Ocean fisheries
The shoreline waters of the continents and the more temperate islands yield herring, salmon, sardines, snapper, swordfish, and tuna, as well as shellfish.
The Celebes Sea has warm clear waters and harbors about 580 of the world's 793 species of reef-building corals, which grow as some of the most bio-diverse coral reefs in the world, and an impressive array of marine life, including whales and dolphins, sea turtles, manta rays, eagle rays, barracuda, marlin and other reef and pelagic species.
According to studies made by the Department of Environment and Natural Resources, Philippines, this body of water holds one third of the all world's marine biodiversity, thereby making it a very important area for the ecosystem.
Because of the threats to the ocean environment presented by oil spills, marine debris, and the incineration of toxic wastes at sea, various international treaties exist to reduce some forms of pollution.
When tropical waters exceed 85 degrees Fahrenheit for an extended period of time, microscopic plants called zooxanthellae die off.
[12] The habitats supported by the reefs are critical to such tourist activities such as fishing and diving, and provide an annual economic value to Caribbean nations of $3.1-$4.6 billion.
The outer margins of the wide continental shelves of Yucatán and Florida receive cooler, nutrient-enriched waters from the deep by a process known as upwelling, which stimulates plankton growth in the euphotic zone.
Being nearly landlocked affects the Mediterranean Sea's properties; for instance, tides are very limited as a result of the narrow connection with the Atlantic Ocean.
Evaporation greatly exceeds precipitation and river runoff in the Mediterranean, a fact that is central to the water circulation within the basin.
[17] Evaporation is especially high in its eastern half, causing the water level to decrease and salinity to increase eastward.
[18] This pressure gradient pushes relatively cool, low-salinity water from the Atlantic across the basin; it warms and becomes saltier as it travels east, then sinks in the region of the Levant and circulates westward, to spill over the Strait of Gibraltar.
A 1994 study of the seabed using trawl nets around the coasts of Spain, France and Italy reported a particularly high mean concentration of debris; an average of 1,935 items per square kilometre.
In the Norwegian Current, a branch of the Gulf Stream carries warm water masses northward and contributes to the mild and moist climate in Norway.
Nowadays, shifts and fluctuations in these currents are closely monitored, as they are thought to be indicators for an ongoing climate change.
Fishing fleets from Russia, Japan, South Korea, and Taiwan also exploit the Indian Ocean, mainly for shrimp and tuna.
The Arabian Sea is a region of the Indian Ocean bounded on the east by India, on the north by Pakistan and Iran, on the west by Arabian Peninsula, on the south, approximately, by a line between Cape Guardafui, the north-east point of Somalia, Socotra and Kanyakumari (Cape Comorin) in India.
A number of large rivers – Ganges, Brahmaputra, Ayeyarwady, Godavari, Mahanadi, Krishna and Kaveri – flow into the Bay of Bengal.
The Bay of Bengal is full of biological diversity, diverging amongst coral reefs, estuaries, fish spawning and nursery areas, and mangroves.
The coast line of the Great Australian Bight is characterised by stunning cliff faces (up to 60 m high), surfing beaches and rock platforms, ideal for whale-watching.
While most continental shelves are rich in sea life and make popular fishing areas, the barren deserts north of the bight have very little rainfall, and what there is mostly flows inland, to dissipate underground or in salt lakes.
In consequence, the Great Australian Bight receives very little of the runoff that fertilises most continental shelves and is essentially a marine desert.
[30] A geologically young body of water, the Gulf of Aden has a unique biodiversity that contains many varieties of fish, coral, seabirds, and invertebrates.
The natural environment of the Persian Gulf is very rich with good fishing grounds, extensive coral reefs, and abundant pearl oysters, but its ecology has become increasingly under pressure from the heavy industrialisation and in particular the repeated major petroleum spillages associated with recent wars fought in the region.
The reefs form platforms and sometimes lagoons along the coast and occasional other features such as cylinders (such as the blue hole at Dahab).
Illegal, unreported, and unregulated fishing, especially the landing of an estimated five to six times more Patagonian toothfish than the regulated fishery, likely affects the sustainability of the stock.
A 10-metre (32.8 feet) long colossal squid weighing 495 kilograms (1,091 lb) was captured in the Ross Sea on 22 February 2007.
The Antarctic toothfish is caught from the Polar Convergence (at about 60° S) south to the Antarctic continent, whereas the Patagonian toothfish is mainly caught north of 65° S. The Ross Sea region is unusual because between these latitudes both species are abundant and show considerable overlap in their distribution.
However, during January and February, areas of open water (called polynas) allow access to the continental shelf and slope.
Longline vessels (predominantly from New Zealand, but also from South Africa, Russia, and Uruguay) have taken advantage of this to develop an exploratory fishery.
They start working in the deep south, and as the season progresses they move north to stay ahead of the freezing sea ice, and by May are restricted to the northernmost fishing grounds.
