The Eastern Tropical Pacific islands show an exceptional concentration of sharks, according to a new regional assessment. Sites like Galápagos, Malpelo, Clipperton, and Revillagigedo stand out for hosting populations that surpass records from other pristine areas of the planet.
This scenario contrasts alarmingly with what happens in marine parks along the coasts of Ecuador and Costa Rica. There, the ecosystem appears impoverished, with few fish and almost no predators, even within areas declared protected.
The research, developed by regional teams, driven by conservation institutions, and published in the journal PLOS One, used baited underwater cameras to record large fish and sharks. The method revealed patterns that describe an ocean divided between biological richness and degradation.
An oceanic refuge where life still thrives
In the remote parks of the Eastern Pacific, species abundance remains high. The food chain remains active, and sharks occupy their key role as top predators. In Galápagos and Malpelo, large populations of common hammerhead sharks stand out, while in Revillagigedo and Clipperton, the silver-tip shark predominates.
Each site fulfills a particular function within the life cycle of these animals. Clipperton acts as a critical space for juveniles, suggesting a role as a natural nursery. Galápagos and Malpelo, on the other hand, primarily concentrate adults, which use these areas for foraging or aggregating in groups.
This network of islands functions as a biological corridor that supports different life stages. Their isolation and environmental conditions favor a marine richness that today stands out against the widespread deterioration of other ecosystems.
The severe degradation of coastal areas
The outlook changes when the observation shifts to parks closer to the continent. In Machalilla, Galera San Francisco, and Isla del Caño, the presence of large fish is minimal. The almost total absence of sharks reveals a deeply altered ecosystem.
The recorded pattern coincides with a phenomenon known as fishing down the food web. As fishing removes large predators, the pressure falls on medium-sized species and finally on small fish. The entire system loses complexity and resilience.
On the Ecuadorian coasts, intensive pressures and non-selective gear also converge. Even populations of herbivorous and planktivorous fish are low, suggesting an alteration affecting from the upper levels to the base of the food chain.
A balance that depends on predators
The disappearance of sharks in coastal areas of the Eastern Pacific modifies the ecological structure throughout the region. Top predators regulate herbivores and medium-sized carnivores, maintain order in the food chain, and protect the health of reefs.
Without them, opportunistic species proliferate, reefs lose stability, and biodiversity decreases. This loss of regulation is amplified in coastal waters already pressured by fishing, pollution, and climate change.
The oceanic islands function as engines of life for the Eastern Pacific. Their ability to sustain sharks allows for maintaining genetic connectivity, healthy migrations, and a balance that extends beyond their borders. If these refuges deteriorate, the entire regional ecosystem would be affected.
The urgency of strengthening marine protection
The study exposes a deep gap between strictly protected areas and those where fishing is still allowed. In the Eastern Pacific, there are more than 70 marine protected areas, but many allow extractive activities that reduce their effectiveness.
Strengthening control and expanding reserves where fishing is prohibited becomes key to preventing the collapse of species already showing signs of depletion. Satellite monitoring and cooperation between countries can accelerate a recovery necessary to meet the global goal of protecting 30% of the ocean by 2030.
The Eastern Tropical Pacific still retains spaces where marine life thrives, but its future depends on firm political decisions. The oceanic islands offer a model of ecological success; the challenge now is to extend that reality to the coasts that show alarming deterioration.
