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New nets make shrimp trawling more sustainable in Latin America and Caribbean

  • When fishers accidentally catch non-target species, they either sell the so-called bycatch or throw it back into the ocean, almost always dead.
  • Newly invented nets have allowed shrimp trawlers to reduce bycatch by 20 percent.
  • Globally, almost 10 million tons of potentially usable fish are thrown back into the ocean every year.

Among the fisheries of Latin America and the Caribbean, shrimp has the highest export value after tuna. Trawling, the most popular and efficient way to harvest shrimp, has been a source of controversy due to its negative effect on marine biodiversity and the artisanal fishing sector. Traditional fishers say they lose catches to the trawlers’ large nets, which scoop up other forms of marine life along with the shrimp. According to the Food and Agriculture Organization of the United Nations (FAO), shrimp trawlers’ nets can inadvertently catch up to 25 times more non-target species than shrimp.

The fishers sell some of the non-target species, or bycatch, that they bring in. However, they return a larger amount to the ocean, almost always dead. Most of the discarded organisms are young fish with little to no market value due to their small sizes. Invertebrates like crustaceans and mollusks also get discarded, along with the occasional marine turtle, ray, or shark netted with the shrimp.

Bycatch from trawlers poses a threat to sustainability, and also puts livelihoods and long-term food security at risk. To reduce this impact, Colombia, Brazil, Suriname, Costa Rica, Trinidad and Tobago, and Mexico have embarked on a project with the goal of introducing changes in the technology of trawling nets. The preliminary results are promising, showing up to 20 percent less bycatch and discards.

‘Smart’ nets


The FAO is conducting the project, known as The Sustainable Management of Bycatch in Latin America and Caribbean Trawl Fisheries (REYBAC LAC II), between 2015 and 2020 with the intention of meeting international guidelines for the responsible management of bycatch. With the help of traditional and large-scale fishers, the project consists of testing net prototypes that reduce the negative effects of trawling on marine biodiversity while still catching shrimp.

The new nets have different characteristics than those usually used by fishers, mainly in regard to the size of the holes in the fabric of the net. “The nets that are being tested have, in the lower part that forms a ‘bag’ when it is in the sea, a [mesh size] similar to a traditional net,” Mario Rueda, a researcher at the Marine and Coastal Research Institute (INVEMAR), a Colombian nonprofit, and the national coordinator of the net project, told Mongabay Latam. “However, in the upper part, the [mesh size] is larger. This allows the bycatch, which get caught in the net, to escape from it.”

Rueda said the shrimp harvesters were able to see how the shrimp move to the bottom of the net where the holes are smaller so they do not lose their catch.

A prototype of a net that may prevent the capture of fish during industrial shrimp trawling. Image courtesy of INVEMAR.

Additionally, if some of the entrapped non-targeted fish fail to get away through the wide holes, the net has another escape route: a “window” made with an even larger mesh size.

The new nets are woven from different materials than those commonly used in other nets. The nets are consequently lighter, which creates less friction against the ocean floor, reducing the force needed to move through the water and enabling the boats to use less fuel.

Willingness to compromise


The results have been encouraging: bycatch and discards have decreased by up to 20 percent and the boats’ fuel use has also decreased.

The bycatch does have some economic value for the shrimp harvesters who sell it. “At first, the fishers think that they will lose money,” Rueda said. However, “that reduction in revenue is compensated for by the saving of fuel.”

Rueda emphasized that the project’s success depends on the participation of both industrial and traditional fishers. “More than imposing [the nets on the fishers], they have realized the benefits, so they are accepting the net prototypes,” said Rueda.

The construction of a net prototype for traditional fishing. Image courtesy of INVEMAR.

According to the project’s guidelines, one of its goals is to address the negative impacts of shrimp trawling while considering ecological well-being, economic growth, and food security. Therefore, while those involved in the project are working to decrease the number of discarded sea creatures, they are also trying to put a commercial and/or food value on all creatures that are caught. This way, instead of dead animals being thrown back into the sea, they will be used.

Bycatch is often an essential part of community members’ diets, according to Carlos Fuentevilla, the project’s regional coordinator. “This is why we should reduce the number of incidental captures, but also make sure that we don’t create a negative impact on food security,” Fuentevilla said.

