Fish farming in cages: a practice to be restricted in Brazil

Abstract

World aquaculture has been growing sharply in recent decades and Brazilian production of fish in cages has grown considerably since the end of the 1990s. This increase is related to the development of federal government regulations and the large number of medium and large hydroelectric reservoirs. The main areas of fish production in cages in Brazil are currently located in the Northeast and Southeast regions and along the Southeast/South border. Tilapia production in cages in Brazil, as well as other species produced in cages in other regions of the world, has economic advantages for the producer. On the other hand, limnologically, tilapia production in cages causes enormous damage, as it promotes the process of artificial eutrophication and, possibly, introduces this exotic species. One way of reducing artificial eutrophication is the use of Integrated Multi-trophic Aquaculture (IMTA); however, its use in fish cages installed in Brazilian reservoirs is not possible yet. Therefore, our view is that government agencies restrict the production of fish in cages to the utmost.

Editorial: Freshwater sustainability and aquatic ecology in a fast-changing world

“…It is important to point out that fish conservation effectiveness relies on integrated evaluations, since fish ecology dynamics are complex and dependent on interactions at the population and community levels. In this regard, two articles discuss the ecological effects of non-native fish species on native and endemic fish assemblages in Brazil (Garcia et al, 2019;Camargo & Amorim, 2020). In addition to concerns about the introduction of species, Garcia et al (2019) discuss the deleterious effects of introducing fish parasites, which would not occur under natural conditions, and how this introduction can directly affect native fish fauna.…”

“…In addition to concerns about the introduction of species, Garcia et al (2019) discuss the deleterious effects of introducing fish parasites, which would not occur under natural conditions, and how this introduction can directly affect native fish fauna. Likewise, it is worrisome how the production of exotic fish species can cause environmental damage such as eutrophication (Henry-Silva et al, 2019;Camargo & Amorim, 2020). In two related opinion pieces, Camargo & Amorim (2020) contend that fish farming in cages should be restricted in Brazil, whereas Henry-Silva et al (2019) discuss practices and conditions that can affect the sustainability of fish farming in cages of reservoirs in Brazil's semiarid region.…”

Impacts of the Residual Trace Metals of Aquaculture in Net Cages on the Quality of Sediment

“…Other studies have reported the sedimentation of feed residues [ 15 ], greater sedimentation in the net cage area [ 16 ], an increase in organic matter in the sediment [ 13 ], heavy metals sedimentation through feed, antifouling and antirust paints [ 9 , 17 , 18 ].…”

“…Studies have shown the relationship between fish farming in net cages and sediment, demonstrated under the following conditions: the sedimentation of feed residues [ 15 ]; greater sedimentation in the net cage area [ 16 ]; an increment in organic matter in the sediment [ 13 ]; and heavy metals in feed, antifouling and antirust paints [ 9 , 17 , 18 ].…”