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The wanderings of Irish tope
Paddy Fitzmaurice and Peter Green
The tagging of marine sportfishes was initiated in 1970 by the Inland Fisheries Trust. The tagging programme was introduced to discover the migratory patterns of sea angling species and as a conservation measure to get sea anglers to release their catches alive. The tagging operation was carried out on a voluntary basis and the charter boat skippers gave their full co-operation. The tope were tagged in the dorsal fin with jumbo rototags, which were originally designed as a tag for cattle.
The distribution of tope was known to be confined to the North East Atlantic
Ocean but nothing was known of their migratory patterns until this study
was initiated. Up to December 2000, a total of 3,220 tope were tagged
and released. To date 268 (8.3%) have been recaptured. The migratory movements
are shown in the illustration.
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| Results of migration patterns of 268 tagged tope in the North East Atlantic. |
The greatest distance travelled by a tagged tope was 2,185 miles. This fish, released in Tralee Bay was recaptured in the Mediterranean Sea off the cost of Tunisia in less than 3 years after being tagged. The longest period a tagged tope had been at liberty was 5,538 days - over 15 years. This tope was tagged in Donegal Bay in 1982 and was taken on rod and line off the west coast of Scotland in 1997 and was released again alive.
Tope are recaptured in gill nets, tangle nets, by trawlers of various nationalities and by anglers at home and abroad. Recaptures have been made recorded from such locations as Denmark, Norway, the North Sea, Faroe Islands, United Kingdom, France, Spain, Portugal, the Atlantic coast of Morocco, the Canary Islands and the Azores Islands. Three recaptures were made in the Mediterranean Sea, off Spain, Algeria and Tunisia. Of course quite a number of tagged tope have been taken all around the Irish Coast.
A number of tope tagged in Irish waters have been recaptured close to their release point shortly after tagging. One fish was recaptured after 405 days close to its tagging site, was released alive and was again recaptured after another 405 days at liberty only 50 miles away. This poses the question - where did this fish travel to in the intervening periods? If a similar study was to be carried out off the Iberian coasts, the Canary Islands and the Azores further information would be obtained which might show cyclical movements within its distribution range.
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| A tagged tope ready for release (Photo by K. Farrell). |
We know that some tags have fallen off tope after being released. Tags have been returned after they were found on beaches on Irish shores and from Penzance in Cornwall. A few tags were returned after they were found caught up in gill nets, demonstrating that there could be a significant loss of tags when tope come into contact with gill nets. Undoubtedly some of these tags would fall out of the gill nets and be lost.
The 8.3% recapture rate must be regarded as a minimum figure. It is expected that additional returns will be made on fish tagged over the last three to four years. It is also a possibility that some captors may not return their tags and an allowance must also be made for fish shedding their tags.
A lot of valuable information has been collected during this voluntary tagging programme. The charter skippers take details of the tagged fish and also note the number of anglers on board, the other species of fish caught as well as the nationalities of the anglers. On the 88 charter boats participating last year, the total number of rod angling days was 38,430.
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