|Scientific Name:||Pristis pristis (Western Atlantic subpopulation)|
See Pristis pristis
Pristis perotteti Müller & Henle, 1841 (Western Atlantic)
|Taxonomic Notes:||In a recent study, Faria et al. (2013) demonstrated that the existing taxonomy of the Pristidae required modification, recognising a total of five species in two genera. Pristis pristis had been recognised previously as consisting of up to three species (Pristis pristis, P. microdon and P. perotteti), but utilising a combination of mitochondrial DNA and morphological characters appears to be one species. While the P. pristis group is best considered a single species, it can be composed of a network of geographical units (subpopulations) that are not genetically distinct, but may be considered ecologically different.
Largetooth Sawfish (Pristis pristis), formerly known as P. perotteti in the Atlantic, has been referred to by many other names throughout its range. For instance, it has been called P. antiquorum (as cited in Bigelow and Schroeder 1953), P. zephyreus (Beebe and Tee-Van 1941), P. pristis (McEachran and Fechhelm 1998), or P. microdon (Garman 1913, Fowler 1941, Chirichigno and Cornejo 2001, Heymans and Vakily 2002).
|Red List Category & Criteria:||Critically Endangered A2cd ver 3.1|
|Assessor/s:||Carlson, J. & Smith, K.|
|Reviewer/s:||Simpfendorfer, C. & Harrison, L.|
|Facilitator/s:||Harrison, L. & Kyne, P.M.|
Western Atlantic Largetooth Sawfish (Pristis pristis) were once found from Uruguay to the United States and commonly found from Brazil to Mexico. They have been nearly extirpated primarily by fishing (trawl and inshore netting) throughout their range inferring a population reduction based on a reduction in extent of occurrence (EOO) of ≥80% over a period of three generations (i.e., 1961 to present). Despite protections in Brazil, Nicaragua, Mexico and the United States (it is possibly extinct in the latter two range states), the species is still subject to threats region-wide from gillnets used in rivers, river mouths, estuaries and nearshore waters, and trawling. Coastal development and the loss of mangroves also contributed to the decline and will slow any potential recovery of the species. Current records indicate that Largetooth Sawfish can only be regularly encountered today in the Amazon River basin, the Rio Colorado-Rio San Juan area in Nicaragua, and possibly some remote areas of French Guiana, Suriname, and Guyana. Declines and continuing threats result in a Critically Endangered assessment for this subpopulation.
|Range Description:||In the Western Atlantic, Largetooth Sawfish were widely distributed throughout the tropical and subtropical marine and estuarine waters. Largetooth Sawfish were found from Uruguay through the Caribbean and Central America, the Gulf of Mexico, and seasonally to the United States (Burgess et al. 2009, Faria et al. 2013). Currently, Largetooth Sawfish are thought to primarily occur in freshwater habitats in Central and South America. Largetooth Sawfish have been recorded in locations at least 1,340 km from the ocean in the Amazon River, as well as in Lake Nicaragua and the San Juan River and other east coast Nicaraguan rivers. The species has also been reported in coastal systems in Brazil, French Guiana, Suriname, Guyana and Columbia in South America. In Central America, scattered reports still exist for Largetooth Sawfish in Panama, Costa Rica, Nicaragua, Honduras and Belize. In Mexico, the lack of records may indicate the species is no longer found west of the Yucatan Peninsula (R. Graham pers. comm. 2012). Throughout the Caribbean Sea, the species presence was historically uncertain and early records may have been Smalltooth Sawfish (P. pectinata). Though historically reported in the United States, it appears that Largetooth Sawfish were never abundant and was likely a season migrant. The species has not been reported in the United States since the 1960s (Burgess et al. 2009).|
Native:Belize; Brazil; French Guiana; Guyana; Honduras; Nicaragua; Suriname
Possibly extinct:Mexico; United States; Uruguay; Venezuela, Bolivarian Republic of
|FAO Marine Fishing Areas:||
Atlantic – southwest; Atlantic – western central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The population size of this species remains unknown. There are no data or information on trends in abundance, thus the population status is inferred from reports of capture records. Its abundance has been continuously declining over the past few decades to the point that it can now be considered rare or even extirpated in some areas where it was previously considered a common species. Burgess et al. (2009) reported on recent records of Largetooth Sawfish in the Western Atlantic. Over the last 10 years, records have only been consistently found in Brazil (Burgess et al. 2009). Records of fishermen still catching sawfish in Panama, Nicaragua, Honduras and Belize have been reported but are scarce (R. Graham pers. comm. 2012). While the species is protected in some areas, illegal fishing and bycatch landings continue to occur which indicates the population still may be in decline except in the most remote areas.|
|Habitat and Ecology:||
Largetooth Sawfish are generally restricted to shallow (<10 m) coastal, estuarine, and fresh waters, although they have been found at depths of up to 26 m in Lake Nicaragua. Largetooth Sawfish are often found in brackish water near river mouths and large bays, preferring partially enclosed waters, lying in deeper holes and on bottoms of mud or muddy sand (Bigelow and Schroeder 1953). This species, like the Smalltooth Sawfish (P. pectinata) is, in parts of its range, highly mangrove-associated (Burgess et al. 2009). Largetooth Sawfish move across salinity gradients freely and appear to have more physiological tolerance of freshwater than Smalltooth Sawfish (see Thorson 1982). In Lake Nicaragua, individuals spent much, if not all, of their lives in freshwater with reproduction of the population occurring primarily in the lake (Thorson 1982).
