Mobulas Face Extinction Threat in the Gulf of California

The Gulf of California is home to the mesmerizing mobulas, known as Devil Rays, which are currently facing a significant risk of extinction. These remarkable rays, characterized by their graceful movements underwater and spectacular jumps above the surface, are threatened by overfishing, incidental capture, and the impacts of climate change.

Mobulas belong to the elasmobranch subclass, which includes sharks and skates, and are primarily composed of cartilage. Alarmingly, more than one-third of elasmobranch species are currently classified as endangered or vulnerable. Of the nine recognized mobula species, seven are listed as endangered by the International Union for Conservation of Nature (IUCN).

Founded in 2020, Mobula Conservation is a collaborative effort among marine biologists and fishermen aimed at protecting these vulnerable rays. The organization, supported by the Manta Trust, is spearheaded by researchers who met on El Pardito Island, situated in the Gulf of California, which hosts five species of mobulas. The smallest, Mobula munkiana, has a wingspan of approximately 1.1 meters, while the largest, Mobula birostris, can reach up to 7 meters across.

The team at Mobula Conservation employs various strategies to monitor and safeguard these rays. Techniques include implanting acoustic transmitters to track their movements, utilizing drones to observe their behavior, and recording the effects of fishing practices on populations. Additionally, researchers are investigating the illegal trade of mobula meat and body parts.

A recent study indicates that mobulas are being captured in 43 countries, with consumption reported in 35. In Latin America, these rays are targeted for their meat, while in parts of Africa and Asia, their gill plates are sought after for use in traditional medicine, despite a lack of scientific evidence supporting such claims.

Bycatch is another significant threat to mobulas, with reports of up to 200 rays being caught in a single fishing net. Between 1993 and 2014, over 58,000 mobulas were documented as caught in the eastern Pacific, and the tuna industry alone accounts for approximately 13,000 incidental catches each year.

The exact population numbers of mobulas remain unknown; however, observed landings suggest drastic declines across various species and regions. Researchers are actively studying both industrial and artisanal fishing practices to better understand the impact on mobula populations and to encourage sustainable fishing methods.

Mobula munkiana is known for forming large groups, sometimes consisting of thousands of individuals, across vast areas of the ocean. This species is especially noted for its jumping behavior, which is distinct from other elasmobranchs. While many fish jump to remove parasites or engage in mating displays, Mobula munkiana's jumping appears to serve multiple communicative purposes that remain largely unexplained.

Unfortunately, the phenomenon of aggregation can also expose these rays to fishing practices that use gillnets and purse seines. Compounding their vulnerability is their slow reproductive rate; it can take between five to ten years for mobulas to reach sexual maturity, and they typically produce only one offspring after a lengthy gestation period of over a year, with intervals of two to seven years between pregnancies.

Climate change further exacerbates the situation, as approximately 23% of elasmobranch species in the Tropical Eastern Pacific are highly vulnerable. Warming seas disrupt nutrient distribution, affecting food availability for these and other marine species.

To gather data on mobula behaviors and habitats, researchers have begun employing passive acoustic telemetry, where small devices are implanted in the rays before they are released back into the ocean. This method allows scientists to track their movements and identify critical breeding areas.

Despite regulatory efforts, the international trade of mobula products remains a significant concern. Although CITES has allowed for regulated trade since 2013, illegal trafficking continues. A study involving multiple countries revealed that the demand for mobula meat and gill plates is high, particularly in Asian markets, where prices for gill plates can reach exorbitant levels.

While marine protected areas (MPAs) have increased in size over the last 15 years, only a small fraction of critical habitats for sharks and rays are fully protected from fishing activities. UN biodiversity targets aim to designate 30% of marine areas as protected by 2030, yet current protections fall short.