Cape May, New Jersey is home to hundreds of Atlantic Bottlenose dolphins. Bottlenose dolphins are a migrating species of cetacean that travel to warmer weather in the winter. However, Cape May is where they come back to each year to give birth and raise their young. This makes Cape May a great location to study Atlantic Bottlenose dolphins. For almost 40 years the Cape May Whale Watch & Research Center has been studying the resident dolphins that come back each year. Utilizing photo identification, researchers are able to learn more about the dolphins without ever disturbing them in their natural habitat. Increasing knowledge about all facets of dolphin life. This non-invasive research can discover: lifespan, sex, social behavior, and health of a dolphin. In recent years researchers across the globe have been studying the prevalence and effects of skin lesions. 

The presence of skin lesions on Bottlenose Dolphins has become commonplace globally. Dolphins in both captivity and the wild have been noted to have skin lesions present in their populations. Most studies have conducted research through non-invasive photo identification, therefore it is unknown what the exact cause of the lesions are. However, it is understood that they could be caused by changes in temperature, parasites, infection, pollutants, and even autoimmune viruses (Harzen). Due to their highly social behaviors, infections and parasites can be easily spread through populations. But do these lesions change over time or ever resolve?

Through the months of May to the end of July 2019, photo identification was used to track the changes in skin lesions on the Atlantic Bottlenose dolphins present off the shores of Cape May. Photos were taken exclusively from the American Star, using a canon digital single lens reflex camera with a 300mm lense, provided by WDC. Of about 4254 pictures taken there were about 130 pictures of skin lesions. With multiple types of skin lesions present throughout the population. Also both inshore resident dolphins and offshore transient dolphins exhibited skin lesions. Of the 130 pictures with skin lesions present there were no visible changes in any of the lesions between the months of May and July.

Unknown individual: 6/26/19
Unknown individual: 7/10/19

The example images above are the same individual dolphin and were taken two weeks apart. There are no visible changes between the skin lesions between the two week period. While the same camera was used on both days, the cloud cover or weather conditions could be causing a lightening effect of the skin lesions. It may also not be a long enough time period to witness any change in skin health. Other studies have seen a higher prevalence of certain skin lesions in juvenile dolphins than both calf and adult dolphins (Van Bressem). Suggesting that adults have the immunity to defend against skin lesions and that juveniles are likely to grow out of their skin lesions once they have a stronger immune system. Therefore with a longer study period it could be possible to see changes in the skin lesions in Atlantic Bottlenose dolphins off the coast of Cape May.

Rachael Bradbury

Intern at Cape May Whale Watch and Research Center

Stockton University

References:

Harzen, S.; Brunnick, B. “Skin disorders in bottlenose dolphins (Tursiops truncatus), resident in the Sado estuary, Portugal.” Aquatic Mammals. 23.1, 59-68. 1997.

Van Bressem MF, Van Waerebeek K, Aznar FJ, Raga JA and others (2009). Epidemiological pattern of tattoo skin disease: a potential general health indicator of cetaceans. Dis Aquat Org 85:225-237. https://doi.org/10.3354.dao02080