| Common names: swordfish (English), pez (Espanol) |
Xiphias gladius Linnaeus, 1758
An elongate, rounded body, tapering to rear; head large, with a very long flattened bill; no teeth on jaws in adult; 1st dorsal fin short based, high, curved, 34-49, well separated from 2nd dorsal (4-6), which is small, at rear of body; no pelvic fins; pectoral fins low on the sides, 16-18; 1st anal fin, 13-14, short based, fin long and curved, between the 2 dorsals, 2nd anal 3-4, tiny, under 2nd dorsal; tail base with a large keel on each side and a deep notch above and below just before tail fin; tail fin large, strongly concave; no scales in adult.
Blackish brown on back fading to light brown or silvery on sides; first dorsal fin dark blackish brown; other fins brown or blackish brown.
Maximum size 457 cm; all-tackle world rcord 100.24 Kg.
Habitat: pelagic, oceanic.
Depth: 0-2878 m.
Circumglobal in tropical, temperate, and adjacent cold seas; southern California to the mouth of the Gulf of California to Peru and the offshore islands, common around the Galapagos.
Global Endemism: All species, TEP non-endemic, Circumtropical ( Indian + Pacific + Atlantic Oceans), "Transpacific" (East + Central &/or West Pacific), All Pacific (West + Central + East), East Pacific + Atlantic (East +/or West), Transisthmian (East Pacific + Atlantic of Central America), East Pacific + all Atlantic (East+West)
Regional Endemism: All species, Eastern Pacific non-endemic, Tropical Eastern Pacific (TEP) non-endemic, Continent + Island (s), Continent, Island (s)
Climate Zone: North Temperate (Californian Province &/or Northern Gulf of California), Northern Subtropical (Cortez Province + Sinaloan Gap), Northern Tropical (Mexican Province to Nicaragua + Revillagigedos), Equatorial (Costa Rica to Ecuador + Galapagos, Clipperton, Cocos, Malpelo), South Temperate (Peruvian Province )
Regularity: Regularly occurring
Type of Residency: Year-round
Regularity: Regularly occurring
Type of Residency: Year-round
Inshore/Offshore: Offshore Only, Offshore
Water Column Position: Surface, Near Surface, Mid Water, Water column only
Habitat: Water column
FishBase Habitat: Pelagic
Habitat and Ecology
This species uses its sword to kill prey. It feeds mainly on fishes but also on crustaceans and squids. Large individuals may accumulate high concentrations of mercury in the flesh (Collette 1995).
The distribution of larval swordfish in the Pacific Ocean indicates that spawning occurs mainly in waters with a temperature of 24°C or more. Spawning appears to occur in all seasons in equatorial waters, but is restricted to spring and summer at higher latitudes (Nishikawa and Ueyanagi 1974). In the Atlantic Ocean, spawning occurs in the upper water layer at depths between 0–75 m, at temperatures around 23°C, and salinity of 33.8–37.4 ppt. Pairing of solitary males and females is thought to occur when spawning (Palko et al. 1981). Spawning in southern Brazil occurs from November to February in between 20–28°S and 40–47°W (Amorim and Arfelli 1980). Estimates of egg numbers vary considerably, from one million to 16 million in 168,000 g female (Palko et al. 1981) and 29 million in a 272,000 g female (Wilson 1984).
Determination of age is difficult since the otoliths are very small and scales are missing in adults. Year rings have been successfully counted on cross sections of the fin rays (Arocha et al. 2003, DeMartini et al. 2006). Longevity is estimated to be 15 years (based on Arocha et al. 2003, DeMartini et al. 2006), and age of first maturity is estimated to be five years (based on Arocha and Lee 1996, Hinton and Maunder, unpublished data). These life history parameters do not differ greatly between stocks, therefore, the generation length for this species was estimated to be 6.5 years globally. The generation length is calculated as: age of first reproduction + z * (longevity - age of first maturity), where z is 0.15 (Collette et al. 2011).
Maximum size is 445 cm. The all-tackle game fish record is of a 536.15 kg fish caught odd Iquique, Chile in 1953 (IGFA 2011).
