Impacts of HABs on Marine Mammals
Just as human consumers of seafood contaminated with biotoxins
of algal origin are at risk, many animals at higher levels of the marine food web
are impacted by HABs. Some toxins are fat soluable and bioaccumulate in higher
trophic levels. Others still transfer through successive stages, sometimes having
lethal impacts where they are least expected, such as with this humpback whale,
one of 14 that died near Cape Cod, MA in a one-month period due to saxitoxin in
mackerel that they had consumed. Photo courtesy of G. Early.
It has now been confirmed that more than 150 deaths of the Florida manatees
occurred in 1996 due to affects of algal toxins produced by G. breve. Estimates
suggest that about 10% of the endangered population was wiped out. Both stomach
contents and lung tissue contained the toxins suggesting that the toxins entered
through the food web as well as from direct contact of the toxic aerosols when the
animals broke the surface to breathe. Photo courtesy of Florida Department of Environmental Protection.
