Close-Kin Mark Recapture Methods – Designing a scientific study to increase the use of fisheries independent data in management for Atlantic Mako Sharks

Grant funds awarded to the Lenfest Ocean Program will support a feasibility study to determine whether new genetic methods, called Close-Kin Mark-Recapture (CKMR), can be used to estimate the abundance of shortfin makos in the Atlantic Ocean. Shortfin makos are targeted and incidentally caught by fisheries, but it remains technically challenging to approximate overall population sizes of these fish at a resolution that is required to inform sustainable management and conservation of this species. 

Briefly, the new technique identifies pairs of close relatives using genetic analyses of tissue samples from makos, which are then used to calculate absolute abundances of these sharks using an adapted mark-recapture approach - a foundational method in ecology. However, in order to determine whether this approach could be applied to Atlantic shortfin mako sharks, a preliminary scoping phase will be completed to determine the required data, sampling needs, and statistical design principles that would be required to complete a full-scale CKMR assessment for these fish. 

The Lenfest Ocean Program will support Dr. Mark Bravington at Australia’s Commonwealth Scientific and Industrial Research Organization (CSIRO) to complete a technical scoping study working collaboratively with members of the International Commission for the Conservation of Tuna (ICCAT) shark species group to evaluate the usefulness of incorporating CKMR analyses into their management decisions.

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