Habitat use, connectivity, migratory routes and status of shark populations

From underwater censuses using stereo cameras in 2013 and 2014, we found that Darwin and Wolf (DW), the two northernmost islands within the GMR, harbor the largest shark biomass on the planet. In our study, we identified several species of sharks, including hammerhead (S. lewini), galapagos (C. galapagensis) and blacktip (C. limbatus) sharks. This high concentration of sharks is possible due to the nutrient-rich currents reaching these islands, making them highly productive areas. Additionally, the total ban on shark fishing within the GMR helps in maintaining a high density of sharks in the area. However, illegal fishing continues to pose a threat to these apex predators within the GMR. Thus, ongoing protection is necessary if we are to protect the high biomass and diversity of northern Galapagos.

Through the use of satellite tags on tiger sharks (Galeocerdo cuvier) between 2014 and 2017, we found these sharks show a resident pattern, as they spent over 90% of their time within the boundaries of the GMR. This pattern is unusual in this species because they tend to be highly migratory elsewhere in the world. However, the high abundance of food in the Galapagos, particularly of green sea turtles, is likely the main driver behind the residency pattern found at the GMR. Additionally, analyses of their movements allowed us to establish that they have a tendency to gather around green turtle nesting beaches, their preferred prey item in the archipelago.

An in-depth understanding of the patterns of distribution and abundance of sharks, as well as of the biological and environmental variables that influence said patterns, is necessary to develop and evaluate conservation and management plans. In 2015, we deployed baited remote underwater stereo-video systems (stereo-BRUVS) at 48 sites across the GMR. This allowed us to identify spatio-temporal patterns in the composition of shark assemblages within the GMR.

We found a total of 877 sharks of 10 species, which represents just over 1% of all marine animals identified in these videos. The highest abundance (number of individuals) of sharks was found at Darwin and Wolf islands. However, the highest diversity (number of species) of sharks was found at Isabela, Floreana, Santa Cruz and the Daphne islets. The most common shark species across the GMR were the galapagos, hammerhead, blacktip and whitetip, which represented 83% of sharks identified in our videos. These species occupy similar habitats which is why we usually find them together.

We also found sharks did not distribute themselves evenly across the archipelago. Instead, changes in environmental variables, such as seawater temperature, are highly influential in their distribution. Finally, although we found some differences in shark distribution between seasons, they were not big enough to be considered significantly different by our analysis.

Thanks to a collaborative effort between the Charles Darwin Foundation, the Galapagos National Park Directorate and Ocean Exploration Trust, we were able to go on expedition on board the E/V Nautilus in June 2015. During this expedition, we explored deep-sea environments within the GMR. Using two Remotely Operated Vehicles (ROVs), we investigated the sea floor around the Iguanas-Pinguinos hydrothermal vent located at a depth of 1.5 km, north of Darwin Island.
We found 157 egg cases from Bathyraja spinosissima, a deep-sea skate, in the area surrounding a vent. The egg cases pictured below were in various states of development, and most of them were found within a 150 m radius of active vents.
Seawater temperature measurements confirmed that the temperature increased as the distance to the vent decreased. This suggests that B. spinosissima is using the warmer area around the vents to incubate its egg cases, which can take as long as 1,500 days (just over 4 years) to hatch.

Since egg cases were found in higher quantities around the hydrothermal vents, we can conclude that this is the first record of these habitats being used as nurseries (areas hosting a great number of juveniles). Due to the long incubation period of these species, these skates are particularly vulnerable to changes in their environment. For this reason, it is necessary to give these areas the highest possible level of protection against human intervention.

To foster support for shark conservation campaigns, it is of vital importance that we understand the attitudes of local communities towards sharks. To evaluate the public’s perceptions of sharks within the GMR, our team surveyed residents and visitors over 15 years of age in Puerto Ayora (largest human settlement in the archipelago) between October and November 2015.

Based on survey responses, we identified that the aesthetic value, environmental role and their perceived dangerousness were the variables with the biggest influence on the public’s attitude towards sharks.
We also found attitudes varied based on gender, occupation and island residency status. Despite this variability, we found a strong positive correlation between positive attitudes towards sharks and tolerance/support for shark conservation programs.
Our recommendation is for shark conservation policies go in hand with the promotion of positive attitudes towards these animals.

Outreach and Education 

Our education campaign “Protect the Fins and the Ocean Wins” was carried out in 2016 on the four inhabited islands of the archipelago: Santa Cruz, Isabela, San Cristobal and Floreana. The main objectives were to change the negative perceptions about sharks and to promote the Galapagos as a model for sustainable co-existence between humans and these animals.

We visited schools to teach children about the importance of sharks in maintaining the health of marine ecosystems, and supporting the local human communities. Overall, we reached more than 1,500 children aged between 9 and 12 years.
In 2017, thanks to the support from Save Our Seas Foundation, we created the Marine Education project. This scheme does not only base itself on scientific information, but it also offers opportunities to experience and explore the marine world to members of the local community. This way they can learn about the marine ecosystems surrounding their islands, and the sharks that inhabit them.

The Charles Darwin Foundation’s Van Straelen Interpretation Center was renovated in 2018, and a permanent exhibition called “Marine World” was set up. This display presents information about the ecological role and anatomy of sharks, the species that inhabit the archipelago, as well as results obtained from our 2016 educational campaign to local, national and international visitors.

Moreover, we created the ‘Sharks Ambassadors’ club, which has more than 50 members, who are local students aged between 12 and 17 years. This program teaches the ambassadors about methodologies that our scientists use to study sharks and other marine species. The club also offers them the opportunity to learn more practical skills, such as species identification while snorkeling. The Shark Ambassadors are empowered to develop activities that promote the conservation of local marine ecosystems so that they can become positive agents of change in their communities.