Vaquitas get action from CITES as totoaba poaching resumes

By Barbara Taylor, Lorenzo Rojas-Bracho and Kristin Nowell


On 27 March 2023 the Secretariat of the Convention on the International Trade of Endangered Species (CITES) notified signatory countries to stop all commercial trade in CITES-listed (in Appendix I or II) species from Mexico. This decision stems from the inadequacy of actions taken by Mexico to prevent totoaba from being poached and vaquitas from being ‘collateral damage’ in the illegal gillnet fishery. The sanctions will remain in place until Mexico submits an adequate compliance action plan. Once approved, Mexico’s implementation of its action plan will be evaluated at the next meeting of the CITES Standing Committee in early November in Geneva to determine whether sufficient progress has been made by then. Further details are given in several news reports:


While gillnet fishing effort remains much lower than in the past within the Zero Tolerance Area (ZTA) (see previous CSG news posting), outside this small area there is no evidence that gillnetting has been reduced. Further, fishing with alternative vaquita-safe methods is very rare in waters near the ZTA. Totoaba are just arriving on their annual spring migration to spawn, and recent reports indicate that they are being subjected, immediately upon arrival, to intensive poaching pressure ( or a machine translated English version here).


The Mexican Navy’s deployment of concrete blocks with entangling hooks within the ZTA, where vaquitas have spent most of their time in recent years, appears to have had a positive effect so far. The number of gillnetting pangas (small fishing boats) observed inside the ZTA has been reduced. This reduction may be due not only to the deterrence effect of the anti-gillnet devices but also to the Navy’s enforcement efforts with support from the Sea Shepherd Conservation Society (SSCS). Since vaquitas cannot survive for long in waters where gillnets are used, the species’ recovery depends on both rigorous adherence to the ZTA’s no-entry rule and ensuring that all fishing in vaquitas’ historical range in the Upper Gulf outside the ZTA is vaquita-safe.

Good News from the Zero Tolerance Area in late 2022: Less illegal gillnetting and more evidence of vaquita survival

By Kristin Nowell, Cetacean Action Treasury


In 2022 there was a major new development in the Zero Tolerance Area (ZTA), the 225 km2 polygon inside Mexico’s Vaquita Refuge in the Upper Gulf of California. The ZTA, which was delineated to encompass all recent vaquita sightings and acoustic detections, has been designated as a no-fishing and no-entry zone since September 2020. However, there is strong evidence of lax enforcement: fishing skiffs (pangas) were observed inside the ZTA on 88% of observation days from October 2021 to May 2022. In response to persistent violations, the Mexican Navy developed a radical proposal to deter the use of illegal gillnets which have driven the precipitous decline of the Critically Endangered vaquita population. Between July 8 and September 30 (normally a season of low fishing activity), a grid of 193 gillnet-deterrent structures was installed on the ZTA seabed. They were lowered by crane into the water and placed in a grid about 1.1 km apart. The structures are concrete blocks a meter square, with two 3.5 m tall, 1 ½ inch diameter iron rebar hooks protruding from the top, intended to entangle gillnets as they drift with the tides (Figure 1).

Figure 1 – Gillnet deterrent structures being deployed in the Zero Tolerance Area

Anti-trawl structures have been used by other countries to stop trawl nets from operating in protected areas (such nets are dragged along the seafloor), but this approach has never been tried against gillnets outside of shallow waters (ZTA depths range from 10-30 m). Counts of fishing pangas in the ZTA from Sea Shepherd Conservation Society (SSCS) and scientific vaquita surveys were used to determine if there were any initial deterrent impacts (see full report for details).

The highest-ever recorded count of pangas in the ZTA in recent years (117) was in the fall 2021 shrimp season. To try to prevent a repeat in the fall 2022 shrimp season, Cetacean Action Treasury’s Mexican partner organization, Pesca ABC, with support from the International Conservation Fund of Canada, made five posts on its Facebook page in September through October, providing the ZTA coordinates and offering to assist fishers to input them into their GPS. Over a dozen fishers came to Pesca ABS’s office in San Felipe for assistance, and overall the posts garnered nearly 18,000 views.

It is well known locally that gillnetters prefer to work in spring tides (strong tidal fluctuations associated with the full and new moons, with approximately two such tidal periods per month). Maximum daily panga count data for 2021 and 2022 were grouped and averaged for consecutive spring tides (days when the difference between consecutive tide peaks – high or low – are over 350 cm). Although panga counts were not available for all spring tide days due to occasional absence of SSCS ships from the area, comparing consecutive tides for the two years suggests a significant reduction in gillnetting in the ZTA in 2022 subsequent to the first major fishing effort in the second October spring tide (Table 1). In other words, many fishers with gillnets apparently began to avoid the area.

