State of our Oceans

“Under attack from over-fishing, climate change,

noise, and chemical pollution, our oceans

are approaching a point of no return.”

Fact 1:  OVER-FISHING

Commercial long-liners targeting swordfish accidentally kill 40,000 sea turtles, 300,000 seabirds, and millions of sharks annually.  These non-target catches make up as much as 25 percent of the global catch.

Fact 2:  OCEAN WARMING

Ancient ice shelves are disintegrating and fears are growing that if the West Antarctic Ice Sheet ever surges, it would raise sea levels by as much as 23 feet worldwide.

Fact 3:  MARINE POLLUTION

At least one in eight American women of childbearing age has unsafe levels of mercury in her blood, and 15 percent of babies born in the U.S. in 2000 were exposed to unacceptable levels of mercury.

Fact 4:  EUTROPHICATION

Nutrient deposits from the mighty Mississippi River outflow into the Gulf of Mexico delivering enough nitrogen to stimulate explosions of plankton and microalgae, which deplete oxygen below the level necessary to sustain life.  The result is the second largest dead zone in the world, an area larger than New Jersey.

Fact 5:  CORAL REEFS

Global warming is the single greatest threat to coral reefs.  As it stands, 20 percent of the world’s reefs are not likely to recover, and another 50 percent hang in the balance.

Fact 6:  OCEAN NOISE

The Navy’s low frequency active sonar (LFA), used to detect almost-silent diesel submarines, is such an intense sound source it has been associated with the death and stranding of some species of whales.

Fact 7:  CARBON DIOXIDE

About half of the total CO2 emitted into the atmosphere is absorbed back into the ocean increasing its acidity.  The level of acidity expected for 2050 predicts that shells and skeletons possessed by corals, mollusks, and phytoplankton would dissolve within 48 hours of exposure.

Fact 8:  PROTECTED AREAS

In 2003, the World Conservation Union listed 102,102 protected areas on earth.  Less than 0.5 percent of these protected areas were world oceans.

Fact 9:  MARINE BIODIVERSITY

Under current conditions, the North Atlantic Right whale, numbering less than 350 animals, are predicted to go extinct within the next 200 years.  Leatherback sea turtles have been a part of our planet for the past one hundred million years; the next ten may be their last.

Fact 10:  INVASIVE SPECIES

Behind habitat destruction, invasive species are the greatest threat to native species.  It is estimated that more than 10,000 marine species each day travel around the globe in the ballast water of cargo ships, and are accidentally introduced into new areas.

1.      OVER-FISHING

Fishing faster and harder than ever before, the 4 million fishing vessels worldwide are driving large predatory fish toward global extinction. The U.N. Food and Agriculture Organization states that fishing pressures are at or exceeding the sustainable yields of 75 percent of all oceanic fisheries.

Fish is the primary source of protein for one in six people on earth.  Globally, wild fish catches grew by 500 percent between 1950 and 1997. Regardless of increased and more sophisticated fishing efforts, the global wild fish catch has been declining by more than 3 percent per capita per year in the past 10 years. 

Longliners

Seven of the ten most popular fish are classified as fully exploited or over-exploited.

One of the biggest culprits is long-lining in which a single boat sets monofilament line across 60 or more miles of ocean, baited with up to 10,000 hooks, designed to catch a variety of pelagic species such as tuna and swordfish.  In so doing, long-liners kill far more other species that take the bait.  These incidental kills include some 40,000 sea turtles, 300,000 seabirds, and one million sharks annually.  These non-targeted catches, which get thrown back into the ocean either dead or dying, equate to an amazing 88 billion pounds of life each year, making up at least 25 percent of the global catch.  Longliners at one time were catching on average 10 fish per 100 hooks.  Today, due to depletion, they are lucky to catch 1 fish per 100 hooks. 

Trawlers

The destructiveness of the trawl fishery drag nets across every square inch of the continental shelf every two years, equivalent to bulldozing 150 times the total area of forests clear-cut on land each year.

Driftnet

Driftnet fisheries span their invisible curtains of monofilament lines across more than 150 miles and 1600 feet below the surface, left unattended, many times lost or abandoned in storms, continuing to trap and kill prey, and decay, attracting more predators. 

For a detailed overview of modern fishing practices and their impacts, visit the Monterey Bay Aquarium Website.

