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Sea Facts
- The blue whale (Balaenoptera musculus) is the largest known animal ever to live on sea or land. Individuals can reach more than 33 metres and weigh nearly 180 tonnes. This is more than the weight of 50 adult elephants!
The blue whale's blood vessels are so big that a full grown trout could swim through them to its heart, which is the size of a small car.
Green turtles can migrate more than 1400 miles to lay their eggs.
A group of herrings is called a siege.
A group of jelly fish is called a smack.
Penguins "fly" underwater at up to 90 kilometres per hour.
Horseshoe crabs have existed in the same form for 135 million years.
Dugongs are the only fully plant eating marine mammal, and the only sea cow to occur in Australia.
Six of the Earth's seven species of turtle are found in Australia: the Green Turtle, Hawksbill Turtle, Loggerhead Turtle, Leatherback Turtle, Pacific Ridley Turtle and the Flatback Turtle. The Flatback Turtle is only found in Australia.
Three species of seal breed in mainland Australian waters: the Australian sea lion, Australian fur seal and the New Zealand fur seal. The Australian sea lion is only found in Australia. Seven species of seal breed in Australia's subantarctic islands and the Antarctic Territories.
Eight species of baleen whales and 35 species of toothed whale, porpoises and dolphins are found in Australian waters.
Australia has 30 of the world's 58 species of seagrass. Seagrasses are critical nursery, breeding and feeding habitats for scores of species - from hundreds of fish species to western rock lobsters to green sea turtles and dugongs.
362,000,000 km² or 71% of the Earth's surface is water! The oceans hold 1,300,000,000 km³ of water.
The deepest spot in the Earth's oceans is the Mariana Trench, which is 11.7 km deep.
Australia is responsible for 11 million square kilometres of ocean within its Exclusive Economic Zone of 200 km. Australia shares maritime borders with 5 other nations: Indonesia, Papua New Guinea, Solomon Islands, New Zealand and France.
The destruction of sea grass by increased sedimentation and high levels of nutrients is one of the biggest problems facing the Australian marine environment.
At any one time around 500 seals in Tasmanian water have 'collars' of plastic litter around their necks.
The Great Barrier Reef is the largest complex of coral reefs in the world, consisting of 2,900 separate reefs and is 2,500 km in length. It has an area of around 344,000 km².
Most frequently found items found in beach clean ups are plastics, followed by plastic foam, plastic utensils, glass and cigarette butts.
There are 109 countries with coral reefs. Reefs in 90 countries are being damaged by tourism - cruise ship anchors, sewage, tourists taking chunks of coral, and by commercial harvesting for sale to tourists. The anchor from one cruise ship can destroy a sea bed area the size of half a football field.
Source of the above: http://www.abc.net.au/oceans/facts/default.htm Oceans Alive 1998.
Marine Facts by Topic
How old are Australia’s coral reefs?
The world's first coral reefs occurred about 500 million years ago, and the first close relatives of modern corals developed in southern Europe about 230 million years ago. By comparison, the Great Barrier Reef is relatively young at just 500,000 years old. The current reef's structure is much younger at less than around 8,000 years old.
Source: http://www.barrierreefaustralia.com/the-great-barrier-reef/coralfacts.htm
What is a marine protected area?
A marine protected area (MPA) is an area of sea especially dedicated to the protection and maintenance of biodiversity, and of natural and associated cultural resources, and managed through legal or other effective means. MPAs include marine parks, nature reserves and locally managed marine areas that protect reefs, seagrass beds, shipwrecks, archaeological sites, tidal lagoons, mudflats, saltmarshes, mangroves, rock platforms, underwater areas on the coast and the seabed in deep water, as well as open water. In many parts of the world there is a growing focus and appreciation of the need for more MPAs and for better management generally of coastal and marine environments.
Source: http://www.environment.gov.au/coasts/mpa/publications/wpc-benefits.html
What are Seagrasses and why are they important?
