Sharks typically enter a natural state of paralysis when inverted. This state is called "tonic", and the shark can remain in this state for up to 15 minutes, thereby allowing us to observe the effects of chemical repellents. After behavioral controls are established, a successful chemical repellent will awaken a shark from this tonic state. We can quantify dose sizes, concentrations, and time to awaken from these studes. A microliter autopipettor is used to observe effects at the 10-100uL level. A 60cc syringe is used as a baseline, looking for a prelimiary response.

A juvenile lemon shark in tonic state.

Joy Young and Bryan Franks escorting a shark out of its holding pen for tonic immobility testing.

Research team performing a TI test with plastic syringe held in front of shark's nares.

A juvenile lemon shark right at the moment it awakens from tonic state (note the mouth opened wide, and the chemical plume is not through the gill rakes).

Eric, Mike, and Grant during a TI test at South Bimini.

Matthias, Mike, and Eric using a 10 microliter pipettor on a tonic nurse shark

When possible, we will also perform tonic immobility studies on hooked sharks. Here is Grant Johnson with a 120cm C. limbatus alongside the boat. After the hook is removed, controls and test are performed with the immobilized shark. After these tests, certain sharks are also tagged. All test subjects are released at approximately 10 minutes after capture.