To examine variation in diet and daily ration of the bonnethead shark, Sphyrna tiburo (Linnaeus 1758), animals were collected from three areas in the eastern Gulf of Mexico: northwest Florida (*29 400N, 85 130W), Tampa Bay near Anclote Key (*28 100N, 82 42.50W), and Florida Bay (*24 500N, 80 480W) from March through September, 1998–2000. In each area, diet was assessed by life stage (young-of-t...

The unique head morphology of sphyrnid sharks might have evolved to enhance electrosensory capabilities. The 'enhanced electroreception' hypothesis was tested by comparing the behavioral responses of similarly sized carcharhinid and sphyrnid sharks to prey-simulating electric stimuli. Juvenile scalloped hammerhead sharks Sphyrna lewini and sandbar sharks Carcharhinus plumbeus oriented to dipole...

Kinematics and critical swimming speed (Ucrit) of juvenile scalloped hammerhead sharks Sphyrna lewini were measured in a Brett-type flume (635 l). Kinematic parameters were also measured in sharks swimming in a large pond for comparison with those of sharks swimming in the flume. Sharks in the flume exhibited a mean Ucrit of 65±11 cm s-1 (± s.d.) or 1.17±0.21 body lengths p...

• Novel eDNA survey for detecting critically endangered scalloped hammerhead sharks. Enables the first detection of hammerheads in Guam since 1971. A single-day sampling effort outperforms five decades visual surveys. The method is non-invasive, cost-effective, and user friendly. Survey application allows rapid data generation science-based conservation. Among sharks, ( Sphyrna lewini ) have un...

Understanding distribution ranges and the daily movement patterns of pelagic fishes are key aspects for the establishment and planning of protected areas for their conservation. In this study the vertical and horizontal movements of scalloped hammerhead sharks, Sphyrna lewini, were recorded in Malpelo and Cocos Island using satellite telemetry. Nine sharks were tagged with satellite transmitter...

This study investigates the motor pattern and head movements during feeding of a durophagus shark, the bonnethead Sphyrna tiburo, using electromyography and simultaneous high-speed video. Sphyrna tiburo feeds almost exclusively on hard-shelled crabs, with shrimp and fish taken occasionally. It captures crabs by ram feeding, then processes or reduces the prey by crushing it between molariform te...

The tiger shark Galeocerdo cuvier (Carcharhinidae) is a large elasmobranch suspected to have, as other apex predators, a keystone function in marine ecosystems and is currently considered Near Threatened (Red list IUCN). Knowledge on its ecology, which is crucial to design proper conservation and management plans, is very scarce. Here we describe the isolation of eight polymorphic microsatellit...