| What do a bull shark and a leopard shark have in common? They both can be found within a National Estuarine Research Reserve! Many shark species utilize shallow, protected estuarine bays to give birth to their young. These back bays provide young sharks with plenty of food and protection from potential predators, such as larger sharks. Many Reserves are interested in better understanding how sharks use the estuaries within their boundaries. |
In Naples, Florida the Rookery Bay NERR (RB NERR) started a study in 2000 to gain an understanding of shark nurseries and relative distributions before, during and after the restoration of an area within the reserve. This may be the first study ever to address the effects of restoration on shark populations. Bull Shark, Bonnethread Shark, Lemon Shark, and Black tip Shark are some of the common species recorded by the monitoring project that continues today. This research gained national spotlight when it was featured on Ocean Mysteries with Jeff Corwin.
Leopard sharks are abundant in Elkhorn Slough National Estuarine Research Reserve (ES NERR) during spring and summer. These part-time slough residents come into the shallow water to give birth. The adults can be up to 7 feet long, feeding on animals that live in the mud, like the Fat Innkeeper Worm. These sharks are not harmful to humans due to their small teeth and timid nature.
Leopard sharks are generally nocturnal, spending their days near the bottom and becoming more active at night. Low tides in summer are a great time to visit the ES NERR as these sharks can often be seen from land - cruising the shallow waters. They are taken occasionally by recreation anglers in the slough. They are oviviparous giving birth to live young, up to 20 in one litter. The young sharks, like many other fish spend their early days in the warm sheltered bays and tidal creeks of the slough. As they grow, they venture into deeper waters before eventually making their way to the Bay and Ocean.
The elasmobranchs (or cartilaginous fishes) of Elkhorn Slough are especially well studied. Background information comes from angling derbies in the late 1940s. More recently, researchers have studied feeding ecology, reproduction and age and growth of slough elasmobranchs. Currently, a team from the Pelagic Shark Research Foundation is monitoring sharks and rays at ESNERR.