Migratory round-trip of individually identified humpback whales at the Strait of Magellan: clues on transit times and phylopatry to destinations Ciclo migratorio de ballenas jorobadas individualizadas del estrecho de Magallanes: indicios sobre la duración de la migración y filopatría en los destinos

Humpback whales undertake seasonal migration between productive high-latitude areas where they feed in summer and low-latitude tropical waters where mating and calving occur during winter. In the eastern south Pacific, the species breeds off Colombia and Ecuador, and feeds primarily in the western Antarctic Peninsula and in the waters of the Strait of Magellan (SM), recently described as a new feeding ground for humpback whales. Comparison of fluke photographs of 62 individuals from the SM obtained during the austral summer from 1999 to 2005 and 1,042 individuals from Colombia, provided conclusive matches for six individuals, with an overall interchange Índex of 0.093. Eight migratory trips between summer and winter grounds were registered for four whales during a complete migratory round-trip in consecutive years. The mínimum distance traveled in a one-way trip ranged from 6,650 to 7,000 km. The duration of the two fastest trips between these migratory destinations was 88 and 99 days, with a mean speed of migration of 76 and 67 km day-1 respectively. Five of the whales present in both areas were males and three mitochondrial DNA haplotypes were identified: EM-1 for three individuals, EM-2 for two and EM-3 for the last one, all of which have been previously described for humpback whales from Colombia. All six individuals were seen several days in each season in the SM (as many as 39 days in one case), with an average stay of 72 ± 40 days (n = 20) per year, ranging from 3 to 125 days. On average, each of the six individuals was seen in the SM during 71 ± 18 % of the seven monitored summers. Three individuals were re-sighted in the SM six out of the seven surveyed years, during four to six consecutive years. These results provide the first direct evidence to include humpback whales that feed in the Strait of Magellan as part of the eastern south Pacific population of whales that feed off Colombian waters.La ballena jorobada migra estacionalmente entre latitudes altas donde se alimenta en verano y latitudes bajas donde cría y se aparea en invierno. En el Pacífico sureste, la especie se reproduce en Colombia y Ecuador y se alimenta principalmente al oeste de la península Antartica, y en el estrecho de Magallanes (EM) recientemente descrito como nueva área de alimentación. Al comparar las fotografías de las colas de 62 ballenas individualizadas en el EM durante el verano austral entre 1999 y 2005 con 1.042 individuos de Colombia, se encontró a seis individuos comunes, lo que representa un índice de Intercambio migratorio de 0,093. Se registraron ocho migraciones para cuatro de estas ballenas entre el EM y Colombia en el ciclo migratorio de años consecutivos. La distancia mínima recorrida en una sola dirección varió entre 6.650 y 7.000 km. La duración de los dos viajes más rápidos registrados entre estos dos destinos fue de 88 y 99 días, con una velocidad promedio de migración de 76 y 67 km día-1 respectivamente. Cinco de las seis ballenas comunes entre las areas fueron machos. Entre las seis ballenas se encontraron tres haplotipos de ADN mitocondrial todos descritos previamente en ballenas jorobadas de Colombia: tres ballenas con el haplotipo EM-1, dos con el EM-2 y uno con el EM-3. Los seis individuos se avistaron reiteradamente en el EM (hasta 39 días en una estación en un caso), con una permanencia promedio de 72 ± 40 días (n = 20) por año y un rango entre 3 y 125 días. En promedio, estas seis ballenas se vieron durante el 71 ± 18 % de las siete temporadas muestreadas en el EM y tres se registraron seis de lo siete años estudiados, por 4-6 años consecutivos. Esta es la primera evidencia directa para incluir las ballenas jorobadas que se alimentan en el estrecho de Magallanes como parte de la población del Pacífico sureste que se reproduce en aguas colombianas

Genetic differentiation between humpback whales (Megaptera novaeangliae) from Atlantic and Pacific breeding grounds of South America

Humpback whales wintering in tropical waters along the Atlantic and Pacific coasts of the South American continent are thought to represent distinct populations or “stocks.” Here we present the first analysis of genetic differentiation and estimates of gene flow between these breeding stocks, based on both mitochondrial DNA (mtDNA) control region sequences (465 bp) and 16 microsatellite loci from samples collected off Brazil (n = 277) and Colombia (n = 148), as well as feeding areas near the western Antarctic Peninsula (n = 86). We found significant differentiation between Brazilian and Colombian breeding grounds at both mtDNA (FST = 0.058) and microsatellite (FST = 0.011) markers and corroborated previous studies showing genetic similarity between humpbacks from Colombia and those from Antarctic Peninsula feeding areas. Estimates of long-term gene flow between Brazil and Colombia were low to moderate, asymmetrical, and mostly mediated by males. Assignment procedures detected some cases of interchange and individuals of admixed ancestry between breeding grounds, indicating limited mixing of individuals between these stocks. Overall, results highlight the differentiation of humpback whale breeding populations with adjacent feeding grounds. This appears to be a remarkable example of fidelity to seasonal habitat in the absence of any contemporary barriersThis work was supported by Coordenac ~ao de Aperfeic oamento de Pessoal de N ıvel Superior (CAPES) to ALC-S; Conselho Nacional de Desenvolvimento Cient ıfico e Tecnol ogico (CNPq) to SLB; Fundac ~ao de Amparo a Pesquisa do Estado do Rio Grande do Sul (FAPERGS) to SLB; Instituto Chico Mendes de Conservac ~ao da Biodiversidade/Minist erio do Meio Ambiente (ICMBIO/MMA); and Petr oleo Brasileiro S.A (PETROBRAS). Special support was given by CAPES for the scholarship award to ALC-S to conduct part of her doctoral research as a visiting student at Oregon State University (OSU). Biopsy samples were collected off Brazil under permit SISBIO 21489-1