Table 1. Reduction in average maximum daily count of pangas in the ZTA over consecutive bi-monthly spring tides in 2022 compared to 2021

Monthly spring tide cycle Oct – #2 Nov – #1 Nov – #2 Dec – #1
2021 27.6 74.5 42.5 41.6
2022 21.3 14.8 11.0 5.8
Reduction 33% 81% 74% 86%


On November 16, Pesca ABC warned the community in its social media that they knew of fishers getting their nets stuck on the structures. On January 11 2023, another San Felipe CAT partner organization (MAREM) asked fishers on Facebook to share coordinates of lost nets to aid in their removal. Although the only public comment on the post was “Nobody wants to cooperate” (which is illustrative of local non-compliance with the December 8 2021 requirement to report lost fishing gear within 24 hours), ultimately eight sets of coordinates were provided by fishers. Two sets were outside the ZTA, but all six sets reported inside the ZTA coincided with coordinates of deterrent structures, suggesting that the structures had been at least partially effective at snagging gillnets.

Active deterrence actions by the Mexican Navy increased significantly in fall 2022 compared to the previous year. SSCS ships assisted compliance monitoring by sending situation reports (SITREPs) of gillnetting in the ZTA; Navy actions are described in SSCS daily Scientist reports. The Navy was generally responsive to SSCS SITREPs during the spring tides of 2022, and was observed to “drive pangas out of the ZTA” on multiple occasions, with several instances where gillnets were seized or fishers were directed to remove them. In contrast, although Navy patrol boats were present during the 2021 fall vaquita survey (first two spring tides in Table 1), no interaction with pangas was observed.

The reduction of illegal gillnetting may have contributed to an observed increase in the rate of vaquita acoustic encounters after installation of the deterrent structures (Armando Jaramillo-Legorreta, pers. comm.). Eight acoustic sampling exercises (see here for background on Mexico’s acoustic monitoring program), supported by CICESE and CONANP and facilitated by community fishers associated with Pesca ABC and MAREM, were carried out in neap tide periods in 2022 (when few gillnetters would be expected to be present, thus minimizing the potential for loss of or tampering with monitoring equipment). Vaquitas were detected in every sampling exercise, indicating that at least some individuals were consistently present in the ZTA. Based on distance between encounters and maximum potential swimming speeds, 11.7% of 77 total encounters in 2022 were considered likely to have been detections of different individuals or groups of individuals. Comparing five exercises with comparable sampling effort, the number of vaquita encounters per day (number of acoustic detections >30 minutes apart) increased noticeably after installation of the deterrent structures was completed (Table 2). An increased acoustic encounter rate could reflect a change in vaquita behavior (vaquitas generally echolocate when hunting prey) associated with reduced gillnetting in the ZTA, but does not signify a change in population trend, which is still declining (A. Jaramillo-Legorreta, pers. comm.).

Table 2. Rate of vaquita acoustic encounters/day in the ZTA increased in late 2022

Sampling exercise Vaquita acoustic encounters/day Ending date
Installation of gillnet deterrent structures underway
4 0.057 20/09/2022
Installation of gillnet deterrent structures completed
5 0.045 04/10/2022
6 0.183 20/10/2022
7 0.248 18/11/2022
8 0.122 18/12/2022

Source: A. Jaramillo-Legorreta pers. comm., research supported by CICESE/CONANP


The Navy and CONANP had been warned in advance that pangas with gillnets would likely concentrate around the ZTA, creating an edge effect and increasing the risk to vaquitas that move outside the ZTA, which they certainly do. Since early February 2023, SSCS has been conducting panga counts in a one nautical mile buffer zone around the ZTA, and hopefully the Mexican Navy will be as responsive to reports of illegal gillnetting around the ZTA as inside it. Time-bound compliance processes in 2023 under CITES and the USMCA will further increase the pressure on Mexico to enforce its gillnet ban more effectively in the Upper Gulf of California. Unfortunately, a program to frequently inspect and clean the deterrent structures of entrapped or snagged net material, which could pose an entanglement risk to vaquitas, has not yet been implemented. There will be continued urgency to prevent fishers with other types of gillnets from entering the ZTA as the fishing seasons change in spring from shrimp to commercial finfish fishing and totoaba poaching. Some types of finfish and totoaba gillnetting usually do not involve setting on the bottom, as shrimp gillnets are, and these other types of gillnetting may not be deterred by the seabed concrete structures. Therefore, security for vaquitas during the coming months will depend on increased voluntary compliance by the fishing community and enforcement actions by authorities.

