Modelo probabilístico de distribuição de peixes migradores na bacia hidrográfica do rio Jacuí (RS)

• Ano de defesa: 2008
• Autor(a) principal: Alves, Thais Paz
• Orientador(a): Fontoura, Nelson Ferreira
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Pontifícia Universidade Católica do Rio Grande do Sul; Porto Alegre
• Palavras-chave em Português: BIOLOGIA; PEIXES; ZOOLOGIA; ICTIOLOGIA
• Link de acesso: http://hdl.handle.net/10923/5405

The aim of the present study was to identify the distribution patterns of migratory fishes in the Jacuí River basin (Rio Grande do Sul, Brazil), proposing a mathematical model of presumed distribution based on geomorphologic environmental data. Through maps of occurrence probability, we hope to contribute to decisions regarding basin environmental management. The analyzed species were: Salminus brasiliensis (dourado), Leporinus obtusidens (piava), Prochilodus lineatus (grumatã) and Pimelodus maculatus (pintado). Samples were made through interviews with fishermen and local inhabitants, covering the main channel and tributaries of the rivers Jacuí, Taquarí-Antas, Vacacaí, Vacacaí-Mirim, Pardo, Pardinho, Sinos and Caí. The probability of migratory fishes occurrence were adjusted through the LOGIT routine of the Software Idrisi Andes: P = e (bo + b1. altitude + b2. basin areas). (1+e(bo + b1. altitude + b2. basin area))-1, where P is the occurrence probability of the species (0-1) and b0, b1 e b2 are the equation parameters. The sampling program resulted in 204 interviews, being 187 considered as valid at 155 different sites. P. maculatus, present in 109 points (70. 3%), was the specie with wider distribution; while L. obtusidens, present only in 49 points (32. 6%), was the specie with the most restricted distribution. P. lineatus and S. brasiliensis showed intermediate results: 68 (43. 9%) and 56 points (36. 1%), respectively. Model accuracy, for estimated presence, ranged from 82% to 93%. Equation parameters were estimated as follow: S. brasiliensis: b0= -2,8762 ± 0. 2597; b1= -1,3028 ± 0. 0332; b2= 1,1487 ± 0,0301; L. obtusidens: b0= -0. 8364 ± 0. 2213; b1= - 1. 5564 ± 0. 0462; b2= 0,9947 ± 0,0206; P. lineatus: b0= -0. 3176 ± 0. 2731; b1= -1. 3067 ± 0. 0544; b2= 0,8128 ± 0,0177; P. maculatus: b0= -0,9487 ± 0. 3688; b1= -0,8269 ± 0. 0496; b2= 0,9255 ± 0,0304.