Nursing Galapagos shark populations back to health

The Galapagos Marine Protected Area

Heralded as a ‘living museum and a showcase of evolution’, the Galapagos islands comprise a chain of 19 volcanic islands situated 1000 kilometres off the South American coast. The oceanic archipelago is placed at the confluence of three different ocean currents, that, in combination with the extreme isolation make for the most unusual and rich animal life on the planet.

Due to its impressive biodiversity (the Galapagos is home to over 3000 marine species), it has been a designated Marine Protected Area (MPA) since 1998 to preserve this one-of-a-kind ecosystem. This marine reserve encompasses more than 130,000 square metres of protected habitats ranging from coral reefs to wetlands and is a no-take fishing zone within its boundaries.

In recent times the encroachment of industrial fishing fleets has taken advantage of the overspill from the MPA. This has led to calls for expansion of the boundary to include more migratory and transient species within the protected area such as shark populations.

Shark Populations

Currently 100 million sharks are killed globally through illegal fishing or accidental bycatch, and are particularly affected by the fin trade. The Galapagos is one of the most densely populated areas for sharks in the world, including the scalloped hammerhead which recently reclassified from endangered to critically endangered. In the past twenty years, seven of the nine species residing in the Galapagos have become endangered. Characteristics such as late maturity, long gestation periods, and their migratory nature make sharks highly susceptible to human influence. This has heavily attributed to their decline over the past century.         

Despite this, sharks have high value economically and ecologically. In tourism, sharks are often used as a flagship species for conservation efforts and attract a high number of tourists to the Galapagos. Within the ecosystem, they play a fundamental role as apex predators and are a useful indicator species reflecting the ecosystem’s health as a whole.

Shark Nurseries

In spite of such a large aggregation of adult hammerheads and black tips, there was very little known about their nursery grounds until 2018 when scientists from the Charles Darwin Foundation stumbled upon mangroves with a high abundance of juvenile sharks. They discovered that individuals use this crustacean-filled refuge to protect their young before heading out into the open ocean. These sites allow females to leave their pups in sheltered food-rich environments protected from larger predators before they reach maturity.

Since then, these areas have been termed ‘shark nurseries’ and this project consistently monitors them to conserve these natural breeding sites. Multiple sites have been found in Santa Cruz where scientists are working to map these ‘true’ nurseries. The areas are defined by a high density of pups over time, high site fidelity, higher growth rate, and decreased mortality. To locate remote nursery grounds and accommodate scientists, the Pelorus Foundation has partnered with this project to provide scientific research vessels as a platform from which the research will be conducted.

This project aims to survey abundance by drone and gillnet, use models, and ground-truthing to indicate other sites and to minimise human impact. To make this all happen, the Pelorus Foundation provides a network of support including scientific experts and other conservation organisations. Initial findings have established a standardised protocol for working with juvenile sharks. They have found that using drone surveys is more accurate than gillnet and this has resulted in the creation of a ‘Shark Day’ to raise awareness of these species. Through funding from Pelorus clients and help from volunteers, we are striving to protect Galapagos shark populations and ensure the success of this project.