on Cape Cod
Mass Stranded Dolphins Tracked by Aquarium Biologists
On Monday July 17 a group of up to 20 dolphins was reported in shallow water off First Encounter Beach in Eastham, Massachusetts. Two of the animals, Atlantic white-sided dolphins stranded however the others in the group made it out. On Tuesday July 18, five more dolphins, likely part of the same pod (group of dolphins), also stranded at First Encounter Beach. On both occasions, the Cape Cod Stranding Network (CCSN) received the first report and sprang into action. They initiated an emergency phone tree to contact other network partners and trained volunteers. As a partner to CCSN, the Rescue Team at the New England Aquarium dispatched two trucks to the stranding events.
All animals were given health exams on the beach and blood samples were drawn. NEAq staff veterinarians and biologists analyzed the blood in the Aquarium's mobile diagnostic ambulance while the dolphins were placed on stretchers and carried to a waiting flatbed trailer. Blood results and health assessments from all dolphins revealed apparently healthy animals. The decision was made to transport the animals to deeper water for release. Police escorted a convoy of emergency marine mammal response vehicles and a specially designed flat bed trailer through Eastham, Wellfleet, Truro and Provincetown.
Once at the release site, Herring Cove in P-Town, the animals were placed on foam pads in front of the water while satellite tags or dorsal fin tags were placed on the animals. A satellite tag was placed on one of the two dolphins from the July 17 stranding and two satellite tags were placed on two of the five dolphins involved in the July 18 stranding. The satellite tags allow researchers from the New England Aquarium to determine post release survivorship of mass stranded, beach-released dolphins. While many studies have been done on the post release survivorship of dolphins after rehabilitation, this is the first study we are aware of that examines the post release survivorship, movements and habitat use of beach released dolphins from mass stranding events. To date, the tags show that the tagged animals have made it out of Cape Cod Bay, a natural trap for whales, dolphins and porpoise. Scientists from the Rescue team at the Aquarium are learning a great deal about habitat use and movements of these animals.
Biologists' Field Notes
7/19/06 - Through the cooperative effort of several groups and many people, three Atlantic White-sided dolphins were satellite tagged and released over two days. Two animals were relocated from First Encounter Beach, Eastham and released on 17 July one of which was satellite tagged. On 18 July five animals were relocated, again from First Encounter Beach, Eastham, and released with two animals satellite tagged. Enclosed is a map of their locations as of 0700 GMT today (7/19/06).
7/21/06 - We have heard from 54736 again. It appears to have hooked up with 49783 which is the same animal that he was released with. 54736 is a male; 49783 is a female. The animal released on Monday the 17th (49786) is off to Stellwagen Bank.
54736 and 49783 are very close to shore in the evening - just something to be aware of.
7/23/06 - After a stressful Sunday (the dolphins had moved back just off Wellfleet harbor), they have finally moved out of Cape Cod Bay.
7/26/06 - The three dolphins continue to stay out to sea. 49786 is way out by the North Channel of Georges Bank. Number 5 and Number 3, 54736 and 49783 respectively, seemed to have turned back southward towards Cape Cod Bay. They, this morning, were ~13 km west of Provincetown, MA. With any luck they'll stay out there.
7/27/06 - Thankfully 49783 and 54736 have moved out into the basin between Stellwagen Bank and the mainland. 49786 is still out by the northern channel of Georges Bank hopefully there is good fishing out there. I'll be decoding the dive data from 54736 this week so we can get some insight into his diving abilities since he was released.
7/28/06 - All is pretty much the same as yesterday with the exception of 49786 moving north across the Northeast Channel towards Browns Bank.
I have decoded some of the dive data from 54736. This is one of the animals that was released on the 18th of July in a group of five. The data covered from the 18th till the 27th. All of the dive activity up to the 22nd took place between 0 and 10 meters. After the 22nd the dives started getting progressively deeper and using more of the water column down to ~ 150m on the 27th. As far as dive durations are concerned, most of the dives are in the 420 second (6-7 minute) range. The longest dive lasting just over 20 minutes. The temperatures he is spending time in range from 12 - 21 deg C with most of the time spent between 15 - 18 deg C.
7/29/06 - More movement today by 49783 and 54736. They have moved to the eastern side of Stellwagen Bank while 49786 has moved to the distant western edge of German Bank off Nova Scotia. Very shortly, the maps (updates) will come out every other day, instead of every day. This is due to the tags broadcasting every other day for 14 days.
8/9/06 - The dolphins seem to be getting along OK and have moved out into the Gulf of Maine. 49783 and 54736 have seemingly split up with '83 in the Cashes Ledge area and '36 out by German/Browns Bank area. For those who don't know, 54736 is a male 265 cm in length and 49783 is a female (240 cm). Both were released in the company of two juveniles (165 and 180) and another female (250 cm).49786 continues to stay out in the Gulf in the area just southwest of German Bank (Nova Scotia).
More seal data is available in the current WhaleNet Listserv. Sort and go to FIND for "NEAq1-06" entries.