|Scientific Name:||Phocoena sinus Norris & McFarland, 1958|
|Taxonomic Notes:||Genetic (Rosel et al. 1995) and morphological (Brownell et al. 1987) data suggest that Vaquitas are most closely related to porpoises in South America. Genetic data suggest divergence from two sister taxa (Burmeister’s porpoise, Phocoena spinipinnis and spectacled porpoise Australophocaena dioptrica) in the Pleistocene (i.e., at least 2.5 million years ago).|
|Red List Category & Criteria:||Critically Endangered A2a+4d; C1+2a(ii); D; E ver 3.1|
|Assessor(s):||Rojas-Bracho, L. & Taylor, B.L.|
|Reviewer(s):||Reeves, R. & Jaramillo-Legorreta, A.|
|Facilitator/Compiler(s):||Lowry, L., Chiozza, F., Pollock, C.M.|
The Vaquita qualifies for listing on the IUCN Red List as Critically Endangered based on criteria A2a, C1, C2a(ii), D, and E.
Criterion C2a(ii): The total population numbers around 30, so clearly the number of mature individuals is fewer than 250, there is a continuing observed decline, and all mature individuals are in one subpopulation.
Criterion D: The total population numbers around 30, so clearly the number of mature individuals is fewer than 50.
Criterion E: Projections of the 2015 population abundance using the observed rate of decline resulted in extinction being likely (>50%) within 10 years (a single generation) (Taylor et al. 2016). This analysis was acknowledged to underestimate risk but still clearly meets the criterion to exceed a 50% probability of extinction within three generations (30 years).
|Previously published Red List assessments:|
The Vaquita is known to occur only in the northern Gulf of California, Mexico, mainly north of 30º45'N and west of 114º20'W (Gerrodette et al. 1995). The area of highest remaining numbers is centred at Rocas Consag, some 40 km northeast of the town of San Felipe, Baja California.
Native:Mexico (Baja California, Sonora)
|FAO Marine Fishing Areas:|
Pacific – eastern central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||There have been three complete surveys for Vaquitas, resulting in abundance estimates as follows: in 1997 abundance was estimated to be 567 (95% CI, 177-1,073; Jaramillo-Legorreta et al. 1999); in 2008 abundance was estimated to be 245 animals (95% CI, 68-884; Gerrodette et al. 2011); and in 2015 abundance was estimated to be 59 (95% CRI 22-145; Taylor et al. 2016). These three abundance estimates revealed a catastrophic population decline has been occurring. Past (1997-2007) and ongoing acoustic monitoring programs (2011-2017) provide additional datasets that also document this catastrophic decline (Jaramillo-Legorreta 2008, Jaramillo-Legorreta et al. 2016). Using the 2015-2016 acoustic monitoring data and the 2015 abundance estimate, the species was likely to number only about 30 individuals as of November 2016 (posterior mean = 33, median = 27, 95% CRI: 8 to 96; CIRVA 8, 2016) and will likely be extinct within a decade.|
As noted above, between 1997 and 2008 Vaquita numbers declined by an average of 7.6%, from an estimated 567 to 245 animals. The acoustic monitoring program between 1997 and 2007 also independently estimated an average decline rate of 7.6%/year. This decline was consistent with mortality rates estimated by D’Agrosa et al. (2000) and plausible growth rates estimated by Gerrodette and Rojas-Bracho (2011). Between 2008 and 2015, Vaquita numbers declined from an estimated 245 to only 59 animals. Separately, a passive acoustic monitoring program from 2011 through 2015 estimated Vaquita abundance was declining by 34%/year (95% Bayesian CRI, -48% to -21%; Jaramillo-Legorreta et al. 2016) over that time period. Additional acoustic monitoring between 2015 and 2016 revealed the annual average decline was -49% (95% CRI = -82% to +8%).
The only demographic data for Vaquita relevant to maximum net productivity rates come from Hohn et al. (1996). Interbirth interval was estimated to be 2 years based on inspection of ovaries of a limited number of adult females. This differs from the 1-year interval typical of other porpoises. A modelling exercise (Gerrodette and Rojas-Bracho 2011) used the Hohn data plus data from Harbor Porpoises (Phocoena phocoena) (Moore and Read 2008) and arrived at a posterior mode of 3.8%/year (95% CRI, 1.5 to 7.8%). In a population modelling exercise using data on fishing effort, 1997 abundance, and passive acoustic monitoring (1997-2007), it was estimated that historic population level of Vaquita previous to its capture in fishing activities could have been about 5,000 individuals (95% credible interval 2,088-10,697) (Jaramillo-Legorreta, 2008). This implies that current population level could be less than 1% of the historic level.
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||The Vaquita lives in a relatively shallow (<50 m), turbid and dynamic marine environment (Vidal 1995, Rojas-Bracho and Jaramillo-Legorreta 2002). Vaquitas feed on a variety of demersal or benthic fishes, squids, and crustaceans. They have been observed singly and in small groups of up to 8-10 individuals (mean = 2), but many such groups can be loosely aggregated over several km².|
|Continuing decline in area, extent and/or quality of habitat:||Unknown|
|Generation Length (years):||10|
|Movement patterns:||Not a Migrant|
Mortality in gillnets of various mesh sizes has long been recognized as the most serious and immediate threat to the Vaquita's survival (Vidal 1993, 1995, Reeves and Leatherwood 1994, IWC 1995, Rojas-Bracho and Taylor 1999, Rojas-Bracho et al. 2006). The only available estimates of the Vaquita bycatch rate are 39 (using one method) and 84 (using a different method) animals killed per year by boats from a single port (D'Agrosa et al. 2000). This alone would represent 7 or 15%, respectively, of the estimated total population size (Rojas-Bracho and Jaramillo-Legorreta 2002). Other potential threats that have been suggested, but that appear not to be significant risk factors at present, include inbreeding depression, pesticide exposure and ecological changes as a result of reduced flow from the Colorado River (Taylor and Rojas-Bracho 1999, Brusca et al. 2017).
An International Committee for the Recovery of the Vaquita (Comité Internacional para la Recuperación de la Vaquita, CIRVA) was established in 1997 and has developed many recommendations over its nine reports (current through July 2017). The most consistent and important recommendation is to permanently ban the manufacture, possession, or use of all gillnets on land or sea throughout the range of Vaquitas. In June 2017, a permanent ban was published in the Mexican Federal Register that made the use or transport of gillnets illegal, with exemptions for two fish species (Curvina, Cynoscion othonopterus, and Pacific Sierra, Scomberomorus sierra). Night fishing was banned and legal entry (departure from land) and exit (landing) points were restricted. Since many of these provisions were temporarily in place from 2015-2017 and illegal fishing continued to occur at high rates, better compliance and enforcement are essential and it remains to be seen whether this will be forthcoming.
CIRVA also recommended that as many Vaquitas as possible be removed into protective sanctuary as quickly as possible. An international team (VaquitaCPR) was formed to carry out this effort. The first attempt to capture and maintain Vaquitas is planned for autumn 2017.
The Vaquita is listed on Appendix I of the Convention on International Trade in Endangered Species.
|Citation:||Rojas-Bracho, L. & Taylor, B.L. 2017. Phocoena sinus. The IUCN Red List of Threatened Species 2017: e.T17028A50370296.Downloaded on 15 August 2018.|
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