An overview of the Brazilian frog farming

Genetic structure of American bullfrog populations in Brazil

“…Little information about these individuals is available, and the outcome of this introduction is not confirmed nor discussed in the literature. The same is true for small-scale occasional introductions supported by individual breeders, without any official registers, such as a supposed bullfrog batch introduced from Mexico in the early 2000’s 38 .…”

“…Although there is very limited knowledge about the possible impacts of bullfrogs over native species in Brazil, this species is widespread in the south and southeast regions of the country, with limited distribution in the northeast and north 37 , 38 . There are over 150 known breeding facilities in the country, that produce around 400 tons/year, moving around 1.9 million USD 38 .…”

“…Although there is very limited knowledge about the possible impacts of bullfrogs over native species in Brazil, this species is widespread in the south and southeast regions of the country, with limited distribution in the northeast and north 37 , 38 . There are over 150 known breeding facilities in the country, that produce around 400 tons/year, moving around 1.9 million USD 38 . According to published accounts, bullfrogs were first imported to Brazil to produce meat for human consumption in 1935 by a Canadian technician named Tom Cyrril Harrison who brought either 300 individuals 39 or pairs 40 from an unknown locality to a Brazilian government breeding facility in the city of Rio de Janeiro 41 , 42 .…”

“…Escape and release of bullfrogs from farms are spatially correlated with feral bullfrog populations 43 – 45 , being the most likely cause considering the disconnected distribution of these populations in Brazil, although the dispersive potential of bullfrogs is not well documented. Although advances in technology and increased market demand have enabled bullfrog farming to expand greatly over the last 10–15 years 46 , many of the earlier frog farms failed in the 1990s 38 , resulting in massive releases of bullfrogs when businesses closed (Valdir Alves, owner of Pedrinhas bullfrog farm, personal communication). In the 1970s, an additional 20 pairs of adult bullfrogs were imported to Brazil 28 from the University of Michigan to São José do Rio Preto in São Paulo state by Luiz Dino Vizotto (C. M. Ferreira, personal communication).…”

“…If all the introduction events were successful, different lineages in the country might be going through an introgressive hybridization process due to the common practice among farmers of purchasing breeding stock from multiple farms in different states with the goal of increasing the genetic diversity of the frogs bred in their facilities (Romar’s bullfrog farm owner, personal communication) 38 . If only one event was successful, followed by strong selective pressures of breeding facilities, the genetic diversity of bullfrog populations in Brazil should be quite limited.…”