|Scientific Name:||Isurus oxyrinchus Rafinesque, 1810|
|Taxonomic Source(s):||Eschmeyer, W.N., Fricke, R. and Van der Laan, R. (eds). 2017. Catalog of Fishes: genera, species, references. Updated 30 March 2017. Available at: http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp. (Accessed: 06 April 2017).|
|Red List Category & Criteria:||Data Deficient (Regional assessment) ver 3.1|
|Assessor(s):||Walls, R., Soldo, A., Cailliet, G.M., Cavanagh, R.D., Kulka, D.W., Stevens, J.D., Clò, S., Macias, D., Baum, J.K., Kohin, S., Duarte, A., Holtzhausen, J., Acuna, E., Amorim, A.F. & Domingo, A.|
|Facilitator/Compiler(s):||Walls, R. & Dulvy, N.|
European regional assessment: Data Deficient (DD)
Shortfin Mako (Isurus oxyrinchus) is an offshore littoral and epipelagic species, found in tropical and warm-temperate seas from the surface down to at least 500 m. It is an important target species, a bycatch in tuna (Thunnus spp.) and billfish (Xiphiidae and Istiophoridae) longline and driftnet fisheries, particularly in the high-seas, and is an important coastal recreational species. Most catches are inadequately recorded and underestimated and landings data do not reflect numbers finned and discarded at sea. Various analyses suggest that this species may have undergone significant declines in abundance over various parts of its range.
Several subpopulations of Shortfin Mako have been assessed separately for the IUCN Red List, however further data are required to determine whether individuals occurring in the Mediterranean constitute a subpopulation (based on the definition of "subpopulation" as given in the IUCN Red List Categories and Criteria). Recent investigations in the Mediterranean Sea suggest that the western basin is a nursery area where bycatch of this species from the tuna and Swordfish (Xiphias gladius) fishery consists almost exclusively of juveniles. It is possible that this nursery area corresponds to the Eastern Central Atlantic subpopulation, which is affected by the Swordfish longline fishery off the western coast of Africa and the Iberian Peninsula. In other areas of the Mediterranean Sea, this shark is caught sporadically. Reports from the Ligurian Sea show a significant decline since the 1970s. In the Adriatic Sea, it was considered common at the end of 19th/beginning of the 20th centuries, but since 1972 there have been no records of this species reported despite a large increase in fishing pressure and introduction of new fishing gear to the area. Given the fact that nothing has changed in terms of management or fishing effort in the Mediterranean Sea since the previous assessment, the status will be carried over. Therefore, on the basis of inadequate management resulting in continuing (if not increasing) fishing pressure, the high value of its meat and fins, its sensitive life history characteristics, the absence of records from some localised areas in the Mediterranean Sea, evidence of large declines in other regions, and captures of juveniles in a probable nursery area, this species is threatened in these waters.
In the Northeast Atlantic, data for this shark pertaining to population size and trends are scarce. It is believed that Shortfin Makos occurring in this region are just a small portion of a North Atlantic-wide stock, therefore this assessment should be revisited and analysed along with data from the Northwest Atlantic. The species is faring worse in the Mediterranean Sea than anywhere else in the world, and that the Mediterranean Sea and north Atlantic stocks may be connected. However, there is no information on the status of the Northeast Atlantic subpopulation, and it is unknown which region formerly held more individuals. Thus, this species is assessed as Data Deficient throughout European waters.
This pelagic shark is circumglobal in most tropical and temperate seas, from 50°N (up to 60°N in the Northeast Atlantic) to 50°S. In the Northeast Atlantic there have been occasional records from Norway (from about 60°N) and around the British Isles, though it is more common further south, including off the Bay of Biscay, Spain, Portugal, the Azores and northwest Africa (Ebert and Stehmann 2013). The southern limit of the Northeast Atlantic subpopulation is assumed to be 5°N as with Swordfish (Xiphias gladius), based on the oceanography of equatorial waters (ICES 2013).
This species also occurs in the Mediterranean Sea, where the highest abundance has been reported in the west, while it has rarely been reported from the east (Aegean Sea and Sea of Marmara). Individuals several months old were reported from the western Ligurian Sea (Orsi Relini and Garibaldi 2002) and other regions including Campania, Sicily and Sardinia (MEDLEM Database). However, the species may be very close to local extinction from the Mediterranean Sea, having last been reported from Malta in 2005 (Soldo et al. 2014). It has never been reported from the Black Sea. Recent sightings data reveal its presence in the eastern Mediterranean Sea with a possible spawning and nursery area in the Aegean Sea (Kabasakal and Kabasakal 2013, Soldo et al. 2014). Its depth limit is zero to 500 m.
