The Problems of our Oceans

Standard Page - 2011-06-21
Human activities are changing ocean ecosystems the world over. From whaling to industrial fishing, waste dumping to oil drilling to climate change, we are exerting unimaginable pressure on the ocean. Even the Western and Central Pacific – once one of our healthiest oceans – is now facing grave threats from overfishing and destructive fishing practices.

Human activities are changing ocean ecosystems the world over. From whaling to industrial fishing, waste dumping to oil drilling to climate change, we are exerting unimaginable pressure on the ocean. Even the Western and Central Pacific – once one of our healthiest oceans – is now facing grave threats from overfishing and destructive fishing practices.

Overfishing

Our appetite for fish is exceeding the oceans’ ecological limits.

Overfishing – catching more fish than the population can support – is devastating for not only the fish but also the marine ecosystem as a whole. As larger fish are wiped out, smaller fish species are targeted next and so on. As overfishing pushes species towards extinction, ecosystems face the risk of collapse. Degraded and stripped of their diversity, the oceans are losing their fragile balance. Learn more about overfishing.

The world's largest tuna fishing vessel, the Albatun Tres can take 3,000 tonnes of tuna in a single fishing trip – almost double the annual catch of some Pacific island countries.

The magnificent tuna is at particular risk from overfishing. Its popularity in sushi and other foods is spelling doom for this amazing creature. Bluefin tuna is already critically endangered in the Atlantic and Mediterranean. Now it is at risk in the Pacific as well. Learn more about tuna.

Destructive Fishing

Modern fishing practices are incredibly wasteful. Bycatch refers to everything accidentally caught or killed by large fishing ships using modern technology. Every year, fishing nets kill hundreds and thousands of whales, dolphins and porpoises globally – and that’s just one kind of fishing method.

Long-line fishing catch many endangered sharks, turtles, marine mammals and seabirds. The purse seining of skipjack tuna – usually made into canned tuna – results in large bycatch of young bigeye and yellowfin tuna and other species. These fish end up in the nets and are thrown back dead.

Purse seining is even worse when combined with a Fish Aggregating Device, which artificially attracts sharks, rays, turtles and other species.

A purse seine vessel with a whale shark caught as bycatch in the Pacific

Whale sharks, being slow swimming filter feeding fish, act as natural aggregation devices for tuna in tropical oceans and are killed in unsustainable numbers in purse seine fisheries.

Moreover, some fishing practices destroy habitat as well as inhabitants. Bottom trawling, for example, destroys entire ancient deep-sea coral forests and other delicate ecosystems. In some areas it is the equivalent of ploughing a field several times a year. Learn more about bycatch and destructive fishing.

Whaling

In the 18th and 19th centuries, humans hunted whales to the point of extinction, for their blubber, whale oil and more. Today, there is no longer a commercial need for whaling, yet the hunt continues, needlessly. Greenpeace began its whaling campaign in 1975, and since then, we have achieved remarkable victories: through our efforts, the International Whaling Commission established a global ban on commercial whaling in 1982, but Japan restarted their whaling program in 1987 in the name of scientific investigation.

After years of confronting whalers on the high seas, we are now working to change the perception of whaling in Japan itself. In a breakthrough investigation, our Japanese campaigners (known as the Tokyo Two) found hard evidence of bribery and whale meat smuggling within the whaling industry. These discoveries have shocked Japan, where whale meat is no longer popular and the whaling industry is supported largely through taxpayer subsidies.

You can read more about Greenpeace’s whaling campaign, and more on the Tokyo Two.

Climate change

Did you know that our oceans are already being irreversibly damaged by climate change? For example, rising ocean temperatures is slowly causing coral reefs to die out (‘bleaching’) through lack of oxygen. Coral reefs are critical to biodiversity – they play host to the thousands of tropical fish and plants that make a reef a colorful, exotic ecosystem. But when corals die, so does the life that depends on them. Unfortunately, even conservative predictions suggest that coral reefs may die out completely by the end of the 21st century without immediate action on climate change.

Other climate change impacts on the oceans include ocean acidification, rising sea levels and changing currents. These can be hugely problematic for humans: rising sea levels can wipe out seaside towns, while changing currents can affect weather and storm patterns. And whole species of marine animals and fish are at risk due to warmer oceans – they simply cannot survive in the changed conditions.

For more on what we are doing to combat climate change, please visit our climate and energy section.

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