Recreational dive sites

Tropical waters of high biodiversity and colourful sea life are popular recreational diving tourism destinations.

South-east Asia, the Caribbean islands, the Red Sea and the Great Barrier Reef of Australia are regions where the clear, warm, waters, reasonably predictable conditions and colourful and diverse sea life have made recreational diving an economically important tourist industry.

Recreational divers may accept a relatively high level of risk to dive at a site perceived to be of special interest.

They are generally found where more interesting and pleasant diving is not locally available, or may only be accessible when weather or water conditions permit.

Sea and ocean shorelines, reefs and shoals are salt water sites and may support high biodiversity of life forms.

As they are not entirely natural environments and usually privately owned, quarries often contain features intentionally placed for divers to explore, such as sunken boats, automobiles, aircraft, and abandoned machinery and structures.

Caves containing water provide exotic and interesting, though relatively hazardous, opportunities for exploration, and are found both inland and at the coast.

Few sites are reliably mapped or have a published description with an accurate position, and many of these are caves or wrecks of identified ships.

Scuba diving tourism is the industry based on servicing the requirements of recreational divers at destinations other than where they live.

Temperate and inland open water reef sites are generally dived by people who live relatively nearby.

[17] The Great Barrier Reef can be seen from outer space and is the world's biggest single structure made by living organisms.

With 20% of the world's coral reefs, over 3,000 different species of fish and about 600 coral species, deep water trenches, volcanic sea mounts, World War II wrecks, and a very large variety of macro life, scuba diving in Indonesia is excellent and relatively inexpensive.

[22]Bunaken National Marine Park, at the northern tip of Sulawesi, claims to have seven times more genera of coral than Hawaii,[23] and has more than 70% of all the known fish species of the Western Indo-Pacific.

Some of the most famous diving sites in Indonesia are also the most difficult to reach, like Biak off the coast of Papua and the Alor Archipelago.

The recreational diving area is in the tropical Delagoa ecoregion in the north of kwaZulu-Natal, which extends from Cape Vidal northwards into Mozambique.

The temperate regions, or middle latitudes are between the tropics and the polar circles in each hemisphere, but are even less clearly an indication of water temperature.

The break at Cape Point is very distinct in the inshore depth ranges, and the waters of the east and west sides of the peninsula support noticeably different ecologies, though there is a significant overlap of resident organisms.

Much depends on the biological productivity of the reef, which can be strongly affected by currents, river inflow, and particularly areas subject to deep-water upwellings, such as on the temperate west coasts of several continents and islands.

The finer detail is usually less complex than on coral reefs, but the large scale structure can be impressive, particularly when visibility is good enough to appreciate the landforms.

In plan it can be anything from nearly straight to highly convoluted, with gullies, curves, sudden changes of direction, transverse canyons, and offshore stacks.

Most wall dive sites are in the sea, but they can also be found inland in sinkholes, caves, and flooded quarries and mines.

Inshore dive sites in North America with vertical rock faces include Puget Sound in Washington, Monterey Bay, and Catalina Island in California.

Regardless of construction method, artificial reefs generally provide hard surfaces where algae and sessile ebibenthic invertebrates such as barnacles, corals, and oysters attach; the accumulation of attached marine life in turn provides intricate habitat and food for mobile benthic invertebrates and assemblages of fish.

In addition to shipwrecks, there are artificial reefs made from decommissioned subway cars, concrete, electrified steel, and even the cremated remains of divers.

[34] Occasionally sculpture works have been placed underwater singly or in groups, as attractions for divers, and they also function as artificial reefs.

Many quarry mining operations are located in areas where filling from other, less clean sources, such as rivers and surface runoff of rainwater is not as likely.

Only a small fraction of the world's shipwrecks are in known positions suitable for access by divers, and their condition deteriorates over time.

During the 20th century recreational scuba diving was considered to have generally low environmental impact, and was consequently one of the activities permitted in most marine protected areas.

The increase in the popularity of diving and in tourist access to sensitive ecological systems has led to the recognition that the activity can have significant environmental consequences.

[43] Environmental impact can expand in scope when a destination is commercially developed to provide more facilities to encourage the expansion of tourism.