Native:Albania; Algeria; Bosnia and Herzegovina; Croatia; Cyprus; Egypt (Egypt (African part), Sinai); France (Clipperton I., Corsica, France (mainland)); Gibraltar; Greece (East Aegean Is., Greece (mainland), Kriti); Ireland; Isle of Man; Israel; Italy (Italy (mainland), Sardegna, Sicilia); Lebanon; Libya; Malta; Montenegro; Morocco; Norway; Palestinian Territory, Occupied; Portugal (Azores, Madeira, Portugal (mainland)); Spain (Baleares, Canary Is., Spain (mainland), Spanish North African Territories); Syrian Arab Republic; Tunisia; Turkey (Turkey-in-Asia, Turkey-in-Europe); United Kingdom (Great Britain, Northern Ireland)
|FAO Marine Fishing Areas:|
Atlantic – northeast; Atlantic – eastern central; Mediterranean and Black Sea
The International Council for the Exploration of the Sea (ICES) considers a single stock of Shortfin Mako (Isurus oxyrinchus) throughout the North Atlantic (ICES 2012); the North and the South Atlantic subpopulations do however constitute genetically distinct groups (Heist et al. 1996). The relationship between the Atlantic and Mediterranean Sea subpopulations is still unclear, therefore the two areas are assessed separately. Major declines in this species’ abundance have occurred, notably in the eastern Mediterranean Sea where they are now rarely seen (ICES 2012). In the North Atlantic, population declines of up to 70% have also been documented (ICCAT 2005), but it is unclear to what extent this decline is applicable specifically to the northeast region.
In 1989, Bonfil (1994) estimated that 5,932 individuals were caught by Korean longliners in the (mainly equatorial) Atlantic and that 763 tonnes of makos (Isurus spp.) were landed in the Spanish Swordfish fishery in the Atlantic Ocean and the Mediterranean Sea. In the early 2000s, these sharks comprised about 7% (~2,500 tonnes) of the total catch of the large Spanish pelagic longline Swordfish fleet in the Atlantic Ocean (Mejuto et al. 2005). Muñoz-Chapuli et al. (1994) estimated that some 4,500 individuals per year were landed from a longline fishery based at Algeciras, southern Spain (given an average weight of 20 kg this would represent about 90 tonnes). The landings of this shark as bycatch from the Swordfish fishery of the Azorean fleet also showed a decrease (Castro et al. 1999). Landings reported to the International Commission for the Conservation of Atlantic Tuna (ICCAT) from Portuguese surface longline fisheries in the North Atlantic averaged about 698 tonnes during 1993-1996 and 340 tonnes for the period 1997-2002.
Analyses of catch per unit effort (CPUE) from US pelagic longline fishery logbooks reported that makos might have declined by about 40% in the Northwest Atlantic between 1986 and 2000 (Baum et al. 2003). A more recent assessment of observer data for the same fishery found a similar instantaneous rate of decline of 38% between 1992 and 2005 (Baum and Blanchard 2010). A similar analysis of the same dataset and species grouping that restricted the areas of analysis to account for unbalanced observations, resulted in an overall decline of 48% from beginning to end of the time series (1992-2005; Cortés 2012). A 2004 ICCAT stock assessment workshop reported that stock depletions for North Atlantic Shortfin Mako are likely to have occurred based on CPUE declines of 50% or more. Demographic model results varied widely, with one approach suggesting that present stock size is about 80% of virgin level, and another approach suggesting reductions to about 30% of virgin biomass (1950s) (Cortés 2012).
Uncertainties about demographic parameters and catches, and the uninformative nature of available catch data indicate that further analysis is necessary to properly delineate stock status. If historical catch is higher than the estimates in this report, the likelihood of the stock being below the biomass at maximum sustainable yield will surely increase (ICCAT 2005). A standardized catch rate index from the commercial large pelagic fishery off Canada suggested a decline in the 1970s and stable abundance since 1988 (Campana et al. 2005). However, the analysis did not have the statistical power to detect anything less than a severe decline and these sharks represent the margins of the population. The most heavily fished areas lie outside Canadian waters. The median size of makos in the commercial catch has declined since 1988, possibly indicating a loss of larger individuals (Campana et al. 2005).
