Revista Chilena de Historia Natural 81 (4): 547-560, 2008
RESEARCH ARTICLE
Migratory round-trip of individually identified humpback whales at the Strait of Magellan: clues
on transit times and phylopatry to destinations
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 index 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 minimum 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<sup>-1</sup> 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.
Key words:
Colombia, humpback
whales, migration, photo-identification, Strait of Magellan
