Relaxing at the beach on a summer day in southern New Jersey you've probably seen small groups of dolphins swimming just off shore; it's almost as if they want to say "hello". To most of us they all look alike, but imagine our surprise at the first OWL meeting of 2006 when we found out otherwise!!

Jackie Toth, a Masters student at Rutgers University and an employee with the National Oceanic and Atmospheric Administration (NOAA), discussed the research that is being conducted on the Tursiops truncatus (a.k.a. Western Atlantic bottlenose dolphins). Gray with pinkish tinged undersides, these intelligent creatures are found in all of the oceans in the temperate latitudes. They can grow to 8'-12' long and weigh between 600-1400 pounds. The dolphin has a lifespan of 40-60 years and becomes sexually mature at 10 years. Their gestation period is 12 months and the resulting calf stays with its mother for 4-5 years.

The western Atlantic bottlenose dolphin ranges from New Jersey (during the summer months) and on south to Florida. In 1988-1989, 800 dolphins were stranded all along the east coast, but researchers couldn't pinpoint the precise reason. The event raised many questions not only about why the strandings occurred, but if it was a threat to the long-term health of the dolphin population.

The failure to isolate a reason for the strandings precipitated NOAA to conduct a research effort to better understand the dynamics of the dolphin population and if they were being depleted, and how could they bring about more effective management to ensure the dolphins' survival. Questions to be answered were: what type of habitat do they prefer; how many are there; are the same animals coming back year after year; where do they spend the winter months; what is their predominate diet; and how do they interact socially.

Jackie photographs a dolphin.

One of the things researchers needed to due was to identify individual animals. Three main methods to accomplish this include photo I.D., genetic biopsies and live captures. Jackie has been involved in all three, and first explained how individual dolphins are identified by photographing them from a boat. Because dolphins are very social beings, their dorsal fins become notched and scratched through play and sexual habits, which gives each dolphin its own distinctive ID (similar to fingerprints). Photographs are taken of groups of dolphins. Each photo is sharpened and through a fin-tracing computer program known as Finscan, each individual dorsal fin is traced along its edges and stored in the database, and compared to other dorsal fins to distinguish individuals to a high degree of accuracy.

Of the 6400 photographs taken in 2003-2004, 391 were entered into Finscan; this resulted in the identification of 156 individuals. Out of this select group, 73 were dolphins that had been seen more than once. Interestingly enough, of that number, 51 were seen only around Brigantine, which indicates what their habitat preferences are. Photographing dolphins requires calm weather and logging many miles along the New Jersey coastline. In one day she may cover as many as 70 miles.

Biopsy sampling is used to determine, among other things, dolphin food habits and to get genetic information from individuals. Jacki explained that she needed to complete a 16-week preliminary training period before she could attempt to take biopsy samples. The samples are obtained using a modified crossbow to shoot an arrow that houses a sterile dart encased in a foam cylinder into the dolphin. The darts only penetrate just below the skin to collect a tiny plug of skin and blubber, and immediately fall out of the dolphin and into the water. The arrow floats on top of the water where they are retrieved and the plug of tissue is sent to a lab for analysis. Jacki explained that although the amount of tissue that is removed from a dolphin with biopsy sampling is very small, and the discomfort that they experience, if any, is minor, to be on the safe side they avoid taking samples from a mother with a calf, or don't shoot into a group of dolphins. She said that in 2005, 37 samples were taken, predominately from dolphins living within 10 miles of the shoreline. These tissue samples reveal what dolphins have been eating, and also contain an individual dolphin's DNA, to further aid in collecting data on individual animals.

Jackie aims her crossbow at a dolphin.

The third way to gather information from individual dolphins, and the most costly and time consuming process, involves capturing them alive. This requires at least 4 boats, and many people with diverse, experienced backgrounds to make sure that the animals are captured safely. A veterinarian is on-hand to monitor their heart rate and other vital signs, and to collect blood samples and other biological data. Captured dolphins also have a number freeze-branded on their dorsal fin to make it easier to identify individuals. The technique is similar to branding cattle, only the brand is very cold instead of being very hot.

In order to track the movements of dolphins, researchers use a satellite tag. A VHF transmitter is implanted in the dorsal fins. According to Jacki implanting a transmitter takes 2-3 hours but if the dolphin shows any sign of distress it is immediately let go. In New Jersey seven dolphins have been tagged. By following the movements of these tagged "Jersey dolphins" in this way it has been revealed that they winter at Cape Lookout, North Carolina, and then gradually move north to spend the summer off the southern New Jersey coast.

Jacki said that studying dolphins is an amazing challenge and gave one example that she learned while studying them in the field. She stated that the dolphins she was studying learned how to recognize the sound of individual boat motors quickly. As a result, researchers have to change their boats on a weekly based to outsmart them.

What a fascinating look into the up-to-date research concerning these intelligent creatures. Thank you again, Jacki.

-- Sandy Norman

Addendum: Continuing in our tradition of asking our guest speakers to provide their personal booklist, Jacki offered the following: Small Is Beautiful by I.F. Schumacher, Song for the Blue Ocean by Carl Sofina and Lamb by Christopher More.

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