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.
Learn about these four destructive fishing practices that are killing our oceans:
Long-lines consist of short lines (called snoods) carrying baited hooks, attached at regular intervals to a longer main line. Main lines can be over 150 km long and can carry several thousand hooks.
Long-lines catch many endangered sharks, turtles, marine mammals and seabirds. Birds dive for the bait planted on long fishing lines, swallow it (hook included), and are pulled underwater and drowned. Around 100,000 albatrosses are killed by long-line fisheries every year – because of this, many species are facing extinction.
Fish aggregating devices (FADs)
FADs are like deadly magnets for fish. They float in the ocean and are used to attract tuna. Unfortunately, many other animals come to the FADs as well – endangered sharks, turtles, skates and rays, immature tuna and other fish. After the FAD attracts enough fish, the tuna and all other accumulated marine life is scooped up in a huge net, in one fell swoop.
Over 70% of the world’s tuna fisheries use FADs. Not only do these FADs kill thousands of turtles and sharks each year, they also further endanger the critically overfished bluefin, yellowfin and bigeye tuna. That’s because purse-seine fisheries for skipjack tuna – commonly used in canned tuna – frequently use FADs, which attract lots of juvenile yellowfin, bluefin and bigeye tuna as well. As a result, many young tuna are killed before they have a chance to reproduce.
A staggering 100 million sharks and rays are estimated to be caught and discarded each year. Tuna fisheries, which in the past had high dolphin bycatch levels, are still responsible for the death of many sharks. An estimated 300,000 cetaceans (whales, dolphins and porpoises) also die as bycatch each year, because they are unable to escape when caught in nets.
Bottom trawling is a destructive way of ‘strip-mining’ the ocean floor, harvesting the species that live there. This not only picks up target fish species but also many other creatures – just one pass of a trawler removes up to 20% of the seafloor fauna and flora. Shrimp fisheries have the highest levels of bycatch: over 80% of a catch may consist of marine species other than shrimp.
Images © Marco Care, Paul Hilton, Alex Hofford & Malcolm Pullman / Greenpeace (in order)