NOAA's Coastal Georgia Dolphin Health Assessment examines the beloved bottlenose for clues to the wellness of their underwater world.
Have you ever wondered what it must be like to be a bottlenose dolphin in the wild—swimming, eating, and socializing with fellow dolphins somewhere along a nearly pristine stretch of coastal Georgia, when suddenly a veritable convention of human “dolphin doctors” decided you were due for your head-to-fluke checkup?
You probably never have. But take a moment to do so now, and you may well be able to imagine the unusual experience that 29 of the captivating creatures had when they were (temporarily) captured as part of NOAA’s Coastal Georgia Dolphin Health Assessment near Sapelo Island and Brunswick, Georgia.
A team of volunteers experienced in dolphin catch-and-release methods escorts a subject to the boat for his physical on a specially designed raft.
They may have been wondering themselves. Dolphins are intelligent animals, who, like us, are mammals. They breathe air, give birth to live young, and live in social groups. And because they are among the top (apex) predators in their environment, they can serve as “sentinels” or indicator species of ocean health.
The purpose of the field study, led by NOAA researchers from both the National Ocean Service and the NOAA Fisheries Service, and involving a dedicated team of over 50 partners and volunteers including veterinarians, lab and veterinary technicians, marine-mammal experts, commercial fishermen, and others, was to gather data on the dolphins’ overall health and to measure the levels of certain chemical contaminants in their tissues.
Aboard the Megamouth, NOAA's specially equipped research vessel, the team quickly and efficiently conducts a detailed physical exam that includes an electrocardiogram and various fluid samples.
The dolphins are captured in a net and treated with the utmost care in order to minimize their stress. This is a difficult task because adult dolphins can be more than eight feet long and weigh 400 to 500 pounds. A team of more than 40 people, seven or eight boats, and specially designed nets and equipment are required to safely capture and restrain animals of this size in the water.
Researchers enter the water to determine each dolphin’s gender, record vital signs, and draw a blood sample from the underside of the flukes. Females get an ultrasound exam to determine if they are pregnant. If so, they receive an abbreviated exam and are released.
Once the lead veterinarian clears an individual to undergo a full examination, the dolphin is transferred to a specially designed research vessel waiting nearby. Researchers then do more detailed tests (e.g., hearing, echocardiogram, advanced vitals), while veterinarians collect nasal, gastric, urine, and fecal samples.
The toothsome marine mammal’s 100 teeth are also examined for wear. (Imagine having to see your doctor and dentist in the same visit.) The vets also check the dolphin for indications of previous human interactions, such as wounds from fishing line.
Finally, a radio transmitter is attached, and the animal is branded for identification purposes. Then the dolphin is gently escorted back into (and under) his/her enigmatic underwater world, where certain well-probed bottlenose may have a whale of a tale to whistle to their companions and offspring for generations to come.
This is how one tests a dolphin’s hearing. The research will shed light on dolphins’ hearing mechanisms and their sensitivity to sound in the marine environment.
A network of 14 remote receivers, designed by a researcher from the Medical University of South Carolina working with NOAA’s Center for Excellence in Oceans and Human Health at Hollings Marine Laboratory, was deployed along a 90-kilometer stretch of coast to monitor the dolphins’ movements. Over the next several months, the receivers will track where the dolphins go, where they feed, and what types of habitats they prefer, and relay the information back to the researchers via cellphone text messaging.
The data will be logged round-the-clock; eventually, the dolphins’ movement patterns will give the researchers a clearer picture of where the animals spend time and how they may be exposed to contaminant sources in the ecosystem. The implications for human health may be far-reaching since dolphins and people share many aspects of the marine environment. The NOAA researchers are currently hard at work analyzing the data, and plan to present the results of their work at the annual meeting of the American Association for the Advancement of Science in February 2010.
The Coastal Georgia Dolphin Health Assessment is a collaboration among NOAA’s National Ocean Service, National Centers for Coastal Ocean Science, NOAA Center of Excellence for Oceans and Human Health at Hollings Marine Laboratory, NOAA Fisheries Service Marine Mammal Health and Stranding Response Program, the Sapelo Island National Estuarine Research Reserve, the National Institute of Standards and Technology, the Georgia Department of Natural Resources, Chicago Zoological Society's Dolphin Research and Conservation Institute, and other partners.