Habitat Type: Marine
Water temperature and chemistry ranges based on 146797 samples.
Depth range (m): 0 - 4700
Temperature range (°C): 1.478 - 27.910
Nitrate (umol/L): 0.050 - 32.106
Salinity (PPS): 30.771 - 37.537
Oxygen (ml/l): 2.521 - 7.737
Phosphate (umol/l): 0.022 - 2.072
Silicate (umol/l): 0.481 - 80.155
Depth range (m): 0 - 4700
Temperature range (°C): 1.478 - 27.910
Nitrate (umol/L): 0.050 - 32.106
Salinity (PPS): 30.771 - 37.537
Oxygen (ml/l): 2.521 - 7.737
Phosphate (umol/l): 0.022 - 2.072
Silicate (umol/l): 0.481 - 80.155
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.
Recorded at 800 meters.
Habitat: pelagic. Oceanic but sometimes found in coastal waters (Ref. 9354). Generally above the thermocline (Ref. 9354). Prefers temperatures of 18°C to 22°C (Ref. 9987). Larvae are frequently encountered at temperatures above 24 °C (Ref. 9702). Migrates toward temperate or cold waters in the summer and back to warm waters in the fall. Adults are opportunistic feeders, known to forage for their food from the surface to the bottom over a wide depth range (Ref. 9702). Uses its sword to kill its prey (Ref. 9354). Feeds mainly on fishes but also on crustaceans and squids (Ref. 9354). Good food fish, marketed fresh or frozen, and can be made into sashimi, teriyaki or fillets (Ref. 9354). Large individuals may accumulate large percentages of mercury in its flesh (Ref. 9354).
Non-Migrant: No. All populations of this species make significant seasonal migrations.
Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
Diet: octopus/squid/cuttlefish, Pelagic crustacea, bony fishes
Life History and Behavior
Evolution and Systematics
The tails of swordfish help them swim fast over long distances due to their stiffness and crescent shape.
"The fast marathon swimmers of the ocean, like the tunny or the swordfish, have very stiff crescent-shaped tails. This shape also makes it easier for the fish to change direction suddenly. The tunny is the speediest of the ocean fishes, able to attain 70 kmph." (Foy and Oxford Scientific Films 1982:188)
Learn more about this functional adaptation.
- Foy, Sally; Oxford Scientific Films. 1982. The Grand Design: Form and Colour in Animals. Lingfield, Surrey, U.K.: BLA Publishing Limited for J.M.Dent & Sons Ltd, Aldine House, London. 238 p.
Molecular Biology and Genetics
Barcode data: Xiphias gladius
Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
-- end --
Download FASTA File
Statistics of barcoding coverage: Xiphias gladius
Public Records: 86
Specimens with Barcodes: 120
Species With Barcodes: 1
CITES: Not listed
IUCN Red List Assessment
Red List Category
Red List Criteria
- 1996Data Deficient
National NatureServe Conservation Status
Rounded National Status Rank: NNR - Unranked
Rounded National Status Rank: NNR - Unranked
NatureServe Conservation Status
Rounded Global Status Rank: GNR - Not Yet Ranked
The North Atlantic stock of Swordfish is not overfished and overfishing is not occurring (ICCAT 2009). The stock is rebuilding with current biomass levels increasing by 4.4% over a three generation length period based on the ASPIC base case (Figure 20, ICCAT 2009). The reduction was calculated using the first and last data points of the time series considered. The stock is considered to be under adequate management.
The South Atlantic stock was overfished and overfishing had been occurring, but at present, fishing mortality is below FMSY, stock biomass is slightly above BMSY and under current management quotas (13,700 t TAC), the stock is projected to remain above the BMSY and slightly rebuild further (ICCAT 2009). The reduction in biomass for the South Atlantic stock over three generations has been approximately 30.3% based on the ASPIC base case (Figure 30, ICCAT 2009). The reduction was calculated using the first and last data points of the time series considered. The stock is considered to be under adequate management.
