Once again, the Brazilian government is “passing the cattle” and threatening the biodiversity of native species in the country through incentives for the creation of invasive alien species (1). This week Decree No. 10,576 / 2020 was published in the Official Gazette of the Union, which, in addition to allowing the use of reservoirs for the practice of large-scale fish cultivation for aquaculture, passed the responsibility for the process of granting full use to the Secretariat de Pesca, a function that previously belonged to IBAMA because it is a project with possible damage to the environment (2). This measure is worrying, since it is up to IBAMA to ensure the sustainable use of natural resources, licensing, inspecting, monitoring and applying the applicable penalties in case of environmental crimes. With the withdrawal of IBAMA from the environmental licensing process for aquaculture, the current government is making it difficult to comply with important environmental regulations that serve precisely to protect our precious biodiversity. For example, in Law 6.938 / 1981, according to the “Polluter - Payer” principle, if an aquaculture farmer misses an exotic species from his crop, he is obliged to make environmental compensation. With the new decree, without the action of IBAMA, who will inspect and charge the due responsibilities of these producers? In addition, without the supervision of the federal agency, the transfer of the attribution of this process to the states can facilitate agreements driven by regional political pressure and harm the population's interest in favor of the profit of the few. This is yet another action that amplifies the weakening of the main environmental inspection body in the country, which increasingly has a reduced role in the preservation of nature.

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Tilapia cultivation in Brazilian reservoirs: a double-edged sword

Recently, the Secretary of Fisheries Jorge Seif Junior also announced plans to implement the cultivation of tilapia in net tanks in 60 of the 73 Brazilian reservoirs, with the purpose of boosting aquaculture and consequently the suppliers of inputs of the branch, from the structures of the tanks. chain, feed and other products (3). Contrary to what many think, tilapia are not native to Brazil, and were brought to our country in the mid-1930s. This species is of African origin and is currently introduced worldwide (4). The big problem is that exotic species can cause several ecological and economic impacts associated with their cultivation, especially when they escape to rivers and lakes (4, 5). Still, some Brazilian politicians insist on arguing that if there are escapes, the native fish will attack the tilapia, and that they will not survive the typical depths of the reservoirs. In fact, tilapia is a species that adapts easily to different types of environment and studies have shown that the greater the number and number of events of introduction of an exotic species into nature, the greater the chance that it will establish itself in the new environment and cause harm.

Breeding in net tanks is quite problematic in several ways. The damage to the environment, in addition to the escape of exotic fish, is also due to the remains of manure and feed, the addition of large amounts of feces and other tilapia excrement in the water, and the possible contamination of native fish by parasites brought by the species. exotic. Intensive breeding in network tanks can worsen water quality in reservoirs, increasing the amount of nutrients and pollutants in the water, which can irreversibly affect the entire ecosystem, and even increase water treatment costs for the population. (6). In the regions surrounding the reservoirs, the losses for local fishermen, who already face difficulties caused by the damming of the waters, may be even worse, affecting the economy that depends on native species through fishing for family livelihood and sport fishing associated with tourism, as well as reducing the availability of native fish on site. There is also the issue of sanitary control of tilapia cultivation in Brazil, which is very precarious due to the lack of inspection and knowledge of the breeders about possible contamination and the quality of the water and ecosystem as a whole. Contamination by bacteria and viruses is more common in net tanks where there is a large concentration of animals in a small space, and in some cases rendering the fish unfit for consumption. Thus, intensive creation and without adequate technical planning can not only cause an environmental problem, but also a public health problem.

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The dismantling of environmental policy and its consequences for the country

In areas where invasive alien species have been introduced for decades, policies have moved towards changing their legal status to "native" through decrees, so that they can be cultivated where previously prohibited (7). This new decree will only contribute to exotic species spreading more and more in Brazilian water bodies, due to the increase in the number of possible sources of introduction. In addition, there is a greater risk related to the Amazon basin. Although the cultivation of tilapia is not foreseen for the reservoirs in this region, the few regulations that restrict the introduction of exotic species there are not enough to stop any possible addition of these species, and it is probably only a matter of time for their aquaculture to establish itself. (8). Attempts to boost the cultivation of invasive alien species also seem to be closely linked to a lobby in the National Congress, which aims to benefit only a restricted group of sectors of society, especially large businessmen with commercial interests in the entire production chain associated with the creation of fish in net tanks.

