Fish Tagging

Found a Tagged Fish?

Find out how to keep and report a tagged fish (a reward is offered).

Fish Tagging in Shetland

The NAFC Marine Centre tags fish around Shetland to collect information on their distribution, movements and growth.

Why Tag Fish?

Fish are tagged to obtain information on their movements and growth. Both pieces of information can contribute to the more effective management of fish stocks.

Tags identify individual fish so that when they are caught again we can work out how far they have traveled since they were tagged, and how much they have grown.

How are Fish Tagged?

The fish tagged by NAFC are caught by our fishing vessel Atlantia II. The Atlantia's trawl net is fitted with a specially made 'live-fish cod-end' - a watertight bag fitted inside the net - so that that the fish are kept in water while the net is brought on board. The fish are then transferred to tanks of seawater to await tagging.

Each fish is measured and tagged with a 'T-bar' tag (Hallprint) anchored into its back muscle before being released back into the sea. Each tag bears a unique number which is recorded along with its release location, species and length.

What species are tagged?

We have tagged a number of species, including:

  • lemon sole
  • megrim
  • monks (anglerfish)
  • plaice
  • skates and rays

How many fish have you tagged?

To the end of the 2017 tagging season we had tagged 13,301 individual fish (see Table below).

Species20132014201520162017Total
Plaice 1,245 1,956 1,494 870 2,643 8,208
Lemon Sole 446 615 662 323 883 2,929
Monk 144 145 313 60 266 928
Megrim 65 32 57 8 10 172
Cuckoo Ray - - - - 776 776
Thornback Ray - - - - 157 157
Spotted Skate - - - - 131 131
Total 1,900 2,748 2,526 1,261 4,866 13,301

How many tagged fish have been caught?

667 of the fish tagged to the end of 2016 have been caught (8% of the total).

How far have the tagged fish traveled?

There has been considerable variety in the distances traveled, both between species and between individuals of the same species. Most lemon sole were caught fairly close to where they were tagged, while some plaice traveled much further. The greatest distance traveled by any tagged fish was 134 km (measured in a straight line) over 601 days by a monk (anglerfish).

Maps showing the distances traveled by tagged plaice (left), lemon sole and monks (anglerfish; right). Straight lies connect positions of release and recapture and do not represent the actual paths taken by the fish. Download a larger version of this image (pdf).

How much have the tagged fish grown?

Rates of growth have varied between species. Plaice, lemon sole and megrim have typically grown by between 1 and 2 cm per year between release and recapture, although that depends on their length when they were tagged (smaller - or younger - fish tend to grow faster). Monks have typically grown by about 10 cm per year.

Funding

This tagging work has been funded by the Scottish Government (2013), the European Fisheries Fund (2014) and the Scottish Fishing Industry Science Alliance (FISA; 2015).

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