Seagrasses are flowering plants that have evolved to live in sea water. Worldwide, there are about 12 major divisions, consisting of approximately 57 species of seagrass. They are mainly found in bays, estuaries and coastal waters from the mid-intertidal (shallow) region down to depths of 50 or 60 metres. Most species are found in shallow inshore areas. Over 30 species can be found within Australian waters. Seagrass communities are one of the most productive and dynamic ecosystems. They provide habitats and nursery grounds for many marine animals, and act as substrate stabilisers. In northern Australia, seagrass meadows are important as they provide sheltered refuges and feeding areas for prawns and juvenile fish. In some coastal areas, entire fisheries may depend on the productivity of these seagrass beds. Seagrass meadows are a major food source for a number of grazing animals in the Great Barrier Reef region. The dugong and the green turtle mainly feed on seagrass. An adult green turtle eats about two kilograms of seagrass a day while an adult dugong eats about 28 kilograms a day.
Source: AIMS http://www.aims.gov.au/pages/research/project-net/seagrass/apnet-seagrasses01.html
Marine Pests. Did you know…
An estimated 170 exotic marine species have been introduced to Australian waters either intentionally, for aquaculture, or unintentionally in ballast water or by ship’s fouling. Of these, around 10 are regarded as pests and include the northern Pacific seastar (Tas and Vic) the Japanese seaweed Undaria (Tas and Vic), the giant fan worm Sabella (southern and western Australia), some toxic dinoflagellates (southern Australia) and the European green crab (southern Australia).
Source: CSIRO: http://www.marine.csiro.au/LeafletsFolder/27ocean/27.html
Sea Change Phenomenon in Australia - Did you know ?
Retirees contribute to the sea change phenomenon, but are no longer the major drivers of coastal population growth. New residents of high growth coastal regions are actually of a younger age profile than Australia as a whole: 79% of new residents in coastal areas are younger than 50, compared with 71% of Australia overall.
People moving to sea change localities are motivated by a range of “push” and “pull” factors, particularly housing costs, the amenity of coastal areas and employment circumstances.
Source: National Sea Change Taskforce http://www.seachangetaskforce.org.au/Home.html
Climate Change Facts & Figures - Did you know?
The Earth has warmed by approximately 0.75°C since pre-industrial times. Eleven of the warmest years in the past 125 years occurred since 1990, with 2005 the warmest on record. There is overwhelming consensus that this is due to emissions of greenhouse gases, such as carbon dioxide from burning fossil fuels.
Examination of ice cores shows that there is more CO2 in the atmosphere than at anytime in the past 600,000 years. Between 1960 and 2002, annual anthropogenic global emissions of CO2 approximately tripled. They rose by about 33% since 1987 alone.
Warming in this century is projected to be between 1.4 and 5.8°C. The impacts of climate change are already visible. Examples include: the shrinking Arctic ice cap; accelerating se level rise; receding glaciers worldwide; thawing permafrost; earlier break-up of river and lake ice; increasing intensity and duration of tropical storms; lengthening of mid- to high-latitude growing seasons; and shifts in plant and animal ranges and behaviour.
In the Arctic, as peat bogs thaw they are releasing methane, an even more potent greenhouse gas than CO2. Scientists are increasingly concerned about the possibility of abrupt climate change, including reductions in ocean currents, such as the Gulf Stream which warms Europe, and changed patterns of rainfall, such as the monsoon seasons, which would affect food security for billions of people.
The Arctic is warming twice as fast as the global average. The area of the Arctic Ocean covered by ice each summer has been shrinking and the remaining ice is becoming less thick. Because more heat is absorbed by the sea than by ice, a feedback is created which results in further melting. Since 1980, between 20 and 30 per cent of sea ice in the European Arctic has been lost.
Polar bears depend on sea ice, where they hunt seals and use ice corridors to move from one area to another. Pregnant females build winter dens in areas with thick snow cover. They have not eaten for five to seven months when they emerge with their cubs in the spring. They need good spring sea-ice conditions for their own and their cubs’ survival.
As glaciers melt in the world’s great mountain ranges, water supplies to rivers will be affected. In Europe, eight out of nine glaciated regions show significant retreat. Between 1850 and 1980, glaciers in the European Alps lost approximately one-third of their area and one-half of their mass.