The Mediterranean stock is currently considered to be overfished and stock is experiencing slight overfishing. The International Commission for the Conservation of Atlantic Tunas Standing Committee on Research and Statistics (ICCAT-SCRS) report that the Mediterranean Sea swordfish compose a unique stock separated from the Atlantic, although more research is needed to clearly define the stock boundaries. Mitochondrial DNA restriction analysis reveal that genetic differentiation occurs between populations inhabiting the Mediterranean Sea and the tropical Atlantic ocean, indicating little genetic exchange occurring between the two (Kotoulas et al. 1995). The spawning stock biomass (SSB) in 2008 was 46% below the value that would maximize yield-per-recruit. In addition, the majority of the catch includes juveniles. However, landings statistics and population parameters indicate a certain stability over the past 20 years. The estimated decline in total biomass over a three generation period (20 years) ranged from 27–50% depending on whether a regression line or first and last points of the data series were used (Figure 21, ICCAT 2010). The Mediterranean population of Swordfish was therefore regionally assessed as Near Threatened in an overview of the conservation status of Mediterranean fishes (Abdul Malak et al. 2011). This stock is not considered to be well-managed.
In the North Pacific, a two-stock scenario analysing the western and central Pacific (subarea 1) and the eastern Pacific (subarea 2) was considered the most plausible based on analyses of Japanese longline catch per unit data (CPUE) data. Using the two-stock Bayesian production model (Brodziak and Ishimura 2009), a decline of 43.9% was estimated for subarea 1, and an increase of 111.2% in subarea 2 over a three generation length period (20 years). The decline was calculated using a linear regression over the time period considered. The results indicate that the North Pacific population is stable (Brodziak and Ishimura 2010).
In the Western Central Pacific, a MULTIFAN-CL stock assessment of south-west Pacific Swordfish showed a decline in total biomass ranging from 25.7% (optimistic scenario) to 36.9% (pessimistic scenario) over three generation lengths (20 years) (Figure 29, Kolody et al. 2008). The reduction was calculated using the first and last data points of the time series considered. The stock is considered to be under adequate management.
In the Southeastern Pacific, spawning biomass is estimated to have increased by 3.3% over three generation lengths (Figure 4.4, Hinton and Maunder 2006). The percent change was calculated using a linear regression over the time period considered. The stock is considered to be under adequate management.
For the Indian Ocean, an ASPIC model showed a decline in total biomass of 57.8% over the last three generation lengths (20 years) (Figure 59, IOTC 2010). The reduction was calculated using the first and last data points of the time series considered. The model results indicate that biomass is close to the BMSY level, and that overfishing is not presently occurring. The stock is considered to be under adequate management.
Globally, this species has shown a 28% decline over three generation lengths (20 years). The only stock that is not considered to be well-managed is the Mediterranean, which comprises less than 10% of the species' global range.
The largest proportion of Atlantic catches are made using surface drifting longlines, mostly by Spain, United States, Canada and Portugal. However, many additional gears are used (STECF 2009). Other directed swordfish fisheries include fleets from Brazil, Morocco, Namibia, EC-Portugal, South Africa, Uruguay, and Venezuela. The primary by-catch or opportunistic fisheries that take swordfish are tuna fleets from Chinese Taipei, Japan, Korea and EC-France. The tuna longline fishery started in 1956 and has operated throughout the Atlantic since then, with substantial catches of swordfish that are produced as a bycatch of tuna fisheries (ICCAT 2009). In the Atlantic, the Mediterranean stock is considered to be overfished and that overfishing is occurring. The stocks of the North and South Atlantic are considered to be well-managed (ICCAT 2009).
In the Indo-Pacific the main fisheries are Japan and Taiwan. Taiwan has had stable standardized CPUE trends, and Japan has shown variable CPUE trends depending on the fishing area (IOTC 2009). The Indian Ocean, Western Central Pacific and Southeastern Pacific are similarly considered to be under adequate management at present (fishing mortality below Fmsy and biomass above Bmsy; Kolody et al. 2008, IOTC 2009, Hinton and Maunder 2006).
Comments: North Atlantic stock is overfished, but fishing quotas have been reduced in order to let the stock rebuild.
