Migratory species depend on critical habitats throughout their seasonal movements, including breeding and foraging sites as well as the pathways between them. Loggerhead sea turtles, for example, can be found nesting on a beach in Japan, but forage along the Pacific coast of Mexico. During migrations, individual animals travelling through national waters (i.e., within Exclusive Economic Zones) and areas beyond national jurisdiction (ABNJ) may encounter a variety of stressors, from predation and adverse weather to human impacts including habitat destruction, direct and incidental fishing mortality, ship strikes, noise, hazardous substances and other pollutants. The potential cumulative impact of regional-scale stressors may impact populations and are a function of migratory connectivity: how individuals and populations are geographically linked throughout their migratory cycles. Awareness of how a population is connected, how connectivity influences demographic rates, and designing conservation and management measures appropriate for the level of risk associated with various degrees of connectivity, are all critical to the conservation and sustainable use of migratory species.

To address this, the Migratory Connectivity in the Ocean (MiCO) initiative was initiated under GOBI’s IKI grant to connect global policy and conservation processes with actionable knowledge on migratory connectivity. MiCO provides an easily accessible geospatial knowledge hub to facilitate the inclusion of marine connectivity into international management and policy frameworks (including area-based planning processes), and to inform future research and investment needs. In particular, this work seeks to support competent authorities such as CBD and the Convention on Migratory Species of Wild Animals (CMS) to move from descriptions of individual sites to a network approach that considers representativity and connectivity.

Two studies carried out by the MiCO team consolidated the thinking on this issue: Dunn et al. (2019) outlined ways that global ocean policy would benefit from considering migratory connectivity while Hays et al. (2020) compiled case studies for how marine animal tracking data have already helped shape conservation policy and management.

MiCO convened a large community of international partners – including data warehouses, national observing systems, taxa conservation groups, museums, environmental non-governmental organisations, universities, intergovernmental commissions and UN bodies – who contributed connectivity data, expertise and guidance. The resulting MiCO geospatial knowledge hub (https://www.mico.eco) contains information on more than 100 species of marine turtles, marine mammals, seabirds and fish, and their connections worldwide, derived from a literature review (Kot et al 2023) of more than 25 years of published tracking data spanning 173 marine species. This represents the single largest publicly available dataset on connectivity of marine migratory species in the world.  A follow-on paper (Bentley et al., in review) summarises the immense connectivity of marine mammal, seabird, sea turtle and fish movement networks developed from the literature, which provides a first synoptic baseline and an analysis of biases and gaps in the data. GOBI’s work on connectivity included a particular focus on the movements of sea turtles, based on a telemetry dataset of 1,235 individually tagged animals, which has furthered our understanding of their spatial ecology and the networks that tie multiple jurisdictions and areas beyond national jurisdictions (Kot et al. 2022).

Alongside the development of the MiCO system, the team carried out an assessment (Dunn et al., in review) of the migratory species information gathered through the CBD EBSA process, with the aim to support the transition from describing individual EBSAs to the description of a network that meets the CBD criteria for a global network of protected areas. Building on an initial gap analysis of the EBSA portfolio, they found that the vast majority of EBSA descriptions mention marine mammals, sea turtles, seabirds or fish, and approximately a quarter were delineated specifically for due to the use of an area by one or more of these species. Interestingly, half the descriptions contain some information about enhanced management, but this is highly variable and decreases with size and inclusion of areas beyond national jurisdiction.

MiCO has promoted many examples of how migratory connectivity data are already a critical component within marine policy and highlights their potential to strengthen conservation measures. Recommendations from this aspect of GOBI’s work include: 1) targeting research where significant gaps exist, 2) sharing standardised data to accelerate knowledge transfer, and 3) increasing opportunities to build closer relationships among stakeholders from different sectors (e.g., academia, government, non-profit organisations, industry) to reinforce collaboration.

Impact and relevance

Connectivity issues – both physical and ecological – are gaining recognition in international policy processes, including in the targets of the CBD Kunming-Montreal Global Biodiversity Framework, in the Resolutions of the Convention on Migratory Species of Wild Animals, in the development of regional environmental management plans under the International Seabed Authority, and in the new BBNJ Agreement. Provision of accessible, reliable and accurate information about connectivity and the movement of animals in the marine environment is crucial in effectively managing species, habitats, seascapes, and the migratory corridors between them, as well as in the establishment of networks of protected areas to conserve them. GOBI – through its work in developing MiCO and associated products – has provided information on connectivity and migratory species to all these processes as well as to States and regional bodies seeking to better understand connections between national waters and adjacent areas beyond national jurisdiction. The MiCO platform continues to be developed and expanded, and remains a free and open resource for policymakers and scientists alike.

Key publications from this work

Bentley, LK, Nisthar D, Fujioka E, Curtice C, DeLand SE, Donnelly B, Harrison A-L, Heywood E, Kot CY, Ortuño Crespo G, Poulin S, Halpin PN, Dunn DC. (in revision at Nature Communications) Marine megavertebrate migrations connect the global oceans. Preprint available at www.researchsquare.com/article/rs-4457815/v1

Dunn, DC, Bax N, Bentley L, Cleary J, Ortuño Crespo G, Curtice C, DeLand S, Donnelly B, Dunstan P, Barrio Froján C, Fuller M, Gjerde KM, Gunn V, Johnson DE, Klein E, Kot CY, Nisthar D, Halpin PN. (in review) What is an ecologically or biologically significant area? In review at npj Ocean Sustainability

Dunn D, Harrison A, Curtice C, et al. (2019) The importance of migratory connectivity for global ocean policy. Proceedings of the Royal Society B: Biological Sciences 286; doi:10.1098/rspb.2019.1472

Hays GC, Bailey H, Bograd SJ, et al. (2019) Translating marine animal tracking data into conservation policy and management. Trends in Ecology & Evolution 34; doi: 10.1016/j.tree.2019.01.009

Kot CY, Åkesson S, Alfaro-Shigueto J, et al. (2022) Network analysis of sea turtle movements and connectivity: a tool for conservation prioritization. Diversity and Distributions 28; doi: 10.1111/ddi.13485

Kot CY, DeLand SE, Harrison A-L, Alberini A, Blondin H, Chory M, Cleary J, Curtice C, Donnelly B, Fujioka E, Herrero Palacio A, Heywood EI, Mason E, Nisthar D, Ortuño Crespo G, Poulin S, Whitten M, Woolston C, Dunn DC, and Halpin PN (2023) Synthesizing connectivity information from migratory marine species for area-based management. Biological Conservation 283; doi: 10.1016/j.biocon.2023.110142