Philopatry as a Tool to Define Tentative Closed Migration Cycles and Conservation Areas for Large Pelagic Fishes in the Pacific

Abstract

Migrations of large pelagic fishes across the Pacific are usually inferred from tagging or genetic studies. Even though these techniques have improved over time, they still fail to demonstrate large transoceanic migrations, usually proposing ‘routes’ that do not cycle seasonally. The current study uses the concept of ‘philopatry’ in 11 large pelagic fish species, i.e., the tendency for animals to return to their natal site to reproduce. Tentative migration routes and maps emerge by applying this concept to the movements extracted through a comprehensive review of the literature on satellite and conventional tagging, and population and subpopulation linkages inferred from genetic and/or genomic studies. Moreover, when comparing these proposed migration routes and the mapped reconstructed catch (1950–2016, Sea Around Us) of each species in the Pacific, similarities emerge, reinforcing the accuracy of these migration cycles informed by philopatry. Finally, by superposing the migration routes of our 11 species, we identified areas of the Pacific that are part of the inferred migration routes of multiple species, leading to a discussion of possible ‘blue corridors’ that would protect the studied species’ key migration routes and stocks, which are important for the fisheries, culture and nutrition of Pacific islanders.

Lack of genetic differentiation in yellowfin tuna has conservation implications in the Eastern Pacific Ocean

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Stakeholder Perceptions Can Distinguish ‘Paper Parks’ from Marine Protected Areas

“…Moreover, an equal and respectful co-production of knowledge about marine ecosystems will improve participation in MPA management at a global level. Adding non-conventional knowledge to other initiatives that are mainly based on literature reviews, as in the case of so-called 'blue corridors' [45], will improve the connectivity of the habitats used by the exploited species, and ultimately improve the prospects of food security.…”

Multiple Lines of Evidence Highlight the Dire Straits of Yellowfin Tuna in the Indian Ocean

“…We then averaged biomass values for each yellowfin tuna population across ten years to match the BRUVS dataset. The stock assessments compiled here assume a single yellowfin tuna stock for each tuna RFMO, although distinct spawning areas and genetic differences may imply individual stocks or significant heterogeneity in yellowfin tuna distributions (Pecoraro et al, 2018;Vincent et al, 2020;Muñoz-Abril et al, 2022;Relano and Pauly, 2022).…”