WhaleNet Reports
Satellite Tag No.27567

Information Page

Harbor Seal
(Phoca vitulina)

Released - 12:30 PM EDT (4:30 GMT), Thursday, October 23, 1998
Hardings Beach in Chatham, Massachusetts (41 41'N, 69 57'W).

Bristol, Seal #19, was found on June 2 at Inner Heron Island in South Bristol, Maine. She had a severely infected wound on her neck, her hind flipper was cut, and she was underweight and dehydrated. She was rescued by NMAL.



Bristol appears to be staying close to the same position for the past several weeks. Dive data indicates that Bristol is going offshore regularly. We have not gotten a message from the tag for two days now. This is not unexpected because the tag is sending signals that tell us that it is running out of battery power. We estimated that this tag would work for roughly three months, and we are quite close so we have been expecting this tag to shut down any day now.


And here is a seal that is not traveling so much. Bristol is staying close to the same location for the past two weeks. Most of the locations have been from near shore at the Rhode Island Conneticut border. Dive data shows that Bristol is taking some trips to slightly deeper water, but I will have to take a closer look to be sure. Data from the tag shows that the batteries are getting low in this tag and we may only get another week or two of transmissions from it. So far the tag has been working well and has been sending data for more than three months. This is good for one of these small tags. Exactly when the tag will shut down is hard to say for sure, but we will hope for another few weeks.


Still centering around a location on the R.I. Conn. border (Winnapaug Pond actually). Locations seem to show that "Bristol" is moving offshore for short trips but returning to the same area. She has been in this location for about a week, now.


Bristol is still in roughly the same location along the Rhode Island coast, near the Conn. border. Our last location put Bristol 5-6 miles offshore, heading between Long Island and Block Island. If this is a real location hit it may mean Bristol is moving offshore again. Locations from early on the 12th show that Bristol had hauled out for at least several hours.


Bristol has also moves south and offshore. At about the same time that Quid moved away from shore Bristol headed offshore, beyond the islands of Martha's Vineyard and Nantucket, then west again, back near shore. This location is near the Rhode Island Conn. border. It is not far fron Quid's location and we will be watching to see if the two head to the same location near Long Island N.Y. I will be checking the tag data to see how well the batteries are doing for this tag as it is getting to the point where power may be starting to drop.


Bristol appears to be doing much the same thing as Quid, in another location, however. Bristol is also staying near shore and spending time in shallow marshy areas. Bristol, however is near Chatham, Mass.Over the past week some locations have moved around the southern tip of Monomoy Island and it appears that Bristol takes short "day-trips" away from the coast and returns.


Bristol is doing more of the same; keeping in the same general location for the past few weeks (an area roughly five to ten miles in diameter close to Hardings Beach in Chatham, Massachusetts. For the past few days Bristol has been in the shallow entrance to the Chatham Bays.


Still moving around Monomoy Island, staying close to shore. Also staying quite shallow. Most recent locations are near shore in the marshes near west Chatham , Mass.


Still staying within 5-10 miles of release location. Most appear to be on the bay side of Monomoy Island, a large harbor seal haul out spot at this time of the year.


Continues with much the same behavior, keeping close to Monomoy Island. Several good locations put "Bristol" quite close to the beach. So far, though , no signs that she has hauled out since release.


"Bristol" appears to be settling into somewhat of a pattern (if you can call it that). Locations close to shore on either side of Monomoy Island appears to be traveling between South Island and Monomoy. Still not going more than a mile or so off shore.

19 Nov. 1998

Still moving all around the south coast of Cape Cod, crossing through to the ocean every so often, but not staying in one location very long.

