Population structure of two minke whales species (Balaenoptera acuturostrata and B. bonaerensis) in the southern hemisphere.

TEODORO, SARAH; FRUET PEDRO; CYPRIANO-SOUZA, ANA LUCIA; DALLA ROSA, LUCIANO; LIBERALI WEDEKIN, LEONARDO; SECCHI, EDUARDO; ; NEGRETE, JAVIER; MELO-SANTOS, GABRIEL; BONATTO, SANDRO;; PROIETTI, MAIRA

Barcelona

Conferencia; XXXIII Biennial Conference on the Biology of Marine Mammals; 2019

Society for marine mammalogy

In this study, we assessed the population genetic structure of Antarctic (Balaenoptera bonaerensis) and common (B. acuturostrata) minke whales in the Southern Hemisphere (SH), with special attention to the potential connectivity between western South Atlantic (WSA) and Antarctic Peninsula (AP). Mitochondrial DNA control region sequences were obtained for 21 samples (AP n=12, North n=1, Southeast n=5, and South Brazil n=3) of Antarctic minke whale and for 10 samples (South Brazil n=9, AP=1) of common minke whale. The latter were compared to sequences previously reported on GenBank (Northeast Brazil n=8; Chile n=3; South Atlantic n=1 and South Pacific n=14 sectors of the Southern Ocean) to infer population structure at larger scale in the SH, totaling 36 sequences (320bp). Antarctic minke whales showed a high genetic diversity (H=0.994; π=0.8%), with 19 haplotypes (715bp) defined by 55 variable sites. No genetic differentiation was found between WSA and AP whales. The mtDNA sequences for common minke whales revealed a high genetic diversity (H=0.860; π=0.5%) with 12 haplotypes (one newly described) defined by 26 variable sites. South Pacific sector samples were genetically different from all other localities. Additionally, animals sampled in the Northeast were differentiated (Fst=0.23; p=0.05) from those of Southeast Brazil. Mismatch distributions and neutrality tests indicated that populations of both species are not in equilibrium and are possibly experiencing a demographic expansion. Our results showed no genetic structuring between AP and WSA for Antarctic minkes based on mtDNA analysis. Such lack of structure has been previously reported for common minkes in the SH. However, we pinpointed a possible population subdivision within the WSA for B. acuturostrata. Such findings are important for better understanding the population structure and the migratory connections of minke whales in the SH, and should be complemented with other molecular markers for obtaining finer-scale results.