As a charity MCS relies on your generous support


MCS Home

Good Fish Guide

return to search Return to search results


Click to enlarge


Xiphias gladius

Method of production - Caught at sea
Capture method - Longline
Capture area - Western & Central North Pacific (FAO 61,67,71,77)
Stock area - Western & Central North Pacific
Stock detail - All Areas
Certification -
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.


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

View map areas

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. 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.


As for 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 average 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.

There are various bycatch mitigation measures that are available and required including: the use of at least 2 prescribed seabird mitigation measures (e.g. tori line, dyed bait, weighted branch line, night setting, underwater setting chute) in certain areas; 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; permissible sharks are to be fully utilized and no more than 5% of fins to total shark weight can be retained; 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; catch limits for countries targeting sharks; and various monitoring and reporting requirements. However, monitoring is deficient in many fisheries and the effectiveness of these measures has not been evaluated.

Read more about capture methods

Froese, R. and Pauly, D. Editors, 2015. FishBase. Available at [Accessed Dec 2015].

Return to top Return to top

Sign up to get the latest marine information from the Marine Conservation Society


Sign up to get all the latest marine related news from MCS

The UK charity for the protection of our seas, shores and wildlife.

Read more about MCS

The MCS website uses 'Cookies' to enhance your web experience. Please read our data and cookie policy.
If you do not wish to use cookies please read how to disable cookies. Don't show this message again