The techniques and places freedive spearfishers use vary greatly around the world. This difference extends to the species of fish sought and the gear used. Shore diving is probably the most commonplace form of spearfishing and simply involves entering and exiting the sea from beaches or headlands and hunting around ocean architecture, as a rule reef, but also rocks, kelp or sand. Generally shore divers hunt between 5 and 25 meters (about 17 to 83 feet) depth, though it depends on location. In some locations in the South Pacific, divers can experience huge drop-offs from 5 meters up to 30 or 40 meters very close to the shore line. Sharks and reef fish can be abundant in these locations. In more subtropical areas, sharks may be less common, but other challenges face the shore diver, such as entering and exiting the water in the presence of big waves. Headlands are favored for entry because of their proximity to deeper water, but timing entries and exits is important so the diver does not get pushed onto rocks by waves. Beach entry can be safer, but more difficult due the need to consistently dive through the waves until the surf line is crossed.
Besides, shore dives can produce a mixed bag of fish, mainly reef fish, but ocean going pelagic fish are caught from shore dives too, and can be specifically targeted.
Shore diving can also be done with trigger-less spears such as pole spears or Hawaiian slings, but more commonly triggered devices such as spearguns. Speargun setups to catch and store fish include speed rigs, fish stringers.
Bear in mind that usage of catch bags worn close to the body is discouraged because the bag can inhibit movement, especially descent or ascent on deeper freedives. Moreover, in waters known to contain sharks, it is positively dangerous and can greatly increase the risk of attack. The better option is to tow a float behind, to which is attached a line onto which a catch can be threaded. Tying the float line to the speargun can be of great help in the event of a large catch, or if the speargun should be dropped or knocked out of reach.
Blue water hunting is the range of most interest to elite spearfishers, but has grown in popularity by and large a short time ago. It involves accessing commonly very deep and clear water and trolling, chumming for large pelagic fish species such as marlin, tuna, or giant trevally. Blue water hunting is often conducted in drifts; the boat driver will drop one or more divers and allow them to drift in the current for up to several kilometers before collecting them. Blue water hunters can go for hours without seeing any fish, and without any ocean structure or a visible bottom the divers can experience sensory deprivation. Sensory deprivation is the deliberate reduction or removal of stimuli from one or more of the senses. Simple devices such as blindfolds or hoods and earmuffs can cut off sight and hearing respectively, while more complex devices can also cut off the sense of smell, touch, taste, heat-sense, and gravity. Sensory deprivation has been used in various alternative medicines and in psychological experiments (for example Isolation tank). Though short periods of sensory deprivation can be relaxing, extended deprivation can result in extreme anxiety, hallucinations, bizarre thoughts, depression, and antisocial behavior. It can be difficult to determine the true size of a solitary fish when sighted due to the lack of ocean structure for comparison. One technique to overcome this is to note the size of the fish's eye in relation to its body - large examples of their species will have a relatively smaller eye. Though short periods of sensory deprivation can be relaxing, extended deprivation can result in extreme anxiety, hallucinations, bizarre thoughts, depression, and antisocial behavior.
Remarkably, blue water hunters make use of breakaway rigs and large multi band wooden guns to catch and subdue their prey. If the prey is large and still has fight left after being subdued, a second gun can be used to provide a kill shot at a safe distance from the fish. This is acceptable to IBSRC and IUSA regulations as long as the spearfisher loads it himself in the water.
Blue water hunting is organized all over the world, but outstanding hot spots include South Africa (yellow fin tuna) and the South Pacific (dog-tooth snapper). Blue water discoverers like Jack Prodanavich and Hal Lewis of San Diego were some of the pioneers to go after large species of fast moving fish like Tuna.
