Nurse sharks have developed a reputation for biting and not letting go! When human fingers and hands are involved, the nurse
shark is typically sacrificed (decapitated) in order to release it's powerful suction grip on the victim.
Nurse sharks are also remarkably "tougher" to ellicit a response from in tonic immobility testing.
Therefore, this plentiful and easily-handled species of shark is ideal for establishing a repellency behavioral baseline.
In a nurse bite test, a small nurse shark is handled, and agitated so as to
forcefully bite onto a large baitfish or rubber slip. Once it's grip is fully established, a water control is tested, confirming the grip is not released. Repellent is then introduced into the nurse's mouth,
releasing its bite very quickly. Doses observed to date require from 1.5ml to 25ml for the shark to give up its grip.