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Swordfish

Xiphias gladius

Method of production - Caught at sea
Capture method - Longline
Capture area - South Atlantic (FAO 41,31,34,47)
Stock area - South Atlantic
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

Swordfish has a low resilience to overfishing. The 2013 South Atlantic stock assessment had considerable uncertainty and so the status of the fishery with respect to Maximum Sustainable Yield (MSY) reference points could not be established. Despite this the scientific committee were of the opinion that the stock is not overfished nor being subject to overfishing. Bycatch of vulnerable species such as birds, sharks and turtles is of concern in these pelagic longline fisheries. Buy swordfish from fisheries that are well regulated by their flag state to ensure that bycatch mitigation devices are being employed and monitored. There are a number of Marine Stewardship Council (MSC) certified swordfish fisheries in the Atlantic. MSC certified products from these fisheries represent the best option.

There remain large data deficiencies in most tuna and billfish fisheries, particularly with regards to fine scale spatial and temporal data for both target and especially for vulnerable bycatch species. Such information is vital to establish the true impact on the marine ecosystem. For this reason, commercial buyers in particular should establish what measures the flag state and 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
South Atlantic

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Stock information
Swordfish fisheries in the Atlantic are assessed by the International Commission for the Conservation of Atlantic Tunas (ICCAT). Provisional catches for 2014 of 9,885t are lower than the previous five year average of 11,086 and under the Total Allowable Catch (TAC) of 15,000t. The latest stock assessment was carried out in September 2013 and considerable uncertainty has been noted by the scientific committee. The models used in the assessment displayed conflicting values for various analyses, and as a result, Maximum Sustainable Yield (MSY) has not been estimated. The committee stress the need for improved scientific information yet have formed the opinion that the stock is unlikely to be overfished nor being subject to overfishing.

Management

Swordfish stocks range across and are accessed by numerous coastal states, making harmonised and effective management of these individual stocks very difficult. To try and achieve this, 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. For this reason, it is important to choose tuna that has been caught by vessels that are well regulated by their flag state. The ICCAT scientific committee recognised that there may be additional fleets taking swordfish in the Mediterranean, for example, Egypt, Israel, Lebanon, Monaco, and Syria, but the data are not reported to ICCAT or FAO.

Recent decreases in catches may be a result of improved regulation and temporal closures to the fishery, yet large catches of small swordfish, many of which have never spawned, and the low number of large individuals in the Mediterranean catch is cause for concern in these fisheries.

Following are ICCAT management and conservation measures of note that apply to Mediterranean swordfish fisheries, though it is noted that some countries have imposed additional measures in their national waters:

A Mediterranean-wide (EU and ICCAT) driftnet ban which saw the closure of the significant Moroccan drift net fishery at the beginning of 2012.

A three month ban for fisheries targeting swordfish.

A list of authorized vessels with permits to access the various fisheries must be maintained and submitted to ICCAT.

Minimum size of 90 cm Lower Jaw to Fork Length (LJFL) weighing less than 10 kg of round weight or 9 kg of gutted weight, or 7.5 kg of gilled and gutted weight.

ICCAT have developed an IUU vessel register and a register of vessels authorised to undertake transhipments at sea. Additionally, transhipments at sea should only take place if an ICCAT Observer is onboard the receiving vessel.

Capture information

Swordfish in the South Atlantic is taken primarily by surface longliners from (in order): Spain, Brazil, Japan, China, Chinese Taipei, Belize, Portugal and Senegal, but is captured in smaller quantities by various other gears in subsistence fisheries, such as gill nets off the coast of Africa. Longlining is a more fuel efficient method of fishing, but encounters bycatch of large shark and other vulnerable non-target species, including sea turtles and seabirds, depending on area and fishing activity. There are a range of measures that are available and required to be employed to reduce bycatch and mortality of these species including: circle and/or barbless hooks to prevent turtle and shark capture, and weighted branch lines, bird scaring lines, and night setting to reduce the capture of birds. There is also a prohibition to retain at risk shark species including bigeye thresher, oceanic whitetip, hammerhead, silky sharks, and recently added porbeagle. Several species of albatross are threatened with extinction, and whilst there have been many advances in reducing interactions with longline fisheries, it is not clear how effective these have been. Monitoring and data reporting of interactions with vulnerable species in all tuna fisheries is deficient, and the effectiveness of such measures has not been evaluated.

Read more about capture methods


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

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