Acoustic Telemetry Study Finds Strong Manta Site Fidelity in Komodo

Labuan Bajo — — An acoustic telemetry study of giant manta rays in the Komodo Marine Park tracked 41 tagged animals between 2000 and 2003, revealing strong concentration of activity at a few key aggregation sites and clear evidence of site fidelity.

The research, led by Heidi Dewar and colleagues, was published in the journal Marine Biology in 2008 and analysed detections from an array of submerged receivers deployed at up to seven locations in the park.

According to the paper, three monitored sites accounted for more than 90% of recorded manta activity.

What the tracking showed

The most frequently used location was German Flag, off the southern tip of Komodo Island, an area described as having a high degree of underwater bathymetric structure.

Dewar and co-authors reported that individual mantas made between three and 303 visits to monitored sites during the study.

The study found that mantas returned to preferred sites almost daily for up to three months and were re-detected sporadically for as long as two years, demonstrating long-term use of particular areas.

Examination of the longest tracking records suggested local site preference: five of seven individuals with extended monitoring histories spent more than 90% of their recorded time at the location where they were tagged, which the authors interpreted as site fidelity.

The paper noted that, while a few mantas remained at a single site for weeks at a time, most individuals moved among sites and visited more than one monitored area within the park.

Environmental and temporal patterns

The acoustic array allowed the researchers to document movements beyond the presence of divers or snorkelers, generating continuous records over periods of months to years.

According to the Marine Biology article, detections showed that visits were concentrated during daylight hours at all monitored locations.

The authors also described seasonal shifts in use of southern aggregation sites, with manta presence varying in response to changing oceanographic conditions and productivity associated with monsoonal cycles.

Implications for management

Dewar et al. concluded that the repeated use of specific aggregation sites and the apparent residence of some tagged animals supported management approaches centered on protecting these key areas.

The study argued that marine protected zones encompassing manta aggregation sites could help reduce the species’ exposure to local overexploitation, noting that giant mantas have low reproductive rates and may be vulnerable to intensive fishing pressure.

Subsequent regional and global assessments of manta ray ecology and conservation have cited the Komodo findings as evidence that reef and giant mantas can show strong site fidelity and predictable use of aggregation areas, reinforcing the value of protecting such sites.

Data at a glance

• Study monitoring period: 2000–2003, using an array of acoustic receivers in Komodo Marine Park.
• Acoustic-tag deployments: 41 giant manta rays tagged over multiple field seasons.
• Monitoring coverage: up to seven receiver sites within the park.
• Longest individual record: detections spanning up to roughly two years for some mantas.
• Core aggregation sites: three locations accounted for over 90% of recorded manta activity, including German Flag in southern Komodo.

Publication context

The study “Movements and site fidelity of the giant manta ray, Manta birostris, in the Komodo Marine Park, Indonesia” appears in Marine Biology volume 155, pages 121–133, published in 2008.

Later research on manta rays in Indonesia and elsewhere continues to reference the Komodo acoustic telemetry work as an early demonstration of strong site fidelity and repeated use of specific aggregation sites within a marine protected area.

Sources

• Marine Biology article PDF (Dewar et al., Movements and site fidelity of the giant manta ray, Manta birostris, in the Komodo Marine Park, Indonesia) hosted by P
• Residency, movement patterns, behavior and demographics of reef manta rays in Komodo National Park, Indonesia (peer‑reviewed article, PMC)
• Environmental drivers of reef manta ray (Mobula alfredi) visitation patterns at a feeding aggregation site (PLOS ONE, printable article)
• Dewar et al., Marine Biology