In Sirinhaém, an economically disadvantaged municipality in the northern Brazilian state of Pernambuco, researchers from the project were surprised to discover that shrimp trawling did not create significant impact. One reason for this is the short life cycle of the shrimp. Furthermore, Fuentevilla said, discarded fish is one of the community’s main food sources, as it is a free and nutritious option. “Discarded fish are often used as money to pay for the services of the engineer or captain of a boat,” he said.

The researchers predicted that In Sirinhaém, decreasing bycatch would put the community’s food security at risk. Armed with this knowledge, the project’s local leaders decided to adapt to the community’s reality. They changed their focus from avoiding to managing discards, and began to encourage cold treatment and proper cleaning techniques for the discarded fish so people could sell it inside or outside their communities.

The invisible women


The REBYC-II LAC project also seeks to help countries revise their laws and governance agreements, suggesting amendments that favor the fishing sector’s involvement and the establishment of public-private partnerships. Another of the project’s initiatives is to help countries include women in their socioeconomic evaluations of their fishing industry.

According to Fuentevilla, although women constitute half of the shrimp industry’s workforce, they are not counted or considered within the value chain. Women typically work in the secondary sector, peeling or cooking the shrimp. They are usually hired informally by companies and earn cash for each bucket or kilogram of shrimp they process. The temporary and informal nature of these jobs means that the women often have no access to social security.

“The companies, because they have no information about [the women], do not consider them when weighing the impacts of their decisions, so they are rarely reflected in their [bycatch] mitigation plans,” Fuentevilla said. This is why REBYC-II LAC aims to help these women organize civil associations and have a higher-level role in the industry.

Women peeling shrimp. Image courtesy of INVEMAR.

“In Costa Rica, this initiative has already shown results, since women’s labor organizations have formed, and the women now have more access to negotiations with the companies to obtain better employment conditions,” said Fuentevilla.

Despite this, many Costa Ricans who work in the shrimp industry worry about the possibility of the trawling industry coming to an end. In 2013, the country’s Supreme Court of Justice declared trawling unconstitutional because of the damage it inflicts on marine environments. The ruling declared that new trawling licenses would not be granted and existing licenses would not be renewed until it is proven that trawling can be done in a sustainable way. “If we do not demonstrate that trawling can have less impact, it will disappear. The short-term impacts of that would be serious, given that for now there are no alternatives for the people who work in this sector,” said Fuentevilla.

The countries


Although the project has already begun to reduce bycatch and discards in Colombia and Brazil, researchers in Mexico are still conducting studies to determine which types of technology can be applied to the nets there.

In Trinidad and Tobago the work is just beginning. “Their fishing laws are around 100 years old, and they are just now beginning to update them,” said Fuentevilla. However, the new nets have already spurred bycatch reductions of up to 25 percent, and researchers hope the number will increase to above 30 percent.

Testing the prototype of a net for traditional fishing. Image courtesy of INVEMAR

Suriname is the only country involved in the REBYC-II LAC net project whose shrimp trawling fishery is certified as sustainable by the Marine Stewardship Council (MSC), a London-based international nonprofit. The fishery already has devices to reduce bycatch, especially ones that avoid the incidental capture of sea turtles. In Surinam the project aims to further reduce bycatch, optimize the devices in use, and investigate ways to use discards to reduce food loss.

Beyond REBYC-II LAC in Latin America and the Caribbean, other countries are working to reduce bycatch and discards as well. Australia and the United States have been particularly successful, with reductions of up to 30 percent in relation to their data from 15 years ago.

Food security has always been, and will continue to be, one of humanity’s main concerns. “The oceans and seas offer vast potential to feed the near 10 billion people who will live on Earth in 2050,” the FAO has stated. “[To] conserve and sustainably use the oceans, seas and marine resources for sustainable development is a major priority of Agenda 2030,” the sustainable development commitment adopted by U.N. member states in 2015.

Globally, the figures are stark and it’s clear more work remains to be done. A 2017 study in the journal Fish and Fisheries found that every year industrial fishing ships throw almost 10 million tons of potentially usable fish back into the water. This figure is equal to about 4,500 Olympic-size swimming pools of food per year.

Banner image courtesy of INVEMAR

This article was first published by Mongabay Latam. Edits by Rebecca Kessler.

Zeller, D., Cashion, T., Palomares, M., & Pauly, D. (2018). Global marine fisheries discards: a synthesis of reconstructed data. Fish and Fisheries, 19(1), 30-39.