Vaquita

Updated Aug 2021 by Lorenzo Rojas-Bracho and Barbara Taylor

The vaquita (Phocoena sinus) is the most endangered marine mammal species in the world. It has a very restricted distribution, occurring only in the upper Gulf of California in Mexico, mainly north of 30º45’N and west of 114º20’W. The present range of the vaquita is limited to approximately 4,000 km², with the highest-use area about 2235 km², however, the few remaining vaquitas now appear to be concentrated in a small area near San Felipe about 24 x 12 km in size.

Current status

No species, except perhaps the baiji (Yangtze River dolphin) before it became functionally extinct, has been of greater concern to the CSG over the last several decades than the vaquita. Already by the time of its scientific discovery and formal description in 1958, the vaquita was seldom seen, difficult to observe and probably not very abundant. Its status has continued to deteriorate since then because of unrelenting pressure from incidental mortality in fisheries.

In 1997 vaquita abundance was estimated as 567 (CV = 0.51, 95% CI 177–1073). Eleven years later, in 2008, the total abundance was estimated to be 245 animals (CV=0.73, 95% CI 68-884). This is 57% lower than the 1997 estimate, implying an average rate of decline of 7.6%/year, presumably due entirely to incidental mortality in gillnets and other entangling nets. An acoustic study that ran from 1997 to 2007 indicated a 58% decline in acoustic detection rates over ten years, with several sampling stations reporting zero detections.

Vaquita (Phocoena sinus). Photos taken under permit (Oficio No. DR/488/08 from the Comisión Nacional de Áreas Naturales Protegidas (CONANP/Secretaría del Medio Ambiente y Recursos Naturales (SEMARNAT), within a natural protected area subject to special management and decreed as such by the Mexican Government. Photo Credit: Thomas A. Jefferson

The results of those two studies (vessel-based survey and acoustic monitoring) were in close agreement, indicating a very similar rate of decline. The only empirical estimate of incidental mortality was of 39 vaquitas/yr (95% CI 14-93) in 1993-1994, and it applied to only one of the two fishing ports within the vaquita’s range. If the boats from the second port experienced similar bycatch rates, then the total annual removals at that time would have been about double, or 78/year.

An intensive acoustic monitoring programme started in 2011 to see whether the Vaquita Refuge was sufficient to allow recovery. Instead of growth, a dramatic decline was documented (Jaramillo-Legorreta et al. 2016) resulting from the resumption of illegal fishing for totoaba (Totoaba macdonaldi). None of the measures to prevent gillnet fishing were properly implemented by authorities and hence the estimated rate of decline has remained extremely high: 48% decline in 2017 (95% Bayesian credible interval (CRI) 78% decline to 9% increase, Thomas et al. 2017) and 47% in 2018 (95% CRI 80% decline to 13% increase). It was estimated that fewer than 19 vaquitas remained as of summer 2018 (posterior mean 9, median 8, 95% CRI 6–19, Jaramillo-Legorreta et al. 2019).

The acoustic monitoring program experienced serious setbacks in 2019. The suspension of compensation to fishermen who agreed not to fish with gillnets, and the lack of acceptable alternatives to gillnet fishing, resulted in the resumption of illegal fishing with gillnets for traditional target fish species, while the illegal totoaba fishery continued to operate at high levels. Between June and December 2019 illegal fishing activities led to the loss of 61 moorings and acoustic detectors. Consequently, there were over 45% fewer sampling days in 2019 as compared with previous years. In addition, it was not possible to samples 12 of the sites, whereas the greatest number of sites that could not be sampled previously was 6 sites (in 2011 and 2014). Data analysis is under way and it appears as though the vaquita population is continuing to decline.

During its 11th meeting in February 2019, the International Committee for the Recovery of the Vaquita (CIRVA) recommended that efforts be expanded to photo-identify vaquitas with the goal to (i) obtain information on the minimum number of animals alive, (ii) refine understanding of life history including survival rates and (iii) explore the possibility of using photographic capture-recapture techniques to estimate minimum abundance.

