Subject: Sea Otters/Pollution - Ship paints and sea otters (fwd)

Mike Williamson (pita@www1.wheelock.edu)
Fri, 17 Apr 1998 10:19:50 -0400 (EDT) 

---------- Forwarded message ----------
Date: Wed, 15 Apr 1998 08:31:14 -0400
From: Dagmar Fertl <Dagmar_Fertl@mms.gov>
Reply-To: Marine Mammals Research and Conservation Discussion
     <MARMAM@UVVM.UVIC.CA>
To: MARMAM@UVVM.UVIC.CA
Subject: newsclip - Ship paints and sea otters

     Ship paints may lead to sea otter deaths

     (ENN) -- Chemicals used in ship paint to prevent hulls from becoming
     encrusted with barnacles may have contributed to the deaths of
     hundreds of sea otters found on the shores of California,
     according to a researcher at the University of Michigan.

     Tests run on the dead sea otters reveal high levels of the
     anti-fouling agent tributyltin (TBT) and other butyltin (BT)
     compounds, which, according to Dr. Kurunthachalam Kannan,
     may have attributed to immunosuppression in the otters and
     increased their susceptibility to infections.

     Sea otters that died of infectious diseases contained greater
     concentrations of BTs in their tissues than those that died of trauma
     or unknown causes.

     Butyltins are organic tin compounds used in marine ship paints to
     prevent hulls and docks from becoming encrusted with barnacles.

     However, the chemicals have been found to have negative impacts
     on organisms such as mollusks and gastropods and, more recently,
     marine mammals such as dolphins.

     In 1989, TBT was banned in all states on vessels of 25 meters or
     less in length. However, because BTs persist in sediment for years,
     wildlife continues to be exposed to them. In addition, BTs are still
     used on larger vessels and aluminum-hulled boats.

     Large harbors, such as California's Monterey Bay, that handle a
     plethora of ships greater than 25 meters in length and thus are
     legally painted with TBT, continue to experience high inputs of
     BTs.

     Since sea otters tend to hang out in harbors, they are particularly
     vulnerable to this contamination. Sea otters feed on such species as
     scallops, mussels, rock crabs and sea urchins, which accumulate high
     levels of BTs. As a result, levels of BT contamination in some sea
     otters found dead along the California coast were as high as those
     found in dead finless porpoises from Japan and diseased bottlenose
     dolphins from the United States.

     A paper on the findings, written by Kannan and colleagues, will
     appear in a forthcoming issue of Environmental Science and
     Technology.