Study of freshwater turtles to improve treatment of toxins in sea turtles
New research is paying off long-term for endangered sea turtles facing illness and even death during Florida red tides. From 2011-2014, the NCCOS sponsored project “Brevetoxin Metabolism and Physiology – A Freshwater Model of Morbidity in Endangered Sea Turtles” used non-endangered freshwater turtles as models to determine the effects of Florida red tide on endangered sea turtles.
Karenia brevis, the Florida red tide organism, produces a suite of nerve toxins called brevetoxins. The toxins cause human respiratory illness along beaches and accumulate in shellfish, which, when consumed by humans, cause Neurotoxic Shellfish Poisoning. Severe blooms result in mass mortality of fish and a number of protected and endangered species. Among the species impacted are threatened and endangered sea turtles.
With sea turtles, brevetoxin concentrations that compromise organ physiological and immune functions are generally unknown. Due to the legal status of federally protected sea turtles, basic physiological questions cannot be addressed directly, as they require experimental investigation with controlled doses of toxins on healthy animals. The use of freshwater turtles as a surrogate physiological system allows for the determination of effects of brevetoxins on turtle physiology and immunology and helps develop effective treatment plans for sea turtles.
Led by Dr. Sarah Milton (Florida Atlantic University) and co-lead Dr. Catherine Walsh (Mote Marine Laboratory), the research project used freshwater turtles to identify how red tide toxin gets into turtles, how long it stays, and the impacts on organs such as the lungs, muscles, and nervous system. The research continued beyond 2014 with funding from the U. S. National Institutes of Health and other agencies.