Mass Dolphin Stranding - Update and Tracking

Hi Everyone,

Those of you following the blog have read about the mass stranding of white-sided dolphins on Cape Cod on Thursday. Friday proved to be another busy in the field again for the International Fund for Animal Welfare (IFAW) team. They responded to three more live dolphins on Friday, all three were rescued and released. On Saturday one animal was found dead; no additional live animals were found stranded.

As I mentioned in my last post, Kate and I satellite tagged two of the dolphins released on Friday night. Since then we have been tracking their movements. One of the main reasons we started this satellite tag project was to determine weather or not the animals survived after a stranding event, rescue, transport and then beach release. Added up, each of these steps in a rescue is very stressful for the animals involved. We needed some way to determine if our efforts were successful or if the dolphins swam off shore and died with hours or days. The project is complicated. The process of selecting an animal to tag is key, and depends on the level or stress and trauma (that will be another post in itself). In short, it appears that the animals we selected for the satellite tags can survive, at least so far in this study.

In the photo below, Kate is double checking the tag stability prior to releasing the animal. The tag is placed on the dorsal fin with the antennae facing forward.

The photo below shows a close up of the tag. These tags are quite small, weighing somewhere roughly between 60-100 grams. A numbing agent, similar to what you would receive for oral surgery or other short medical procedures is applied to the fin before tag application. The tag site is also thoroughly disinfected prior to the tag application.

In this photo, the animal is being lifted for the final journey into the water. You can see the tag on the dorsal fin if you enlarge the photo.

Okay so now, we track the dolphins from our computers (more on how this works later, lets just get to the good stuff!)

Kate created the map below on Friday morning using the satellite data we received on that morning. The dolphins left the release site, which was in the middle of the west facing side of the hook at the end of Provincetown (see plot on next map) and were staying about 5 to 7 miles off shore in the general area. As I stated in my last entry, it will take some time for them to recover and regroup, and regain their full strength.

I created the map below yesterday based on Saturday's satellite tag. All the points in yellow are one animal and all the points in purple are the other tagged dolphin. The tags do not transmit at exactly the same time (they will transmit when the dolphins surface to breath, which is not expected to be at the same time). As a result these animals could actually be closer together then what appears on this map.

I began working with the satellite date from this morning but need more time to produce a map of the dolphin locations so far today. I'll do that in the next few hours and blog with another map of today's locations.

The stormy weather and high wind warnings are not great for a group of stressed dolphins that just experienced a traumatic stranding and a stressful day of handling. I'm not sure how this will effect them, but it most certainly is not helping mattes. I'll talk more about that with the next map.

- Connie