October 14, 2011 Featured Article Read More →

Update – Common Skate Acoustic Tagging Project in the Sound of Jura.

100pound

The Marine Lab are offering a £100 reward for the return of their data tags along with details of where the fish was caught.

Only the white tags should be removed and the fish should be returned alive and well. A full sized poster with all the details may be downloaded from here.

October 2011 will see the start of a new tagging project undertaken by Marine Scotland that aims to look in detail at the movement of Common Skate (Dipturis cf. flossada, Dipturis cf. intermedia) around Crinan and the Sound of Jura on the west coast of Scotland.

This project is a single work package that makes up part of the much larger Scottish Marine Protected Area (MPA) project: the MPA project will provide advice to Scottish Ministers on the selection of MPAs in Scottish territorial waters.

At a larger scale the Scottish MPA project aims to fulfil Scotland’s international commitments to form an ecologically coherent network of protected areas in order to conserve marine biodiversity.

As a result of overfishing and their slow growth rate Common Skate are currently listed as critically endangered by the IUCN Red List and are considered locally extinct in many areas of the UK despite previously being – as the name suggests – common around the British Isles.

The current Common Skate tagging programme is well established thanks to the work of a wide range of volunteers and recreational anglers. Skate tagging projects in Scotland are carried out by volunteers as part of the Scottish Shark Tagging Programme (SSTP) operated by the Scottish Sea Anglers Conservation Network (SSACN).

Data collected by recreational sea anglers and the SSTP have proved extremely valuable and has already helped provide a valuable insight into the biology of Common Skate by assessing movements, distribution and growth between points of capture and has provided a strong foundation on which future projects can build. If you are interested in tagging Scottish skate, rays or sharks or becoming more involved in the SSTP or SSACN please send an email to contact@ssacn.org.

The work of the SSTP identified the Sound of Jura as an ecologically important area for Common Skate populations as a result of the high number of skate tagged and recaptured there by anglers. The upcoming project aims to build on this work through a more detailed investigation of Common Skate movements in the area using some sophisticated tagging methods.

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Above: a tagged Common Skate descends to the sea bed after capture and release. Although Common Skate tagging programmes are well established in Scotland detailed information regarding their movements is often lacking. This project by Marine Scotland aims to monitor the movement of Common Skate in the Sound of Jura over a period of one year using acoustic tags and an array of hydrophone receivers.

 

This work package aims to answer several important questions about the movement of Common Skate in what appears to be an ecologically important area for the species: does the Sound of Jura have residential Common Skate populations? Do Common Skate have a home range in which they move? Do Common Skate migrate offshore at any point during the year as seen in many skate and ray species?

Most significantly, this work will feed into the Scottish MPA project and will direct efforts to protect Common Skate populations on the basis that conserving an area of the sea does not necessarily equate to the conservation of a particular species. When dealing with highly mobile species that are free to leave an area at any time it is possible that the designation of an MPA may not prove successful if the species in question regularly leaves that area.

The project aims to answer these questions using tags and acoustic listening devices. A total of 30 pinger tags will be placed on Common Skate in the area; these tags will emit a unique coded signal that can be picked up by any of the 10 hydrophone receivers that are to be strategically placed in the sea around the area.

Receiving stations will accurately plot the location and movement of individual Common Skate out to a range of around 1.5km. Pinger tags are to be left on skate by anglers who recapture the fish for the duration of the project. It is hoped that these tags will help provide a more detailed insight into the movements of a relatively complex species and that the data will show if Common Skate reside in the Sound all year long of if they move out of the area to migrate offshore at any point.

In addition to the pinger tags, data storage tags will be placed on 10 Common Skate in the area; storage tags will continuously record parameters including water depth and temperature. This information will then be downloaded and will show any patterns in Common Skate movements based on the changing attributes of the sea.

Anglers who catch a skate with a data storage tag are encouraged to remove the tag and return it to Francis Neat at Mar Lab Aberdeen; anglers who return data storage tags will be rewarded with £100 per tag.

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This image shows the small tags that will be used in the upcoming project around Crinan and the Sound of Jura. The labelled tag on the left of the picture is a data storage tag and should be returned to Francis Neat at Mar Lab Aberdeen by anglers in return for a £100 reward. The black tag on the right is an acoustic pinger tag; this tag will be used to monitor the movement of Common Skate in the area and should be left on the fish by anglers.

The project will run for one year and hopes to answer some of the questions surrounding the movements of Common Skate. This data will be fed into the Scottish MPA project and will hopefully contribute to the conservation of Common Skate in Scotland.

The SSTP would like to thank Francis Neat at Marine Scotland for the information in this article and for his help in supplying some of the photographs used. We would also like to wish Francis luck in this fascinating project.

Please check www.tagsharks.com regularly for more updates on this interesting project.

Posted in: Shark Bites
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