is torn during penetration into the skin, it can break and cause dentin fragments to be retained in the wound. The stinger can cause laceration, which results in secondary infection, usually caused by Pseudomonas and Staphylococcus. If the stinger reaches internal organs, it can be fatal. As food Freshwater stingrays are often caught by hook-and-line and as bycatch in trawls. In the Amazon, Paratrygon and certain Potamotrygon are the most caught species and the first is the most sought. In the Río de la Plata region, the meat of P. brachyura is particularly prized and locally the species is called raya fina (fine ray). Freshwater rays weighing less than are generally discarded, but have a low survival rate. Their meat is mainly consumed locally, but is also exported to Japan and South Korea. From 2005 to 2010, the reported capture in the Brazilian states of Amazonas and Pará has ranged between per year. In contrast, some fishers believe they only can be used for traditional medicine, incorrectly thinking that the meat (not just the tail region around the stinger) is toxic. In captivity Freshwater stingrays are often kept in aquariums, but require a very large tank and will eat small tank mates. Although generally non-aggressive, their venomous stinger represents a risk and on occasion aquarists have been stung. The ease of keeping varies significantly: Some such as Potamotrygon motoro are considered relatively hardy in a captive setting, while others such as Paratrygon aiereba, Plesiotrygon nana and Potamotrygon tigrina are much more difficult to maintain. Several species are commonly bred in captivity, especially at East and Southeast Asian fish farms, which produce thousands of offspring each year. The more serious captive breeding efforts only began in the late 1990s when Brazil put in restrictions on their export of wild-caught individuals. Some captive farms produce hybrids (both intentionally to get offspring with new patterns and unintentionally because of a lack of males), but this practice is generally discouraged. In several US states there are regulations in place that limit the keeping of freshwater stingrays. Conservation The status of most species is relatively poorly known, but overall it is suspected that river stingrays are declining due to capture (for food and the aquarium industry) and habitat loss (mainly due to dams and pollution from mining). Zoos and public aquariums in Europe and North America have initiated programs, including studbooks, for several Potamotrygonidae species.