Elasmobranchs, the group of cartilaginous fishes that include sharks and rays, are especially vulnerable to overfishing due to their low fecundity (produce fewer offspring) and late sexual maturation even though they comprise less than 1% of the world fisheries catch.

Brazil is among the six countries that have the highest capture rate for elasmobranchs and it lacks an accurate assessment of the impact the fisheries have here due to inaccurate records. Southern Brazil is a known region of high elasmobranch diversity that has a large fishing industry – the two southernmost states, Santa Catarina and Rio Grande do Sul, are responsible for 98% of the catches here. This country is also a big player in the meat trade market with several different species largely under the name “cação” (or possibly “caçonete” and “anjo”), making it difficult to figure out exactly what species are being consumed unless genetic testing is carried out.

The latest studies cite 94 species of sharks and rays making their home off southern Brazil, with 27 being primarily coastal species, many being caught by artisanal and industrial fishers. And while there exists a marine protected area (MPA) through the Lagoa do Peixe National Park, it allows fishing for elasmobranchs so long as the species are not present in the Brazilian list of threatened fauna. MPAs are a widely used spatial management tool in fisheries and conservation and while you may have heard of them being implemented to protect sharks, many are not designed for this reason; the Lagoa do Peixe National Park was created in 1986 with the objective of protecting migratory bird species and coastal ecosystems. 

The types of elasmobranchs that call this area home, along with the fishing pressures presently here, are monitored by the National Park’s internal team yet, according to a new study, there is “no public information on the species of elasmobranchs and their relation to fishing.” Thus, the team set out to investigate shark and ray capture records in this area. Led by Dr. Paulo R. S. Santos of the Universidade Estadual Paulista, the researchers were able to account for 124 individuals of 16 species and 33 egg cases of three other species were recorded. Of the 19 total species, 10 were sharks and nine were rays (of which 88.5% and 66.2%, respectively, are endangered). And there were a few surprises of who showed up! “Certainly, the most unexpected and [exciting species found] were the three records of striped smoothhound shark (Mustelus fasciatus),” said Santos, explaining they had found one small neonate and two adult females. “This species is considered critically endangered (CR) at the national level (Brazil) and at IUCN and is increasingly rare in the region. In addition, these records encouraged me to start a specific project for the records of this species.”

Also known as the striped dogfish, this species was once common off the coast of southern Brazil. Newborns and juveniles have dark bars running across the top part of their head and body that fade with age, hence the common name. Although knowledge of their diet is limited, one study from Brazil suggests they eat large amounts of crustaceans (mostly boxcrabs), followed by fishes and mollusks. Due to significant pressure by commercial and artisanal fisheries, particularly on juveniles and newborns in their nurseries, the species has experienced a significant decline. In fact, in 2017 NOAA Fisheries listed the species as endangered under the Endangered Species Act! So, finding “the large participation of neonates and adult females of endangered species in the area” was gratifying, according to Santos, saying that it reinforced the importance of the National Park for the conservation and management of these animals. “This data help to reinforce the need for the absence of fishing within this area, as it can promote a region of ‘rest’ in the face of the great fishing effort that is employed in the surrounding areas,” commented Santos.

Due to their naturally low abundance, it is unlikely a targeted fishery will ever be created for this species, but they are caught in the multispecies smoothhound fisheries, and are known to be caught as bycatch in fisheries for other fish species such as drums, flounders, and mullets. Knowing this, is it possible the striped smoothhound shark be one of the sharks traded in the meat market labeled as “cação”? For now, it seems unlikely, as they have not shown up as a species in the fish markets of southern Brazil. However, previous DNA barcoding studies have found 43.3% of their total sampled consisting of species listed in some IUCN risk category (e.g. Carcharias taurus, Carcharhinus falciformis, Sphyrna lewini, S. zygaena, Squatina guggenheim); another found the most abundant shark species in their samples were Prionace glauca and S. lewini (23.8 and 22.2%, respectively).

All the above just shows the need for researchers and government officials to actively and constantly work together alongside the fishery sector to accurately identify and monitor local fishery landings.