Racing to research Tanzania’s rhino rays
Despite the critical conservation status of wedgefish and guitarfish, little is known about these species in Tanzania – and even less in terms of conservation action tailored for their survival. Bigeyo is exploring the biology, threats and conservation needs of wedgefish and guitarfish species in the African country to promote sustainable fishing practices and conserve these endangered species and their habitat. Armed with baseline data, she will be able to inform Non-Detriment Findings to control trade, support the development of the Kilwa Seascape and Rufiji Delta into marine protected areas, and update Dar es Salaam Seascape to a full candidate Important Shark and Ray Area.
Bigeyo Kuboja
Born in Kigoma and raised in Tanga and Morogoro, Tanzania, I am a dedicated researcher at the Tanzania Fisheries Research Institute and have made a significant contribution since 2005. I hold an MSc in marine environment and ecology from Vrije Universiteit Brussel and a BSc in marine biology from the University of Dar es Salaam. I specialise in fisheries ecology, conservation biology and marine resource management.
During my career I have gained notable international experience, for example as a visiting researcher at the China Scientific Authority for CITES and at the Centre for Tropical Marine Ecology in...
Exploring Biology, Threats, and Conservation Needs of selected rhino rays species: Case study of Tanzania
To address the knowledge gaps and conservation challenges relating to wedgefish and guitarfish species in Tanzania through research, conservation efforts and education, ultimately aiming to promote sustainable fishing practices and protect these Critically Endangered species and their habitats.
This project addresses the critical conservation needs of understudied rhino rays facing overfishing, habitat degradation and anthropogenic threats. Listed under CITES, these species have fins that are highly valued in international trade. The project aims to collect species-specific data for scientifically sound Non-Detriment Findings to control trade and implement conservation strategies. It also seeks to develop Kilwa Seascape and Rufiji Delta into marine protected areas and upgrade Dar es Salaam Seascape to an Important Shark and Ray Area.
Critically Endangered wedgefish and guitarfish face a high risk of extinction in the wild due to declining populations and habitat loss, according to the IUCN. Studies have documented significant declines – exceeding 65% – in catch and abundance, especially for bottlenose wedgefish in the Eastern and Western Indian Ocean since 1977.
A survey of fishers and traders in Zanzibar noted that Rhynchobatus species are of particular interest, as their fins are highly valued by traders. Their populations are declining and the species are now considered rare. Despite their critical status, species such as Acroteriobatus zanzibarensis, Rhina ancylostomus, Rhynchobatus australiae and R. djiddensis, including pregnant females and juveniles, are still commonly caught in artisanal fisheries of Kenya, Tanzania, Mozambique and Madagascar.
No conservation measures are in place for these species in Tanzania and evidence-based assessments of their biology and the threats to them are lacking. This means that information about their status and population structure is limited and data for stock evaluation are inadequate, hampering management and conservation efforts. Moreover, life-history traits such as a slow growth rate, longevity (over 40 years) and a low reproductive capacity increase their vulnerability to overfishing.
These species are restricted to shallow coastal waters and have relatively small home ranges. Coastal ecosystems like coral reefs, sea-grass beds, mangroves and intertidal areas play a pivotal role in their life cycle, but little is known about their movements and migration patterns. Their biological vulnerability and habitat preferences make them extremely susceptible to being caught in multiple-gear nearshore fisheries. However, there is a paucity of information available, especially species-level catch data in Tanzania, so the stock status is highly uncertain. A lack of skills and capacity for data collection and fishery monitoring has resulted in limited information and hindered the implementation of sustainable fisheries management strategies for wedgefish and guitarfish in Tanzanian waters.
The overall aim is to explore the biology, threats to and conservation needs of wedgefish and guitarfish species in Tanzania in order to promote sustainable fishing practices and contribute to conserving these Critically Endangered species and their habitat. This will be achieved by:
- Identifying and mapping the primary fishing grounds utilised by wedgefish and guitarfish fishers in Tanzania to understand the species’ habitat utilisation patterns.
- Collecting spatial and temporal data on the distribution and abundance of wedgefish and guitarfish species.
- Evaluating the biological characteristics of wedgefish and guitarfish, including population dynamics, reproductive behaviour and fishery indicators.
- Identifying the key stakeholders in the wedgefish and guitarfish market and analysing the supply chain dynamic.
- Improving the capacity of artisanal fishers to collect data, identify species and keep records and thus foster their active involvement in conservation initiatives.