16 Nov. 1998

As you can see, we are getting more locations per day (good news). After spending some time in marshes in the upper reach of Chatham Harbor, it appears that Bristol has moved out to the area between South Chatham and Monomoy Island. If you look closely you will see how difficult it is to tell which side of the narrow beach to the east of Chatham (Nauset Beach) she is. This is where even a small inaccuracy in locations can make a big difference. Unfortunately, errors tend to be greater in longitude than latitude, so you can see how this complicates things here. From her dive data I am guessing that "Bristol" actually has made it to the ocean side of the beach, but does not seem to be going further than a mile or so offshore (although I do not know how far a little harbor seal can see, this would be about as far as a person could get away from the beach and still see the shore)

10 Nov. 1998

As you can see for the past several days we have been getting much better location (and dive ) data. We are getting at least a location per day. The latest location s put Bristol behind Nauset Beach (a long barrier beach) in Chatham inner harbor. The locations from Monday put her near some of the deeper water in the harbor just south of Pleasant Bay. This is not very deep (about 4-5 meters), but it appears that she is diving about to that depth. It appears that she has not hauled out since her release.

04 Nov. 1998

I just got done looking at what we have from the tag so far, so this is the story so far (as of today). After spending a little more than a week swimming in shallow water and marshes along the south coast of the Cape (between Chatham and Osterville), #19 has moved east and through the gap between South Beach and Monomoy Island and now is on the ocean side of Monomoy. Monomoy is the area where the largest groups of harbor seals gather during the winter. Two days ago she had swum up the Bass River in Yarmouth, and spent much of the day there.

So far we have gotten thirteen location messages in as many days. We have also received one hundred "data messages" that give information about her diving behavior (so far we have data on nearly 4,500 dives). This is actually less signals and data than we were expecting, although we seem to be doing better as she moves into open water and begins to do more diving. The data we have received tells us that the tag is not signalling very often. This is most likely due to the position the seal has been keeping in the water. When the seal is stationary or moving slowly with he head up, the tag will be under water and will not signal. The low signalling rate says this is most likely what is going on. The good news is that the low rate of signalling will conserve battery life in the tag and means the tag will run for more days at this rate.

So far her dives have been quite shallow. Her deepest dives have been to about forty feet and roughly 95% of her dives have been between 6-12 feet deep. She has spent roughly 70% of her time between the surface and 6 feet deep (a little more than 20% of her time between 6-12 feet). Most of her deeper dives have come in the last day, now that she appears to be getting into deeper water. This much shallow diving is probably not a great thing in the long run, but may just be "Bristol" getting used to the new surroundings (spending a lot of time gawking). The next few weeks should, hopefully show more deep diving and consistent diving to a depth where she might be looking for food. A good sign, though, is that while her dives have been shallow some of them have been quite long (some as long as 15 minutes or more). Although roughly 50% of her dives have been one minute or less in length almost 30% have been between 1-2 minutes long and about 15% have been between 2-3 minutes long. The next few days should be interesting, as we see if she remains near Monomoy or continues to move.

These 11/04/98 locations put her on the ocean side of Monomoy Island, a major seal haul out. A better place than a few days ago. See the separate message for some of the dive data.

25 Oct. 98

Newest tagged seal (harbor seal pup). So far we have been getting only a few locations (about one per day). It is not unusual to have relatively few messages for the first few days after release. Also in this location satellite coverage is not as good as further north. Weather can also cause us to get fewer signals if the sea state is choppy enough to block signals. Enough excuses. It looks like Bristol is still keeping close to shore and has moved southwest along the south coast of the Cape and is near Osterville (and may have moved into one of the marshes near that area...).

  • Data Sheet - "Bristol" Satellite Fixes, the Harbor Seal, Tag No. 27567

  • Tracking Map - , Present and Past Locations Map (Release Location).

  • "Bristol" Main page

    Seal Notes:

  • Fact Sheet #1 - Information About Pinnipeds

  • Fact Sheet #2 - Information About Harbor Seal Ranges

  • Fact Sheet #3 - Information About Increasing Seal Populations in the Gulf of Maine

  • Fact Sheet #4 - Harbor Seal Information

  • Additional Maps

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