Right whales found off
Grand Manan Island are regularly exposed to toxins from their food source,
Right whales eating
ENVIRONMENT: Toxins present, say scientists
studying off Grand Manan
The toxin that
causes paralytic shellfish poisoning may also be contributing to the declining
North Atlantic right whale population.
the University of Rhode Island doing research off Grand Manan Island have found
that right whales are regularly exposed to the toxins causing paralytic
poisoning by eating contaminated zooplankton.
found that the zooplankton that the right whales are feeding on have
significant levels of PSP toxin in them," Dr. Edward Durban said Monday.
It is estimated that only 300 of the whales are left in
the world. They travel to the Bay of Fundy late every summer and spend a few
months feeding in the area.
The team led by "Mr. Durban
recently published its findings in the journal Harmful Algae showing
that the whales could be ingesting enough of the toxin to affect their
breathing and how deep they can dive.
Limits on diving
ability could reduce how much food they can consume and ultimately have an
impact on reproduction abilities, he said.
The toxin in
the red tide algae stops nerves from functioning.
zooplankton, which are a preferred source of food for the right whales, are
picking up the toxin from the algae that contaminates clam flats around the Bay
Humans who eat contaminated shellfish
experience muscle weakness. Higher doses can result in death when breathing
shuts down because of the nerve toxin.
The study was a
collaborative effort using information from other studies that showed how deep
the whales were diving to feed.
"They were feeding at a
very specific depth, about 140 metres, and there was a very dense layer of
zooplankton at that level," he said.
The Rhode Island
team was able to collect samples of zooplankton from that part of the ocean and
measure the toxins in the organisms.
An estimate of how
much toxin the whales were ingesting was made based on the concentration of it
in the zooplankton combined with how long the whales spent feeding in the area.
We don't have
funding to go out and
investigate this further
DR. EDWARD DURBAN
"It's a significant
level," he said.
The toxin is water soluble so it would
not be stored in tissues but would have an affect on the whales during the time
they feed on the contaminated plankton.
The Rhode Island
team would like to go to the next level to try to discover if there is a link
between the health of the right whale population and the toxin from the red
tide algae that gets into their food supply.
have specific funding to go out and investigate this further at this point," he