The 2018 photo-ID expedition had provided evidence of an absolute minimum of 6 individuals alive as that many were seen at one time. The expedition also obtained evidence that vaquitas may calve annually (Taylor et al. 2019). The 2019 field efforts resulted in seven vaquita sightings including several different mother-calf pairs. All vaquitas observed appeared healthy.

History of Conservation Efforts

It was clear from the very first surveys of cetaceans in the northern Gulf that vaquitas were rare. Aerial surveys in the early 1990s recorded from 1.8 to 7.2 vaquitas/1000 km, a very low encounter rate compared to other cetaceans in the Gulf of California. The first vaquita abundance estimates derived from vessel surveys applied line-transect methodology to four datasets from the period 1986-1993. Even though none of the surveys covered the entire range of the species, the analysis suggested that there were only hundreds (not thousands) of vaquitas and that numbers were declining. The most precise and accurate of the four estimates was 224 individuals (CV = 0.39) in 1993.

Although no formal bycatch estimate was available for many years following the scientific description of the vaquita in 1958, interviews with fishermen and observed carcasses indicated that incidental mortality in gillnets was high. From the 1980s onwards, it became clear that vaquitas were dying in most, if not all, types of gillnets used in the northern Gulf. The deaths of at least 128 vaquitas in fishing gear were documented between early March 1985 and early February 1992.

Conservation efforts for the vaquita were slow to start because for many years Mexican authorities were unconvinced that any action was needed. When it was finally acknowledged that the vaquita was endangered, authorities focused on upstream dam construction on the Colorado River in the United States and the resultant loss of freshwater input to the northern Gulf as the primary cause of the porpoise’s decline. In reality, the vaquita’s vulnerability is probably determined by both natural processes and human interactions. All data suggest that the vaquita is a naturally rare species: its population may never have been large, its range is limited, and there is only one population. These factors, combined with the fact that it inhabits a region where fishing is the main economic activity, make this porpoise uniquely vulnerable to incidental mortality.

Vaquita (Phocoena sinus). Photos taken under permit (Oficio No. DR/488/08 from the Comisión Nacional de Áreas Naturales Protegidas (CONANP/Secretaría del Medio Ambiente y Recursos Naturales (SEMARNAT), within a natural protected area subject to special management and decreed as such by the Mexican Government. Photo Credit: Thomas A. Jefferson

CIRVA

A critical step towards vaquita conservation was the creation of the International Committee for the Recovery of the Vaquita (CIRVA) by the Mexican Ministry of Environment, Natural Resources and Fisheries. Established in 1996, CIRVA’s primary goal was to develop a recovery plan based on the best scientific evidence. Several CSG members have participated in this ad hoc recovery team from the beginning; Lorenzo Rojas-Bracho established the team and has chaired CIRVA since its inception.

CIRVA was expected to resolve the dispute over the factors causing the vaquita’s decline, in particular regarding the relative roles of the fishing industry and the depleted flow of the Colorado River. At its first meeting, CIRVA concluded:

• The reduced flow of the Colorado River seems not to be an immediate (i.e., short-term) threat to the vaquita, based on three factors:

1. Nutrient concentrations and rates of primary productivity are reported to be high in the northern Gulf;
2. Vaquitas have a fairly diverse diet and do not appear to depend exclusively on one or a few prey species;
3. None of the vaquita specimens examined thus far has shown signs of starvation or poor nutritional status.

• In the long term, changes in the vaquita’s environment due to the reduced flow of the Colorado River (e.g., nutrient decline) are matters of concern that should be investigated.

• Incidental mortality in gillnets constitutes the greatest immediate threat to the survival of the vaquita.

Vaquita (Phocoena sinus). Photos taken under permit (Oficio No. DR/488/08 from the Comisión Nacional de Áreas Naturales Protegidas (CONANP/Secretaría del Medio Ambiente y Recursos Naturales (SEMARNAT), within a natural protected area subject to special management and decreed as such by the Mexican Government. Photo Credit: Thomas A. Jefferson

At later meetings, CIRVA made a series of recommendations, most important amongst them that “bycatch of vaquitas must be reduced to zero as soon as possible, … gillnets and trawlers should be banned from the Biosphere Reserve, … research should start immediately to develop alternative fishing techniques to replace gillnets, and … the international community should be invited to join the Government of Mexico and provide assistance to implement the conservation measures”.