Yet Another Threat to Taiwanese White Dolphins Is Imminent

By Randall Reeves (CSG Chair) and Louisa Ponnampalam and Brian Smith (CSG Asia Coordinators)


On 13 February 2022, an article appeared on this website concerning the existential threat of net entanglement to Taiwan’s endemic humpback dolphin subspecies (Sousa chinensis taiwanensis; known locally as Taiwanese white dolphin). After nearly 15 years of this dolphin being IUCN red-listed as Critically Endangered ( and five years of its being listed as Endangered under the U.S. Endangered Species Act, essentially nothing significant has been done by the Government of Taiwan to address entanglement, or any of the numerous other threats to this very small and declining population (thought to have numbered only about 60 individuals in 2017, the survey year for the most recent abundance estimate reported by Araújo-Wang et al. 2022).


It recently came to the CSG’s attention that a possibly final, decisive blow to the Taiwanese white dolphin’s survival is on the horizon. Taiwan’s parliament is apparently moving ahead with a proposed Taichung Outer Port Area Expansion Project, which would ‘reclaim’ (in other words, transform into an industrial moonscape) another large portion of nearshore marine and estuarine habitat in the heart of the dolphins’ distribution.


John Wang, the world’s leading expert on Taiwanese white dolphin’s and recipient of the international Society for Marine Mammalogy’s 2021 Conservation Merit Prize (, pointed out after analyzing extensive data on dolphin movements and ecology, that the proposed expansion of Taichung Port to enable construction and installation of a liquified natural gas (primarily methane, a powerful greenhouse gas) terminal would only exacerbate an already desperate situation. Wang’s report, prepared in 2018 at the request of the Wild At Heart Legal Defense Association (a local NGO concerned about the Taiwanese white dolphin’s dire state), concluded that for many sightings by his research group, the animals were moving quickly through waters fronting Taichung Port, which had already been artificially deepened by dredging and made much deeper than the shallow waters preferred by humpback dolphins. Expansion of the harbour would force the animals into even deeper waters as they attempt to travel to and from their priority habitat north and south of Taichung Port (something that very nearly 100% of the dolphins do). This would not only disrupt movements but also likely stop some individuals from even trying to cross these waters. The truth is that for successful conservation of Taiwanese white dolphin’s over the long term, there should be no port expansion. Rather, the northern shore of the Dadu River Estuary, which is the dolphins’ most important remaining habitat, needs to be restored. This habitat was once a sprawling, highly productive littoral zone but that zone is now occupied by the concrete and tetrapod walls of the massive Taichung power plant (see photos).


Taichung power plant and artificial shoreline as observed in 2012 (left) and 2013 (right). Photos: John Y. Wang / CetAsia Research Group

According to Wang, “Even without any new habitat-damaging or habitat-destroying development, the Taiwanese white dolphin’s survival is precarious. Any addition to existing stressors (big or small) will only speed up the Taiwanese white dolphin’s demise.”


The outlook for the Taiwanese white dolphin is therefore increasingly bleak, and reminiscent of those we faced with the now-extinct Yangtze River dolphin (baiji) in China and are facing with the very nearly extinct vaquita in Mexico (see our most recent vaquita news here). The best available science forces us to conclude that:

  • Approval by the Taiwan government of any further expansion of the Taichung Outer Port Area will almost certainly have catastrophic impacts on Taiwanese white dolphins;
  • No ‘countermeasure’ can be taken to mitigate those impacts; and
  • Together with the other ongoing threats, especially gillnet entanglement, identified and described in numerous workshop reports and publications (most recently in the 2019 Recovery Plan produced by experts from Taiwan, the United States, and Canada, and delivered to the Ocean Conservation Administration in Taiwan), further land reclamation and industrial development in these dolphins’ core habitat will almost certainly result in another cetacean extinction.


It is also important to note in this present context that one of the main outcomes of the recent Convention on Biodiversity Conference of Parties (COP15) was a call for “maintaining, enhancing and restoring ecosystems, including halting species extinction and maintaining genetic diversity.”

An Open Letter from the Cetacean Specialist Group to the Taiwan Authorities and Others Engaged in Industrial Development in Taiwan was sent at the end of January 2023, highlighting concerns that expanding the Taichung Outer Port Area would almost certainly cause irreparable damage to the dolphin population.



Araújo-Wang, C., Wang, J.Y., Draghici, A.M., Ross, P.S. and Bonner, S.J. 2022. New abundance and survival estimates for the critically endangered Taiwanese white dolphin indicate no signs of recovery. Aquatic Conservation: Marine and Freshwater Ecosystems 32(8):1341-1350.


More Information and other News Stories on the Taiwanese White Dolphin:

Dead Taiwanese White Dolphin stranded in Tainan City

Critically Endangered Taiwanese white dolphin: International Collaboration for Recovery Plan

Initiative to save Taiwanese white dolphins from extinction