Yellowfin Tuna

(Thunnus albacares)

Yellowfin tuna, Yellowfin tunny, Geelvin tuna, Geelvin-tuna

1. What is it?

Yellowfin tuna (Thunnus albacares) are relatively long-lived, migratory fish found in open waters that often form mixed schools with other species of tuna. It is highly valued for sashimi and therefore often served in restaurants. Atlantic Ocean yellowfin tuna is considered to be overexploited but not undergoing overfishing whilst Indian Ocean yellowfin tuna is considered to be overexploited and undergoing overfishing as fishing mortality is above the maximum sustainable yield (MSY) levels.

2. How was it caught or farmed?

Pelagic longline

Yellowfin tuna mainly caught in the South African pelagic longline fishery in both the Atlantic and Indian Ocean. Pelagic longlines consists of a double-line system suspended at different depths covered in baited hooks and which are several kilometers long. Bycatch is a significant issue in the fishery. Specifically, bycatch of seabirds, fish, sharks and turtles as many of these species are considered to endangered, threatened or protected (ETP) species. Catches of sharks by the fishery in recent years have increased substantially, with sharks making up almost 50% of the catch in 2014.

Pole and line

Yellowfin tuna are caught using pole fishing or polling. In this type of fishing, rigid poles (2-3 meters) are attached to a feathered jig containing a barbless hook attached by a short piece of line. This fishery contains 191 vessels making it one of the largest pelagic fisheries in South Africa. Fishing operations have very little impact on the surrounding habitat or species. Accidental catches of birds and sharks occur in very low amounts and in most cases result in the release of the individual back into the ocean.

3. Where is it from?

Pelagic longline

Yellowfin tuna is harvested by South Africa in the Indian Ocean and occasionally from the Atlantic Ocean. Due to its migratory nature and demand, yellowfin tuna are managed by Regional Fisheries Management Organizations (RFMOs). The Atlantic Ocean component is managed by the International Commission for the Conservation of Atlantic Tunas (ICCAT) whilst the Indian Ocean component is managed by the Indian Ocean Tuna Commission ( IOTC). Member countries or co-operating non-member countries are then responsible for ensuring the implementation and adaptation of the recommended quotas and regulations. Management effectiveness of the Atlantic Ocean component is largely uncertain whilst management effectiveness of the Indian Ocean component is largely ineffective. Management in South Africa is considered to be partly effective due to concerns surrounding the management of bycatch species.

Pole and line

Yellowfin tuna is caught in the open waters of the Indian Ocean. Due to its highly migratory nature the stock is managed by the International Commission for the Conservation of Atlantic Tunas (ICCAT) which allocates a portion of the total global TAC for South Africa each year. Management in South Africa is regulated by the Total Allowable Effort (TAE) which limits the number of boats allowed to fish and the amount of tuna each boat is allowed to catch. Management in South Africa is effective however management by ICCAT is not always strong which may influence the stock negatively in the future.