In 1993 the Mexican government created the Upper Gulf of California and Colorado River Delta Biosphere Reserve, which has a goal to protect the vaquita. The Biosphere Reserve banned gillnet fishing in an area near the mouth of the Colorado River. In 2005 an additional Refuge Area for the Protection of the Vaquita covering the central part of the vaquita’s range was created. Gillnet fishing in the Refuge Area was officially prohibited, but there was little enforcement and the ban was widely ignored. The necessity of eliminating vaquita bycatch completely for the species to persist was demonstrated by Gerrodette and Rojas-Bracho (2011) that evaluated three options for a protected area closed to gillnet fishing. The probability of success of each option was estimated with a Bayesian population model, where success was defined as an increase in vaquita abundance within 10 years. If protection remained as it was at that time, within the existing Vaquita Refuge area, the chance of vaquita abundance increasing within ten years was only 8%. If the area under protection was slightly larger as proposed in PACE-Vaquita (see below), the probability of success was still low at 35%. The only management option judged certain of success (>99% probability) was a protected area large enough to eliminate vaquita bycatch throughout the entire range of the species.

In 2007 Mexico’s President announced the Conservation Program for Endangered Species (PROCER), which required Conservation Action Programs (PACE) for selected species. The vaquita was the first listed. The fundamental objective of PACE-Vaquita was to put into practice CIRVA’s recommendations to conserve and facilitate recovery of the vaquita population. The central goal was to eliminate vaquita bycatch. Given that fishing is one of the most important economic activities in the northern Gulf of California, PACE-Vaquita included measures to remove the fishing gear that threatened vaquitas by:

1. Enforcing the existing bans on gillnet fishing in the Biosphere Reserve and Refuge Area, and possibly expanding the ban to a larger protected area;
2. Encouraging alternative methods of fishing that do not catch vaquitas; and
3. Providing economic compensation to fishermen, including a buyout plan and assistance with starting alternative businesses.

Important results from the implementation of PACE were:

1. Declaration of a Vaquita Refuge free of entangling nets and shrimp trawlers;
2. Withdrawal of 230 artisanal fishing boats from fishing activities; and
3. Participation of 105 artisanal fishing boats in the fishing gear replacement program.

The Mexican Government made enormous economic and political investments in supporting vaquita conservation. Prior to 2015, the PACE Vaquita program provided 26 million USD to reduce fishing effort via buy-out/rent-out, improved surveillance and enforcement, providing socioeconomic alternatives to fishermen, and testing alternative fishing gear. However, despite these efforts, about 600 artisanal boats (pangas) continued to fish with gillnets within the range of the vaquita.

Following the resumption of totoaba fishing and the consequent collapse of the vaquita population, the Government of Mexico announced an emergency plan to prevent extinction that included a temporary gillnet ban within the full range of the species. The government, together with the Museo de Ballena (a private conservation organization) and the Sea Shepherd Conservation Society, started a program to remove gillnets from the area, concentrating the effort near San Felipe. Despite the fact that hundreds of nets were removed, dead vaquitas continued to be found and acoustic monitoring data showed the continued sharp decline in vaquita numbers. In response, CIRVA recommended capture efforts to remove as many vaquitas as possible from their gillnet-infested habitat and that they be kept in sanctuary conditions until the gillnet problem could be solved. The VaquitaCPR (Conservation, Protection and Recovery) effort resulted in the capture of 2 vaquitas but it was suspended when both of the porpoises responded by going into shock (the first was released and the second died) (Rojas-Bracho et al. 2018).

