Thursday, October 13, 2016

BayKeeper Blog: Harmful Algal Bloom Present Bay-wide

By Tom Kutcher, Narragansett BayKeeper

You may have heard about a “harmful algal bloom” (HAB) that has taken hold in Narragansett Bay starting last week. This bloom, or overabundant growth of phytoplankton (microscopic plants), is now confirmed throughout the Bay, including East and West Passages, Mount Hope Bay, the Sakonnet River, and all sub-estuaries (coves and smaller bays) and tributaries. The HAB has not been found in RI salt ponds at this point.

The HAB is responsible for releasing a toxin that can cause stomach problems and long and short-term amnesia, according to The R.I. Department of Environmental Management (DEM). It concentrates in the guts and tissues of shellfish as they filter-feed on the algae. Eating the shellfish may expose you to dangerous levels of the toxin. DEM has therefore closed all Bay waters to shellfishing until further notice. This includes both commercial and recreational shellfishing.

DEM does not know what triggered the HAB. It is known that this is a species that is generally present in the Bay at low levels and produces the harmful toxin at very high levels.

The HAB is concerning for a number of reasons:

  1. This closure differs from common bacteria-related closures in that the toxin produced by the HAB is not a living organism and therefore is not eliminated when you cook the shellfish. 
  2. The algae comprising the HAB are a cool-water species, so there is no known timeframe for the persistence of the bloom.
  3. Shell fishermen will therefore be out of work indefinitely until the bloom subsides.
  4. It is unknown at this point how long it takes for the shellfish to purge the toxin once the bloom stops.
  5. Rhode Islanders like me who regularly eat local shellfish are out of luck until the situation passes.
  6. It is unknown whether swimming in the Bay is safe at this point.

DEM and the R.I. Department of Health are working with the State of Maine to try to find answers to all the unknowns. Maine is also currently experiencing their first occurrence of this specific HAB along a significant stretch of their coastline. I will post another blog as I find out more. But, for now, don’t go clamming or eat any local shellfish until you hear that it is safe from our State agencies.

Link this to DEM first mention:

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