In China, highland glaciers are shrinking each year by an amount equivalent to all the water in the Yellow River. The Chinese Academy of Sciences says that 7% of the country’s glaciers are vanishing annually. By 2050, as many as 64% of China’s glaciers will have disappeared. An estimated 300 million people live in China’s arid west and depend on water from glaciers for their survival.
In the past 100 years, global sea level rose between 1 and 2 mm a year. Since 1992 the rate has increased to about 3mm a year, primarily through thermal expansion of warming oceans and freshwater flowing into the oceans from melting ice.
Melting ice is responsible for a significant portion of the observed sea level rise, with the Greenland and Antarctic ice sheets the largest contributors. The Greenland Ice Sheet is melting faster than new ice is being formed. In the Antarctic, three large sections of ice shelves in the Antarctic Peninsula have collapsed over the past 11 years, followed by a marked acceleration and thinning of glaciers that were held back by the shelves.
As sea levels rise, inhabitants of low-lying islands and coastal cities fact inundation. In December 2005, a small community living in the Pacific Island chain of Vanuatu became perhaps the first to be formally moved as a result of climate change.
Climate change also threatens marine habitats and the livelihoods of the people who depend on them. The oceans have absorbed approximately half of the CO2 produced in the past 200 years, producing carbonic acid and lowering the pH of surface seawater. This could affect the process of calcification by which animals such as corals and molluscs make their shells from calcium carbonate.
Source: United Nations Environment Programme – World Environment Day June 2007
http://www.unep.org/wed/2007/english/
General Marine Facts - Did you know?
- Australia has 51,000 km2 of seagrasses, representing the highest biodiversity of seagrasses in the world, the largest areas of temperate seagrass and one of the largest areas of tropical seagrass.
Die-back of seagrass beds is one of the most serious issues affecting Australia’s marine environment, caused in part by elevated nutrients from stormwater and sewage discharges. In Victoria’s Westernport Bay, around 85% of the total biomass of seagrass has been lost.
Australia has the third largest area of mangroves in the world, lining about 6,000 km of Australia’s coast, providing habitat for both bait-fish and table fish.
Research at CSIRO has shown mangroves are also essential nursery habitats for prawns and are vital for sustaining the northern prawn fishery, one of Australia’s most valuable fisheries.
More than 2,000 species of macroalgae (seaweed) have been identified around Australia’s southern coastline from south-west Western Australia to NSW and Lord Howe Island.
Western Australia has 558 species of macroalgae (seaweed) while the tallest kelp forests, up to 30 m high, are off Tasmania’s east coast.
Tropical Australia occupies 42% of the nation’s landmass yet generates 65% of its runoff.
Coastal habitats of tropical Australia (eg seagrasses, mangroves, fringing reefs) are critical to most of the species that sustain indigenous hunting, recreational fishing and tourism, and commercial fishing.
More than 6,000 shipwrecks have occurred in Australian waters in the past 400 years.
One quarter of all Australians live within three kilometres of the coast, 86% in the coastal catchments and two-thirds reside in coastal towns and cities.
Source: CSIRO http://www.marine.csiro.au/LeafletsFolder/27ocean/27.html
International Sea Facts - Did you know?
Oceans cover 70 percent of the Earth's surface.
More than 90 percent of the planet's living biomass is found in the oceans.
Eighty percent of all pollution in seas and oceans comes from land-based activities.
Forty percent of the world's population lives within 60 kilometres of a coast.
Three-quarters of the world's megacities are by the sea.
Plastic waste kills up to 1 million sea birds, 100,000 sea mammals and countless fish each year.
Sea creatures killed by plastic decompose; the plastic does not. Plastic remains in the ecosystem to kill again and again.
Harmful algal blooms, caused by an excess of nutrients - mainly nitrogen from agricultural fertilizers - have created nearly 150 coastal deoxygenated 'dead zones' worldwide, ranging from 1 to 70,000 square kilometres.
