Abstract
Franciscanas are the most endangered dolphins in the Southwestern Atlantic. Due to their coastal and estuarine habits, franciscanas suffer from extensive fisheries bycatch, as well as from habitat loss and degradation. Four Franciscana Management Areas (FMA), proposed based on biology, demography, morphology and genetic data, were incorporated into management planning and in the delineation of research efforts. We re-evaluated that proposal through the analysis of control region sequences from franciscanas throughout their distribution range (N = 162), including novel sequences from the northern limit of the species and two other previously unsampled localities in Brazil. A deep evolutionary break was observed between franciscanas from the northern and southern portions of the species distribution, indicating that they must be managed as two Evolutionarily Significant Units (ESU). Furthermore, additional FMAs should be recognised to accommodate the genetic differentiation found in each ESU. These results have immediate consequences for the conservation and management of this endangered species.
Highlights
The franciscana Pontoporia blainvillei (Gervais & d’Orbigny, 1844), is a small dolphin endemic to the Southwestern Atlantic, from the state of Espırito Santo, Brazil (,18uS), to the province of Chubut, Argentina (,42uS) [1]
Our analyses indicate the existence of five franciscana populations (ARG+URU+RS/SC+PR+SPS+SPC/SPN+RJS/Rio de Janeiro (RJN)/efforts. FMAIa (ES)), of which RJN and ES are the genetically most differentiated
The analyses reveal that the species is subdivided into two Evolutionarily Significant Units, each with a higher number of populations (Franciscana Management Areas) than previously recognised
Summary
The franciscana Pontoporia blainvillei (Gervais & d’Orbigny, 1844), is a small dolphin endemic to the Southwestern Atlantic, from the state of Espırito Santo, Brazil (,18uS), to the province of Chubut, Argentina (,42uS) [1]. Franciscanas are the most endangered dolphins in the Southwestern Atlantic [4,5] representing the only South Atlantic dolphin species in the Red List of the International Union for Conservation of Nature (listed as vulnerable, A3d). Due to their coastal and estuarine habits, franciscanas inhabit areas of heavy human activity, which poses several threats to their conservation. Where franciscanas still exist in proximity to urban centers, contamination levels are a matter of concern [18,19,20,21,22,23]
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