|Overfishing is destroying the last fisheries
(Photo: Jerry Huang)
Editor’s Note: One of the most compelling reasons to report on the oceans is because it is here that sweeping changes are happening now, not in 50-100 years. The final destruction of the major ocean reef habitats as well as the collapse of major fish populations is well underway. As of 2007, both may be destroyed beyond repair within a few years.
The encouraging news is this doesn’t have to happen. Where coral reefs have been protected from destructive fishing practices, they have often began to show signs of revitalization within a few years. If overfishing were stopped with some strong international agreements, within a few years many fisheries would again begin to yield sustainable harvests larger than today’s unsustainable harvests.
It is difficult to know where to begin when reporting on the world’s oceans, after all, Earth is a water planet. With 70% of the earth’s surface consisting of ocean, the myriad of ways they nourish us and nurture vast ecosystems defies easy summaries. Even deforestation is a problem in coastal waters, where the mangrove forests are being cut down. Tsunamis and cyclones can rampage far further inland when mangrove forests are destroyed, as they frequently are to make room for aquaculture. Intact coral reefs also act as effective storm barriers. But the coral reefs are failing – as much from overfishing as from global warming.
CO2 in the air becomes carbonic acid as it is absorbed by the ocean, reportedly increasing the acidity of the world’s oceans to the highest levels seen in hundreds of thousands of years. Increasing seawater acidity eventually becomes toxic to many reefs and other ocean species. This alarming data could well be the most compelling reason of all to be concerned about rising levels of atmospheric CO2.
- Ed “Redwood” Ring
|A Right Whale in the Southern Ocean
A Right Whale slowly sinks to the bottom of the ocean. At 70 years old, it had survived attacks from fisherman and killer whales, but something was going to get it eventually; twenty large propeller cuts along the left side of the animal hint that the whale’s death was caused by a ship…
One might think that this whale has nothing left to offer as it makes its way closer to the black abyss of the deep sea hundreds of feet below, but that is far from the truth.
Everything in the ocean has a purpose. Even the 90 ton whale carcass has a specific role in the spectacular deep sea niche on the ocean floor. In fact, a whale carcass is an ecosystem in itself. The decomposing animal provides a feast for scavengers such as hagfish, lobsters and sleeper sharks. A few weeks later, large amounts of sulphur seep into the environment from the bacteria decomposing the whale. This creates the perfect habitat for a variety of worms, clams and other organisms. NOAA states that “the decay of bone lipids supports remarkably dense bacterial mats, mussels, vesicomyid clams&the diversity of species found in these dense populations far outnumber local species richness in other extreme deep-sea environments&” Many worms-some only recently discovered-survive solely on the bones of animals that drift to the ocean floor. These ‘whale-fall’ specialists survive on nothing else. A ‘whale-fall’ community may survive for years on a single carcass. (Ref. BBC Science & Nature)
A variety of deep sea arthoropods may have already gone extinct as fewer and fewer whales found their way to the ocean floor over the years. Like everything in an ecosystem, marine animals are linked to one another. These marine food webs are described in more detail by the Scottish Fisheries and Research Services: “All&life forms, from the smallest microbes to the dolphins and whales, are part of the marine food web, a complicated network of who-eats-who, or predator-prey relationships.”
Ultimately the whole system is dependent on the amount of inorganic carbon, nitrogen and phosphorus fixed as organic matter by some of the microbes and phytoplankton as a result of photosynthesis. Phytoplankton and bacteria are eaten by the micro – and larger zooplankton which in turn are eaten by krill and fish, and ultimately by the marine mammals. Fish-eating seabirds also participate in this food web. Countless animals are affected with the death of one species. (Ref. Scottish Fisheries & Research Services)
Fascinating organisms are found everywhere, even in the vast expanses of the deep sea where life seems impossible. “One study of a deep-sea community revealed 898 species from more than 100 families and a dozen phyla in an area about half the size of a tennis court. More than half of these were new to science,” explains Nasa’s SeaWiFS website. (Ref. NASA Ocean Planet Overview)
Unfortunately, with the increase in pollution, fishing and cargo boats, the largest mammals on earth, not to mention all the other marine species, have to pay the price by association. Just a change in the levels of oceanic bacteria will effect everything in the food chain.
