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3 Miles in 3 years

Friday, 26 June 2015 15:00
McGeoghegan family with the found tag near thier
home at Malin head
McGeoghegan family with the found tag near thier<br>home at Malin head
(c) E. Johnston 2015

3 Miles in 3 Years

A recent beach clean-up organised at Malin head has provided the answer to a mystery that has puzzled the Inishowen basking shark study group for the last 3 years. What happened to 3 satellite tags the group experimentally deployed on basking shark fins off Malin head? Did the sharks simply swim off and never return to the surface or did the tags somehow fall off or get knocked off?

The simple answer is the tags got knocked off the shark’s fins and lay on the bottom of the bay until being washed ashore at Culoort beach and found by the McGeoghegan family (Adrian, Conor, Niamh, Keira and Finley). The McGeoghegans were admirably doing their bit for the local marine environment by helping out with the ‘Atlantic Beach Clean Up’ organised by Local Dan Conaghan when they found the remains of the high tech tag lying amongst seaweed.

The Inishowen Basking Shark Study Group deployed the tag less than 3 miles from the beach at Culoort, Malin head but failed to get any long term returns from any of the three tags deployed using the experimental ‘Fin mount’ method. Two of the tags have subsequently been recovered from nearby beaches without their fin clamps, indicating that the tags came off their mountings. The group know that the tags were well attached so the possibility that the tags were ‘knocked off’ is something they are considering for future investigation.

The group originally decided to develop their own experimental design because they were not happy with existing ‘off the shelf’ tag designs. The rational about attaching the tag to the shark fin was first put forward by Dr. Simon Berrow 1: the shark fin is out of the water more than any part of the body and 2: The fin is also a very stable platform for tag transmission.  Unfortunately the tags didn’t provide any results and the group were forced to go back to the drawing board. Three different designs have been tested since that fateful year and each design has improved on the last.

If you find a tag on the beach please get in contact as it may hold valuable information the group can use to improve future designs and deployments.

With special thanks to Adrian, Conor, Niamh, Keira and Finley McGeoghegan who recovered the tag and helped solve our tag mystery.