Skipjack Tuna

(Katsuwonus pelamis)

Skipjack, Katunkel

1. What is it?

Skipjack tuna (Katsuwonus pelamis) are high fecundity, early maturing, widely distributed fish that form large, migrating schools often associating with other species of tuna (e.g. juvenile yellowfin and bigeye). They are inherently resilient to fishing pressure and are therefore the most commonly caught tuna species worldwide. Stock levels of skipjack tuna are difficult to assess due to their widespread distribution, highly migratory nature and seasonal fluctuations in abundance. There are indications that skipjack tuna are being fished at moderate to sustainable levels in the Western and Central Pacific Ocean (WCPO) and Indian Ocean (IO) component. However, there is increasing concern that the Eastern Pacific Ocean (EPO) component is currently being overfished.

2. How was it caught or farmed?

Fish Aggregating Devices (FAD)-associated purse seine

Skipjack tuna are caught using specialized fish aggregative devices (FADs) which consist of a man-made floating structure, natural logs or even anchored FADs. Nets are places around the FADS and fish that aggregate around them are captured when the net is pulled closed. There is little impact on the surrounding environment. Bycatch, however, tends to be quite high as a number of other fish species are also captured many of which are juveniles. In addition, larger species such as sharks, whales and dolphins are also attracted to the FADs (as they search for food) and sometimes become trapped resulting in high discard rates.

NON- FAD or Free Swimming School (FSS) – associated purse seine

Skipjack are caught using purse seine nets which are placed around a free swimming school (FSS) and then closed capturing the fish. There is little impact on the surrounding environment. Bycatch in this form tends to be low and generally consists of other species of tuna. A few pelagic and coastal sharks can also be accidentally captured in the nets.

Gill net (GILL)

Skipjack tuna are caught in gillnets which consists of fine netting that traps/entangles fish generally by their gills. This method is considered to be the most damaging fishing method as many potentially endangered species are captured and sometimes killed in the nets including sharks, rays, turtles, marine mammals and sea birds. In addition, ghost fishing is significant problem as these nets are often lost or abandoned during fishing trips they will continue to trap and kill species long after the fishers have left.

Pole and line (PL)

Skipjack tuna are caught using pole and line. This method is highly selective with low bycatch rates and no negative impact on the environment. Bycatch tends to consist of other species of tuna such as juvenile yellowfin and bigeye.

3. Where is it from?

Skipjack - Green

Skipjack tuna is harvested from 5 distinct geographical areas namely the Western and Central Pacific Ocean (WCPO), Indian Ocean (IO), Eastern Pacific Ocean (EPO), Western Atlantic Ocean (WAO) and the Eastern Atlantic Ocean (EAO) and then imported into South Africa. Due to its migratory nature and high demand skipjack stocks are managed by Regional Fisheries Management Organizations (RFMOs). The WCPO (Green – PL & NON-FAD) is managed by the Western and Central Pacific Fisheries Commission (WCPFC) and the EPO (Green – NON-FAD) is managed by the Inter-American Tropical Tuna Commission (IATTC) which assigns quotas and various regulations to its various members. Member countries are then responsible for ensuring the implementation and adaptation of the recommended quotas and regulations. Management of the WCPO and EPO region is considered to be relatively effective as stock levels are kept at healthy levels. However this may be due to the high biomass and high recruitment levels found in the region as WCPFC and IATTC has no specific management strategies in places and there is poor implementation within these RFMOs of many of the recommendations put forward by scientists for improved sustainability fishing of tuna.

Skipjack - Orange

Skipjack tuna are harvested from 5 distinct geographical areas namely the Western and Central Pacific Ocean (WCPO), Indian Ocean (IO), East Pacific Ocean (EPO), Western Atlantic Ocean (WAO) and the Eastern Atlantic Ocean (EAO) and then imported into South Africa. Due to its migratory nature and high demand, skipjack stocks are managed by Regional Fisheries Management Organizations (RFMOs). The WCPO region (Orange listing for FAD fisheries) is managed by the Western and Central Pacific Fisheries Commission (WCPFC) and the EPO region (Orange listing for NON-FAD fisheries) is managed by the inter-American Tropical Tuna Commission (IATTC) and the IO region (Orange listing for FAD, NON-FAD & PL fisheries) is managed by the Indian Ocean Tuna Commission (IOTC) which assigns quotas and various regulations to its various members. Member countries are then responsible for ensuring the implementation and adaptation of the recommended quotas and regulations. Management of the Indian Ocean components is considered to be poorly effective. The IOTC has no real management or conservation currently measures in place although it is in the process of developing a quota allocation for tuna species in the region. . Management of the WCPO and EPO region is considered to be relatively effective as stock levels are kept at healthy levels. However this may be due to the high biomass and high recruitment levels found in the region as WCPFC and IATTC has no specific management strategies in places and there is poor implementation within these RFMOs of many of the recommendations put forward by scientists for improved sustainability fishing of tuna.

Skipjack - Red

Skipjack tuna are harvested from 5 distinct geographical areas namely the Western and Central Pacific Ocean (WCPO), Indian Ocean (IO), East Pacific Ocean (EPO), Western Atlantic Ocean (WAO) and the Eastern Atlantic Ocean (EAO) and then imported into South Africa. Due to its migratory nature and high demand, skipjack stocks are managed by Regional Fisheries Management Organizations (RFMOs). The EAO (listed red for FAD & NON-FAD) and WAO (listed red for NON-FAD & PL) region is largely managed by the International Commission for the Conservation of Atlantic Tunas (ICCAT) whilst the IO (listed red for GILL) region is managed by the Indian Ocean Tuna Commission (IOTC) which assigns recommendations and various regulations to its members. Member countries are then responsible for ensuring the implementation and adaptation of the recommended quotas and regulations. Management of the Atlantic and Indian Ocean components are considered to be marginally to poorly effective. ICCAT has no comprehensive strategy to reduce bycatch of seabirds, turtles or sharks, no requirements for logbook reporting no comprehensive observer program and has not yet addressed the overcapacity of the fleet. IOTC has no real management or conservation currently measures in place although it is in the process of developing a quota allocation for tuna species in the region.

Note: Occasionally caught on pelagic longlines in South Africa