Night patrol teams on Cabo Verde beaches saw 30 loggerheads a night as study finds 80-fold rise

A few years ago, patrol teams on Boa Vista in Cabo Verde began noticing a striking change. After years of seeing only a handful of loggerhead turtles during nightly surveys, they suddenly started encountering dozens in a single shift.

Long-term monitoring has now confirmed those early observations, with researchers pointing to the surge as evidence of a major conservation success and a significant recovery for the island's loggerhead population.

What happened?

According to a new study reported by Mongabay News, the researchers recorded an 80-fold rise in loggerhead nesting across three beaches on Boa Vista over 27 years, with the study pointing to decades of local conservation work as the likely reason for the increase.

By 2021, patrols were logging 30 to 40 female loggerheads a night, up from 20 to 30 in 2018 and just five to 10 in the earlier years. Those figures came from years of nighttime nesting-season patrols conducted by staff members and volunteers with the local conservation group Cabo Verde Natura 2000, or CVN2.

The new research found that nest density at Boa Vista's largest nesting beaches reached 22,000 nests per kilometer in 2021. For comparison, Mongabay reported that major loggerhead nesting sites in Florida and Oman have recorded densities of up to 600 nests per kilometer, highlighting just how extraordinary the numbers on Boa Vista have become.

Mongabay noted the increase followed years of habitat protection, anti-poaching enforcement, hatchery programs, beach patrols, and growing community involvement through turtle-watching and monitoring efforts.

Why does it matter?

The rebound is especially notable because loggerhead turtles remain under pressure worldwide. The species has fallen by nearly half over three generations and is still listed as vulnerable by the International Union for Conservation of Nature, Mongabay reported. Habitat loss, marine pollution, fishing bycatch, poaching, and climate-related disruptions have all contributed to that decline.

Conservation efforts on the island have relied heavily on local workers and volunteers, and CVN2 is staffed mostly by Cabo Verdeans. The work has also supported education, local pride, and nature-based tourism.

The findings also show the value of long-term monitoring. Loggerheads are slow to mature, with females taking decades to begin nesting. That means the effects of protection can take years to become visible, but when they do, the results can be dramatic.

However, success brings new risks. Dense nesting areas can be vulnerable to tourism development, poaching, shoreline changes, and rising sand temperatures that may affect these numbers.

What are people saying?

Carlos Angulo-Preckler, a study co-author and member of Saudi Arabia's King Abdullah University of Science and Technology marine research team, told Mongabay, "this study is a good example of how long-term NGO conservation datasets can be transformed into scientific evidence that supports both local conservation and global understanding of sea turtle recovery."

Jeanette Wynecken, a Florida Atlantic University sea turtle biologist who was not involved in the study, said, "since sea turtles are slow to age and late to mature, analysis over such a long period of time is essential to understanding the effect that conservation has on turtle populations."

Lead author Cassandra Roch, a KAUST researcher, added, "Sea turtles have survived significant climate alterations. Therefore, consistent and continuous monitoring of their populations is crucial to identify adaptive strategies to climate change."

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