There have been some changes in U.S. regulations which may have impacted catch rates, but the effects of these remain unknown. It is important to note that since 2003 the catches have been below the total allowable catches (TACs), greatly increasing chances of a fast recovery (STECF 2009). The total allowable catch in the North Atlantic during the 2007–2008 period was 14,000 t per year. The reported catch during that period averaged 11,536 t and did not exceed the TAC in any year. The total allowable catch in the South Atlantic for the years 2007 through 2008 was 17,000 t. The reported catch during that period averaged 13,365, and did not exceed the TAC in any year. There are two minimum size options that are applied to the entire Atlantic: 125 cm LJFL with a 15% tolerance, or 119 cm LJFL with zero tolerance and evaluation of the discards.
Since 1994 there have been quotas and minimum size limits to restrict the harvest of north Atlantic Swordfish. There are also longline area closures in place in the U.S. Atlantic. Reduced landings have been attributed to the International Commission for the Conservation of Atlantic Tunas (ICCAT) regulatory recommendations and shifts in fleet distributions, including the movement of some vessels some years to the South Atlantic or out of the Atlantic. In addition, some fleets, including the United States, EC-Spain, EC-Portugal and Canada, have changed operating procedures to opportunistically target tuna and/or sharks, taking advantage of market conditions and higher relative catch rates of these species previously considered as by-catch in some fleets. Recently, socio-economic factors may have also contributed to the decline in catch. Consistent with the goal of the Commission’s swordfish rebuilding plan (Rec. 96-02), in order to maintain the northern Atlantic Swordfish stock at a level that could produce maximum sustainable yield (MSY) with greater than 50% probability, the Committee recommends reducing catch limits allowed by Rec. 06-02 (15,345 t) to no more than 13,700 t. This reflects the current best estimate of maximum yield that could be harvested from the population under existing environmental and fishery conditions. Should the Commission wish to have greater assurance that future biomass would be at or above BMSY while maintaining F at or below FMSY, the Commission should select a lower annual TAC, depending on the degree of precaution the Commission chooses to apply in management. The Committee noted that allowable catch levels agreed in (Recs. 06-02 and 08-02) exceeded scientific recommendations. The successful rebuilding of this stock could have been compromised if recent catches had been higher than realized. Because of the poor size-selectivity of longliners, regulating minimum landing size may inadvertently have resulted in under-reporting of juvenile catches. Alternative methods for reducing juvenile catches, such as time and/or area closures or technological changes in gear deployment, may be more effective and their utility should be further investigated (STECF 2009). Future TACs above MSY are projected to result in 50% or lower probabilities of the stock biomass remaining above BMSY over the next decade (SWO-ATL-Figure 13) as the resulting probability of F exceeding FMSY for these scenarios would trend above 50% over time. A TAC of 13,000 t would provide approximately a 75% probability of maintaining the stock at a level consistent with the Convention Objective over the next decade (ICCAT 2009).
Until more research has been conducted to reduce the high uncertainty in stock status evaluations for the southern Atlantic swordfish stock, the Committee emphasizes that annual catch should not exceed the provisionally estimated MSY (15,000). Considering the unquantified uncertainties and the conflicting indications for the stock, the Committee recommends a more precautionary Fishery Management approach, to limit catches to the recent average level (~15,000 t), which are expected to maintain the catch rates at about their current level (STECF 2009). In general, catches of 14,000 t or less will result in increases in the biomass of the stock, catches on the order of 15,000 will maintain the biomass of the stock at approximately stable levels during the period projected. Catches in the order of 16,000 t or more will result in biomass decrease. The current TAC is 17,000 t (ICCAT 2009).
In the Mediterranean Sea, there are minimum size regulations, such as 90cm lower jaw-fork length in Spain, 140 upper jaw fork-length in Italy, 130 UJFL in Turkey. However, these minimum size regulations were cancelled because it was considered ineffective as a management tool. In Greece, the fishing season is closed from October to January. In 2009, ICCAT adopted a closed season for the Mediterranean Sea from 1 October to 31 November. The EU has banned all drift nets since January 2002 and ICCAT banned them since 2005 (some illegal drift nets still occur).
