November 24, 2011 Featured Article Read More →

Update: “Sores” on Tagged Skate

43lberLast month some anglers had expressed concern about “sores” around the tag site on recaptured common skate. In the article posted here we discussed how the auto immune response of elasmobranchs to plastic dart tags may in some rare cases appear to cause a sore around the tag.

This week we received a letter from Dr Francis Neat, a fish biologist from Marine Scotland who is currently involved in the common skate acoustic tagging project in the Sound of Jura.

* Please note that the views expressed here are those of Dr Neat and not Marine Scotland.

“I have spent a decade working on scientific research projects involving tagging and tracking fish. This year I had the opportunity to start a research project tracking common skate and this gave me a chance to assess first hand whether there are long-term welfare issues over the external tagging of this species as has been claimed.

“There are genuine welfare concerns over the tagging of wild fish. The implantation of an external tag causes short-term localised damage to the skin and underlying muscle tissue. However, from what I saw there do not appear to be longer-term concerns. Out of 16 skate that were recaptured with external tags, in 15 cases the wound had fully healed and the tag sat proud of a slightly raised area of scar tissue. Only in one instance was there still inflammation around the wound.

“The cause of the inflammation could be that insufficient time had passed since the tag had been implanted or that the tag was inappropriately implanted to begin with. It is critical that the tags are implanted correctly and in the appropriate place and I would recommend guidance and training by an experienced tagger be considered before a novice attempts to tag fish.

“Overall, therefore it is my opinion that any short-term effects caused by tagging are relatively minor, do not persist in the long term and that tagging can be ethically justified given the long-term conservation benefits that can be gained from understanding the movements of the fish.”

The SSTP have long recognised that appropriate tag placement and good tagging practice are vital to the programme. As such the SSTP offer tuition in handling and tagging sharks in the form of a short, free course that has now been running for over 18 months.

Please refer to the SSACN Plastic Dart Tagging Guidelines for more information on good tagging practice.

If you are interested in tagging sharks or if you are experienced tagger who would like a refresher course please send an email to contact@ssacn.org.

Posted in: Shark Bites
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