The vaquita, a small porpoise found exclusively in Mexico’s northern Gulf of California, is the world’s most endangered marine mammal. Its critically endangered status highlights a dire situation that scientists and conservationists are working to address.
The Vaquita: A Brief Overview
The vaquita (Phocoena sinus) is the smallest of all living cetaceans, reaching a maximum length of about 4.9 feet for females and 4.6 feet for males. It possesses a robust body with a distinct triangular dorsal fin, a rounded head, and lacks a pronounced beak. Its coloration ranges from dark gray on its upper body to a lighter gray on its sides, with a white underside. Prominent black patches surround its eyes and lips, extending as a thin line from the mouth to the pectoral fins.
This porpoise inhabits a specific range, primarily found in the shallow, turbid waters of the northern Gulf of California, also known as the Sea of Cortez. This restricted distribution makes the vaquita’s habitat the smallest of any cetacean species globally. Vaquitas prefer waters less than 490 feet deep, often within 16 miles of the shoreline.
Vaquitas are elusive and shy, often avoiding human contact and boats. This behavior, combined with the murky conditions of their habitat, makes them particularly challenging for researchers to observe directly. They generally travel alone or in pairs, sometimes with a calf, but have been seen in small groups of up to ten individuals.
The Perilous Numbers: How Few Remain
The vaquita population has experienced a significant decline, plummeting from an estimated 567 individuals in a 1997 survey. By 2018, the population was estimated to be fewer than 19 individuals. More recent assessments indicated fewer than 10 vaquitas remained in the wild as of February 2022.
In 2023, surveys estimated the population at 8 to 13 individuals. The 2024 survey observed a minimum of 6 to 8 individuals, marking the lowest count on record. This recent estimate is considered a minimum, as it may reflect the specific survey area rather than the entire population, given that vaquitas can move outside the immediate survey zone.
Researchers employ a combination of visual surveys and passive acoustic monitoring (PAM) to track these animals. Visual surveys involve observers on boats scanning the water. However, the vaquita’s shy disposition and the turbid waters of their habitat make visual sightings rare and challenging.
To supplement visual data, scientists deploy underwater microphones called hydrophones or CPODs for passive acoustic monitoring. Vaquitas use high-frequency echolocation clicks for navigation and to locate prey. These devices detect and record the clicks, providing information about the porpoises’ presence and distribution without direct human interference.
The Primary Threat: Illegal Gillnets
The primary reason for the vaquita’s population decline is entanglement in illegal gillnets. Gillnets are nets designed to catch fish by their gills, but they are indiscriminate. Vaquitas, sharing the same habitat, become accidental bycatch when they get ensnared in these nets and are unable to surface for air, leading to drowning.
This threat is primarily driven by the illegal fishing of the totoaba, a critically endangered fish. The totoaba’s swim bladder is highly valued on the black market, particularly in China, where it is believed to have medicinal properties and is sought after as an investment. This lucrative trade creates a strong economic incentive for illegal fishing operations.
Despite the totoaba fishery being officially closed in Mexico since 1975 due to overfishing, the high demand for its swim bladder sustains a persistent illegal trade. The large-mesh gillnets used to catch totoaba are deadly for vaquitas due to their similar size. Illegal fishing often occurs at night, and fishers sometimes abandon their nets, creating “ghost nets” that continue to entangle and kill marine life, including vaquitas.
Urgent Conservation Efforts
Numerous actions and strategies have been undertaken by the Mexican government, international organizations, and scientific bodies to save the vaquita. In 1993, the Upper Gulf of California and Colorado River Delta Biosphere Reserve was established. This was followed by the creation of a Vaquita Refuge in 2005, which banned commercial fishing, including gillnets, in core vaquita habitat.
The Mexican government introduced a two-year gillnet ban in 2015, which was later made permanent in 2016 across the vaquita’s range. Efforts have focused on developing alternative fishing gear that does not endanger vaquitas, such as lightweight trawls and traps, to provide sustainable livelihoods for local fishing communities. However, the adoption of these alternative gears has faced challenges, including lower efficiency compared to traditional gillnets.
Enforcement of gillnet bans remains a significant hurdle, as illegal fishing continues, particularly within the designated “Zero Tolerance Area” (ZTA) where vaquitas are concentrated. To deter illegal activity, the Mexican Navy has deployed concrete blocks with hooks in the ZTA, designed to entangle and tear illegal gillnets. International bodies like CITES and the International Whaling Commission have also urged Mexico to enforce fishing bans and combat the illegal totoaba trade.
Conservation efforts also include programs for removing abandoned gillnets from the sea and engaging local communities to shift away from destructive fishing practices. While a past attempt to capture vaquitas for a temporary sanctuary (VaquitaCPR) was halted due to the animals’ stress responses, ongoing monitoring and enforcement efforts continue. The collaboration between government agencies, conservation groups like Sea Shepherd, and local communities is necessary for the vaquita’s future.