A Caribbean Reef shark.
Shedd Aquarium, a leader of aquatic animal medicine and conservation, in collaboration with Disney’s Animal Programs and Dynasty Marine Associates, is pioneering cutting-edge research for a group of species often perceived to be the toughest creatures in the ocean – sharks. Led by Shedd veterinarian Lisa Naples, DVM, and Natalie Mylniczenko, DVM, M.S., Dip ACZM, of Disney’s Animal Programs, a team of veterinary experts is conducting a blood assessment study on sharks to learn more about how stress affects the species, as published in the July issue of the Journal of the American Veterinary Medical Association (JAVMA). The ongoing research involves topics that are the first of its kind in the animal science community.
Sharks may hold the top spot in the marine food chain, but researchers have discovered the animals can have life-threatening physical responses to certain environmental factors, such as heavy pollution or being caught on a fishing line. Evidence shows that stress can cause major declines in shark populations, creating greater peril for a group of species threatened by overfishing and pollution, among other challenges.
In the Florida Keys this June, the team conducted health assessments on 46 sharks over two and a half days, gathering critical information from the field about sharks’ primary and secondary stress responses, which involve changes in blood values and stress proteins.
Findings from the multi-year study of sharks in the wild will be evaluated based on data gathered over the last eight years from the sharks at the aquarium. Samples obtained from sharks at Shedd through annual examinations from animal health experts provided key information to validate “normal” blood values in various shark species, which are used as a reference throughout the scientific and animal care community.
“The research that we’re conducting today has significant implications for sharks in the future,” said Dr. Naples. “With the support of all my colleagues, our work will study the impact that issues such as climate change, oil spills and other environmental factors have on the overall health of sharks.”
When a shark experiences a stressful event, such as being accidentally caught on fishing lines, the animal becomes acidotic, meaning the acidity of their blood increases. While similar to a process in humans that causes lactic acid to build after vigorous exercise, sharks can quickly become sick and even die from the condition. By understanding the physiological makeup of the species, experts involved in the ongoing study will help develop alternatives to counter this process by creating best practices in the veterinary field, methods tailored for fishing industries, and ultimately even a form of medical intervention, or a “chill pill,” to help prevent critical illness.
“It’s a new area of exploration in shark health that helps us to understand decades of conservation challenges that influence declines in shark populations,” said Dr. Mylniczenko. “The data translates into critical knowledge that is shared throughout the international community to help protect these surprisingly vulnerable animals.”
Tim Lewthwaite