Before anyone can honestly care how important it is to protect marine habitats, one needs to appreciate the vast quantities of marine life that exists in the ocean. It is hard for some people to relate to something they never see.
However, it makes sense that the vast expanse of water and its inhabitants, covering 70% of the planet, affects us all.
|A Fimbriated Moray Eel lurks in the coral
(Photo: Francis Tan)
Most marine animals are found near coral reefs. These colorful underwater forests naturally spring to mind with the mention of scuba diving or underwater life. Conservation International, one of the world’s largest organizations dedicated to habitat and species conservation, describes these habitats: “Coral reefs are constructed by living plants and animals, primarily corals that surround their small anemone-like tentacles in a hard skeleton that forms much of the reef structure.
They generally occur in clear, tropical or semi-tropical seas to a depth of approximately 100 meters (328 feet). Coral reefs fringe approximately one sixth of the world’s coastlines and are the biologically richest of all shallow-water marine ecosystems. They support as many as 1 million species of animals and plants, but only a small fraction have been described. Among the best known groups are at least 5,000 species of fish, over 10,000 species of mollusk and more than 800 species of reef-building corals.”
Corals are not only important to fish. Reefs are important to the human population for a wide variety or reasons: For one, they are a food source. A majority of people make their living fishing near coral reefs and an even larger part of population enjoys eating some of the catch. Unfortunately, “If current trends of over-fishing continue, and we deplete fisheries as fast as we are, then this food source will eventually run out,” explains Brian Huse, Executive Director of the Coral Reef Alliance – a non-profit organization dedicated to sustaining Coral Reefs, ” scientific evidence shows that 90% of top predators in the ocean are now extinct because of over-fishing – predatory fish include anything salmon sized and above&all the way through sharks&On the other hand, killing off the grazing species of fish at reefs allows algae to build up, which in turn kills the coral.” With 30% of oceanic fish making their home near coral reefs at one time or another, reefs are essential in maintaining a healthy fish population and many of the fish maintain the coral in return. Sustainable fishing is a must.
Corals aren’t only a food source. “There is also a clear connection between tsunamis and storm events having a much greater impact on eroding coast lines than healthy ones,” Huse continues to explain; “Healthy reefs protect coastlines from the damage of massive waves. During the recent tsunami in Indonesia, for example, coastlines protected by reefs and mangrove forests remained intact and experienced much less impact than coasts that did not have reefs [to defend against oncoming waves].”
Pollution is a major threat to the ocean. Pollution comes in many forms and shapes, but most have one thing in common: Almost all ocean pollutants stem from land based human activity. Waste produced on land eventually finds its way to the ocean. It is not uncommon to find beaches littered with plastic bags and bottles that finally came to rest on shores. Rivers carry dirt, oils, sewage and chemicals out to sea. Garbage also finds its way to ocean. Seeing plastic bags floating around the water instead of fish is not a pretty sight. Washed up garbage on the sand will definitely ruin a nice beach vacation. With many third-world countries relying on tourism for income, it is important to maintain the ocean and beaches in as pristine a condition as possible.
|A Parrotfish presents an almost thoughtful gaze
(Photo: Jerry Huang)
Chemicals are constantly absorbed by the ocean. Chemicals have a drastic effect on fish populations and the fishing industry. Chemicals absorbed by animals at sea will also harm the human population that consumes them. Mercury is a chemical now commonly found in larger predatory fish such as tuna and shark. The Food and Drug Administration explains how this chemical finds its way to sea: “Mercury occurs naturally in the environment and also can be released into the air through industrial pollution. Mercury falls from the air and can accumulate in streams and oceans. Bacteria in the water cause chemical changes that transform the mercury into methylmercury. It is this type of mercury that can be harmful to unborn babies and young children. Fish absorb the methylmercury as they feed in these waters. Methylmercury builds up in the tissue of some types of fish and shellfish more than others depending on what the fish eat.” (Ref. U.S. FDA)
High levels of mercury can poison the human body, have adverse effects on the nervous system and prevent a baby from developing normally in the womb. This is just one of the harmful chemicals that are actively absorbed by the ocean. Those of us who enjoy the occasional tuna salad sandwich or swordfish steak have been absorbing natural and industrial chemicals from the meat for a few years now (Thankfully, it has not been proven harmful in occasional small doses, but it certainly can’t be healthy).