In Chile there is a size limit for this species, and total effort for this species has declined as they moved from driftnets to longlines. However, recent catches in this region are mostly targeted by the Spanish fleet. Given the potential for rapid change in the nature of the gill-net and longline fisheries that are increasingly targeting swordfish in the Eastern Pacific region, the trends in standardized catch per unit effort should be closely monitored for indications of changing status of these stocks (Hinton 2003, Hinton and Maunder 2006). The Western Central Pacific Fisheries Commission has recommended to limit the number of boats as well as catch and effort for the southwestern stock (WCPFC 2008).
The Scientific Committee recommends that management measures focused on controlling and/or reducing effort in the fishery targeting Swordfish in the southwest Indian Ocean be implemented (IOTC 2006).
Relevance to Humans and Ecosystems
Swordfish (Xiphias gladius; from Greek ξίφος: sword, and Latin gladius: sword), also known as broadbills in some countries, are large, highly migratory, predatory fish characterized by a long, flat bill. They are a popular sport fish of the billfish category, though elusive. Swordfish are elongated, round-bodied, and lose all teeth and scales by adulthood. These fish are found widely in tropical and temperate parts of the Atlantic, Pacific, and Indian Oceans, and can typically be found from near the surface to a depth of 550 m (1,800 ft). They commonly reach 3 m (9.8 ft) in length, and the maximum reported is 4.55 m (14.9 ft) in length and 650 kg (1,430 lb) in weight.
The swordfish is named after its bill resembling a sword (Latin gladius). This makes it superficially similar to other billfish such as marlin, but upon examination, their physiology is quite different and they are members of different families.
They commonly reach 3 m (9.8 ft) in length, and the maximum reported is 4.55 m (14.9 ft) in length and 650 kg (1,430 lb) in weight. The International Game Fish Association's all-tackle angling record for a swordfish was a 1,182 lb (536 kg) specimen taken off Chile in 1953. Females are larger than males, and Pacific swordfish reach a greater size than northwest Atlantic and Mediterranean swordfish. They reach maturity at 4–5 years of age and the maximum age is believed to be at least 9 years. The oldest swordfish found in a recent study were a 16-year-old female and 12-year-old male. Swordfish ages are derived, with difficulty, from annual rings on fin rays rather than otoliths, since their otoliths are small in size.
Swordfish are ectothermic animals; however, along with some species of sharks, they have special organs next to their eyes to heat their eyes and brains. Temperatures of 10 to 15 °C above the surrounding water temperature have been measured. The heating of the eyes greatly improves their vision, and consequently improves their ability to catch prey. Of the 25,000+ fish species, only 22 are known to have a mechanism to conserve heat. These include the swordfish, marlin, tuna, and some sharks.
Behavior and ecology
Contrary to popular belief, the "sword" is not used to spear, but instead may be used to slash at its prey to injure the prey animal, to make for an easier catch. Mainly, the swordfish relies on its great speed and agility in the water to catch its prey. It is undoubtedly among the fastest fish, but the basis for the frequently quoted speed of 97 km/h (60 mph) is unreliable.
Swordfish prefer water temperatures between 18 and 22 °C (64 and 72 °F), but have the widest tolerance among billfish, and can be found from 5 to 27 °C (41 to 81 °F). This highly migratory species typically moves towards colder regions to feed during the summer. Swordfish feed daily, most often at night, when they rise to surface and near-surface waters in search of smaller fish. During the day, they commonly occur to depths of 550 m (1,800 ft) and have exceptionally been recorded as deep as 2,878 m (9,442 ft). Adults feed on a wide range of pelagic fish, such as mackerel, barracudinas, silver hake, rockfish, herring, and lanternfishes, but they also take demersal fish, squid, and crustaceans. In the northwestern Atlantic, a survey based on the stomach content of 168 individuals found 82% had eaten squid and 53% had eaten fish, including gadids, scombrids, butterfish, bluefish, and sand lance. Large prey are typically slashed with the sword, while small are swallowed whole.
Swordfish are not schooling fish. They swim alone or in very loose aggregations, separated by as much as 10 m (33 ft) from a neighboring swordfish. They are frequently found basking at the surface, airing their first dorsal fin. Boaters report this to be a beautiful sight, as is the powerful jumping for which the species is known. This jumping, also called breaching, may be an effort to dislodge pests, such as remoras or lampreys.
