The threat of fishing on the rays of Brazilian coast

In early 2025, we were able to follow several news reports of the sighting of large schools of rays along the south-eastern coast of Brazil. On February 1, the photographer Iuri Sena recorded a group in Bombinhas, a beach located in Santa Catarina, also on March 4 another flagrant was made in the middle of the carnival, moment in which these animals did a real parade on the beach of Leme, in Rio de Janeiro. 

Caption. Left: Cardume de Ticonha (Rhinoptera bonasus and R. brasilienses) sighted in Santa Catarina . Right: Cardume de Ticonha (Rhinoptera bonasus and R. brasilienses) sighted in Rio de Janeiro. Source: Left: Photographer Iuri Sena, via Instagram. Right: Playback via YouTube Canal Infornational.

In the midst of these reports that delight nature lovers, on February 25 we had news of a shoal with more than 100 animals found dead on the coast of São Paulo with suspicion of interaction with trawl fishing nets. In all the cases mentioned, although there is no information so far that the observed groups are related to each other, biologists and professionals of the area stated that the shoals were animals commonly known as ticonia rays, species Rhinoptera bonasus and R. brasilienses. Both species are popularly known by the same name due to the difficulty of differentiating them, since, according to the biologist Ricardo Gomes, from the Instituto Mar Urbano, differentiation is only possible through the analysis of animal dentition. Nevertheless, both species are at risk of extinction according to the IUCN, with R. bonasus classified as near to extinction (NT) and R. brasilienses as critically endangered (CR).

Caption. Left: Cardume de Ticonha (Rhinoptera bonasus and R. brasilienses) found dead on the coast of São Paulo. Source: UNESP São Vicente via Instagram.

Unlike what many people think, rays, like sharks, belong to the class of Chondrichthyes, a group characterized by cartilaginous composition rather than bone skeleton. Another characteristic of these animals is the flattened dorso-ventrally body and the large, flat pectoral fins that merge with the head. In relation to biology, these animals are considered demersal, that is,  they live associated with the seabed, where they camouflage and feed on mollusks, crabs, small fish and other small animals (CASTRO; HUBER, 2012).

Another point to be highlighted is that rays are considered k-strategist species (DE OLIVEIRA, 2019), following a reproductive strategy characterized by slow but expressive growth and low reproduction rate. Thus, due to the small number of chicks, populations may take decades to recover from the impacts resulting from human activities, including fishing.

According to the Executive Summary of the National Action Plan for the Conservation of Sharks and Endangered Marine Rays of ICMbio, overfishing is considered the main threat to marine elasmobranchs in Brazilian waters. In this context, trawl fishing, although prohibited by the Bill 347/22 of the Commission for the Environment and Sustainable Development, still occurs illegally. In it the fishing net is pulled and dragged over the seabed capturing organisms found directly on or near the bottom and because it is a form of non-selective capture, generates a great trail of destruction by the so-called bycatch, or accidental capture, in which species that are unintentionally fished are killed and discarded (CASTRO; HUBER, 2012). And it was so, that it is believed that the shoal found on the coast of São Paulo at the beginning of the year was killed. 

In addition to bycatch, ghost fishing caused by abandoned nets and other threats such as habitat degradation of marine-coastal ecosystems, oil and gas exploitation, and maritime traffic itself affect rays and several other species. According to data from a survey carried out in 2019, according to IUCN data, 35% of the species already evaluated in Brazil are in a worrying state, and according to ICMBio this percentage rises to 38.3%. (DE OLIVEIRA, 2019). Thus, measures of regulation and supervision of fishing and other maritime activities are essential for the conservation of the aquatic environment, of the populations of rays and so that news such as the one reported in São Paulo is not repeated. 

Author: Luiza Torquato - Director of Regional Representatives of GEAS Brazil

Review: Iago Junqueira - GEAS BRASIL Partner by The Wild Place

March/2025 Wild Panel

REFERENCES

DE OLIVEIRA, C. D. L. et. al. Diversidade de raias marinhas na costa do Brasil e seus estados de ameaça nacional e global. Arquivos de Ciências do Mar, Fortaleza, v. 52, n.1, p. 7-20, 2019.

INSTITUTO CHICO MENDES DE CONSERVAÇÃO DA BIODIVERSIDADE (ICMBio). Sumário Executivo do Plano de Ação Nacional para a conservação dos Tubarões e Raias Marinhos Ameaçados de Extinção

CASTRO, Peter; HUBER, Michael E. Biologia Marinha. 8. ed. Porto Alegre: AMGH, 2012.

O ECO. Cardume de raias faz desfile surpresa em pleno Carnaval carioca. 25 fev. 2025. Disponível em:https://oeco.org.br/salada-verde/cardume-de-raias-faz-desfile-surpresa-em-pleno-carnaval-carioca/Acesso em: 3 mar. 2025.

CNN BRASIL. Vídeo: cardume de raias é flagrado em praia de Santa Catarina. CNN Brasil, 24 fev. 2025. Disponível em:  https://www.cnnbrasil.com.br/nacional/sul/sc/video-cardume-de-raias-e-flagrado-em-praia-de-santa-catarina/. Acesso em: 3 mar. 2025.

G1. Mais de 100 raias ameaçadas de extinção aparecem mortas em praia do litoral de SP. G1 Santos e Região, 25 fev. 2025. Disponível em: https://g1.globo.com/sp/santos-regiao/noticia/2025/02/25/mais-de-100-raias-ameacadas-de-extincao-aparecem-mortas-em-praia-do-litoral-de-sp-video.ghtml. Acesso em: 8 mar. 2025.