Juvenile manta rays stay coastal as adults migrate beyond protected reserves

Juvenile giant manta rays in Central America remained in shallow coastal refuges, where they could find food, hiding places and reef cleaning services, while most of the mature animals tracked at large spatial scales made long-distance movements along the continental shelf break. The finding comes from the first multi-scale telemetry study of giant manta ray movement in Central America, based on observations at five locations between 2018 and 2025. Researchers combined three methods—acoustic telemetry, satellite telemetry and photo identification—to reveal a pronounced change in habitat use as the animals mature.

Acoustic telemetry, which uses underwater sound pulses, monitored fine-scale movements of 59 giant manta rays at coastal aggregation sites such as cleaning stations. Satellite transmitters followed the larger movements of 12 individuals, and photographs helped researchers distinguish individual animals. Together, these approaches generated more than 12,000 detections.

Mantas with disc widths of about three meters or less stayed within shallow nearshore waters. The study interpreted these coastal areas as refuges for young animals, providing feeding opportunities, places to hide and access to services such as cleaning. The combined dataset also indicated that young rays repeatedly used the same coastal refuges, with some individuals observed there more than once a year.

The pattern differed markedly among mature rays. Nine mature mantas undertook expansive migrations along the continental shelf break, while the tracking record also showed that some adults returned to familiar coastal locations. One ray, nicknamed Mickey Mouse because of the pattern on its belly, was tagged multiple times over several years and therefore provided a continuous dataset.

It registered 462 acoustic detections at the coastal hub of El Secreto in 2020. Three years later, it returned to the same shelf and remained there for 38 days. This documented return concerns that individual adult; the study did not establish a general return schedule for all mature manta rays.

The researchers described nearshore cleaning stations as social hubs where courtship and reproductive interactions can occur, in addition to their cleaning function. The movements create a conservation challenge because protection does not necessarily follow the animals across their range. Giant manta rays can grow to nine meters long, with discs spanning seven meters and body masses reaching 2,000 kilograms.

At maturity, around eight to 10 years old, their large size and ability to dive deeply can help them evade threats. Once adults leave coastal marine reserves and travel through unprotected international corridors, however, the authors say their legal protection may fall to zero. The results therefore support the authors’ call for multinational “conservation swimways” connecting domestic juvenile coastal refuges with the migration corridors used by adults, because isolated marine protected areas do not cover the full movement range of this highly mobile species.

Its geographic scope was Central America, and the sample tracked by satellite was smaller than the group monitored acoustically. Even so, the combined methods establish an initial multi-scale baseline for the species and document distinct movement patterns by life stage: juvenile giant manta rays remained tightly associated with shallow coastal refuges, whereas most of the mature individuals tracked over large distances migrated along the continental shelf break. The authors said the baseline could guide future collaboration and research into protecting both the coastal sites used by young animals and the international routes used by adults.

Subject of Research: Movement and habitat use of juvenile and adult giant manta rays in Central America

Article Title: Baby manta rays hunker down close to coasts before facing the open ocean’s dangers

Article References: Baby manta rays hunker down close to coasts before facing the open ocean’s dangers. Original publication (Bibliographic details unavailable.)

Image Credits: AI Generated

DOI: Not provided

Keywords: giant manta rays, animal tracking, acoustic telemetry, satellite telemetry, coastal refuges, continental shelf break, marine migrations, marine protected areas, conservation corridors, Central America, Baby, manta