|
Seafood to Avoid
Bigeye tuna
Scientific name: Thunnus obesus
Other names: Ahi
Ranking: E (Red – Worst Choice) |
 |
Description: longline fisheries for this highly migratory species of tuna occurs mainly in the West and East Coast of the North Island from the Bay of Plenty north. New Zealand represents only 3.5 percent of the Pacific catch which is now managed by the Western and Central Pacific Fisheries Commission.
The main concerns with this fishery are: uncertainty about the state of the stocks, declining stock trend, lack of a management plan plus the bycatch of sharks, seabirds and fur seals. Bigeye is internationally listed as a vulnerable threatened species.
The fishery assessment plenary report states: On a regional level "The estimate of MSY is lower than recent catchesÉ Current catches from the stock are not sustainable and will move the stock towards and then below a size that will support the maximum sustainable yield." (MFish, 2007, p101).
Market: Main market are Japan, Australia and USA. The export value of all tuna species combined was $36 million in 2004.
Status and sustainable yield
Status: Uncertain but likely to above Bmsy.
Annual catch limit: 714 tonnes in 2004.
Recorded catch: Latest reported annual landings of 178 tonnes in 20064.
Population size: South Pacific migratory population.
Stock trends: Declining.
Fishing method
Method: Longlining around the North Island.
Habitat damage: Low.
Bycatch: Sharks, seabirds and New Zealand fur seals are caught in the longline fishery.
Ecological effects: Removal of large predator species as bycatch in the longline fishery.
Management
Stock assessment: No New Zealand quantitative assessment but a 2006 assessment for the Western and Central Pacific Fisheries Convention is used.
Management plan: No.
Quota Management Species: Yes from 2004.
Biology
Distribution: Big eye tuna are caught mainly on the East and west coast of the North, mainly in the Bay of Plenty North.
Maximum age (years): 14+
Age at sexual maturity: 4-6
Growth rate: Medium.
Reproductive output: Medium.
Age exploited: 2
References: Overview of the Western and Central Pacific Ocean Tuna Fisheries, 2000, A Lewis and P Williams, Oceanic Fisheries Programme, Secretariat of the Pacific Community, New Caledonia, August 2001; National Tuna Fishery Report 2001 - New Zealand, T Murray and L Griggs, NIWA; Report from the Fishery Assessment Plenary, May 2007: stock assessments and yield estimates. Part 1: Albacore to Groper. Sullivan et al, Science Group, Ministry of Fisheries; Guidebook to New Zealand Commercial Fish Species, Revised Edition 1990, NZ Fishing Industry Board.
This page was updated on
9 November, 2007
|
