Global cownose ray population genetics

Cownose rays (genus Rhinoptera) are a group of 7 – 11 species of stingray found in coastal waters around the world. Over the past four decades, some populations have declined as much as 86% due to unregulated fishing, targeted eradication, and bycatch mortality. These declines are particularly alarming as cownose rays possess very low fecundity, producing a single pup per year, making populations biologically incapable of rapid recovery.

Despite this, fundamental aspects of their biology remain poorly understood. Cownose ray species look similar to one another, and many occur together in the same waters, making accurate species identification extremely difficult. As a result, biological data collected from one species (reproductive rates, habitat use, dietary preference) may be misapplied across the entire genus in scientific literature. This means that species-specific conservation needs may be obscured, and the true extent of population declines remain unclear.

This project addresses these foundational gaps through a large biobank of cownose ray tissue comprising over 1,000 samples collected from across the globe. Using a multi-tiered genomic approach of mitochondrial gene sequencing for broad-scale species identification, complete mitogenome sequencing for phylogeographic analysis, and genome-wide SNP genotyping for population structure, we aim to resolve how many valid Rhinoptera species exist and where they live, characterise patterns of genetic diversity and connectivity across regions, infer the demographic history of the group, and develop standardised molecular identification tools to support future research and management. 

For further information on this project, please contact Helen Weber or Dr Emily Humble