Protecting the Eastern Pacific's Mysterious Mobula Rays

March 2021

We’re thrilled to announce the launch of Mobula Conservation Project (MCP), a new Affiliate Project of The Manta Trust focused on Mobula rays. Based in the Eastern Pacific Ocean, MCP is an organization of scientists and conservationists working together to study and conserve Mobula rays.

So why mobula rays? Well, besides their fascinating biology, their complex and mysterious social behaviors, and their incredible beauty, Mobula rays are highly threatened by multiple human-driven problems. And while public media and conservation attention has spotlighted the plight of their larger cousins, the manta rays, smaller Mobula species are just as threatened. Sometimes referred to as “devil rays,” there are eight Mobula ray species (together with the two larger manta species, these species make up the genus Mobula).

In fact, Mobula rays face many threats, the most immediate among them being capture and death in fisheries. Mobulas are targeted directly both for their meat and body parts mainly in small-scale fisheries, but are also caught incidentally in large-scale industrial fishing gears, where their habitat often overlaps very closely with valuable species like tuna. This, compounded by their extremely low growth rates, make Mobulas a highly vulnerable group of species.

However, solutions exist! Mobula Conservation Project is working on multiple simultaneous projects to gain crucial scientific information necessary to inform the conservation and management of these species. Based primarily in the Eastern Tropical Pacific, a Mobula biodiversity hotspot, we have several ongoing projects to study and protect Mobulas.

Off the coast of Baja California Sur, we are investigating the habitat use of Mobulas, the impact of small-scale fisheries bycatch on these species, and working with fishermen to test alterations to fishing gear that may yield big benefits for these at-risk species, without compromising fisher livelihoods.

Farther out into the ocean, past the 200-mile zone belonging to coastal countries, high seas fishing vessels also capture Mobula rays as they venture out into the open ocean following their prey. In order to understand their movements at sea — as well as potential overlap with fishing activity — we use modelling techniques to predict where Mobulas might end up, based on the fishing operational characteristics where they may caught and environmental preferences of the study area. This information is crucial to helping fisheries managers make informed decisions and try to avoid Mobula hotspots.

Finally, we’re working with some of those same high seas fishers to understand and address the capture of Mobula rays in large-scale fisheries targeting tuna. Mobulas are captured in high numbers in industrial tuna fisheries, at an estimated rate of 13,000 individuals per year in the Eastern Pacific Ocean. Through a series of workshops, focus groups and surveys, we’re incorporating fisher knowledge to develop mitigation strategies that tuna fishers can use to reduce their impact on Mobula rays.

Mobula Conservation Project (MCP) was founded in 2020 by three conservation biologists: Melissa Cronin, PhD Candidate at UC Santa Cruz, Marta D. Palacios, PhD Candidate at CICIMAR, Baja California Sur, and Dr. Nerea Lezama-Ochoa, Postdoctoral Researcher at the NOAA’s Environmental Research Division. We each use different methodologies, including spatial ecology, habitat modelling, conservation genetics, acoustic telemetry and others. We may use disparate methods, but we have one thing in common: Mobulas! We look forward to understand the ecology and biology of Mobulas, and to promote their the conservation and protection.