Use of dolphins and caimans as bait forCalophysus macropterus(Lichtenstein, 1819) (Siluriforme: Pimelodidae) in the Amazon

Abstract

Summary A new fishery has been developing in the Amazon that uses dolphin and caiman species as bait to catch piracatinga (Calophysus macropterus), having thus the potential to cause adverse food‐web impacts; however a lack of basic understanding of this fishery is a limitation to the necessary management action. Interviews with fishers and analyses of fishing records in Brazil were used for the study, including harvest methods, types of baits used, commercialization chains, and the rate of increase of piracatinga yields in recent years. Piracatinga fishers are subsistence fishers who harvest piracatinga as a means to alleviate economic constraints when the catch of other species is not profitable or banned due to (reproductive) closed seasons. Harvesting is done with wooden and nylon crates and cages in which whole or pieces of caimans and dolphins are placed to attract the piracatinga, entrapping them. The piracatinga are then sold to intermediate sellers for resale to a few large fish freezing and processing plants for export to Colombia. Annual piracatinga yields in the study area increased at an average rate of 446.5% per year, from 865 kg in 2003 to 23 176 kg in 2009. Because dolphins and caimans comprise various endangered species, the Brazilian government has recently implemented a ban on this fishery, which can be enforced at fish freezing and processing plants. However, there is a danger that such enforcement will lead to the development of a geographically dispersed chain of commercialization and export, such as currently exists for other species including caimans, which would be impossible to control.

The Use of Aquatic Mammals for Bait in Global Fisheries

“…In one floodplain system in the Central /Brazilian Amazon, take levels (estimated at 1650 dolphins per year, da Silva et al, 2011) likely exceed sustainable limits, as indicated by decreased survival rates (Mintzer et al, 2013) and a marked population decline (i.e., a per annum mean reduction of 10% since 2000; da Silva et al, 2011). Although tucuxi are rarely targeted, if they become entangled in fishing gear, the carcasses are utilized as bait (Iriarte and Marmontel, 2013a,b;Brum et al, 2015).…”

“…In response to pressure from conservation groups, the Ministry of the Environment in Brazil announced a 5-year moratorium on the selling and trade of piracatinga effective January 2015 (Brum et al, 2015). Because piracatinga is transported to and handled in large processing facilities, monitoring for compliance and enforcement are expected to be relatively straightforward endeavors.…”

“…Because piracatinga is transported to and handled in large processing facilities, monitoring for compliance and enforcement are expected to be relatively straightforward endeavors. However, it is possible that the moratorium will lead to a black market for piracatinga (Brum et al, 2015). Nevertheless, an expected decrease in killing should afford an opportunity to develop alternative baits or livelihoods.…”

“…In another example described in this review (see section on Large River Systems), Brazil established a 5-year moratorium on the fishing and selling of C. macropterus that began in January 2016 (Brum et al, 2015;Beltrão et al, 2017). This ban was put in place to decrease the killing of botos for use as bait and to allow time for the development of alternatives to present to fishers (Brum et al, 2015).…”

“…This ban was put in place to decrease the killing of botos for use as bait and to allow time for the development of alternatives to present to fishers (Brum et al, 2015). Regardless of the fact that the killing of botos takes place in secluded, hard-to-enforce, areas of the Amazon, substantial catches of C. macropterus are processed in large, centralized freezing/distribution plants that should be relatively easy to monitor (Brum et al, 2015). As of mid-2017, the piracatinga fishery and hunt for botos continues (da Silva and Martin, 2017).…”