Islands in the sea: understanding connectivity in Brazil’s lemon sharks
Fernando de Noronha (an oceanic island), Atol das Rocas (the only atoll in the South Atlantic) and Abrolhos (a continental archipelago with Brazil’s largest coral reef system) are critical shark habitats in the nation’s waters, serving as nurseries where juvenile lemon sharks may grow in shallow, protected waters. But oceanic islands and coasts may host isolated shark populations and a loss of connectivity could threaten their survival. Through field work, collaboration with citizen scientists and genetic analyses, Ana wants to understand how lemon shark populations at these three different locations might be connected and what potential barriers to gene flow might exist.
Ana Carolyna Diógenes Bezerra
I was born in Mossoró, a city in the Brazilian state of Rio Grande do Norte and close to the country’s north-eastern coast. Growing up near the beach, I often saw stranded or dead marine animals lying there, and this made a deep impression on me. It sparked my curiosity about their lives, inspired me to pursue a path in conservation and made me determined to protect the ocean and its creatures.
During my undergraduate studies in biology, I worked with aquatic animals in different environments, initially with cetaceans and sea turtles and later with freshwater fish....
Population structure of Negaprion brevirostris in the tropical Atlantic, focusing on Brazilian islands
Our main objective is to investigate the genetic structure and population connectivity of the lemon shark in the tropical Atlantic, focusing on oceanic islands and Brazilian coastal regions and using genetic analyses and ecological niche modelling to inform conservation strategies and support the management of marine protected areas in Brazil.
Understanding the genetic structure, connectivity and behaviour of lemon shark populations is crucial for their conservation. Oceanic islands and coastal regions may host isolated populations, and loss of connectivity could threaten their survival. This project will identify population links, investigate behavioural patterns, highlight critical habitats and provide information for the management of marine protected areas. By ensuring that conservation efforts are targeted and effective, it will support the species’ long-term survival.
My research focuses on the lemon shark Negaprion brevirostris across three key sites in Brazil: Fernando de Noronha, Atol das Rocas and Abrolhos. These areas are critical habitats, serving as nurseries where juveniles can grow in safe, shallow waters. Although the populations around these islands and in the coastal regions are protected, little is known about how they are connected or how individuals move between them.
Fernando de Noronha, an oceanic island with high marine biodiversity, is a recognised nursery for lemon sharks. During this early stage of their life, juveniles remain in shallow waters, which provide an ideal site to monitor their behaviour and population dynamics. Atol das Rocas, the only atoll in the South Atlantic, is a biological reserve and an important refuge for sharks and rays that also offers protection for juveniles. Abrolhos, a continental archipelago with Brazil’s largest coral reef system, hosts lemon sharks too, but a lack of systematic studies means that there is a significant gap in our knowledge about the species here.
Through field work, genetic analyses – including mitochondrial DNA (mtDNA) and microsatellite markers – and collaboration with citizen scientists, this project aims to understand population connectivity, habitat use and potential barriers to gene flow. Ecological niche modelling will complement genetic data by assessing habitat suitability and the sharks’ mobility across these sites. By integrating ecological, genetic and modelling approaches, this research will reveal how lemon shark populations are structured, how the sharks use their habitats and how individuals move between islands and coastal areas.
- To identify and describe the population structure of lemon sharks in the Tropical Atlantic, focusing on connectivity among individuals between Fernando de Noronha, Atol das Rocas, Abrolhos and the Brazilian coast.
- To model the current ecological niche of the lemon shark in order to assess habitat suitability and identify potential ecological barriers to its distribution.
- To project the ecological niche model under different climate change scenarios to evaluate whether the species will lose suitable habitat, particularly around the oceanic islands near the equator.
- To assess the overall health of lemon shark populations through immunological parameters to understand potential environmental and physiological impacts across the different sampled locations.