Imagine a mass slaughtering of terrestrial animals, which includes the destruction of hundreds of bears, all the surrounding antelope, deer, wolves, and raccoons, in a government-funded operation. Seems unthinkable, but this is exactly what we are doing in our oceans.  The world’s nations subsidize 25 to 40 percent of total global fishing revenues.

An article published in Nature magazine (2001) suggested annual commercial fish catches, despite the advancement of fishing technology and efficiency, the annual catch has been falling since 1988 at about 400,000 tons per year.

An article published in 2003 on modern fishing methods determined that industrialized fishing typically reduces the community of large fish by 80 percent within the first 15 years of exploitation.  With decades of such onslaughts, only 10 percent of all large fish (tuna, swordfish, marlin) and groundfish (cod, halibut, skate, and flounder) are left anywhere in the ocean.

One of the problems with fishing practices is that the more rare or endangered a species gets, the more money it generates and the more people who are willing to pursue it.

With fishing stocks depleting, making fishing more difficult, fishers resort to more desperate and destructive fishing practices such as using poisons and explosives, leading to the complete decimation of species and their ecosystems.  Poor fishers do this mainly to meet the demands of rich nations.  As demand grows with species decline, methods of fishing become extremely destructive.

Shark-Fin Soup

 In China, for those who wish to prove their wealth, can order a $100 bowl of shark-fin soup.  Fishing fleets kill an estimated 100 million sharks per year across the globe even as the World Conservation Union continues to add more shark species to its Red List of Threatened Species.  Sadly, sharks are slow breeders.  Most females have small litters about every 3 years after reaching a late sexual maturity (some not for 25 years).  This makes sharks unlikely to recover from significant fishing pressures.

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2.      OCEAN WARMING

The top half-mile of the ocean has warmed dramatically in the past 40 years as a result of rising greenhouse gases (Scripps Institution of Oceanography, Feb. 2005).

According to the 2004 Status of Coral Reefs of the World , global warming is the single greatest threat to corals.  20 percent of the world’s reefs are not likely to recover and another 50 percent are not far behind.  The massive coral bleaching event caused by the 1998 El Nino, damaged and destroyed 16 percent of the world’s reefs.  These events are likely to become more regular, and possibly annual occurrences in the next 50 years.  Not only are the reefs disappearing but important nursery areas such as seagrass beds and kelp forests.  These represent critical habitats for juvenile fish, invertebrates, and sea turtles.

A modeling study from the National Center for Atmospheric Research in Colorado predicts that global warming 251 million years ago, long before the dinosaur die-off, caused the most severe extinction on the planet.  Atmospheric CO2 caused from massive volcanic eruptions warmed the oceans, increased its salinity, shut down the ocean conveyor belt, and trapped oxygen at depths where most of the world’s ocean became a hypoxic dead zone.  Without anymore sea life to remove atmospheric CO2, warming of the planet accelerated destroying 95 percent of all marine species, and 70 percent of all terrestrial vertebrates, leaving fungi to rule the world for many an eon.

The increased freshening of the oceans due to melting of polar ice caps has the potential to disrupt the ocean conveyor belt, a critical element in providing warmer climates to northern Europe.

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3.      MARINE POLLUTION

A major portion of the world’s pollution eventually ends up in the oceans.  These include massive amounts of toxic chemicals and radioactive waste.  Long-lasting contaminants, such as PCBs, DDT, mercury, and cadmium, once introduced into the food chain, accumulate in the fats of fish and mammals over time.  At certain concentrations, these chemicals may be harmful to one’s health, sometimes causing birth defects and cancer.  The accumulations of toxins in the fats of mothers are often passed in large doses on to their newborns through her milk.

The Marine Conservation Society reported that mining mercury from the livers of seals in the Irish Sea will yield higher concentrations than from the mercury bearing ore from the original mines.

By filling, dredging, and polluting our coastal nurseries of the sea, we destroy coral reefs and kelp forests replacing them with dead zones.

