Spear Guns & Seine Nets : Grand Cayman Department of Environment

No one may use a speargun (includes Hawaiian sling, polespear, harpoon, hookstick or any device with a pointed end which may be used to impale, stab or pierce any marine
life but does not include a striker) or seine net without a licence from the Marine Conservation Board. NOTE: A striker is defined as a wooden pole, at least 10ft long, with a maximum of 2 barb-less prongs attached to one end.
No one may possess a speargun without a license.
No one may import a speargun or any parts for a speargun.
Only Caymanians over 18 may be granted licenses.
Speargun catch limit: Three fish per licensed person per day.
No one may use a speargun in water less than 20ft deep.
No one may possess more than six fish that have been caught by a speargun.
No one may spearfish within a one–mile radius of any Designated Grouper Spawning Area from 1 November through 31 March.
License holders must carry license when using seine net or spear fishing and adhere to license conditions.
No one may use a speargun to take Nassau Grouper.