|Mango-pounamu, poutini (Maori), blue whaler, blue pointer, peau bleue, requin bleu (France), yoshikirizame (Japan)|
Blue shark is a worst choice seafood and should be avoided. There is no alternative.
Blue sharks, like most shark species, are slow growing and highly vulnerable to overfishing. Blue sharks are a highly migratory species and are primarily taken in large numbers in New Zealand’s tuna longline fisheries, mainly in the West and East Coast of the North Island from the Bay of Plenty north. Most of the blue sharks retained (around 72%) are processed and not dumped, after a change to regulations on 1 October 2014 which require fins to be returned with the body.
Blue sharks are caught as bycatch in tuna surface longline fisheries. Concerns include uncertainty about the state of the stocks, limited research and the lack of a quantitative stock assessment or a management plan. Removal of this predatory species may also have considerable negative ecological implications, as does the associated catch of other sharks. Seabirds, turtles and New Zealand fur seals are caught in the longline fishery. The bigeye target tuna longline fishery captures turtles, including leatherback, a vulnerable threatened species. It also has an estimated capture of 593 seabirds a year including vulnerable threatened Gibson’s and Antipodean albatross, and near-threatened southern Buller’s albatross. An estimated 623 seabirds a year are caught in the southern bluefin tuna target fishery, including whitecapped albatross and Buller’s albatross. Whilst there is no management plan for blue sharks, in 2013 a revised New Zealand National Plan of Action for the Conservation and Management of Sharks was developed. This included a requirement that fins and bodies must be returned from the sea together from 1 October 2014 but also allows fish to be discarded.
Not certified under any scheme.
The primary value is in the highly priced fins (and tails), which are exported to East Asian markets. Shark fin export value for all species average $40/kg. Total shark, ray and skates exports in 2015 was $31.33m, of which only $373,000 was shark fins, mainly (95%) exported to Singapore. New Zealand is amongst the top 20 global exporters of shark product.
No regional or fishing method difference.
|Population size:||Unknown – South Pacific migratory population.|
|Annual catch limit:||Limit set at 1860 tonnes since 2004.|
|Recorded catch:||Landings of 117 tonnes reported in 2013-14. Only 18.6% of blue sharks caught are retained while 89.2% of the discarded sharks are reported to be alive (but there is very low observer coverage to verify this).|
|Stock trends:||Uncertain: estimates of reference and current biomass are not available. At a CSIRO scientific meeting in 2007, blue sharks were estimated to have declined by 40% in the Tasman Sea over the last 10 years.|
|MSY Status:||Uncertain. Listed on IUCN Red List as a near-threatened species.|
|The Ministry of Primary Industries assessment plenary report includes:||“Blue sharks are the most heavily fished of the three large pelagic shark species (blue, mako and porbeagle sharks) commonly caught in the tuna longline fishery. Compared to mako and porbeagle sharks, however, blue sharks are relatively fecund, fast growing, and widely distributed. The status of the stock is unknown. (MPI, 2015, p116-118).|
|Distribution:||Blue sharks range and are caught in longline fisheries all around New Zealand.|
|Maximum age (years):||22|
|Age at sexual maturity:||8 for males and 7 to 9 for females|
|Reproductive output:||Low – 4 to 135 pups with 9-12 months gestation period, and fecundity is low overall.|
|Ability to recover:||Low|
|Fishing method(s):||Longlining around the North Island. 55% of blue shark are caught in the target bigeye tuna fishery while 36% were caught in the target southern bluefin tuna fishery.|
|Habitat damage:||No seabed impact.|
|Habitat of particular significance:||Hasn’t been defined in New Zealand.|
|Bycatch:||Other sharks are caught in the longline fishery. Shark species caught in the longline fishery include porbeagle, mako, deepwater dogfish and thresher shark. Sharks combined make up over 90% of the bycatch by number. Porbeagle, mako and thresher sharks are listed as vulnerable threatened species by the IUCN.|
|Ecological effects:||Removal of large predator species as bycatch in the longline fishery can have considerable ecological implications. The practise of shark finning without returning shark bodies has now been prohibited.|
|Bycatch:||Blue sharks are primarily caught in the tuna longline fisheries that catch seabirds, turtles and New Zealand fur seals. Some of these longline fisheries also catch vulnerable turtles at an observed rate of about one per year but, given level of observer coverage, actual numbers could be 10-40 times this. It is also estimated that four New Zealand fur seal captures occur per year (based on the last 5 years). In the bigeye tuna fishery an estimated 593 seabirds a year, including vulnerable threatened Gibson’s and Antipodean albatross, and near-threatened southern Buller’s albatross (includes cryptic mortality) are caught. In the southern bluefin tuna fishery an estimated 623 seabirds are caught. Southern bluefin tuna fishery also catches an estimated 100 fur seals a year (based on the last 5 years).|
|Management component:||Single species but the scale of the blue shark stock is uncertain – it could be a South Pacific stock or even a larger Southern hemisphere stock. From tagging data so far, most tagging returns are from the Western South Pacific.|
|Quota Management Species:||Yes in 2004|
|Management plan:||Highly Migratory Species management plan for 2010-15 is out of date, and has yet to be reviewed and replaced. There is no operational plan and the old management plan lacks key environmental standards. The National Plans of Action on Seabirds and Sharks are more relevant but they are slow to be implemented. There is no international management plan and the Western and Central Pacific Fisheries Commission (WCPFC) has yet to apply effective measures to prevent over-fishing.|
|Stock assessment:||No New Zealand quantitative stock assessment, but WCPFC has been attempting an assessment for blue sharks since 2012. The 2016 attempt “is preliminary and is considered to be a work in progress. As a result, it cannot be used to determine stock status and form the basis of management advice” (WCPFC, 2016).|
|Research:||There is no directed research on blue sharks in the fishery.|
|Observer coverage:||Observer coverage of 4.7% annually over the last 5 years. Coverage is not spatially or temporally representative of the fishing effort.|
National Tuna Fishery Report 2001 – New Zealand, T Murray and L Griggs, NIWA; Report from the Fishery Assessment plenary, November 2015: stock assessments and stock status – Volume 1: Introductory Sections to Ray’s Bream. Science Group, Ministry for Primary Industries; Ministry for Primary Industries (2016) Aquatic Environment and Biodiversity Annual Review 2015. Compiled by the Fisheries Management Science Team, Ministry for Primary Industries. 682p. The Guidebook to New Zealand Commercial Fish Species, 2007 Revised Edition, The New Zealand Seafood Industry Council Ltd. Seafood NZ, 2016. New Zealand Seafood Exports to December 2015. 133p. New Zealand National Plan of Action for the Conservation and Management of sharks (2013), Ministry of Fisheries. Ministry of Fisheries (2010) Operational Management Plan for Large Pelagic Species. 27p. WCPFC (2016) Report of the Scientific Committee of WCPFC. 232p.