2012 03 22- An unbelievable tally of fluke IDs before the humpbacks migration past Bermuda Print E-mail
Written by Andrew Stevenson   

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march fluke IDs 13-23 March

To see our batch of fluke IDs from the 13th to the 23rd of March, click on the Flickr link above.

Over the past ten days we have had summer-like weather in Bermuda with benign winds and ocean waves barely noticeable. Normally we have our North Atlantic mid-winter storms at this time of year. The ocean around us seems to be alive with marine mammals. I have seen four sperm whales, a large pod of spinner dolphins and Cuvier's Beaked whales. Already we have managed to obtain 122 (and still counting) indvidual humpback whale fluke IDs!!! Remember, the total inventory of humpback fluke IDs from 1967 to 2006 made by visiting scientists and local residents was 145 or roughly 3+ per year over 40 years. Recently we have been obtaining an average of about 150 fluke IDs annually, mostly in the last week of March through April when the main migration of humbacks come by Bermuda. These individual fluke IDs from the unique patterns of black and white pigmentation on the ventral or lower side of the humpbacks flukes (tails) are as unique as human fingerprints and serve to identify the animal thorughout its life.

The first reaction to this unexpected early bumper crop of whale identifications might be that it is due to global warming and the whales are coming by ahead of schedule. That may be the case, but based on our data, doesn't seem to be. Last year, 20% of our whale identifications (mostly made in April and early May) were of whales we had sighted in the previous four years. Of the 122 whales identified already this season, we've only had 5 re-sightings from previous years, and all of these previous sightings were in March as well. We have few whale fluke IDs in March from previous years because generally, we can't get out onto the water to look for the whales much during March, hence the lower number of re-sightings. If this wave of whales around Bermuda was here early (due to global warming) you would expect we would have matched more of them to fluke IDs made from previous years in April.

Many of the whales we have identified over the past days have been seen some days in a row. The longest seen so far are the two images below, taken on the 14th and 21st of March, a spread of seven days.

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I expect that we will have longer resightings within this season if we can continue to get out on the water and obtain these fluke IDs.

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We photographed the two whales above side by side here in Bermuda three weeks ago and Roger Etcheberry matched these IDs to two whale fluke IDs taken in the same area in August 1978 in Newfoundland. It would seem to be another indication that humpbacks are meeting here to move up north together to their common feeding grounds.The matching photos taken by Professor Hal Whitehead 34 years ago are below.

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We also photographed a pair of whales together here in Bermuda on the 17th of March 2012 which were also photographed together on the 21st of March 2010 here in Bermuda. It can't be a coincidence that these two whales were together in the middle of the ocean at the same time two years apart. Below is our 0344 photographed in 2010 and 2012 another indication that they may travel northwards in associated groups.

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Thanks to Judie Clee who has spent hundreds of hours processing all this data almost as soon as we get ashore and send them to her, we have been able to make these connections virtually in real time, while the memories of the whales' activities are still fresh in our minds. It will take years of concerted effort before we can draw any conclusions but with a rapidly growing base-line data to work from we can get closer to understanding the pelagic social behaviour of the North Atlantic humpbacks.

Thanks to Judie Clee for keeping our records straight and doing so much of the analysis immediately after I send the photos to her, to our boat captains, Charlie Kempe, Roland Lines, David Brown, Geoff Gardner, and Michael Smith for getting us out there, and to the photographers who send us their photos, particularly Richard Lee. Also thanks to Michael Heslop and Paul Fox at Fantasea and Michael Hayward and BUEI and Tim at the BZS for their great cooperation as commercial whale watch operators.

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