Smalleye Stingrays

Project Overview.

In 2008 MMF researchers made a landmark discovery: a large population of the gigantic and elusive smalleye stingray, Megatrygon microps, living off the coast of Mozambique. The discovery represented a range extension for the species of over 5000 km, and some of the first live sightings of the species. Elsewhere, sightings of this enormous stingray are infrequent, suggesting it remains rare and patchily distributed. 

A Mysterious Giant

Despite being the largest known marine stingray, little is known about the biology or ecology of smalleye stingrays. The species is currently listed as ‘Data Deficient” on the IUCN’s Red List of Threatened Species. Regular sightings on inshore reefs in southern Mozambique confirm that this area is not only a critical habitat for the species but is also the best area to study them. 

Conservation Needs for Smalleye Stingrays

A marked increase in the use of indiscriminate fishing practices such as gill-netting, long-lining, and seine netting along the Mozambican coast represents a clear threat to smalleye stingrays. The large size of this species, and their curiosity towards people, make them easy targets. To exacerbate the problem, large stingrays typically take years to reach adulthood and have small litters, making them particularly susceptible to overexploitation. Considerable research on this species is needed to address the lack of biological data and these conservation concerns.

Objectives.

Now that we have determined that the natural spot patterning on these stingrays is stable enough to use in long-term individual identification studies we are beginning to estimate the abundance and movements of these rays along the southern Mozambican coast.

The use of advanced telemetry equipment will allow us to study the movements of this large and unusually mobile ray for the first time. In particular, we aim to collect the first information on their home ranges, habitat use, daily movement patterns, depth preferences, and general behavior. The collection of small tissue samples from individual rays will allow us to examine their ecological role in the area.

We will also be monitoring artisanal fisheries to quantify catches of this species along the coast and to identify ‘hotspot’ areas for further investigation.