A cool, wet cloth lightly draped over its head can calm an energetic shark.  (Poisson et al, 2012)

Inserting a seawater hose in its mouth might improve an animal’s chance of survival if, for an unavoidable reason, the shark cannot be released right way. (Poisson et al, 2012)

For crew safety, avoid the animal’s jaws (some suggest placing a fish in its mouth to prevent bites), and regardless of the animal’s state (live or moribund) be cautious at all times. (Poisson et al, 2012)

Most importantly, attempt to release the animal AS SOON AS POSSIBLE. (Poisson et al, 2012)