Mercury

The global mercury pollution is caused mainly from emissions from coal and chlorine industries.  The lethal molecule hitches a ride on raindrops, settling to the bottom of our oceans and lakes, and eventually getting absorbed by aquatic bacteria.  These contaminated bacteria get incorporated into plankton, which are eaten by subsequent marine organisms up the food chain, each time, bioaccumulating into higher concentrations at each level in the food chain.  Top of the chain predators such as swordfish, shark, king mackerel, and tilefish may carry as much as 1 million time higher levels of mercury that he waters around them.  The U.S. Environmental Protection Agency now estimates at least 1 in 8 American women of childbearing age has unsafe levels of mercury in her blood, and as many as 15 percent of babies born in the United State in 2000 were exposed to unacceptable levels of mercury.  The European Union warns pregnant women to limit consumption of tuna and swordfish because of brain damage to their unborn children.  Yet, by circumventing the Clean Air Act, coal-fired power plants need not curtail their mercury emissions until 2018. An average of 10 tons of mercury comes down the Mississippi every year, with an additional ton added by the offshore drilling industry, dumping into the Gulf Coast causing a large portion of the gulf to be so biologically dysfunctional that it is the largest dead zone in the United and States, and second largest on the planet; an area large than New Jersey.  The Gulf of Mexico is becoming some of the most polluted waters in the world with mercury levels among the highest ever recorded.  Blue marlin caught in the Gulf of Mexico have been found with mercury levels 30 times what the EPA deems safe for human consumption. 

To find out about the safety of locally caught fish and shellfish in your area, visit the Environmental Protection Agency’s Fish Advisory website.

Plastics

The presence of so much floating plastic debris across the ocean has doubled the spread of exotic species that hitch rides on these artificial boats.  Fish and invertebrates mistake the plastic for food and ingest them, poisoning themselves and their predators.  Sea turtles and marine mammals perish from ingesting plastic bags, which resemble jellyfish.

Organic pollutants (POPs) such as PCBs and DDT are found in such large concentrations in some Beluga whales that they are characterized as toxic waste.  These pollutants accumulate within the body fats of marine mammals and can pass from a mother’s breast milk while poisoning her children.  Levels of POPs in the tissue of Greenland Inuit’s that rely on marine mammal meat for survival have POP levels in their tissue that are nearing levels known to suppress the immune system.

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4.      EUTROPHICATION

Eutrophication is a process where bodies of water receive excess nutrients that stimulate excessive plant growth.  This excessive plant growth, often called an algal bloom, absorbs most of the oxygen in the water column, creating an oxygen-deprived or “hypoxic” dead zone.  These “dead zones” are triggered mainly by an excess of nitrogen from farm fertilizers, sewage, and emissions from vehicles and factories, flowing untreated into our water systems. 

Nearly all 150 currently identified dead zones on earth lie at the mouths of rivers.  Sometimes enough nitrogen is delivered to cause an explosion of plankton and microalgae, some known as the red tides responsible for major fish, dolphin, and manatee die-offs.  Robert Diaz form the Virginia Institute of Marine Science calculates that the number of dead zones is doubling every decade and hypoxia in some areas is becoming more of a threat to fisheries than overfishing.

Long before hurricane Katrina, the Gulf of Mexico has become one of the world’s most polluted marine ecosystems.  An average of 10 tons of mercury comes down the Mississippi every year directly impacting the Gulf Coast, and an additional ton is added by the offshore drilling industry.  With oxygen levels is some areas below what is necessary to sustain life, the Gulf has become so biologically dysfunctional that it is the largest dead zone in the United and States, and the second largest on the planet; an area larger than New Jersey.

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5.      CORAL REEFS

Coral reefs are often referred to as the rainforests of the oceans because of the rich diversity of marine life they support.  Although they occupy less than one percent of the world’s oceans, they support more than twenty five percent of all fish species.  They have been around for well over 100 million years and are the largest structures on earth.  Australia’s Great Barrier Reef is more than 2,000 km long and can be seen from outer space.

Coral reefs help protect the coastlines of 109 countries from storm surges and hurricanes.  Coral reefs also supply 10 percent of the world’s diet, and generate $375 billion in annual revenue.  They are valuable resources for medicine providing compounds used in antihistamines, antibiotics, to treat asthma, and heart disease.  More than half of all new cancer drug research focuses on marine organisms.

A report from the World Resources Institute in 1998 suggested that 60 percent of the world’s coral reefs are threatened by human activity.  Threats from over-fishing, coastal development, and rising temperatures are destroying corals and the marine life they support. 

Corals are extremely slow growing (some grow as little as 30 cm in 1,000 years) and need very specific conditions for survival.

Twenty percent of the world’s coral reefs have been destroyed.  A frightening 10 percent of the world’s reefs were destroyed in the last four years alone, a number that could rise to 20-30 percent by 2010.

The major threats to coral reefs include coral bleaching, destructive fishing, coastal development, and pollution.