In the international scenario, as the impacts caused by invasive alien species go beyond political borders, agreements between countries are fundamental for the construction of global strategies that seek to control these species. The current government's measures go against the international agreement signed in the Convention on Biological Diversity (CBD), which establishes in its article 8, paragraph h, that it is “fundamental to prevent introductions, control and eradicate exotic species that threaten ecosystems, habitats or species” . Unfortunately, Brazil has been criticized for inconsistencies and inconsistencies with important negotiations at the CBD, taking a stand against investments and efforts to conserve the planet's species and natural resources (9).

In fact, the cultivation of exotic species in network tanks threatens native biodiversity (10) and, therefore, there is an urgent need for the scientific community to be consulted on this issue and for the process to be reassessed by technicians from the environmental area before the situation comes out. of control. In addition, more sustainable measures such as the creation of native species must be studied and expanded, avoiding the spread of a known invasive species such as tilapia, but at the same time bringing the socioeconomic benefits associated with aquaculture. Brazil must begin to value its biodiversity, exploring its economic value and ensuring sustainability in the production of local species, unfortunately the opposite of what we have observed recently.

A sustainable path for Brazilian aquaculture is the strong investment in research for the zootechnical exploitation of truly native species in order to minimize conflicts of use and diversify production, something that would increase the availability of fishing resources and decrease price fluctuations. It is necessary to avoid the cultivation of exotic and / or transgenic species in open waters as much as possible, and restrict these only to truly closed systems, leak-proof, and that guarantee the real confinement of the species.

 

References

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1. MFG Brito, ALB Magalhães, DP Lima-Junior, FM Pelicice, VM Azevedo-Santos, DAZ Garcia, AM Cunico, JRS Vitule, Brazil naturalizes non-native species. Science, 361, 139 (2018).

2. DECREE No. 10,576, OF DECEMBER 14, 2020 - DOU

3 https://economia.estadao.com.br/noticias/geral,bolsonaro-quer-criar-tilapia-em-itaipu-mas-peixe-pode-acabar-com-especies-nativas.70003546463

 

4. GC Canonico, A. Arthington, JK McCrary, ML Thieme, The effects of introduced tilapias on native biodiversity. Aquat Conserv, 15, 463-483 (2005).

5. FAS Cassemiro, D. Bailly, D., WJ da Graça, AA Agostinho, The invasive potential of tilapias (Osteichthyes, Cichlidae) in the Americas. Hydrobiology, 817, 133-154 (2018).

6. L. Guo, Z. Li, P. Xie, L. Ni, Assessment effects of cage culture on nitrogen and phosphorus dynamics in relation to fallowing in a shallow lake in China. Aquac Int, 17, 229-241 (2009).

7. FM Pelicice, JRS Vitule, DP Lima-Junior, ML Orsi, AA Agostinho, A serious new threat to Brazilian freshwater ecosystems: the naturalization of nonnative fish by decree. Conserv Lett, 7, 55-60 (2014).

8. AA Padial, AA Agostinho, VM Azevedo-Santos, FA Frehse, DP Lima-Junior, ALB Magalhães, RP Mormul, FM Pelicice, LAV Bezerra, ML Orsi, M. Petrere-Junior, JRS Vitule, The “Tilapia Law” encouraging non-native fish threatens Amazonian River basins. Biodivers Conserv, 26, 243-246 (2017).

9. https://www.oeco.org.br/noticias/brasil-trava-negociacoes-na-convencao-sobre-diversidade-biologica/

10. JRS Vitule, CAF Freire, D. Simberloff, Introduction of non-native freshwater fish can certainly be bad. Fish Fish, 10, 98-108 (2009).