Almost 50 species of parasites have been documented in swordfish. In addition to remoras, lampreys, and cookiecutter sharks, this includes a wide range of invertebrates, such as tapeworms, roundworms, and copepods. A comparison of the parasites of swordfish in the Atlantic and in the Mediterranean indicated that some parasites, particularly Anisakis spp. larvae identified by genetic markers, could be used as biological tags and support the existence of a Mediterranean swordfish stock.
Except for humans, fully adult swordfish have few enemies. Among marine mammals, killer whales sometimes prey on adult swordfish. The shortfin mako, an exceptionally fast species of shark, sometimes take on swordfish; dead or dying shortfin makos have been found with broken-off swords in their heads, revealing the danger of this type of prey. Juvenile swordfish are far more vulnerable to predation, and are eaten by a wide range of predatory fish.
In the North Pacific, batch spawning mainly occurs in water warmer than 24 °C (75 °F) during the spring and summer, and year-round in the equatorial Pacific. In the North Atlantic, spawning is known from the Sargasso Sea, and in water warmer than 23 °C (73 °F) and less than 75 m (246 ft) deep. Spawning occurs from November to February in temperatures above 20 °C (68 °F) in the South Atlantic off southern Brazil. Spawning is year-round in the Caribbean Sea and other warm regions of the west Atlantic.
Large females can carry more eggs than small females, and between 1 million to 29 million eggs have been recorded. The pelagic eggs measure 1.6–1.8 mm (0.063–0.071 in) in diameter and 2.5 days after fertilization, the embryonic development occurs. The surface-living and unique-looking larvae are 4 mm (0.16 in) long at hatching. The bill is evident when the larvae reach 1 cm (0.39 in) in length.
Swordfish have been fished widely since ancient times, among others in the sea between Sicily and Calabria, such as off the Tyrrhenian coast in the Reggio Province. It is a typical dish in the cuisine of this region.
Swordfish are vigorous, powerful fighters. When hooked or harpooned, they have been known to dive so quickly, they have impaled their swords into the ocean bottom up to their eyes. Although no unprovoked attacks on humans have been reported, swordfish can be very dangerous when harpooned. They have run their swords through the planking of small boats when hurt.
|This section needs additional citations for verification. (February 2010)|
Recreational fishing has developed a subspecialty called swordfishing. Because of a ban on long-lining along many parts of seashore, swordfish populations are showing signs of recovery from the overfishing caused by long-lining along the coast.
Various ways are used to fish for swordfish, but the most common method is deep-drop fishing, since swordfish spend most daylight hours very deep. The boat is allowed to drift to present a more natural bait. Swordfishing requires strong fishing rods and reels, as swordfish can become quite large, and it is not uncommon to use five pounds or more of weight to get the baits deep enough during the day, up to 2000 ft is common. Night fishing baits are usually fished much shallower, often less than 90 metres (300 ft). Standard baits are whole mackerel, herring, mullet, bonito, or squid; one can also use live bait. Imitation squids and other imitation fish lures can also be used, and specialized lures made specifically for swordfishing often have battery-powered or glow lights. Even baits are typically presented using glow sticks or specialized deepwater-proof battery operated lights.
Swordfish are classified as oily fish. Many sources, including the United States Food and Drug Administration, warn about potential toxicity from high levels of methylmercury in swordfish. The FDA recommends that young children, pregnant women, and women of child-bearing age not eat swordfish. (See mercury in fish for more details.)
The flesh of some swordfish can acquire an orange tint, reportedly from their diet of shrimp or other prey. Such fish are sold as "pumpkin swordfish", and command a premium over their whitish counterparts.
Swordfish is a particularly popular fish for cooking. Since swordfish are large animals, meat is usually sold as steaks, which are often grilled. Swordfish meat is relatively firm, and can be cooked in ways more fragile types of fish cannot (such as over a grill on skewers). The color of the flesh varies by diet, with fish caught on the East Coast of North America often being rosier.
|This section needs additional citations for verification. (December 2011)|
In 1998, the US Natural Resources Defense Council and SeaWeb hired Fenton Communications to conduct an advertising campaign to promote their assertion that the swordfish population was in danger due to its popularity as a restaurant entree.
