Marine Animal Dictionary
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Feb.6, 2004
Promising recaptures of tagged redfish

The Marine Research Institute (MRI) has invested substantially in the development of Underwater Tagging Equipment (UTE) which has been developed in collaboration with STAR-ODDI, Marine Device Manufactoring. The main reason for MRI's interest is associated with the unknown stock structure of Sebastes mentella redfish, stock components in the Irminger Sea and along the shelf and slopes of Iceland, Greenland and the Faeroe Islands. As long as the stock structure and possible interrelation between possible stock components remain unknown, it will always be difficult to assess the status of the stock(s) and to give reliable advice on how to manage this important resource.

In October 2003, 200 S.mentella were tagged with the device about 150 nautical miles Southwest of Reykjanes-Ridge on the research vessel Bjarni Sæmundsson. By now, 2 fishes have been recaptured, the first only 4 days after tagging. As the tag was observed during processing of the fish, no information about the recapture place or the condition of the fish is available.

On January 21 a second fish was recaptured only 2.2 nautical miles from the area where it was tagged. The fish was taggedon October 25 at a depth of 504 metres. When recaptured, the fish was 40 cm and wheiged 830 gr. It was a mature female with developed ovary, and would probably have spawned in March if it had not been caught now. When investigating the fish, nothing visibly indicated that the fish was any different from untagged fish of this size and time of the year. Therefore we conclude that the tagging did not affect it's life expectancy much compared with untagged ones. Injuries due to the tagging had started to heal and there were no indications of swelling around the wound. Furthermore, no indications of internal damages due to the tagging were observed.

Alltogether, the tagging equipment definitely seems to work as expected. In June 2004, a 2-week cruise is planned for further tagging.



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