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Swordfish

Xiphias gladius

Method of production - Caught at sea
Capture method - Longline
Capture area - North & Central Pacific (FAO 61,67,71,77)
Stock area - Western & Central North Pacific
Stock detail - All Areas
Certification - None
Fish type - Oily fish

Sustainability rating Click for explaination of rating

This fish, caught by the methods and in the area listed above, is not the most sustainable choice of fish to eat. Click on the rating icon above to read more and on the alternatives tab below to find more sustainable fish to eat.


Sustainability overview

The latest stock assessment for swordfish in western-central North Pacific Ocean was undertaken in 2014 and indicated that the swordfish stock does not appear to have been overfished or to have experienced overfishing throughout most of the period between 1951-2012. Similarly, results indicated it was very unlikely that the stock was currently overfished or being subject to overfishing. Bycatch of vulnerable species such as birds, sharks and turtles remains of concern in these pelagic longline fisheries. There are a range of mitigation measures available, but the degree to which these measures are implemented and effective is unknown as monitoring is deficient in many fisheries. It is therefore important to buy swordfish from fisheries that are well regulated by their flag state.

Commercial buyers in particular should establish what measures the flag state or fleet is taking to improve these deficiencies and specify the need for ongoing and demonstrable improvements. Large buyers should consider supporting such improvements.

Biology

Swordfish is the only member of the family Xiphiidae. It is a highly migratory species, moving towards temperate or cold waters in summer to feed and returning to warmer waters to spawn. They are apex predators that feed opportunistically. Squids and fishes are major prey items. In the Atlantic, spawning takes place in spring in the southern Sargasso Sea. In the Pacific, spawning occurs during spring and summer, and in the Mediterranean between June-August. Usually solitary, it forms large schools during spawning. A fast growing fish, swordfish begin to mature at two years of age, when they are about 150 to 170 cm in length, and by age four all are mature. They can attain a maximum size of 4.5m and a weight of 650kg. Swordfish tolerate temperatures of about 5 to 27C, but their optimum range is about 18 to 22C, and larvae have been found only at temperatures exceeding 24C.

Stock information

Stock area
Western & Central North Pacific

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Stock information
The swordfish stock in the western central North Pacific Ocean is managed by the Western and Central Pacific Fisheries Commission (WCPFC) and assessed by the International Scientific Committee for Tuna and Tuna-like Species in the North Pacific Ocean (ISC). In recent years, catches and harvest rates of swordfish in the region have had a declining trend. Since 2007, the biomass has remained stable at around 70,000t. The latest stock assessment was undertaken in 2014 and indicated that the swordfish stock does not appear to have been overfished or to have experienced overfishing throughout most of the period between 1951-2012. Similarly, results indicated it was very unlikely that the stock was currently overfished nor being subject to overfishing.

Management

As with tuna, individual swordfish stocks range across and are accessed by numerous coastal states, making harmonised and effective management of these individual stocks very difficult. As a result, intergovernmental Regional Fisheries Management Organisations (RFMOs) have been established. There are five main tuna RFMOs worldwide and it is their responsibility to carry out data collection, scientific monitoring and management of these fisheries. Whilst the RFMOs are responsible for the development of management and conservation measures, the degree to which they are implemented, monitored and enforced still varies significantly between coastal states. The main countries reporting swordfish catches in this region are (In order) Japan, Taiwan and the USA with smaller catches from many Pacific coastal states.

There is no Total Allowable Catch (TAC) set for this stock yet WCPFC participating coastal states are expected to have set national TACs which are not to exceed the maximum level reported in any one year between 2001 and 2006. Management measures that apply to directed tuna fisheries are expected to also benefit swordfish stocks.

To help address IUU, the WCPFC maintains an IUU Vessel List; and all transhipments at sea are to be documented and 100% observed as part of the regional observer programme.

There is 5% observer coverage for vessels over 20m.

Capture information

In the western central North Pacific Ocean, swordfish are mostly caught in mixed species longline fisheries, although there are some significant drift net and set net fisheries in Japan and USA. The largest catches have been taken by Japan for more than five decades, however in recent years this has reduced (to a little over 4,000t) and the Taiwanese catch has increased to nearly the same level (3,600t). The USA has averaged approximately 1,600t in recent years with lesser amounts taken by a wide range of Pacific countries. Pelagic longlining is associated with the bycatch of vulnerable species including: shark, turtles, sea birds and other billfish. Various bycatch mitigation measures are available and required.

In 2017 a new seabird measure came into force for longliners, requiring vessels to use one or more of the following, depending on vessel size and fishing location: weighted branch lines, night setting, tori lines, side setting with a bird curtain and weighted branch lines, blue-dyed bait; deep setting line shooter; management of offal discharge. The commission is also beginning a project in 2017 to estimate seabird mortality.

WCPFC Scientific Committee research in 2016 into sea turtle mitigation in longline fisheries found that interaction rates are lower when large circle hooks are used, higher at hooks closest to floats and higher when squid baits are used. Current measures relating to turtles include: the use of circle hooks for shallow set gear to reduce turtle capture, along with the requirement to carry line cutters and de-hookers and to promptly release turtles or to foster to recovery any sick or comatose turtles captured.

In 2016, catches of silky sharks in the longline fishery were around three times higher than in the purse seine fishery. Shark measures include: full utilisation of permissible sharks and retention of no more than 5% of fins to total shark weight; a prohibition to land silky and oceanic whitetip sharks; a prohibition on the use of wire leaders and lines running directly off the longline floats or drop lines - known as shark lines; and for fisheries specifically targeting sharks, WCPFC countries are also required to develop management plans, demonstrating how they intend to avoid or reduce catches of highly depleted shark species. Data on the effectiveness of the WCPFC ban on shark finning is very limited. In 2016, WCPFC adopted measures to improve recording of manta and mobula rays discarded and released, and to treat these species as key shark species for assessment and research.

In general, the effectiveness of the above measures has not been evaluated. Monitoring is deficient and the reporting of interactions with vulnerable species is poor.

Read more about capture methods


References
Froese, R. and D. Pauly. Editors. 2016. FishBase. Available at www.fishbase.org [Accessed Dec 2016].

ISC, 2016. Report of the sixteenth meeting of the international scientific committee for tuna and tuna-like species in the North Pacific Ocean: plenary session. Sapporo, Hokkaido, Japan, 13-18 July 2016. Available at http://isc.fra.go.jp/reports/isc/isc16_reports.html [Accessed Dec 2016].

ISSF, 2016. Status of the world fisheries for tuna: Management of tuna stocks and fisheries, 2016. ISSF Technical Report 2016-14.International Seafood Sustainability Foundation, Washington, D.C., USA. Available at http://iss-foundation.org/downloads/13305/ [Accessed Nov 2016].

WCPFC, 2016. Conservation and management measures. Available at https://www.wcpfc.int/conservation-and-management-measures [Accessed Dec 2016].

WCPFC, 2016. Scientific committee meeting: summary report. Twelfth regular session. Bali, Indonesia, 3-11 August 2016. Available at https://www.wcpfc.int/meetings/sc12 [Accessed Dec 2016].

WCPFC, 2016. Thirteenth regular session of the commission. Denarau Island, Fiji 5-9 December 2016. Available at https://www.wcpfc.int/meetings/13th-regular-session-commission [Accessed Dec 2016].

WCPFC, 2014. Western and Central Pacific fisheries commission scientific committee: summary report. Tenth regular session. Majuro, Republic of the Marshall Islands, 6-14 August 2014. Available at https://www.wcpfc.int/meetings/10th-regular-session-scientific-committee [Accessed Dec 2016].

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