Thon

Species scientific names: Thunnus albacares, Thunnus obesus, Katsuwonus pelamis, Thunnus alalunga

FAO area: 87

Fishing methods: Purse seine and long line

Last audit date: 10/07/2016

Next audit within: 09/07/2017

Status: Surveillance audit in progress

Audit Report

Ecuador – Tuna – Purse seine & Long line fleets – FAO 87

Species: Thunnus albacares, Thunnus obesus, Katsuwonus pelamis, Thunnus alalunga
Gear type: Purse seine, long line
Fishing Area: FAO Area 87 Pacific Southeast

Fishery management: The Inter-American Tropical Tuna Commission (IATTC) is the competent regional organisation for fisheries management in the region (FAO area 87), responsible for the conservation and management of tuna and other marine resources in the Eastern Pacific Ocean (EPO). EPO stocks are assessed by the IATTC staff, who makes recommendations to the IATTC. The Scientific Advisory Committee can also make recommendations to the IATTC.

Stock Status:

According to the IATTC, the fishing mortality rate for Skipjack and Bigeye stock is below FMSY. For the Yellowfin tuna, the fishing effort is estimated to be below the level that would support the MSY. Skipjack and bigeye biomasses are above BMSY. There is uncertainty about recent levels of recruitment and biomass of yellowfin tuna, although it is estimated that, if fishing effort is maintained at the present levels, both spawning biomass and catches are predicted to increase.

According to the most recent stock assessment (2012), the fishing mortality reference point for albacore tuna in the South Pacific is estimated to be at low risk of overfishing. The total biomass has been reduced to around 82% (62%–93%) of unfished levels, while the spawning biomass (mature females) has been reduced to 63% (35%–80%) of unfished levels. Both of these are considered moderate levels of depletion. The ratios of the current total biomass and spawning biomass to that needed to produce the maximum sustainable yield (Bcurrent/BMSY = 1.6 (1.4–1.9) and SBcurrent/SBMSY = 2.6 (1.5-5.2)) are both above 1.

Bycatch: The fleet follows procedures to prevent bycatch of endangered species. Endangered species accidentally caught are released alive. Independent monitors operate onboard each approved vessel.

The most commonly bycaught species by purse seiners and longliners are mahi mahi (Coryphaena hyppurus), swordfish (Xiphias gladius), and blue shark (Prionace glauca).

According to the most  updated assessment (2014), the fishing mortality rate of blue shark was around 34% of that needed to produce the maximum sustainable yield (ISC 2014b). Therefore overfishing is not occurring.

Fishing mortality rates for mahi mahi in the EPO are not known, but the IATTC is in the beginning stages of assessing them. IUCN does not consider there to be any major threats to mahi mahi from commercial fishing (College et al. 2011). Preliminary analysis for the planned assessment of mahi mahi in the EPO shows variable but somewhat steady catch per unit effort trends in abundance (IATTC 2013).

Swordfish stocks are healthy in the northeastern Pacific and southeastern Pacific, as the stocks are not overfished and overfishing is not occurring and biomass is greater than the biomass at which maximum sustainable yield is produced.

References:

IATTC, Stock Assessment Report 16 https://www.iattc.org/StockAssessmentReports/StockAssessmentReport16ENG.htm

ISSF. 2016. ISSF Tuna Stock Status Update, 2016: Status of the world fisheries for tuna. ISSF Technical Report 2016-05B. International Seafood Sustainability Foundation, Washington, D.C., USA.

IATTC SCIENTIFIC ADVISORY COMMITTEE 2ND MEETING La Jolla, California (USA) 9-12 May 2011  Michael G. Hinton and Mark N. Maunder.