In 2010, 4,005 tonnes of landed Shortfin Mako were reported to ICCAT in the North Atlantic, 3,546 tonnes of which were from longline fleets and 459 tonnes from others (ICES 2012). This is the largest catch recorded since 1970 (the extent of the database), apart from 2004, which was > 1,000 tonnes larger. However, this figure is in the same region as seen in 2007 and 2009. The main countries reporting catches in the North Atlantic are Spain, Portugal, USA, and Japan, accounting for 52%, 36%, 5% and 3% of total reported landings in 2010, respectively. National landings reported to ICES for 2011 were 20.6 tonnes for the Northeast Atlantic, with the majority of this from the Azores waters by Portuguese fleets (15.6 tonnes), and smaller amounts reported by Spain (including Basque country) and France (ICES 2012).
Previous ICCAT Shortfin Mako assessments used two other estimates of landings for this stock, the tuna (Thunnus spp.) ratio (logged observations of shark catches relative to tuna catches) and the fin trade index (shark fin trade observations from the Asian market used to calculate caught shark weights based on catch effort data; Clarke et al. 2006; ICCAT 2005 and 2008). These figures were much higher than actual reported landings. Similarly, discard data - where available - are considered a large underestimation (ICES 2012).
CPUE data were compiled at the ICCAT assessment in 2004 (ICCAT 2005) and 2008, and these indicated a declining trend for this species in the North Atlantic between 1975 and 2004. The US pelagic longline logbook program (1986 to 2010) and the US pelagic longline observer program (1992 to 2010) indexes of abundance showed an initial decline until the late 1990s, followed by an upward trend to 2010 (Cortés 2012). The Marine Recreational Fisheries Statistics Survey data (1981 to 2010) showed high variability, with a peak in the mid 1990s, followed by a decline, then a stable trend over the last ten years (Babcock 2013). Standardized CPUE from logbook data of the Japanese tuna longline fishery in the North Atlantic (1994 and 2010) was low and stable between 1994 and 2005, and then showed a continuous increasing trend (Semba et al. 2012). However, a filtering method removed assumed unreliable data. In general the available catch per unit effort series showed increasing or stable trends for the final years of each series since the last stock assessment (ICES 2012).
Despite this knowledge, it is unclear as to whether this information would directly apply in the Northeast Atlantic, and it is unrealistic to assign a trend or status to a partial stock. While it is likely this species is declining in European Atlantic waters, the data provided from these regions cannot be used to estimate trends.
Towards the end of the 19th century, this shark was considered common throughout the Mediterranean Sea. “Tonnarella” (tuna-trap) catches in the Ligurian Sea from 1950 to the 1970s showed a rapid decline and eventual disappearance of the species (Boero and Carli 1979). Landings from Maltese waters for 1979-2001 (data from the Maltese fishery department) showed a decline, although fishing pressure did not change. Since 1998, there have been few records from the central and eastern Mediterranean Sea.
In the eastern Adriatic Sea, Shortfin Mako was considered common a century ago (Katuri 1893 and Kosi 1903), while publications from the 1990s considered it to be rare (Mili’I’ 1994, Jardas 1996). Soldo and Jardas (2002) report that there have been no records of the species in the eastern Adriatic Sea since 1972.
Between 1998 and 2000, this shark was caught more often in the Swordfish fishery in the Mediterranean Sea than any other fishery, with a mean CPUE of 0.07 fish per 1,000 hooks in the “American type” longline and 0.05 fish per 1,000 hooks in the standard longline. It was more abundant in the Alboran Sea and the Levantine basin than other areas of the Mediterranean Sea surveyed by Megalofonou et al. (2005). The Azorean fleet mako landings decreased by almost 50% in numbers from 1987 to 1994 (Castro et al. 1999). This species may have been one of the most overfished pelagic sharks in the Mediterranean Sea (Megalofonou et al. 2005). More recently, across the Mediterranean Sea, total reported landings of this shark for 2011 were just two tonnes (ICES 2012). Since 1997, the Mediterranean Sea catches have always been low (less than nine tonnes), with peak reported catches of 17 and 10 tonnes in 2005 and 2006, respectively.
