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| courtesy: NOAA |
The drastic decline in Hawaii's critically endangered monk seal
(Monachus schauinslandi) population may have a natural cause. Ciguatoxins are potent neurotoxins concentrated in fish eaten by the seal. Scientists from NOAA suspect that seals are exposed to significant levels that may play a role in their collapsing population. Numbers of monk seals in the Hawaiian islands are estimated at between 1100 and 1200. Samples were collected from dead and live animals to be analyzed at NOAA's National Center for Coastal Ocean Science. Both sample groups showed ciguatoxin activity. Monk seals are endemic to the islands and efforts have been made to stabilize their population which is declining at 4% per year. Environmental degradation is a factor in their declining health, but the neurotoxin presents a challenge to species management. More study of causation is needed according to Charles Littnan, lead researcher for NOAA. The only previous report of ciguatoxin exposure was in 1978. In humans ciguatera poisoning is an illness associated with eating fish that contain toxins produced by a marine microalgea,
Gambierdiscus toxicus. It is not unusual for marine invertebrates to release toxins as a defense mechanism, some of which can be deadly to mammals, when
under environmental stress. It is well known that reefs all over the world are dying due to pollution and seawater temperature increases. In 2010 a
massive die off killed an estimated 16% of the world's coral reefs.