Tagging targets
ICCAT-AOTTP will tag 120,000 tropical tuna overall with conventional 'spaghetti' tags. Of these 20% should be double-tagged, allowing 'tag-shedding rates' to be estimated. 10,000 will be tagged chemically, a procedure which makes ageing the fish easier, while smaller numbers (approximately 600) will be tagged with 'pop-up' and 'archival' electronic tags.
Tagging species by quarter
Tagging Phases
ICCAT AOTTP tagging at sea is planned to take place over two Phases, the first being 18 months in duration, the second 12 months. Data collected during Phase 1 will be analysed to inform and improve tagging activities during Phase 2.
Tagging platforms
During ICCAT AOTTP the majority of fish will be tagged by baitboat. This type of fishing is done by pole and line using live bait (small pelagic fish such as sardines) caught beforehand and kept alive on board in tanks until they are needed. The baitboat metier is preferred because it results in lower mortality among the released fish. In some places, however, such as the territorial waters of the USA there are no local baitboat fleets and longliners and recreational fishers will be used instead.
Aita Fraxku
Aita Fraxku
Tagging zones:
Golfo de Guinea (2017)
Açoriana
Açoriana
Tagging zones:
El Grande Primero
El Grande Primero
Tagging zones:
El Macizo
El Macizo
Tagging zones:
Tarrynamy
Tarrynamy
Tagging zones:
Ponta Calhau
Ponta Calhau
Tagging zones:
Tubarão Tigre
Tubarão Tigre
Tagging zones:
Tramsmar I
Tramsmar I
Tagging zones:
Estrela Dalva
Estrela Dalva
Tagging zones:
Sinuelo
Sinuelo
Tagging zones:
Eagle Eye II
Eagle Eye II
Tagging zones:
BLACK PEARL
BLACK PEARL
Tagging zones:
LEVANA
LEVANA
Tagging zones:
Aldebarán I
Aldebarán I
Tagging zones:
Nuevo Batabano Primero
Nuevo Batabano Primero
Tagging zones:
Species targeted
ICCAT AOTTP will target the three main tropical tuna species (bigeye, skipjack, and yellowfin). Additionally, two coastal species (little tunny and wahoo) will also be tagged on a more opportunistic basis. These species are actually preferred as food by many West African communities.
Tag types
ICCAT AOTTP is using three types of tag (conventional dart, pop-up, and archival). Conventional 'dart' or 'spaghetti’ tags are simple strips of plastic anchored into the base of the second dorsal fin.
Each tag is inscribed with a unique ICCAT ID number, prefixed by 'ATP', and the ICCAT AOTTP email address (aottp@iccat.int) enabling tag recoverers to contact ICCAT AOTTP Coordination. The majority of tuna are being tagged with bright yellow tags.
Around 8%, however, will have red spaghetti tags which denote that the fish has been marked, either chemically, or has an electronic tag 'on board'. Fish with red tags must be retained so that they can be analysed for various biological data, e.g. sex, weight and age.
Injecting Oxytetracycline into musculature of 143 cm yellowfin tuna
Note: Chemical tagging is marked by a red tag.
Electronic pop-up tag
Electronic internal tag
Red conventional tag used in ICCAT AOTTP to denote either chemical marking or electronic tag
Releasing tuna with electronic internal and red conventional tag
Injecting oxytetracycline into musculature with a red tag
Electronic pop-up tag implanted in large yellowfin together with red conventional tag
Electronic pop-up tag locations (via satellite)
Electronic internal (archival) tags
Pop-up tags are also fixed externally, while archival tags are placed in the ventral cavity of the fish. Both of these types of electronic tag continuously measure light, depth, and temperature while on the fish. After a pre-determined time pop-up tags release themselves from the fish, float to the surface where they transmit the data to researchers via satellite. Archival tags on the other hand must be recovered before their data can be accessed. Conventional tags, provide data on growth but depend on being caught in the fishery; while pop-up tags provide data detailed information on habitat utilisation etc., no information on growth and are fishery independent.
