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Unsustainable Fishing Practices and Their Long-lasting Effects on Marine Life

| Erin Murphy, International Marine Mammal Project
Topics: Dolphin Safe Tuna, Dolphins, Plastic Pollution, Pollution, Tuna Industry, Whales

"Ghost gear"

640,000 tons of fishing equipment is abandoned in the ocean each year. To illuminate the severity of this number, this is equal to more than 1 billion pounds of nets and gear left behind by fishers, according to the United Nations Environment Program. Called “ghost gear” or “ghost nets,” these retired materials remain in the ocean for as long as 600 years before decomposing, which means the cycle of killing valuable wildlife and damaging ecosystems almost never ceases. This gear is shown to damage coral reefs, trap and entangle marine animals, including whales and dolphins, and contributes to the significant amount of waste already present in the sea.

World Animal Protection (WAP) has been a leader in discovering and publishing this recent information about ghost gear, stating that it is “a problem that spells catastrophe for marine life as we know it.” WAP found that 45 percent of the marine mammals on the International Union for the Conservation of Nature’s Red List of Threatened Species has been affected by this abandoned gear - mostly killed or injured.

If almost half of our threatened marine animals are negatively affected by old fishing gear, then why is this gear still out there, and why is it even being used in the first place?

To provide background, commercial fishing may include any of the following types of practices: gillnets, trawling, line fishing, or purse seines. All of these options can be deemed unsustainable by researchers; however, they tend to be the most effective at catching seafood in great quantities. What they also catch are marine animals like whales, dolphins, turtles, seals, birds and non-target fish species like sharks that accidentally got in the way. This category is called bycatch, and amounts to about 40 percent of global annual catch, according to Oceana. This number does not even include all the wildlife that suffers after nets have been discarded into the sea.

A leader of the global fishing industry, the U.S. reels in, according to the US National Marine Fisheries Service, annual revenue of more than $200 billion and almost 10 billion pounds of fish. America seems to be increasing its footprint in the fishing industry, while still importing around 6 billion pounds of seafood from other countries -- the second largest importer of seafood after Japan. With our access to research and technology, we have the responsibility to investigate the effects of our practices and the sustainability of them on marine life.

Photo: NOAA Fisheries

Here is what we know thus far:

Gillnets are sets of mesh panels that come together to form a large vertical wall in an area of the ocean. There are two types of gillnets: set and drift. Set gillnets are attached to poles in the substrate whereas drift gillnets float at one depth with the assistance of buoys or weights. The mesh holes are just large enough for fish to poke their heads in but small enough that they catch on the fishes’ gills. The more the fish try to escape, the more entangled they become. The most disturbing fact about gillnets is that they can span for vast distances, sometimes as long as two or more miles, even though large-scale drift nets have been banned by the United Nations.

The International Marine Mammal Project (IMMP) of Earth Island Institute has worked to end the use of gill nets for fishing, including supporting the United Nations ban, prohibiting use of gill nets to catch tuna from our Dolphin Safe tuna program, and successfully pushing to end use of gill nets in nearshore waters of California.

Bottom trawling is similarly harmful. It is performed by dragging a large net with weights attached to it from a boat so that it catches and demolishes everything in its path. Fortunately, bottom trawling (dragging nets along the seafloor) has been banned in most coastal U.S. states, as well as New Zealand, Indonesia, and the Mediterranean. IMMP’s Dolphin Safe standards also call for participating tuna companies to prohibit the use of bottom trawling in their affiliated businesses. This is due to the vast amounts of irreversible damage done on the environment. For example, the South Atlantic Fishery Management Council banned bottom trawling in deep-sea coral reefs spanning from Florida to North Carolina after 90 percent of a bank of Oculina corals was destroyed.

Purse seining for tuna also has extremely adverse effects. Many times, purse seine fishing involves setting a net around schools of tuna associated with dolphins. Chasing and netting dolphins to catch tuna, for example, killed more than 7 million dolphins before IMMP’s Dolphin Safe tuna program went into effect. Some nations, such as Mexico, Venezuela, and Colombia still pursue dolphins to catch tuna, so buying tuna with a legitimate Dolphin Safe tuna label is important to ensure protection for dolphins and more sustainable tuna fisheries. For more information on Dolphin Safe tuna and a list of companies monitored by IMMP to ensure that they are fishing Dolphin Safe, go to www.DolphinSafe.org

With this knowledge about harmful and unsustainable fishing practices, the primary concern is how to transition to improved practices when we already have such a high demand for seafood. Additionally, how can we ensure gear used for commercial fishing does not become ghost gear, abandoned in the ocean for hundreds of years?

Many fishing practices that are considered sustainable stem from indigenous cultures. For example, the Tagbanuas people of the Philippines fish for specific species at certain times of the year using hook and line methods and make sure to only catch what they need to sustain their population. They have also created protected areas within their coral reefs where fishing is prohibited. Furthermore, native Hawaiians use cast-net fishing and spearfishing to target selected species. This is a common practice also seen in South America, Africa, Australia, and Asia. Both of these methods result in very little or no bycatch and ensure the fish populations are not depleted more quickly than they can reproduce. They also eliminate the possibility of large nets and gear being abandoned in their waters and reefs.

While it may not be realistic for the entire world to transition to the above practices, they provide a starting point, evidence that sustainable fishing can indeed be done. The safest course for the oceans at this moment is to ensure that fishing boats retrieve their nets and do not dump old or torn nets at sea, but bring them into port where the nets can be disposed of properly. The fishing industry should be required to develop and use alternatives, including net materials that eventually break down and dissipate in the ocean instead of remaining intact for decades.

Since whales and dolphins can become entangled in fishing lines used to retrieve crab and lobster traps, some fishermen are experimenting with traps that need no lines, but that can be electronically set to float to the surface for retrieval. Similar innovation can help maintain fishing jobs while reducing harm to marine life.

Some organizations have taken action to remove such ghost gear from our oceans:

Hopefully, with the help of these organizations and with improved fishing practices, we can remove debris from the oceans and ensure the sustainability of not only the fishing industry but of our marine ecosystems.

Header photo of entangled whale courtesy of Shutterstock.

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