|Scientific Name:||Pristis pristis (Eastern Pacific subpopulation)|
See Pristis pristis
Pristis perotteti Müller & Henle, 1841 (Eastern Pacific)
|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), has been referred to by many other names throughout its range. It was formerly known as P. perotteti in the Atlantic and sometimes in the Eastern Pacific, and has variably 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. & Kyne, P.M.|
|Reviewer/s:||Simpfendorfer, C. & Harrison, L.|
|Facilitator/s:||Harrison, L. & Kyne, P.M.|
Eastern Pacific Largetooth Sawfish (Pristis pristis) were formerly present from Peru to Mexico but are now found only in Columbia, Nicaragua, and Panama (few records) 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). Threats are ongoing for Eastern Pacific Largetooth Sawfish, from longline fisheries targeting sharks to inshore netting. Furthermore, there has also been a substantial decline in mangroves which are critical habitat for sawfish. Declines and continuing threats result in a Critically Endangered assessment for this subpopulation.
|Range Description:||In the Eastern Pacific, the historic range of Largetooth Sawfish was limited by the cooler water currents to the north of its range (California current) and the Humboldt Current in the south (V. Faria pers. comm. 2012). The historic range is thought to occur from Mazatlán, Mexico to Peru (Chirichigno and Cornejo 2001, Cook et al. 2005, Faria et al. 2013). Other references (i.e., Amezcua-Linares 2009) suggest that it occurred south from Topolobampo (some 440 km further north than Mazatlán), highlighting the uncertainty over its historic range. The occurrence of Largetooth Sawfish in Peru may have represented seasonal migration from the species’ core range in Central America. Largetooth Sawfish were historically reported from a number of freshwater systems in the Eastern Pacific (as summarised by Cook et al. 2005).|
Native:Colombia; Nicaragua; Panama
Possibly extinct:Ecuador; Guatemala; Mexico; Peru
|FAO Marine Fishing Areas:||
Pacific – eastern central; Pacific – southeast
|Range Map:||Click here to open the map viewer and explore range.|
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. While historically found from Peru to Mexico, the only recent records (within the last 10 years) are from Columbia, Nicaragua, and Panama (R. Graham pers. comm. 2012). Costa Rica’s Osa Peninsula, which encompasses the Corcovado National Park’s Rio Sirena and the Térraba-Sierpe Wetland are thought to host a remnant population of sawfish, based on fisher interviews of recent but unconfirmed sightings (I. Zanella pers. comm. 2011). However, in the contiguous Golfo Dulce (Costa Rica), artisanal hook and line and net fishers interviewed in 2004 reported that they had not seen a sawfish in decades (R.T. Graham pers. comm. 2012).
Largetooth Sawfish existed in Panama’s Pacific-draining man-made Lake Bayano in 1982 (Montoya and Thorson 1982), but there are no recent records from that site or other parts of Panama or nearby Colombia, based on an IUCN Shark Specialist Group (SSG) survey of members and researchers sent out by the SSG in 2011–2012. The species may now possibly be extinct in several countries such as Mexico, Guatemala, Ecuador and Peru; there are no confirmed records in many parts of the region for the past decade. This represents a significant contraction in the species’ extent of occurrence in the Eastern Pacific. There are some poorly studied parts of the region with suitable sawfish habitat (e.g., the Darien, Panama), suggesting that surveys are required to locate any remnant populations.
Given the degree of mangrove loss and the level of artisanal net fishing, it is likely that the remnant population is still in decline.
|Habitat and Ecology:||
There is no ecological or life history information available for Largetooth Sawfish in the Eastern Pacific. Life history information is available from conspecifics in the Indo-West Pacific and from Lake Nicaragua (which drains into the Caribbean, despite being closer to the Pacific).
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). In northern Australia, parturition probably occurs in brackish or saltwater and juveniles spend ~4–5 years in the freshwater reaches of rivers and floodplain waterholes before migrating to estuarine and marine waters (Thorburn et al. 2007, Whitty et al. 2008, Whitty et al. 2009, P. Kyne unpublished data).
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 was from Lake Nicaragua in the 1970s (Thorson 1976) with other observations from northern Australia. 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 five months. The reproductive cycle is possibly biennial in the Western Atlantic (Thorson 1976) but annual in the Indo-West Pacific (Peverell 2008). Size at birth ranges 72–90 cm TL (Thorson 1976, Thorburn et al. 2007, Peverell 2008).
Age at maturity has been estimated at 8–10 years (Queensland, northern Australia; Peverell 2008) and ~10 years (Lake Nicaragua, Thorson 1982). Size at maturity is ~300 cm TL for females and ~280–300 cm TL for males (Thorson 1976, Thorburn et al. 2007, Peverell 2008, Whitty et al. 2008). Peverell (2008) using a preliminary vertebral growth ring analysis estimated a maximum age of 35 years in northern Australia. 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 using life history data from 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 Eastern Pacific, Largetooth Sawfish were caught by gillnets, longlines and trawl nets.
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.
All take of Largetooth Sawfish is banned in Mexico (where it already appears to be extinct). Elsewhere throughout the Pacific range of Largetooth Sawfish, there are no conservation or management measures, and these are urgently needed.
|Citation:||Carlson, J., Smith, K. & Kyne, P.M. 2013. Pristis pristis (Eastern Pacific subpopulation). In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 06 December 2013.|
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