More than 90 percent of goods traded between countries are transported by sea.
Each year 10 billion tons of ballast water is transferred around the globe and released into foreign waters. Ballast water often contains species - such as the zebra mussel and comb jellyfish - that can colonize their new environment to the detriment of native species and local economies.
Pollution, exotic species and alteration of coastal habitats are a growing threat to important marine ecosystems such as mangroves, seagrass beds and coral reefs.
Tropical coral reefs border the shores of 109 countries, the majority of which are among the world's least developed. Significant reef degradation has occurred in 93 countries.
Although coral reefs comprise less than 0.5 percent of the ocean floor, it is estimated that more than 90 percent of marine species are directly or indirectly dependent on them.
There are about 4,000 coral reef fish species worldwide, accounting for approximately a quarter of all marine fish species.
The Great Barrier Reef, measuring 2,000 kilometres in length, is the largest living structure on Earth. It can be seen from the Moon.
Reefs protect human populations along coastlines from wave and storm damage by serving as buffers between oceans and near-shore communities.
Nearly 60 percent of the world's remaining reefs are at significant risk of being lost in the next three decades.
The major causes of coral reef decline are coastal development, sedimentation, destructive fishing practices, pollution, tourism and global warming.
Climate change threatens to destroy the majority of the world's coral reefs, as well as wreak havoc on the fragile economies of Small Island Developing States.
The High Seas - areas of the ocean beyond national jurisdiction - cover almost 50 percent of the Earth's surface. They are the least protected part of the world.
Although there are some treaties that protect ocean-going species such as whales, as well as some fisheries agreements, there are no protected areas in the High Seas.
Ninety percent of the world's fishermen and women operate at the small-scale local level, accounting for over half the global fish catch.
Ninety-five percent of world fish catch (80 million tons) is from near-shore waters.
More than 3.5 billion people depend on the ocean for their primary source of food. In 20 years, this number could double to 7 billion.
More than 70 percent of the world's marine fisheries are now fished up to or beyond their sustainable limit.
Populations of commercially attractive large fish, such as tuna, cod, swordfish and marlin, have declined by as much as 90 percent in the past century.
Destructive fishing practices are killing hundreds of thousands of marine species each year and helping to destroy important undersea habitats.
Each year, illegal longline fishing, which involves lines of up to 80 miles long, with thousands of baited hooks, kills over 300,000 seabirds, including 100,000 albatrosses.
As many as 100 million sharks are killed each year for their meat and fins, which are used for shark fin soup. Hunters typically catch the sharks, de-fin them while alive and throw them back into the ocean where they either drown or bleed to death.
Global by-catch - unintended destruction caused by the use of non-selective fishing gear, such as trawl nets, longlines and gillnets - amounts to 20 million tons a year.
The annual global by-catch mortality of small whales, dolphins and porpoises alone is estimated to be more than 300,000 individuals.
Mangroves provide nurseries for 85 percent of commercial fish species in the tropics.
Source: United Nations Environment Programme: Website: www.unep.org World Environment Day. 2004
WA Marine Facts:
WA’s marine environment is among the most pristine – and biologically diverse – in the world. Ningaloo Reef, for example, is the largest fringing coral reef in Australia and Shark Bay is one of only 17 areas in the world that meets all four natural criteria for World Heritage listing.
Western Australia’s coastline is more than 13,500 kilometres long and makes up about 40 per cent of Australia’s continental coastline.
Hamelin Pool located in Shark Bay World Heritage area, is one of only two places in the world with living marine stromatolites, or "living fossils". Stromatolites are communities of diverse inhabitants with population densities of 3000 million individuals per square metre!
Source: http://www.naturebase.net/content/view/2167/935/
Ningaloo Reef is one of the longest fringing reefs in the world and only one of two coral reefs in the world that have formed on the western side of a continent.
The Ningaloo Reef is one of only two areas in the world where Whalesharks regularly congregate in numbers that facilitate tours and human interaction.
Source: http://www.exmouthwa.com.au/pages.asp?code=24
Photo by Aengus Moran
Supported by the Australian Government 