Ferretti et al. (2008) grouped Shortfin Mako with Porbeagle (Lamna nasus) for an analysis of elasmobranch population declines in the Mediterranean Sea, finding the largest declines in the Camogli tuna trap of > 99.99% over 56 years, in both abundance and biomass. Similar rates of decline were observed in the northern Ionian Sea, where a large drop in mackerel sharks (family Lamnidae) caught by pelagic longlines was observed in the early 1980s. It should be noted that catch rates were very low even at the beginning of the data series, with an average of 0.2 sharks per 1,000 hooks. The meta-analytical estimate of the rate of decline was more than 99.99% for biomass (IRD: –0.15; CI 95%: –0.21, –0.10; time range: 106 years) and abundance (IRD: –0.12; CI 95%: –0.22, –0.03; time range: 135 years).
It is thought that the area around the Strait of Gibraltar is possibly a nursery area for the North Atlantic subpopulation of this species. However, the status of this nursery is unclear following the severe declines seen throughout the Mediterranean Sea, and indeed the disappearance reported for most Mediterranean regions (Soldo et al. 2014).
Specific data on population trends from the Northeast Atlantic are unknown. As there is no information on which region formerly held more individuals, it is not possible to infer the trend of the subpopulations in the Northeast Atlantic from the one of the Mediterranean Sea.
|Current Population Trend:||Unknown|
|Habitat and Ecology:|
This is an active, offshore littoral and epipelagic species, found in tropical and warm-temperate seas from the surface down to at least 500 m (Compagno 2002). In the Northwest Atlantic, a tagging study showed that this species makes extensive movements of up to 3,433 km, with 36% of recaptures caught at greater than 420 km from their tagging site (Casey and Kohler 1992). Only one tagged fish crossed the mid-Atlantic ridge, suggesting that trans-Atlantic migrations are not as common as for Blue Shark (Prionace glauca).
In the Mediterranean Sea, it is presumed that the Strait of Gibraltar is a nursery area (Buencuerpo et al. 1998, Tudela et al. 2005). It is possible that this nursery area is from the Eastern Central Atlantic subpopulation, which is affected by the Swordfish longline fishery off the west coast of Africa and Iberian Peninsula (Soldo et al. 2014). Stevens (2008) suggested that nursery areas would likely be situated close to the coast in highly productive areas, based on the majority of reports, with nursery grounds off West Africa in the Eastern Central Atlantic.
Maia et al. (2007) reported length at 50% maturity in the Northeast Atlantic as 1.80 m total length (TL) in males, but no estimate was obtained for females as no mature individuals were caught. Compagno (2001) reported that males mature between 203 and 215 cm TL, reaching a maximum size of 296 cm TL, and females mature between 275 and 293 cm TL, reaching a maximum of almost 400 cm TL. In the Northwest Atlantic, size at maturity is ~195 and 265-280 cm TL in males and females, respectively (Pratt and Casey 1983, Stevens 1983, Cliff et al. 1990). Age at maturity in the same region is eight years for males and 18 years for females (Natanson et al. 2006). Longevity has been estimated as 29-32 years (Bishop et al. 2006, Natanson et al. 2006). Its generation length is estimated to be 25 years.
The species is live bearing with yolk sac and oophagous, and what little is known of its reproductive cycle indicates a gestation period of 15-18 months, with a three year reproductive cycle (Mollet et al. 2000). Litter size is four to 25 pups (possibly up to 30, mostly 10-18), which are about 60-70 cm TL at birth (Garrick 1967, Compagno 2001). Cortés (2002) calculated a finite rate of population increase (lambda) of 1.141 (1.098 to 1.181 95% CI, r = 0.13) and the average reproductive age as 10.1 years (9.2 to 11.1 95% CI).
|Generation Length (years):||25|
|Movement patterns:||Full Migrant|
|Use and Trade:||This is one of the most valuable shark species for its high quality meat. The meat is utilized fresh, frozen, smoked and dried-salted for human consumption; the oil is extracted for vitamins; the fins used for shark-fin soup; the hides are processed into leather and the jaws and teeth are used for ornaments (Compagno 2001).|
Shortfin mako has a very low capacity to withstand fishing mortality, yet it is experiencing intense exploitation (Dulvy et al. 2008). For this species, regional variation in the intensity of fishing mortality is an important factor in determining their conservation status. They are sought for both their meat and fins; thus unlike many other oceanic pelagic sharks, they are frequently targeted by the large longline fleets in the Atlantic Ocean. The species comprises approximately 7% of total catch (weight) in the Atlantic Swordfish fishery and approximately 10% (weight) of all North Atlantic shark catch (Mejuto et al. 2006a,b; Hareide et al. 2007). It is also a highly prized recreational gamefish (Dulvy et al. 2008).
