Researchers Hope Whale Tragedy Will Help Explain Dolphin Deaths
BOSTON (AP) _ Contaminated mackerel were found in the stomachs of nine whales found dead recently along Cape Cod beaches, a discovery that may help explain other mysterious marine fatalities, researchers said Saturday.
″We have what appears to be an unprecedented mortality in marine mammals,″ marine pathologist Joseph R. Geraci told reporters.
″Perhaps not unprecedented in that it occured, but unprecedented in that we have discovered for the first time a biological toxin that is directly reponsible for the deaths.″
Residues of a paralytic shellfish toxin, originating in algae known as red tide, were detected in the internal organs of mackerel found in the whales’ stomachs and in the organs of fresh mackerel caught off Cape Cod. The whales washed ashore on Cape Cod in the past three weeks.
″The link is more than circumstantial,″ he said at the New England Aquarium.
Scientists will use the discovery to re-evaluate the deaths of some 500 bottlenose dolphins along the mid-Atlantic coast since the summer, as well as other unexplained marine fatalities, including dead geese found in the same region as the whales, he said.
″I’m not suggesting at the moment there is a close link (with the dolphin deaths), but we can’t disregard it,″ he said. ″We will be redirecting our efforts.″
Researchers attributed their discovery to Thursday’s finding of a fresh humpback whale carcass, which held tainted mackerel.
″By the time they are ashore, the state of the carcass provides us with very limited opportunity to investigate the cause of mortality,″ said Geraci, a marine mammal expert from the University of Guelph in Ontario.
Paralytic shellfish poison is a toxic substance usually found in shellfish in the spring, summer and fall, said Don Anderson of the Woods Hole Oceanographic Institute.
″It’s well known that fish can die from the particular poison,″ Anderson said. ″The unusual thing here is that the fish are carrying what appears to be a substantial level of toxin″ without being affected themselves.
The toxins were found in the internal organs of the mackerel and not in their flesh, said Ralph Timperi of the Massachusetts Department of Public Health.
The department issued an advisory Friday against public consumption of mackerel as a precaution while further testing is done.
″There is a bit of a mystery as to where the toxins may have originated, or if they originated sometime ago,″ said Anderson.
The scientists doubt the poison originated in the immediate area because shellfish along the New England coast have not shown signs of the toxin.
A second poison also has been identified in the mackerel and whales, but not enough information has been gathered to determine if it was involved in the deaths, said Timperi. He said it was too early to say exactly what the poison was.