Gonyaulax tamarensis has caused
harmful levels to humans of paralytic shellfish poison in
most years since 1968 in shellfish from sites on the British
east coast between 54.5°N and 56.7°N. The months of maximum
toxicity are May and June.
(2) Red tides of the naked dinoflagellate Gyrodinium aureolum
have caused mortalities of wild marine animals in south-west
England in 1978 and in North Wales in 1971, and killed farmed
salmon in the west of Scotland in 1980. These red tides
occurred between August and October. The dinoflagellate
occurs all along the west coast of Britain and is often abundant
at fronts.
(3) Blooms of 'flagellate X', possibly a species of Olisthodiscus
or Chattonella, have killed farmed fish in sea-lochs on the west
coast of Scotland in 1979 and 1982.
