Date of introduction and origin
Coscinodiscus wailesii was first detected in the
English Channel in 1977 (as Coscinodiscus nobilis Grunow)
and is thought to originate from the Indian and Pacific Oceans
(Boalch & Harbour 1977; Boalch 1987; Wallentinus in
Method of introduction
Unknown method of introduction, but ballast water transport
cannot be ruled out and importation with oysters has been
hypothesised as another potential vector (Rincé & Paulmier
1986; Wallentinus in press).
Reasons for success
Rate of spread and methods involved
It spread rapidly and was recorded from the English Channel
(near Plymouth, Devon) in 1977; Atlantic coast of France by 1978
and Norway by 1979 (Hasle 1990; Wallentinus in press).
It is found in the English Channel, Atlantic coast of France,
Frisian Islands, Helgoland and Norway (Rincé & Paulmier 1986;
Wallentinus in press).
Factors likely to influence spread and distribution
Effects on the environment
It can reach high numbers and produce copious mucilage which
'in sinking' can accumulate insoluble skeletons of planktonic
organisms and mineral particles, increasing its volume and density
(Boalch & Harbour 1977) and blanket the seabed.
Effects on commercial interests
Fishing trawls may become clogged or broken by heavy grey
slime. It may interfere with the hauling of fishing gear and
prolonged washing or air drying may not completely remove it
(Boalch & Harbour 1977).
Control methods used and effectiveness
Boalch (1987) reported Coscinodiscus wailesii to be
still present in the Plymouth area and to have become a major
constituent of the winter centric diatom population.
Boalch, G.T. 1987. Changes in the phytoplankton of the western
English Channel in recent years.
British Phycological Journal, 22: 225-235.
Boalch, G.T., & Harbour, D.S. 1977. Unusual diatom off the
coast of south-west England and its effect on fishing.
Nature, 269: 687-688.
Rincé, Y., & Paulmier, G. 1986. Donnée novelles sur la
distribution de la diatomée marine Coscinodiscus wailesii
Gran & Angst (Bacillariophyceae). Phycologia. 25:
Hasle, G.R. 1990. Diatoms of the Oslo fjord and the Skagerrak.
Species new to the area: immigrants or overlooked in the past?
Blyttia 48 : 33-38.
,Wallentinus, I. In press.Status of introductions of
non-indigenous marine species to north Atlantic waters:
introductions and transfers of plants. ICES co-operative