Blue crabs affected by blue-green algae – and other stories

18 August 2013

Woman collecting mussels at low tide.  Photo: Bill Harding

Women collecting mussels at low tide. Photo: Bill Harding

An article from from Richmond (Virginia, USA) reports that the cyanobacterial liver toxin, microcystin, has been found in blue crabs near the mouth of the James River. According to the report, there is no cause for concern right now.  Fish, filter feeders and, it seems, crabs, can accumulate cyanobacterial toxins in their flesh.  Some years ago I was involved with a South African case where mussels, which formed an important component of the diet or income source for a poor community, were affected by an algal bloom in the lake upstream of the estuary. For interest I have included chromatograms from my analyses of two liver toxins, microcystin-LR and -YR in the algae and in the mussels.

Chromatograms showing accumulation of the cyanotoxins M-LR and M-YR in the flesh of marine mussels (Photo: Bill Harding)

Chromatograms showing accumulation of the cyanotoxins M-LR and M-YR in the flesh of marine mussels (Photo: Bill Harding)

Portland’s (Oregon) Blue Lake might need to consider a name change as a another blue-green algal bloom has been reported.  Fern Ridge Lake, also in Oregon, is also off-limits right now. Together with Blue Lake, Lake Dorena and Dexter Lake, this makes four in Oregon this summer.

A health advisory was issued for Blue Lake due to algae Tuesday. The public was asked to avoid contact with Blue Lake water until the advisory is lifted. The advisory was issued after blue-green algae scum was found on Blue Lake, near Wood Village, said a spokesman for the Oregon Health Authority. Authorities were determining weather the algae contained harmful toxins. Until then, people and animals should avoid coming in contact with lake water. Officials said algae toxins could not be removed by boiling, filtering or treating the water. Homes or campers using water directly from the lake should find an alternate water source. Fish caught from Blue Lake should have all fat, skin and organs removed before cooking. Officials also advised that clams and mussels from Blue Lake should be avoided.

Canada’s state of Alberta seems to be having a very bad year for algal blooms.  Yet another one has been reported for Travers Reservoir (Eagle Lake).  Staying in Alberta, blooms have also been reported for Pigeon Lake and Lac du Nonne (Edmonton) and Alix Lake.

In Ohio, Lake Erie remains in the algal news with reports of blooms developing in the western basin.  “Noteworthy” levels of toxin have been recorded east of Toledo at Maumee State ParkWarnings also have been posted at beaches at Grand Lake St. Marys in western Ohio, East Fork State Park near Cincinnati and Buckeye Lake in central Ohio.

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