Applying the phylogeographic concept to identify franciscana dolphin stocks: implications to meet management objectives

High numbers of franciscanas (Pontoporia blainvillei) have been bycaught in gillnets for at least four decades. The impact is strong but not homogeneous along the species distribution range, and there evidence that one local population declining. Reliable stock determination important to evaluate how bycatch affects stocks so they can be preserved through management actions. Following phylogeographic approach Dizon et al. (1992), which applies a hierarchical classification scheme designations, available information relevant franciscana discreteness was reviewed, including data on distribution, response, phenotype genotype. Data mtDNA, morphometrics parameters all together provide splitting into stocks: two inhabiting coastal waters Brazil; third occurring Rio Grande do Sul State (southern Brazil) Uruguay, fourth Argentine waters. areas where these occur are herein called Franciscana Management Areas or FMA I IV. Although some cases such sub-division weak due lack data, use proposed FMAs recommended warrant effective scale.