This mako is not only an important species for pelagic longline, but also driftnet, set gillnet and hook-and-line fisheries wherever it occurs, particularly from nations with high seas fleets (Holts et al. 1998). It is taken as a bycatch from tuna (Thunnus spp.) and billfish (Xiphiidae and Istiophoridae) longline fisheries worldwide, with carcasses and high value fins retained. Big-game sports angling for makos is widespread, and the International Game Fish Association lists this species as a record game fish. Fisheries for Shortfin Mako exist or existed in the Eastern Atlantic and the Mediterranean Sea (Compagno 2001).
In the Northeast Atlantic, the data provided on this mako is incomplete and very limited, which is currently confounding trend analyses and hampering calculations of bycatch levels. Shortfin Mako is of high value to both the finning and meat trade, and many European fisheries land specimens gutted, with the head attached. The practice of finning is likely to result in undocumented catches and mortality of the species in some fleets (ICES 2012). Using a novel method of filtering fishery logbooks to obtain CPUE data, and to deduce the levels of underreporting of shark species, Nakano and Clarke (2006) found that this shark was underreported by an average of 33% across all logbooks analysed, with the worst example revealing an underreporting of 65%.
The historical use of generic shark categories is problematic, although many European countries have begun to report more species-specific data in recent years (ICES 2012). There have been significant discrepancies between reported catch in databases from ICCAT, the Fisheries and Aquaculture Organisation (FAO) and the Statistical Office of the European Communities (EUROSTAT). The ICCAT Secretariat consolidated these three data-sources into a unique database, and currently progress is being made on its validation and the associated analysis of equivalent data series at various aggregation levels (Palma et al. 2012). FAO data have been revised in recent years, and historical catch figures have increased from those previously reported (ICES 2012).
In the Hong Kong shark fin market, some traders mentioned infrequent mixing with the less abundant Longfin Mako (I. paucus) (Clarke et al. 2006). Combining results of the genetic analyses from this study with the stochastic modelling of trade records allowed the contribution of individual species to the trade to be determined. Shortfin Mako fins showed an 85% concordance with the market category ‘qing lian’, which equates to a trade proportion for this species of approximately 2.7% (probability interval 2.3–3.1%). The actual percentage is likely to be somewhat higher, as the species was also present in the ‘wu yang’ (Silky Shark Carcharhinus falciformis) trade category.
This shark is highly susceptible to overexploitation by pelagic longline fisheries in the Atlantic Ocean, according to a productivity and susceptibility analysis carried out by Cortés et al. (2010), which revealed it to be amongst the most sensitive. The analysis also revealed that the species has a lower productivity than previously thought based on more recently acquired life history variables, and that post-capture mortality was 92%.
This species has been caught in large numbers particularly on the high seas in pelagic longline fisheries, but also in other commercial pelagic fisheries and recreational fisheries. The first longline fisheries were prosecuted by Japan in western equatorial waters beginning in 1956 (Uozumi and Nakano 1996). The fleet expanded rapidly in the 1960s, and covered almost the entire Atlantic by the late 1960s (Bonfil 1994), including the areas currently fished by the American fleet. Throughout the Atlantic, the fleet landed mako sharks and fins (Nakano 1993). It has been estimated that in the early 1990s, the Spanish longline fleet caught approximately 750 tonnes per year of Shortfin Mako in the Atlantic Ocean and Mediterranean Sea (Bonfil 1994, Compagno 2001).
No complete data are available specifically for the Northeast Atlantic, but the species is taken as a bycatch of the pelagic fishery. The area around the Strait of Gibraltar is considered a nursery area for Eastern Central Atlantic Shortfin Mako and most specimens caught are juveniles. This area is heavily fished by the Swordfish longline fishery off the west coast of Africa and Iberian Peninsula. Shortfin Mako became increasingly targeted in the western Mediterranean Sea at the end of the 20th century. European Union (EU) vessels fishing for small pelagic teleost (bony fish) species off the western coast of Africa are also known to take significant elasmobranch (shark and ray) bycatch, including Shortfin Mako in unknown numbers.
