Electronic Tagging 2019: Update, Planning and Recreational Sea Anglers
The Thunnus UK electronic tagging season is now well underway. In the first four weeks of the season, 17 bluefin tuna have been tagged with MiniPAT satellite tags and 2 with short-deployment accelerometers (due to release on the 12th of September), 2 bycaught bluefin tuna (Brixham and Looe) have been subject to post-mortem and 2 tags from last year have detached (one off northwest France and another off the Channel Islands) and transmitted data back to us. Looking ahead, we have a further 10 MiniPAT satellite tags and 10 accelerometery tags to deploy. Some of these accelerometery tags are re-deployable, so we hope to catch approx. another 20-25 fish in the forthcoming weeks. We’re also expecting 5 more satellite tags that were deployed last year to pop-up in the next few weeks and are hoping that they’ll be close enough to Falmouth to retrieve, very exciting!
An additional element to the electronic tagging programme this year is the inclusion of recreational sea anglers (RSAs) during scientific fishing activities. Experienced RSAs (see this page for details of how to apply as an RSA) are permitted to book a trip with participating Volunteer Vessels to aid in the capture of bluefin tuna for electronic tagging purposes. Bluefin tuna captured by RSAs aboard any of the Volunteer Vessels are then transferred to a central tagging vessel, where they are measured, tagged and released.
Due to the scientific nature of these fishing operations, there are a few key differences between fishing as an RSA during this project and during a normal charter. The Volunteer Vessel Code of Conduct document, which can be accessed here by clicking on the link, delineates the basic operational plan.
In addition to the standard code of conduct there are several extra differences that RSAs should be aware of when booking a scientific fishing trip:
We have experienced higher catch rates this year compared to last year, and to ensure we have sufficient tags to last the season, we will generally aim to deploy only one tag per day unless circumstances suggest we should do things differently (i.e. the fish become harder to catch and patchy or the weather closes in for the season). After the tag(s) for the day have been deployed, the Thunnus UK fishing operations are finished for that day.
Not all fish captured will necessarily be tagged, and occasionally scientific staff may have reason to reject the fish based on one of several criteria.
When all the tags available to the project have been deployed, the project will end for the season. At the time of writing twenty tags remain. We are currently experiencing high catch rates so dates booked for the end of the season may be limited.
Occasionally the tagging vessel may have to sail to physically recover a tag that has been previously deployed. On these days, fishing activities may have to be curtailed or even cancelled entirely. These days, although rare, can often be planned and every effort will be made to ensure RSAs do not incur unnecessary costs.
We're hugely thankful for all the interest and support in the project this year and are looking forward to continuing to work together to study bluefin tuna off the British Isles.
If, after reading this, you have any question about these aspects of the programme then please get in touch by contacting bluefin@exeter.ac.uk.
Many thanks
The Thunnus UK team