Southern Monterey Bay

Today was a good day! We were able to obtain two more biopsy samples from bottlenose dolphins today, and we are optimistic that the identification photos taken will allow us to link the samples with the specific individuals that they were taken from. These ones now bring our total biopsy samples collected to four, and we are quite pleased with the progress on this front.

Biopsy samples are taken with a crossbow and specially-modified dart that is fitted with a stopper, which prevents the hollow tip of the dart from penetrating more than about an inch into the dolphins back. The dart bounces off the dolphin, and if we are lucky, there will be a small piece of skin and a plug of blubber inside. We then scoop the dart out of the water, and we now have sample that can tell us a lot about the dolphins.

The skin biopsy samples are analyzed back at our laboratory in San Diego, and we can tell the sex (or gender, if you prefer) of the dolphin. The remaining part is used for population genetic studies, and can even be used to examine relationships between individuals. The blubber part is sent to another lab for ecotoxicology work-up. We will be able to get information on the amount of environmental contaminants (like the pesticide DDT and the hazardous class of chemicals known as PCBs). If there is enough tissue, we may even be able to determine the reproductive status of the dolphin and what is has been feeding on!

Although biopsy sampling causes a very small injury and some behavioral disturbance, extensive research has shown that the scars heal-over very quickly and the disturbance is very short-term and generally not significant. However, it is important to remember that biopsy sampling has the potential to cause serious harm to the dolphins (and to humans!), and should thus not be done unless it provides essential information for sound management and conservation. And even then, biopsy sampling should only be conducted by experienced experts.

The biopsy samples that have been collected in this project so far are providing this critical information (coastal bottlenose dolphins rarely strand along the California coast, and so opportunities for tissue sampling are rare). We have been careful to try and minimize the risk and disturbance to the dolphins. It is quite amazing to think that such a small piece of tissue can teach us so much. It is our hope that these little chunks of dolphin  will allow us to better understand and conserve these fascinating animals!

Best wishes,
Tom

photos submitted by Donna Konkright. Learn more about the Marine Mammals of Monterey experience on Donna's Blog