In the US and Canadian pelagic longline fisheries, this shark is one of the most commonly caught species. The index of abundance in the commercial longline fishery off the Atlantic coast of US has shown a steady decline (Cramer 1996) and other reports on declines are now available (Baum et al. 2003, ICCAT 2005, Cortés 2012: see Population section for details). As for recreational fishing, Casey and Hoey (1985) stated that the recreational catch of this species along the US Atlantic coast and in the Gulf of Mexico in 1978 was 17,973 fish weighing some 1,223 tonnes.
Even though driftnetting is banned in Mediterranean waters, this practise has continued illegally (WWF 2005). The Moroccan Swordfish driftnet fleet in the Alboran Sea operates year round, resulting in high annual effort levels (Tudela et al. 2005). Even though sharks are a secondary target or bycatch of this fishery, some boats deploy driftnets one to two miles from the coast where the chance of capturing pelagic sharks is higher. The catch rate for Shortfin Mako is nearly three times higher in boats actively fishing for sharks (from 0.6 to 1.9 N/fishing operation and 0.06 to 0.14 catch per km net). Both annual catches and mean weights of Shortfin Mako have fallen as a result of fishing mortality in the Moroccan driftnet fishery, illustrating the likely effect of this illegal fishery on stocks in the Alboran Sea and adjacent Atlantic (Tudela et al. 2005).
In 2013, the EU banned the removal of shark fins on board vessels through Regulation No. 605/2013, in line with advice from the IUCN SSG and other shark fishery experts, in order to enhance enforcement of the 2003 EU ban on shark finning (Regulation No. 1185/2003) and facilitate improved shark fishery data collection.
Shortfin Mako was listed in 2008 under Appendix II of the Convention on Migratory Species (CMS), based on a proposal from Croatia. The species is thereby covered under the 2010 CMS Memorandum of Understanding (MoU) for Migratory Sharks and an accompanying 2012 Conservation Action Plan for MoU listed sharks, but no species-specific, regional plans or measures have resulted from this listing to date.
Although plans for implementation are not yet evident two years later, Parties to the Barcelona Convention agreed in 2012 that elasmobranch species listed in Annex II of the Protocol concerning Specially Protected Areas and Biological Diversity in the Mediterranean Sea -- which includes Shortfin Mako -- cannot be retained on board, transshipped, landed, transferred, stored, sold or displayed, or offered for sale, and must be released unharmed and alive, to the extent possible.
Despite their commercial importance, catches of Shortfin Mako are not limited by European fishery regulations. They are however a protected species in Croatian waters. Efforts by the EU and the United States to secure international Shortfin Mako fishing limits through ICCAT have been unsuccessful to date.
Shortfin Mako is listed as a highly migratory species under the 1995 United Nations Agreement on the Conservation and Management of Straddling Fish Stocks and Highly Migratory Fish Stocks (UNFSA). The Agreement specifically requires coastal and fishing States to cooperate and adopt measures to ensure the conservation of listed species. Also of relevance is the Fisheries and Aquaculture Organisation’s International Plan of Action for the Conservation and Management of Sharks (IPOA-Sharks) that recommends that Regional Fisheries Organisations (RFOs) carry out regular shark population assessments and that member States cooperate on joint and regional shark management plans.
A vast improvement in the collection of data is required and effective conservation of this species will require international agreements. Fishing pressure must be considerably decreased through reduction in effort, catch limits, measures to enhance chances of survival after capture, when released and possibly through the implementation of large-scale oceanic non-fishing areas. Closed areas can only be effective if overall fishing effort is reduced, rather than merely displacing effort outside of the closed area (Baum et al. 2003).
|Citation:||Walls, R., Soldo, A., Cailliet, G.M., Cavanagh, R.D., Kulka, D.W., Stevens, J.D., Clò, S., Macias, D., Baum, J.K., Kohin, S., Duarte, A., Holtzhausen, J., Acuna, E., Amorim, A.F. & Domingo, A. 2015. Isurus oxyrinchus. The IUCN Red List of Threatened Species 2015: e.T39341A48934371.Downloaded on 23 September 2017.|
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