Using eDNA to understand

the diversity, distribution and ecological role of sharks and rays in the Tropical Eastern Pacific

Funding: Mark and Rachel Rohr Foundation

eCSI: “e” (environmental DNA) “C” (Conservation), “S” (Shark) “I” (Investigation)

Summary

Human activities are responsible for major declines in population sizes and local species extinctions in most ecosystems across the globe. Marine “defaunation” has disproportionately impacted elasmobranchs (sharks and rays) because of their high economic value. Yet, the magnitude and ecological consequences of the decline of most coastal and highly mobile species, remain difficult to quantify because of the absence of historical data, and, as inherently shy and elusive animals, they are difficult to census and study. The paucity of information on the distribution and ecology of elasmobranchs also challenges the design of effective conservation strategies.

Marine Protected Areas (MPAs) are increasingly advocated as a strategy for protecting and managing shark and ray populations. MPAs are meant to decrease fishing pressure while simultaneously reducing local stressors. Yet, they are often designed without sufficient information on the biology and ecology of sharks and rays. For MPAs already in place, substantial uncertainty remains regarding which species benefit and how. This is because many traditional survey and monitoring methods for sharks and rays cannot deliver information at the pace needed to support conservation.

In this project, we use environmental DNA (i.e., DNA shed in the seawater in the form of mucus, blood, and waste) sequencing to significantly scale up our understanding of the diversity and distribution of elasmobrachs in the Tropical Eastern Pacific.

Objectives

Build a detailed map of the distribution of sharks and rays species in mangrove-fringed bays and estuaries along the Pacific coasts of Panama and Costa.
Characterize seasonal changes in the use of coastal habitats by sharks and rays in the Tropical Eastern Pacific.
Assess where critically endangered and vulnerable species of sharks and rays are present in the study area.
Generate genomic resources for all shark and ray species of the Tropical Eastern Pacific.

This project will provide data that will be very valuable for the development of effective sustainable management strategies, especially in areas where artisanal fisherman communities subsist and rely on the resources provided by these marine ecosystems.