Reef Sharks Move to Deeper Water as They Mature
A new study from Wageningen University & Research (WUR) showed that reef sharks utilize different areas of the reef throughout their lifetime. Using baited video cameras, six different species of reef sharks were recorded around the northern Dutch Caribbean islands. These results will impact the design and implementation of shark conservation strategies for years to come.
Reef sharks play a critical role within the ocean. As a top predator, reef sharks help maintain the delicate balance within (coral) reef environments. In fact, research has found that reefs with healthy shark populations are more resilient and capable of withstanding the pressures of climate change, pollution, overfishing and diseases.
Understanding the dynamics of habitat use of local shark populations is critical when designing effective marine conservation strategies. This is exactly what the latest reef shark study from WUR hoped to achieve. Using baited remote underwater video cameras at 376 locations around the reefs of Saba, Saba Bank and St. Eustatius, fish ecologist Twan Stoffers and his colleagues recorded 126 different shark sightings.
Of the six different species recorded in this study, juvenile Caribbean reef sharks (Carcharhinus perezi) and nurse sharks (Ginglymostoma cirratum) were most commonly recorded. Overall, they observed young sharks in shallow, more complex areas of the reef, whereas the larger, more mature, sharks were observed further away from the reef in deeper habitats up to 65 meter depth. Larger nurse sharks were frequently recorded in seagrass beds. The researchers were surprised that hardly any adults were observed over the course of the entire study.
This knowledge could have an important impact on conservation strategies for reef sharks and other endangered shark species. Since reef sharks use a variety of different habitats (both shallow and deeper water areas), creating an interconnected conservation network is vital for ensuring full protection throughout their life cycle. Sanctuaries such as the Yarari Sanctuary (which includes the marine area around the Caribbean Netherlands) are an important step in creating a network of protected areas. In addition, efforts such as the Caribbean Shark Coalition are important as well, because they work to build capacity for shark and ray research, policy and conservation within the Wider Caribbean Region.
Report your sightings
You can help contribute to the overall understanding of sharks and other species by reporting your nature sightings on sightings and photos on DutchCaribbean.Observation.org or download the free apps (iPhone (iObs) & Android (ObsMapp)).
Species reports by local communities and tourists are invaluable for nature conservation efforts to help increase public awareness and overall species protection.
DCNA, Observation International and Naturalis Biodiversity Center are working together to develop on automated species identification app for your phone for all species on land and in sea. Your uploaded photos are of great value to make this possible. For questions, please contact research@DCNAnature.org
For more information, please find the full report here or follow along on the DCNA’s free digital newsletter BioNews for the latest updates. For questions related to the reef shark study, please contact firstname.lastname@example.org
Article published in BioNews 45 and Special Edition BioNews: Tiger Shark Expedition