Coral Bleaching

Global warming is the most serious threat to coral reefs.  Coral bleaching occurs when water temperatures get too high causing the loss of important symbiotic algae residing within the coral.  This exposes the white calcium carbonate skeletons of the coral colony, a sign that the coral is dead.  Some scientists predict that if global warming continues at it’s present rate of increase, most of the world’s coral reefs could be eliminated in the next century.

Destructive Fishing Methods

As fish sizes and catches decline due to overfishing, fishermen are resorting to more extreme and destructive methods.  These methods are unsustainable and damage the long-term health of fishery resources in order to profit from them.  Scientists estimate that 56 percent of the coral reefs in Southeast Asia are at risk from destructive fishing.  The two most common forms are dynamite and poison fishing. 

Fishing with explosives, allows fishers to collect large numbers of the remaining smaller reef fish in an effort to maintain their catch.   However, it can take hundreds of years for the physical structural damage to the coral to rebuild.  Although illegal, dynamite fishing is practiced in up to 30 countries in Southeast Asia and Oceania, and is also common in Eastern Africa. 

Poison fishing, also known as “cyanide fishing”, is used to capture live fish for the aquarium and food trades.  Fishers dive down to the reef and squirt cyanide or bleach in reef crevices to stun fish, making them easy to catch.  These poisons can cause coral bleaching and coral death but the full extent of the damage caused is unknown.

Coastal Development

Coastal development can threaten coral reefs in a number of ways.  Coastal construction often removes pristine mangrove forests and seagrass beds, which trap eroding sediment from reaching the reefs.  By taking away the sediment barrier, sedimentation covers the coral, blocking the light necessary for photosynthesis of its symbiotic algae.  These symbiotic algae provide the coral with 95 percent of its food.  The root systems from mangrove forests also provide habitat for young, developing fish.

Pollution

Pollution introduces many harmful substances to the reef system including nutrients, pathogens, and trash.  Pollution can kill reefs with poisons, heavy metals, and by causing algae blooms.  The increased nutrients added from sewage and fertilizers can accelerate the growth of certain seaweeds causing them to smother and eventually kill the underlying coral.  The apparent surge of coral diseases has also been linked to increased pollution.

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6.      OCEAN NOISE

Noise is our newest threat to the marine environment.  Most marine species depend on sound as they hunt for food, detect predators, find mates, and monitor their surroundings in the darkness of the sea.  But over the past century, human activity has transformed the acoustical landscape of the ocean.  Researchers are continuing to find evidence that the rise of ocean noise presents a significant, long-term threat to marine species that depend on sound for survival.  

“Undersea noise pollution is like the death of a thousand cuts.  Each sound in itself may not be a matter of critical concern, but taken all together, the noise from shipping, seismic surveys, and military activity is creating a totally different environment than existed fifty years ago.  That high level of noise is bound to have a hard, sweeping impact on life in the sea.” – Dr. Sylvia Earle, Former Chief Scientist, National Oceanic and Atmospheric Administration

The two contributors of anthropogenic ocean noise of greatest concern are military active sonar systems and high-energy seismic surveys.

Military Active Sonar Systems

Active sonar requires the emission of sound signal and listening for the echoes returning from targets in the path of the sound source.  Lower frequencies and greater output power are required to detect more distant objects.

Military active sonar systems emit intense sounds in order to detect and track submarines and other targets.  Medium frequency tactical sonar is defined as sonar emitting sound at frequencies between 1000 and 10,000 Hz.  This type of sonar is used to monitor areas out to a few tens of miles around the vessel.  They are currently installed on close to 200 American Navy vessels, and have been linked to a growing number of whale strandings worldwide.  US Surveillance Towed Array Sensor System Low Frequency Active sonar (SURTASS LFA), is defined as sonar emitting sound below 1000 Hz, and can be used to monitor an area up to 200 miles around the vessel.  This sound pulse can transmit over of 230 decibels of power, intensities loud enough to severely affect marine mammals.  The military is increasingly using both types of systems. 

LFA sonar, which could soon be deployed across 80 percent of the world’s oceans, has been linked to the mass stranding and deaths of dolphins and whales in areas where Navy exercises have been conducted.

Suspected strandings have occurred off the Bahamas, the Canary islands, the U.S. Virgin, North Carolina, Alaska, Hawaii, Greece, Italy, and Japan.  Some of the stranded animals showed bleeding around the brain, emboli in the lungs, and lesions in the liver and kidneys, symptoms resembling severe decompression sickness.  In Navy tests on human divers, at 150-160 decibels, divers suffered from numbness, pain, motion sickness, and seizures.

