Bycatch (fishery)

Catch and bycatch of a shrimp fishery off the east coast of Florida

In fishing, bycatch is the term used to describe those fish and other marine animals that are caught with a net or other mass fishing gear, but are not the actual target of the fish. Some of the bycatch is recycled, but most of it is thrown overboard as waste (technical term discard or discards ). Often the trapped animals do not survive the catch and discard or are seriously injured. Due to legal regulations, the fishermen are not allowed to land some caught fish, even if they could be used. Also, whales , dolphins , seals , sea turtles , seabirds , sharks and stingrays die as by-catch. To catch it comes on the one hand due to un -selective fishing techniques , on the other hand also due to unsustainable fisheries management.

Estimated amounts

Previous estimates have suggested that a quarter of the catch is thrown back into the sea as bycatch. The total amount of bycatch worldwide is just as uncertain; according to Greenpeace, the figures range from 6.8 to 27 million tons. According to Greenpeace, 100 million sharks and rays , around 300,000 whales and dolphins and 100,000 albatrosses end up as bycatch each year . According to the WWF, 250,000 sea ​​turtles , several million sharks and rays as well as more than 300,000 whales and dolphins are lost as bycatch in fisheries every year , as well as two million seabirds within ten years from European fisheries alone .

The amount of bycatch in the shrimp fishery accounts for at least 80 percent of the catch. A particularly large amount of bycatch is disposed of in the North Sea. A third of the catch is thrown overboard as waste every year. That's a million tons of fish and other marine animals. In some fishing areas, the sea is so badly damaged by bycatch that entire ecosystems are affected. By-catches are not included in any catch statistics. They are not taken into account when calculating the catch quotas.

In South Korea, up to a hundred times as many dolphins and whales go into the nets as "accidental bycatch" than in those countries that do not trade in whale meat (as of 2005). It is believed that this is how the South Koreans circumvent the ban on commercial whaling.

Fishing methods and sacrifices

Bottom trawling results

With different fishing methods, different bycatch is drawn on board the ships. Seabirds often get caught on the hooks of longlines . They eat the bait or the fish that hang on the lines, can no longer free themselves from the hooks and drown. According to NABU , more than 200,000 seabirds die in fishing nets every year (2011) due to the fleets of the EU member states alone. It's not just fish that get caught in bottom trawls . There are also mussels , starfish , sponges and jellyfish caught.

Opportunities to reduce bycatch

Acoustic signaling devices are one way of reducing bycatch. These pingers make sounds and are supposed to scare off dolphins. There are already nets with escape hatches for dolphins and other non-target species. Sea turtles are not caught as often by weighting down the shrimp fishermen's nets with steel weights. In longline fishing for tuna, bycatch of sea turtles can be reduced by up to 90 percent by using differently shaped round hooks ("circle hooks"). Significantly fewer sea birds are caught with the longlines if the hooks are fastened differently.

With selective fishing , fishermen limit themselves to a certain type of fish.

Recovery of by-catches

Whether or not by-catches can be used depends on national legislation. In Norway, for example, fishermen have to bring their entire catch into port, while the EU and other countries have a ban on bycatch, which means that bycatch must be thrown overboard.

BirdLife International in Europe calls on the EU Commission to effectively reduce the “bycatch” of European fisheries. In 2010 the European Commission started to develop an action plan to reduce by-catches of sea birds. Nature conservation associations refer to technical protective measures that are easy to implement, for example in longline fishing, which countries such as South Africa and Norway have been using for a long time.

The Federal Agency for Nature Conservation carried out its own studies on the German Baltic Sea coast and worked out proposals for future fishery management in marine protected areas. In this context, NABU demanded: "The member states must provide the urgently needed money to collect bycatch data and further develop environmentally friendly fishing techniques." According to NABU's proposal, fishermen who use these techniques should be rewarded, for example with a preferred one Access to fish stocks or increased catch quotas.

On February 6, 2013, the European Parliament approved a ban on discarding bycatch.

Plastic as bycatch

Plastic waste represents 10% to 30% of bycatch worldwide and has therefore become a significant problem. Since the storage of the garbage on board is time-consuming and the garbage disposal in ports is chargeable, this garbage usually ends up in the sea immediately. Some ports and environmental organizations have started to remove plastic waste free of charge. For example, NABU supports the “ Fishing for Litter ” project, which aims to encourage fishermen to hand over the garbage fished from the North and Baltic Seas in a controlled manner in the ports.

See also

• Marine protection

literature

• Peter Cornelius Mayer-Tasch (Ed.): Sea without fish? Profit and world food. Campus-Verlag, Frankfurt am Main 2007, ISBN 978-3-593-38350-7 .
• S. Buchholz, M. Kreuels et al .: By-catches - annoying or valuable? The value of by-catches in science and environmental planning projects. In: Nature in NRW. (NiN). Vol. 33, No. 4, 2008, ISSN  0947-7578 , pp. 1–4, online (PDF; 764 kB) .

Web links

Commons : Bycatch (fishing)  - Collection of images, videos and audio files

• Mitigating Adverse Ecological impacts of open oceanfisheries - European project MADE (film 28 min)
• Bycatch : a deadly waste wwf.de (with bycatch calculator)
• Summary of the 2009 bycatch report wwf.de (PDF)
• Bycatch: unused, dead or injured back into the sea wwf.at
• Bycatch greenpeace.de
• Fishing nets - deadly traps for dolphins greenpeace.de
• deadline - yaqu pacha eV
• Lighthouse Foundation

Individual evidence

1. ↑ ^{a b c} bycatch greenpeace.de
2. ↑ Caught up, hung up - Unique creatures threatened by bycatch ( Memento of the original from April 22, 2014 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. wwf.de 
3. ^ Threats against the whale embassy in South Korea greenpeace.de, May 27, 2005
4. ↑ Video
5. ^ Lighthouse Foundation: longline fishing
6. ↑ Federal Ministry of Food, Agriculture and Consumer Protection ( Memento of March 8, 2010 in the Internet Archive )
7. ↑ NABU press release : BirdLife and NABU call for an end to the massive bird deaths in fishing nets. No. 94/11, June 29, 2011
8. ↑ European Parliament, Reform of the EU fisheries policy: Parliament calls for an end to overfishing (February 6, 2013)
9. ↑ Laura Habel: Effects and consequences of the increasing pollution of the oceans by plastic waste for marine life and humans. April 28, 2013 ( Memento of the original from April 19, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. 
10. ^ NABU Fishing for Litter