The resulting "Give Swordfish a Break" promotion was wildly successful, with 750 prominent US chefs agreeing to remove North Atlantic swordfish from their menus, and also persuaded many supermarkets and consumers across the country.
The advertising campaign was repeated by the national media in hundreds of print and broadcast stories, as well as extensive regional coverage. It earned the Silver Anvil award from the Public Relations Society of America, as well as Time magazine's award for the top five environmental stories of 1998.
Subsequently, the US National Marine Fisheries Service proposed a swordfish protection plan that incorporated the campaign's policy suggestions. Then-US President Bill Clinton called for a ban on the sale and import of swordfish and in a landmark decision by the federal government, 132,670 sq mi (343,600 km2) of the Atlantic ocean were placed off-limits to fishing as recommended by the sponsors.
In the North Atlantic, the swordfish stock is fully rebuilt, with biomass estimates currently 5% above the target level. No robust stock assessments for swordfish in the northwestern Pacific or South Atlantic have been made, and data concerning stock status in these regions are lacking. These stocks are considered unknown and a moderate conservation concern. The southwestern Pacific stock is a moderate concern due to model uncertainty, increasing catches, and declining catch per unit effort. Overfishing is likely occurring in the Indian Ocean, and fishing mortality exceeds the maximum recommended level in the Mediterranean, thus these stocks are considered of high conservation concern.
In 2010, Greenpeace International has added the swordfish to its seafood red list.
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- Jesse Marsh, Margot Stiles, 2007. "Seafood Watch, Seafood Report, Monterey Bay Aquarium, Swordfish"
- Fritsches, K.A., Brill, R.W., and Warrant, E.J. 2005. Warm Eyes Provide Superior Vision in Swordfishes. Current Biology 15: 55−58
- Hopkin, M. (2005). Swordfish heat their eyes for better vision. Nature, 10 January 2005
- ReefQuest Centre for Shark Research. Haulin' Bass. Quote: "The 60 mph figure listed for the swordfish is based on a corrupted version of calculations made by Sir James Gray to estimate the impact speed necessary for a hypothetical 600-lb swordfish to embed its sword 3 feet in the timbers of ships, as has been known to occur; the figure seems to have entered the literature without question." Accessed 26 December 2011.
- Stillwell; Kohler (1985). "Food and feeding ecology of the swordfish Xiphias gladius in the western North Atlantic Ocean with estimates of daily ration" (PDF). Mar. Ecol. Prog. Ser. 22: 239–241. doi:10.3354/meps022239.
- Mattiucci, S.; Garcia, A.; Cipriani, P.; Santos, M. N.; Nascetti, G.; Cimmaruta, R. (2014). "Metazoan parasite infection in the swordfish, Xiphias gladius, from the Mediterranean Sea and comparison with Atlantic populations: implications for its stock characterization". Parasite 21: 35. doi:10.1051/parasite/2014036. PMID 25057787.
- The Shark Trust. "Shortfin mako". Archived from the original on 2011-07-14. Retrieved 2011-12-26.
- Based on data sourced from the relevant FAO Species Fact Sheets
- http://nuke.prolocobagnara.it/BagnaraCalabra/Storia/LaPesca/LaPescadelPescespada/tabid/495/Default.aspx http://www.biologiamarina.eu/PesceSpada.html http://www.ganzirri.it/spip.php?article9
- "What's an oily fish?". Food Standards Agency. 24 June 2004.
- FDA (1990–2010). "Mercury Levels in Commercial Fish and Shellfish". Retrieved 2011-09-14.
- EPA. "What you need to know about mercury in fish and shellfish". Retrieved 2011-09-14.
- Swordfish Fenton Communications
- NOAA/NMFS FishWatch - North Atlantic Swordfish, Retrieved on April 7, 2010
- Seafood Watch - Seafood Report - Swordfish Monterey Bay Aquarium, 16 July 2008
- "Greenpeace International Seafood Red List". Retrieved 14 September 2012.
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