In 2003, The Natural Resources Defense Council got the courts to severely restrict the Navy’s plan to deploy LFA around the globe and demanded that the NAVY “understand the environmental impacts of its actions, and to mitigate those impacts before flooding vast areas of marine habitat with intense, harmful noise.”  The Bush administration responded by pushing legislation through congress that exempts the military from key provisions of the Marine Mammal Protection Act.

High-energy seismic surveys

High-energy seismic surveys are techniques used to detect oil and gas reserves beneath the ocean floor.  As part of the surveys, air guns are fired every few seconds at intensities that can drown out whale calls over tens of thousands of square miles¹.  More than 100 seismic surveys occur each year of the coast of the United States.  With the passage of the Energy Policy Act of 2005, which mandates an inventory of the entire U.S. outer continental shelf, the numbers of annual surveys are likely to increase significantly. 

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7.      CARBON DIOXIDE

In the past 200 years, the oceans have absorbed close to half of the CO2 produced by the burning of fossil fuels and cement production.  As a result, the surface of our oceans are more acidic.  If global CO2 emissions continue to rise, the average pH of the oceans could fall by 0.5 units by the year 2100.  The primary impact of this acidification will be on the process calcification, a process by which animals such as corals and mollusks make shells and plates from calcium carbonate.   The greatest impact will be seen on calcifying organisms such as phytoplankton and zooplankton, which represent the major food source for fish and other marine animals.  According to some studies, the level of acidity expected for 2050 predicts that shells and skeletons possessed by corals, mollusks, and phytoplankton would dissolve within 48 hours of exposure. 

Research into the affects of ocean acidification is in its infancy.  Whether or not marine species have the ability to acclimate or evolve in response to changes in ocean chemistry remains uncertain.  Reducing our CO2 emissions seems to be the only practical way to minimize the risk of large-scale and long-term changes to our oceans.

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8.      PROTECTED AREAS

In 2003, the World Conservation Union listed 102,102 protected areas on earth.  Less than 0.5 percent is World Ocean.  Over 11 percent of the land surface has been granted some form of sanctuary, but we would need to add 23 times the number of protected areas, and 10 times more total area, to reach the same standard for our oceans.

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9.      MARINE BIODIVERSITY

Biodiversity is defined as the collection of genomes, species, and ecosystems occurring in a geographically defined region.  This diversity is not only a critical indicator of the “health” of our oceans, but is also the key in sustaining the health of our oceans. The diversity of life in our oceans has been dramatically reduced and altered by the increasing and possibly irreversible impacts caused by human population growth.  The major impacting contributors include overfishing and overexploitation of the ocean’s invertebrate and plant stocks, chemical pollution and eutrophication, coastal development, invasions of exotic species, and global warming. 

The National Research Council reported on the potential impacts of continued loss of marine biodiversity.  These included dramatic reductions in the most preferred edible fish and shellfish species, loss of species with important potential for biomedical products, altered aesthetic and recreational value of coastal habitats, dramatic changes in species composition and numbers impacting the basic functioning of ecosystems.

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10.  INVASIVE SPECIES

Nonindigenous species are species that have evolved elsewhere in the world and have been purposefully or accidentally relocated.  Not all are of these introduced species become invasive but some become voracious predators that persist, proliferate, and cause economic or environmental harm, or harm to human health. 

While some species are relocated deliberately, others are relocated accidentally.  When a container ship offloads its cargo, the ballast tanks are filled with water to balance out the ship for their return journey.  When the ship arrives at the next port to take on new cargo, the ballasts are emptied.  An estimated 10,000 marine species each day may travel around the globe in this manner.  Once introduced, the new introduced species can impact native species by eating, competing, or interbreeding with them.  They may also introduce pathogens or parasites that sicken or kill native species.  Just like pollutants, invasive species can change the species composition of the environment, or alter the ecosystem of the environment in which they inhabit.

Preventing the distribution of nonnative species in the first place is the best mode of action.  For example, introducing UV treatment to sterilize ship ballast water before it is expelled.  But once invasive species are established, early detection becomes critical in order to halt their spread as soon as possible.

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Literature Cited

1. Nieukirk, Sharon L., Kathleen M. Stafford, David K. Mellinger, Robert P. Dziak, and Christopher G. Fox, 2004, Low-frequency whale and seismic airgun sounds recorded from the mid-Atlantic Ocean, Journal of the Acoustical Society of America, vol. 115, no. 4, p. 1832-1843.