Many of the boatowners and anglers practice Catch and realase.

See this video where Magni Blástein is catching a big Porbeagle Shark and releasing it afterwards. 

Catch and release is a practice within recreational fishing intended as a technique of conservation. After capture, the fish are unhooked and returned to the water before experiencing serious exhaustion or injury. Using barbless hooks, it is often possible to release the fish without removing it from the water (a slack line is frequently sufficient).

Catch and release techniques

The use of barbless hooks is an important aspect of catch and release; barbless hooks reduce injury and handling time, increasing survival. Frequently, fish caught on barbless hooks can be released without being removed from the water, and the hook(s) effortlessly slipped out with a single flick of the pliers or leader. Barbless hooks can be purchased from several major manufacturers or can be created from a standard hook by crushing the barb(s) flat with needle-nosed pliers. Some anglers avoid barbless hooks because of the erroneous belief that too many fish will escape.

To make a hook barbless, the barb is simply crushed flat with a pair of needle-nosed pliers; a 2-second task. Medium grit sandpaper can be further used to ensure complete removal of the barb, but this is not necessary and is rarely done.

Key aspects of catch and release include:

• Using strong tackle, to minimize fighting times
• Using needle-nosed pliers to aid unhooking
• Using barbless hooks, for quick, easy hook removal and reduced handling times
• Leaving fish in the water during the unhooking and release process, to avoid any handling
  
  

If fish are removed from the water for unhooking and/or a photo, key aspects of handling include:

• Avoiding the use of landing nets; if landing nets must be used, specially designed catch-and-release landing nets (e.g. Special Catch and Release nets)are used
• Avoiding touching the fish with dry hands or dry surfaces (e.g. shirt fronts) or putting them down on dry surfaces (e.g. rocks, boat gunwhales, boat bottoms)
• Never squeeze the fish or rip a hook out
• Only touching the fish with wet hands and wet surfaces (e.g. wet towel)
• Avoiding hanging fish from their jaw/mouth/gills
• Holding fish horizontally, and supporting large fish with a second hand under the belly
• Minimizing time out of the water (e.g. 20–30 seconds)
• Support the fish gently upright in the water until it swims away