Subsequent conservation efforts have consisted of net-removal efforts in the small area near San Felipe, called the Zero Tolerance Area, where the last few observations of living vaquitas (visual and acoustic) have been made. In recent months fishermen have changed their practices from setting gillnets and leaving them through the night or even for several days, to staying close to the nets and/or fishing actively using a “rodeo-type” approach by enclosing the fish with the nets. As a consequence, net-removal efforts are now even more difficult than they were previously, and the number of nets removed is bound to be less.

In March 2019, Mexico’s new administration (elected in August 2018 to take power on 1 December 2018) launched its “Initiative for Sustainability in the Northern Gulf of California” (jointly administered by SEMARNAT and the ministry of Agriculture and Rural Development, SADER). The text of this initiative states that improved governance, sustainability, and responsible fishing using alternative gear are essential for ensuring that local communities are involved in conserving vaquitas and maintaining the health of the Upper Gulf ecosystem. However, this initiative has not been implemented, nor has an explanation been made available of how implementation might proceed, and illegal fishing continues unabated and may even be increasing. The new Fisheries authorities have not provided suitable alternative fishing gear to the communities and the compensation program (such as it still existed) has been cancelled. This has led to the resumption of non-authorized fishing with gillnets for shrimp and finfish, in addition to the illegal totoaba fishery, and a long period of desperate uncertainty for vaquitas and for the fishermen in San Felipe (State of Baja California) and El Golfo de Santa Clara (State of Sonora).

2020/2021

The pandemic enforced a delay to work with vaquita. Communities of the Upper Gulf were also heavily hit by the pandemic. On July 31 2020, World Ranger Day, Paco Valverde, sole ranger of the Vaquita Protection Refuge in Mexico’s Upper Gulf of California succumbed to COVID-19. Paco is irreplaceable and indispensable.  But despite the circumstances (lockdown, etc.) there were efforts to keep the work going.

• During the long neap tide period of September 8-12, 2020 acoustic detectors were placed in clusters at the sites that had in recent years had the most vaquita detections. Vaquitas were detected by 5 out of the 22 deployed detectors, at just 2 of the sampling sites, with a total of 9 acoustic encounters.
• In a joint effort with the National Commission for Natural Protected Areas (CONANP), the Sea Shepherd Conservation Society sponsored a small visual survey effort from November 8-23 2020 with only two of the observers that have participated in many of the vaquita surveys. Seven days had 32 hours of effective search under acceptable conditions (Beaufort 1-3). Observers observed vaquitas on two occasions. Also of note is that Sea Shepherd Conservation Society counted 1108 pangas fishing for shrimp in October 2020.
• In 2020 a workshop that used expert elicitation to better estimate the number of vaquitas seen in the Zero Tolerance Area in 2019 was held. The results of the virtual workshop are available here. Using the Rational Impartial Observer method (EE-RIO) the results of the expert elicitation exercise found that the mean estimated number of calves seen was 3.1 with a 73% belief that there were at least 3 calves. The mean estimate for the number of unique vaquitas seen in all 7 sightings was 10.4 with 66% belief that there were at least 10. Read more in our news article here.
• From September 2020 through January 2021, Mexico enacted a series of new regulations that included establishing a Gillnet Exclusion Zone (GEZ), a Zero Tolerance Area (ZTA), a no fishing and 225 km² no entry zone. Ghost net removal was to resume. Enforcement was to be all day every day using maritime, air and satellite patrols and surveillance. The possession, manufacture, sale, and transportation of gillnets in and around GEZ was banned. Fishers were to turn over all gillnets within 60 calendar days of the date of publication of this Agreement, (effectively before January 2021). Fishing at night was illegal and fishers were to report bycatch and lost gear, and have vessel monitoring systems on their vessels. As of July 2021, none of the actions indicated in the new regulations had occurred. Instead on July 9^th 2021, the fisheries authorities published a complex set of triggers with a sliding scale of punishments. Only if more than 60 boats are in the Zero Tolerance Area on multiple occasions, and more than 500m of net is recovered in one day, will the fishery will be closed, and only in a certain area, from a period of 7 – 30 days. Media and many organizations and experts have expressed their concern on this new regulation that allows a significant number of boats setting gillnets (which remain illegal) inside the Zero Tolerance Area.