The life history of Largetooth Sawfish, like many elasmobranchs, is characterised by slow growth, late maturity, and low fecundity, which generally contributes to a low intrinsic rate of increase. The maximum reported size of Largetooth Sawfish is 656 cm TL, although it has been estimated up to 700 cm TL (Compagno and Last 1999). Maximum size in Lake Nicaragua appeared to be smaller with Thorson (1982) recording females to 429 cm TL and males to 384 cm TL.
The reproductive method of sawfishes is most likely lecithotrophic viviparity. The only known reproductive study of Largetooth Sawfish in the region was from Lake Nicaragua in the 1970s (Thorson 1976). Thorson (1976) found that both ovaries appeared to be functional, though the left seemed to be larger and carry more ova. The breeding season in Lake Nicaragua probably extended from May to July, with parturition taking place from early October into December (Thorson 1976). Litter sizes were 1–13 (mean 7.3) following a gestation period of about 5 months; size at birth was between 73 and 80 cm TL (Thorson 1976). The reproductive cycle is possibly biennial in the Western Atlantic (Thorson 1976).
Age at maturity has been estimated at ~10 years and size at maturity ~300 cm TL in Lake Nicaragua (Thorson 1982). Thorson (1982) determined a life span of over 30 years in Lake Nicaragua.
Using life history information from populations in Central America, Simpfendorfer (2000) estimated an intrinsic rate of increase of 0.05 to 0.07 per year and population doubling times of 10.3–13.6 years. These rates were estimated under ideal conditions (i.e. no fisheries, no population fragmentation, no habitat modification and no inbreeding depression). Moreno Iturria (2012) estimated a generation time of 17.2 years for Atlantic Largetooth Sawfish.
The principal threats to Largetooth Sawfish are from fishing; it was formerly targeted, but is now mostly taken incidentally in broad-spectrum fisheries (CITES 2007). The long toothed rostrum of sawfish makes them extremely vulnerable to entanglement in any sort of net gear, gillnetting and trawling in particular. Depleted populations mean that commercial targeting of most stocks is no longer cost-effective and bycatch mortality is now the primary threat to Largetooth Sawfish (CITES 2007). However, there are indications that sawfish are at times targeted opportunistically for the shark fin trade (CITES 2007).
In the Western Atlantic, the main threats are region-wide gillnets used effectively in rivers, at river mouths, estuaries and nearshore waters (up to 200 km out in case of Amazon-Orinoco estuaries; P. Almeida pers. comm. 2012), and trawling.
Habitat degradation and loss also threaten sawfishes throughout their range (CITES 2007). For at least part of its life cycle, the Largetooth Sawfish relies on a variety of specific habitat types including freshwater systems, estuaries and mangroves; these are all affected by human development (CITES 2007). Agricultural and urban development, commercial activities, dredge-and-fill operations, boating, erosion, and diversions of freshwater runoff as a result of continued coastal and catchment development has caused substantial loss or modification of these habitats (CITES 2007).
All species of sawfish are listed on Appendix I of the Convention on International Trade of Endangered Species (CITES), which effectively bans commercial international trade in sawfish or their parts.
Largetooth Sawfish are protected in Brazil. The commercial fishery for both shark and sawfish is banned in Lake Nicaragua and all take of Largetooth Sawfish is banned in Mexico (where it already appears to be extinct). Largetooth Sawfish are also listed as Endangered under the US Endangered Species Act.
|Citation:||Carlson, J. & Smith, K. 2013. Pristis pristis (Western Atlantic subpopulation). In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 07 December 2013.|
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