Good Fish Guide
Method of production - Caught at sea
Capture method - Longline
Capture area - South West and Central Pacific (FAO 71,77,81)
Stock area - South West Pacific
Stock detail - Certified fleets only
Certification - Marine Stewardship Council (MSC)
Fish type - Oily fish
Swordfish in this region are both targeted for and landed as by-product in directed tuna fisheries using pelagic longlines. They are also taken in artisanal net fisheries. The last stock assessment for swordfish in the South West Pacific Ocean was carried out in 2013. Whilst the assessment indicated that the biomass was not in an overfished state, there were conflicting values for fishing mortality, which suggested that overfishing may or may not be occurring. Further research is being undertaken by the Australian government that should provide further insight into these contradicting model outputs.
This fishery is associated with the incidental capture of vulnerable species including sharks and turtles yet various measures are employed to reduce this and monitoring is undertaken to establish the effectiveness of these measures. These actions are also part of the conditions of the certification of the fishery by the Marine Stewardship Council (MSC).
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.
South West Pacific
Swordfish in the South West Pacific Ocean (SWPO) are assessed and managed by the Western and Central Pacific Fisheries Commission (WCPFC). The latest stock assessment was carried out in 2013 using data up to 2011 and indicated that there had been a relatively steep decline in biomass over the period between 1997 and 2011, corresponding with increased annual catches from approximately 2000t to 10,000t. Estimates of stock size are highly uncertain as a result of high variation in assumed growth and maturity and mortality at age schedules between Australian and Hawaiian data sets. As a result, the ranges of current spawning biomass and fishing mortality with regards to Maximum Sustainable Yield (MSY) models differ, depending on whether the Australian or Hawaiian schedules are used. Assuming the Hawaiian schedule produces estimates between 0.40 to 0.70Fmsy (not being overfished)while, assuming the Australian schedule produces estimates that are between 1.06 to 1.77Fmsy (stock being overfished). However, both schedules indicate that the stock is not in an overfished state, with spawning biomass ranging from 1.15 to 2.54Bmsy. Total recent catches have been relatively stable in recent years, but regional increases have been significant, especially in areas north off 20 degrees south.
The Australian government recently undertook additional research on age, growth and age validation for swordfish. One indication was that swordfish live longer and grow slower than previously estimated. There is consideration of splitting the stock into south-western and central southern to resolve the uncertainties around reconciling the Hawaiian and Australian models. Recommendations will be taken on board for the next stock assessment in 2017.
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, including swordfish. Whilst the RFMOs, in this case the Western and Central Pacific Fisheries Commission (WCPFC), 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 so it is important to buy tuna and swordfish that has been caught in fisheries that are well regulated by their flag state. This particular fleet operating out of the east coast of Australia has been certified as a sustainable and well managed fishery by the Marine Stewardship Council (MSC) and represents the best option.
There is no Total Allowable Catch (TAC) set for this stock yet most participating countries have set national TACs for their components. The WCPFC scientific committee have recommended that due to uncertainty in the assessment, there should be no increase in fishing mortality over current (2007 to 2010) levels. They also recommend developing management measures between the equator and 20 degrees S as this region now represent the largest component of the catch. Management measures that apply to directed tuna fisheries are expected to also benefit swordfish stocks yet the scientific committee has also supported reviewing the existing management measures for swordfish to prevent further increasing catches in this area.
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.
The WCPFC requires 5% observer coverage for longline vessels over 20m.
In the South-West Pacific Ocean, swordfish are mostly caught in mixed species pelagic longline fisheries off the coast of Australia and New Zealand and in the central South Pacific near the Cook Islands and French Polynesia, with smaller quantities taken in artisanal gill and fixed net fisheries. Pelagic longlining in the WCPO is associated with the incidental capture and mortality of vulnerable species including sharks, 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.
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.
Based on method of production, fish type, and consumer rating: only fish rated 2 and below are included as an alternative in the list below . Click on a name to show the sustainable options available.
Froese, R. and D. Pauly. Editors. 2016. FishBase. Available at www.fishbase.org [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, 2013. Scientific committee: summary report. Ninth regular session. Pohnpei, Federated States of Micronesia, 6-14 August 2013. Available at https://www.wcpfc.int/meetings/9th-regular-session-scientific-committee [Accessed Dec 2016].
Sign up to get all the latest marine related news from MCS
The UK charity for the protection of our seas, shores and wildlife.