Spearfishing is fishing using handheld elongated, sharp-pointed tools such as a spear, gig, or harpoon, to impaling the fish in the body. It was one of the earliest fishing techniques used by mankind, and has been deployed in artisanal fishing throughout the world for millennia. Early civilizations were familiar with the custom of spearing fish from rivers and streams using sharpened sticks.
Diving activities are the things people do while diving underwater. People may dive for various reasons, both personal and professional. While a newly qualified recreational diver may dive purely for the experience of diving, most divers have some additional reason for being underwater. Recreational diving is purely for enjoyment and has several specialisations and technical disciplines to provide more scope for varied activities for which specialist training can be offered, such as cave diving, wreck diving, ice diving and deep diving. Several underwater sports are available for exercise and competition.
A diving mask is an item of diving equipment that allows underwater divers, including scuba divers, free-divers, and snorkelers, to see clearly underwater. Surface supplied divers usually use a full face mask or diving helmet, but in some systems the half mask may be used. When the human eye is in direct contact with water as opposed to air, its normal environment, light entering the eye is refracted by a different angle and the eye is unable to focus the light on the retina. By providing an air space in front of the eyes, the eye is able to focus nearly normally. The shape of the air space in the mask slightly affects the ability to focus. Corrective lenses can be fitted to the inside surface of the viewport or contact lenses may be worn inside the mask to allow normal vision for people with focusing defects.
Recreational diving or sport diving is diving for the purpose of leisure and enjoyment, usually when using scuba equipment. The term "recreational diving" may also be used in contradistinction to "technical diving", a more demanding aspect of recreational diving which requires more training and experience to develop the competence to reliably manage more complex equipment in the more hazardous conditions associated with the disciplines. Breath-hold diving for recreation also fits into the broader scope of the term, but this article covers the commonly used meaning of scuba diving for recreational purposes, where the diver is not constrained from making a direct near-vertical ascent to the surface at any point during the dive, and risk is considered low.
Diver communications are the methods used by divers to communicate with each other or with surface members of the dive team. In professional diving, diver communication is usually between a single working diver and the diving supervisor at the surface control point. This is considered important both for managing the diving work, and as a safety measure for monitoring the condition of the diver. The traditional method of communication was by line signals, but this has been superseded by voice communication, and line signals are now used in emergencies when voice communications have failed. Surface supplied divers often carry a closed circuit video camera on the helmet which allows the surface team to see what the diver is doing and to be involved in inspection tasks. This can also be used to transmit hand signals to the surface if voice communications fails. Underwater slates may be used to write text messages which can be shown to other divers, and there are some dive computers which allow a limited number of pre-programmed text messages to be sent through-water to other divers or surface personnel with compatible equipment.
Scuba diving is a mode of underwater diving whereby divers use breathing equipment that is completely independent of a surface air supply, and therefore has a limited but variable endurance. The name "scuba", an acronym for "Self-Contained Underwater Breathing Apparatus", was coined by Christian J. Lambertsen in a patent submitted in 1952. Scuba divers carry their own source of breathing gas, usually compressed air, affording them greater independence and movement than surface-supplied divers, and more time underwater than free divers. Although the use of compressed air is common, a gas blend with a higher oxygen content, known as enriched air or nitrox, has become popular due to the reduced nitrogen intake during long or repetitive dives. Also, breathing gas diluted with helium may be used to reduce the likelihood and effects of nitrogen narcosis during deeper dives.
Solo diving is the practice of self-sufficient underwater diving without a "dive buddy", particularly with reference to scuba diving, but the term is also applied to freediving. Professionally, solo diving has always been an option which depends on operational requirements and risk assessment. Surface supplied diving and atmospheric suit diving are commonly single diver underwater activities but are accompanied by an on-surface support team dedicated to the safety of the diver, including a stand-by diver, and are not considered solo diving in this sense.
Edmonds Underwater Park (EUP) is a local classic scuba diving site in the northern Seattle, Washington suburb of Edmonds immediately north of the Edmonds Washington State Ferry terminal on the Edmonds-Kingston route. EUP is relatively shallow with a maximum depth of about 45 feet. There is a grid network of anchored ropes that lead to a variety of submerged features. The park is built and maintained by a group of volunteers that meet every Saturday and Sunday at 9 am.
