In Murky Waters: Crittercam on Juvenile Bull Sharks (Carcharhinus leucas)

Abstract

Assessing bull shark (Carcharhinus leucas) behavior is relevant for conservation and risk management. However, information on bull sharks—in particular, behavior of juveniles—is very limited in some parts of the world. Studying small-scale habitat use of juvenile bull sharks is challenged by their preferred habitats in estuarine environments with fast-changing environmental conditions. A number of advanced methods including acoustic telemetry, baited remote underwater video, and satellite tagging have been used to shed light on habitat utilization, food preferences, and movement. We tested the application of an underwater video camera recorder (“Crittercam”) combined with acoustic tags on three juvenile bull sharks during daytime and nighttime deployments and demonstrated the feasibility and limitations of this technique for juvenile bull shark research. All three tagged individuals used deeper channels (>5 m) moving alongside the river bank in a crisscross manner. We used additional information on habitat type and depth to support the findings. Our results provide important insights for future tagging studies combining tagging technologies to monitor bull sharks in coastal environments.