A dangerous toxin has been found in the endangered monk seal in the oceans off Hawaii, sparking a hunt for more contaminated sea creatures.

Scientists from the American National Oceanic and Atmospheric Administration (NOAA) discovered ciguatoxin in the Hawaiian monk seal and are concerned other marine mammals may have come into contact with the poison which is produced by marine algae. The toxin can be passed to humans, causing the disease Ciguatera, which has symptoms similar to chronic fatigue syndrome and also causes gastrointestinal problems.

Humans pick up the toxin by eating contaminated fish as the poison passes up the food chain.

There are only some 1,100-1,200 of the seals left in the wild and any threat to their health is taken seriously at a time when the population has been decreasing by four per cent a year as their habitat comes under increasing pressure from humans.

The NOAA team took samples from the seals around the Hawaiian Islands including in the protected Papahanaumokuakea Marine National Monument and tested them in Charleston South Carolina. Their results are published on the American Chemical Society's (ACS) website.

"Based upon this study, we believe that ciguatoxin exposure is common in the monk seal population," said Charles Littnan, study co-author and scientist with NOAA Pacific Islands Fisheries Science Centre. "This study is an important first step. However, we still need to understand more clearly how widespread exposure is and more importantly what role it may be playing in the decline of the species."

Top Image: Hawaiian Monk Seal (Credit: NOAA.)