Advanced Open Water Diver (AOWD) is a recreational scuba diving certification level provided by several diver training agencies. Agencies offering this level of training under this title include Professional Association of Diving Instructors (PADI), and Scuba Schools International (SSI). Other agencies offer similar training under different titles. Advanced Open Water Diver is one step up from entry level certification as a beginner autonomous scuba diver. A major difference between Autonomous diver equivalent Open Water Diver (OWD) certification and AOWD is that the depth limit is increased from 18 to 30 metres.
Scuba Diving International (SDI) is a Scuba training and certification agency. It is the recreational arm of Technical Diving International, a technical diver training organization.
Technical Diving International (TDI) claims to be the largest technical diving certification agency in the world, and one of the first agencies to offer mixed gas and rebreather training. TDI specializes in more advanced Scuba diving techniques, particularly diving with rebreathers and use of breathing gases such as trimix and heliox.
Bob Halstead, has made significant contributions to the sport of scuba diving in a multitude of capacities: photographer, author of eight diving books, early innovator in the development of dive tourism, pioneer in the dive liveaboard industry, diving instructor and educator, marine-life explorer and influential diving industry commentator. An ardent diver since 1968, Halstead has over 10,000 logged dives.
Recreational dive sites are specific places that recreational scuba divers go to enjoy the underwater environment or for training purposes. They include technical diving sites beyond the range generally accepted for recreational diving. In this context all diving done for recreational purposes is included. Professional diving tends to be done where the job is, and with the exception of diver training and leading groups of recreational divers, does not generally occur at specific sites chosen for their easy access, pleasant conditions or interesting features.
Hillary Rika Hauser is an American photojournalist and environmental activist with a focus on the oceans — underwater diving adventure, politics, and conservation. In 2009, in recognition of her ocean environmental work as it relates to underwater diving, Hauser received the NOGI Award for Distinguished Service from the Academy of Underwater Arts and Sciences. In 2013 the Academy elected Hauser as president of its board of directors.
Jill Heinerth is a Canadian cave diver, underwater explorer, writer, photographer and film-maker. She has made TV series for PBS, National Geographic Channel and the BBC, consulted on movies for directors including James Cameron, written several books and produced documentaries including We Are Water and Ben's Vortex, about the disappearance of Ben McDaniel.
Scuba diving fatalities are deaths occurring while scuba diving or as a consequence of scuba diving. The risks of dying during recreational, scientific or commercial diving are small, and on scuba, deaths are usually associated with poor gas management, poor buoyancy control, equipment misuse, entrapment, rough water conditions and pre-existing health problems. Some fatalities are inevitable and caused by unforeseeable situations escalating out of control, though the majority of diving fatalities can be attributed to human error on the part of the victim.
The environmental impact of recreational diving is the effects of recreational scuba diving on the underwater environment, which is largely the effects of diving tourism on the marine environment. It is not uncommon for highly trafficked dive destinations to have more adverse effects with visible signs of diving's negative impacts due in large part to divers who have not been trained to sufficient competence in the skills required for the local environment, an inadequate pre-dive orientation, or lack of a basic understanding of biodiversity and the delicate balance of aquatic ecosystems. There may also be indirect positive effects as the environment is recognised by the local communities to be worth more in good condition than degraded by inappropriate use, and conservation efforts get support from dive communities who promote environmental awareness, and teach low impact diving and the importance of respecting marine life. There are also global coral reef monitoring networks in place which include local volunteer divers assisting in the collection of data for scientific monitoring of coral reef systems, which may eventually have a net positive impact on the environment.
The Women Divers Hall of Fame (WDHOF) is an international honor society. Its purpose is to honor the accomplishments of women divers, and their contributions to various fields of underwater diving. Full membership is restricted to nominees who have been found to meet the WDHOF's criteria, which include being an underwater diver and having contributed to diving in ways recognised as being significant.
