Marine barriers regulate the genetic exchange of sharks and rays

The characteristics and peculiarities of these marine animals caught the attention of Maximilian Hirschfeld, associate researcher at the Galapagos Science Center and currently a PHD student at James Cook University in Australia.

Hirschfeld has worked in the Galapagos studying movements, distribution and genetic connectivity of sharks (and other marine animals such as turtles, marine iguanas and sea lions) since 2010.

His research has focused on identifying marine habitats that are essential for the long-term survival of key marine species in collaboration with the Galapagos National Park, with many recommendations taken into account for the development of the management plan of the Galapagos Marine Reserve.

This time his work is focused on providing a global synthesis that shows how marine barriers and the ecology of sharks and rays define genetic connectivity in the ocean.

For this, Hirschfeld carried out the analysis of hundreds of publications on the genetics of sharks and rays. Through this analysis 45 marine barriers were found, including deep ocean trenches, pronounced changes in salinity or water temperature, and marine currents – all which could limit the genetic connectivity even at small spatial scales.



Researchers dive looking for sharks

For example, small species that live close to the seafloor, including Pacific angel sharks (Squatina californica), lack genetic exchange at distances of less than 100 km. Therefore, the impact of barriers on connectivity also depends on the ecology of individual species.

Thanks to this study, it has been possible to determine what ecological factors are needed for a species to overcome or cross these barriers – such as habitat, the depth to which a species can be submerged, or and even their size.

“Therefore, having access to this scientific information is of vital importance in the creation and modification of public policies, since it shows the capacity of the species to recover from some scenarios such as exploitation or climate change,” emphasizes Hirschfeld.

For many species of sharks and rays that inhabit the waters around Galapagos there is no scientific information on their connectivity between islands within the archipelago or between Galapagos and the continental coast of South America or more broadly with marine regions of other countries.

This study will serve as a guide for current and future Galapagos Science Center studies that seek to use genetic connectivity information to improve the management of Galapagos marine resources.

Written by Daniela González, Communication Coordinator at Galapagos Science Center


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In 2022, the Galapagos Science Center (GSC) and the broader UNC & USFQ Galapagos Initiative will celebrate its 10th Anniversary. We are proud to announce the World Summit on Island Sustainability scheduled to be held on June 26–30, 2022 at the Galapagos Science Center and the Community Convention Center on San Cristobal Island.

The content of the World Summit will be distributed globally through social media and results documented through papers published in a book written as part of the Galapagos Book Series by Springer Nature and edited by Steve Walsh (UNC) & Carlos Mena (USFQ) as well as Jill Stewart (UNC) and Juan Pablo Muñoz (GSC/USC). The book will be inclusive and accessible by the broader island community including scientists, managers, residents, tourists, and government and non-government organizations.

While the most obvious goal of organizing the World Summit on Island Sustainability is to celebrate the 10th Anniversary of the GSC and the UNC-USFQ Galapagos Initiative, other goals will be addressed through special opportunities created as part of our operational planning of the World Summit.

For instance, we seek to elevate and highlight the Galapagos in the island conservation discourse, seeking to interact with other island networks in more obvious and conspicuous ways to benefit the Galapagos Islands, the UNC-USFQ Galapagos Initiative, and the world. We will seize the opportunity to further develop the I2N2 – International Islands Network-of-Networks. Further, we wish to highlight and emphasize multiple visions of a sustainable future for the Galapagos Islands and we cannot do this alone. Therefore, engaging the Ecuadorian Ministry of Environment, the Ministry of Tourism, the Government Council of Galapagos, the Galapagos National Park, and local Galapagos authorities, including government and non-government organizations and local citizen groups, is imperative.

The Galapagos Science Center on San Cristobal Island, Galapagos

Borrowing from Hawaii’s and Guam’s Green Growth Program and the Global Island Partnership, we wish to examine existing global programs that emphasize island sustainability and their incorporation into life, policies, and circumstances in the Galapagos Islands. We will also seek to enhance our connections with the institutional members of our International Galapagos Science Consortium and expand the Consortium through the recruitment of other member institutions. We will also work to benefit islands and their local communities by working with citizen groups as well as important NGOs who seek to improve the natural conditions in the Galapagos and diminish the impact of the human dimension on the future of Galapagos’ ecosystems.

Lastly, we will use the World Summit to benefit UNC & USFQ and our constituencies through a strong and vibrant communication plan about the World Summit, creating corporate relationships as sponsors, identifying funding goals through donors, and benefiting our study abroad program for student engagement in the Galapagos Islands. We plan to develop and issue a Galapagos Sustainability Communique after the World Summit that includes the vision and insights of all its participants for a sustainable Galapagos with applicability to global island settings.

We are eager to hear your perspective and have you join us at the World Summit on Island Sustainability!