Another chemical pollutant is carbonic acid. Atmospheric CO2 is absorbed by the ocean and reacts with the seawater to form carbonic acid – this makes the ocean more acidic and intolerable to a variety of species. The shells of living mollusks have even been known to dissolve in very acidic areas of the ocean. The Royal Society, an independent scientific academy based in the UK and commonwealth, states that “sea creatures such as corals, shell fish, sea urchins and star fish are likely to suffer the most because higher levels of acidity makes it difficult for them to form and maintain their hard calcium carbonate skeletons and shells. For example, even under the ‘low’ predictions for future carbon dioxide emissions into the atmosphere, the combined effects of climate change and ocean acidification mean that corals could be rare on tropical and subtropical reefs, such as the Great Barrier Reef, by 2050.” (Ref. U.K. Royal Society Scientific Academy)
Carbon Dioxide is a greenhouse gas that impedes the escape of heat into outer space, thereby causing temperatures to rise-this is called global warming. In recent years, global warming has changed ocean environments. Since even the slightest fluctuation in ocean temperatures and chemical balances effect marine life, CO2 absorption is a major problem. NASA explains that “Through global warming, the surface waters of the oceans could become warmer, increasing the stress on ocean ecosystems, such as coral reefs. High water temperatures can cause a damaging process called coral bleaching. When corals bleach, they expel the algae that give them their color and nourishment. The corals turn white and, unless the water temperature cools, they die. Added warmth also helps spread diseases that affect sea creatures.” (Ref. NASA Global Warming Worldbook)
The Royal Society explains that “emissions of carbon dioxide from human activities over the past 200 years have already led to a reduction in the average pH of surface seawater of 0.1 units and could fall by 0.5 units by the year 2100. This pH is probably lower than has been experienced for hundreds of millennia and, critically, at a rate of change probably 100 times
greater than at any time over this period.” Most man-made CO2 is inadvertently released with the use of fossil fuels in power generators and transportation vehicles.
Some poisons are intentionally released into the water. Cyanide or pesticides are released in designated areas known to harbor fish and the stunned fish are scooped up in nets and sorted. Even though the poisons don’t always kill the fish, they destroy smaller organisms including the coral reef building animals.
|A Bluering Angel Fish in Coral
(Photo: Jerry Huang)
Huse expresses his concern over losing coral reefs within our lifetimes: “By most scientific estimates,” Huse explains,”we’ve already lost 20-30% of all coral reefs. If we continue to impact the ocean like we are, another 50% of coral will die off within the next decade.”
Obviously over-fishing and pollution will always be a problem. The solution lies in limiting activities that harm the ocean even though the problem will never be completely eliminated. Certain fishing techniques are devastating to marine environments and often unnecessary: ‘Blasting’ is an example; This technique involves bombs that are detonated at sea in the hopes that the fish killed with float to the surface for easy collection. Bottom trawling destroys massive amounts of deep sea ecosystems killing the habitats of the animals they are fishing for. It is fishing practices like these that need improvement.
Controlling the amount of gases released into the atmosphere poses a more difficult problem. The good news is that there IS a potential solution. “Two effective techniques for limiting CO2 emissions would be (1) to replace fossil fuels with energy sources that do not emit CO2, and (2) to use fossil fuels more efficiently,” explains NASA, ” Alternative energy sources that do not emit CO2 include the wind, sunlight, nuclear energy, and underground steam. Devices known as wind turbines can convert wind energy to electric energy. Solar cells can convert sunlight to electric energy, and various devices can convert solar energy to useful heat. Geothermal power plants convert energy in underground steam to electric energy.” (Ref. NASA Global Warming Worldbook)
Fossil fuels are a limited resource as it is and research is currently underway in the hopes of finding alternative (and more environmentally friendly) fuel sources. Until research comes up with less expensive alternative fuels, fossil fuels will continue to be used as the world’s primary energy source.
A few years ago, the idea of an animal surviving the intense pressures of the deep sea was inconceivable. Today, it is a known fact that animals manage to survive at such depths. In fact, the deepest fish on record was found at 27,460 ft (8,370 meters) below sea level.
Unfortunately, with current trends in pollution and deep sea fishing, many species may become extinct before they are even discovered! It is important to protect existing marine habitats, not only to protect a major resource of everything from food to tourism to coastal protection, but to ensure the survival of the creatures that make the world such a fascinating place.