Fish tagging

Fish tagging experiments have been conducted in Icelandic waters since early twentieth century. These tagging experiments have been carried out on several commercial fish stocks mainly: cod, haddock, herring, plaice, saithe, wolfish, and to lesser degree: deep-sea redfish, lumpfish, halibut, dab, witch, anglerfish or monkfish and rough dab. Some invertebrates have also been tagged like Norway lobster, deep water shrimp and Iceland scallop.

Until 1994 only so called conventional tags were used of various types that have in common that they have identification letters and numbers. Since 1995 electronic tags, Data Storage Tags (DSTs), have also been used. These are capsules with sensors and memory chips for recording and storing environmental data. The fundamental data that has been collected is ambient temperature and depth of the fish. The development of this technology has been very fast and more sensors have been developed such as salinity, tilt, sound, etc. 

Where as the conventional tagging methods yield only data that is collected at release and recapture, the use of electronic tags give the additional possibility of data collection in the period between release and recapture. This does not mean that conventional tags are obsolete. Depending on purpose of tagging experiments one could use either conventional tags, electronic devices, or both in combination.

Tagging experiments have mostly been conducted to assess or investigate various aspects of population biology such as abundance, distribution, behaviour, mortality, growth, population structure and for monitoring stocks. The addition of electronic technology has increased research potential in tagging experiments beyond imagination.

Tagging methods