Population Structure of the Endangered Franciscana Dolphin (Pontoporia blainvillei): Reassessing Management Units

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.

Distribution, habitat use, and abundance of the endangered franciscana in southeastern and southern Brazil

“…Correctly identifying and effectively managing anthropogenic threats is paramount for protecting endangered species (Kelleher, ; Slooten et al, ). Based on the potential demographic isolation between franciscanas inhabiting FMA IIa and FMA IIb (Cunha et al, ), results presented in this study should be used to guide local management actions at finer geographic scale. The present results indicate that franciscanas occur in relatively high densities in FMA IIa stratum.…”

Evolutionary impacts differ between two exploited populations of northern bottlenose whale (Hyperoodon ampullatus)

“…Few studies of cetaceans have used the full mitogenome to reconstruct demography with Bayesian skyline analyses (but see Cunha et al, 2014;Morin et al, 2013;Morin et al, 2018). Most have relied on comparatively short fragments of mtDNA (414-2494 bp) (Attard et al, 2015;Phillips et al, 2013;Thompson et al, 2016) and were not able to identify more recent impacts within the last 2-10 kya.…”

Estimating total length in damaged carcasses of franciscana dolphins, Pontoporia blainvillei

“…, Cunha et al . ) and it is recognized that animals from southeastern Brazil have smaller total length than the southern counterparts studied here (Pinedo , Barreto and Rosas ). Consequently, the effectiveness of the presented morphometric relationships to estimate TL in other franciscana populations should be confirmed.…”