Rhino Rays

Project Overview.

Rhino rays, which include the guitarfish and wedgefishes, were recently identified as the world’s most threatened marine fishes, with populations experiencing severe declines on a global scale. Low reproductive rates hinder population recovery and exacerbate their extinction risk, whilst the high value of their fins and meat drives excessive, unregulated fishing throughout their range. To make matters worse, a paucity of focused research or general scientific knowledge – even on which species is which – hinders the development of effective conservation strategies for these animals.

Conservation Needs for Rhino Rays

The listing of 15 rhino ray species as Critically Endangered by the IUCN in 2019 sparked a global call for the rapid initiation of research to better understand this lesser-studied group, and specifically to inform effective conservation strategies that can prevent further decline. Biological and ecological knowledge of these rays is currently lacking and, as a consequence, few management plans exist to protect declining populations worldwide. 

Rhino Rays in Mozambique

The Inhambane Province is an important habitat for rhino rays in south-east Africa. At least three species of identified wedgefish, including the bowmouth guitarfish (Rhina ancylostoma), the bottlenose wedgefish (Rhynchobatus australiae), and the white-spotted wedgefish (R. djiddensis), as well as one species of guitarfish (grey-spotted guitarfish, Acroteriobatus leucospilus) inhabit coastal waters. Fishing pressure in the form of gillnetting, longlining, and targeted capture has increased substantially in the past decade, presenting a major threat to these already vulnerable species. To date, there has been little direct research conducted on this group in southern Mozambique, or elsewhere in Southern Africa. Consequently, their distribution, habitat preference, movements, and baseline numbers remain unknown. 

MMF Research on Rhino Rays

MMF’s rhino ray program has been designed to rapidly collect high-priority information on guitarfish and wedgefish in southern Mozambique and to develop a science-based conservation strategy for them in a region fraught with anthropogenic threats.

Objectives.

Broadly, we aim to gather the data necessary to develop and inform science-based conservation management plans for guitarfish and wedgefish in southern Mozambique. To achieve this, we are employing a range of techniques including visual and photographic monitoring at aggregation sites, satellite and acoustic tracking, and the collection of tissue samples and morphometric data for taxonomic studies.