Migratory round-trip of individually identified humpback whales at the Strait of Magellan: clues on transit times and phylopatry to destinations

Abstract

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 -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.Key words: Colombia, humpback whales, migration, photo-identification, Strait of Magellan. RESUMENLa 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 Antártica, 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 Indice 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...

Patterns of Spatial and Temporal Distribution of Humpback Whales at the Southern Limit of the Southeast Pacific Breeding Area

“…The travelled distance is approximately 3000 to 4000 km longer than that estimated for other migrating humpback whale populations worldwide [9]. This extended migration is explained because humpbacks whales seem to search for warmer habitats to avoid the influence of the cold upwelling waters of the Humboldt Current ecosystem extending from central-southern Chile (∼40°S) to northern Peru (∼4°S) during their breeding migration [10], [11].…”

Short‐term recovery of humpback whales after percutaneous satellite tagging

“…Our results suggest that the tag does not impair reproductive behavior, as shown by the female that returned with a new calf every 3 years after tagging. Lack of reproduction in 2 of our whales does not indicate reproductive failure, at least for this population, considering that of 51 adult females monitored within 2–17 years in the Magellan Strait, 31.4% were never observed with a calf (Capella et al ). However, we recognize the potential impacts of tagging on whale health and breeding success as previously suggested (Gendron et al ).…”

“…We tagged whales at the Francisco Coloane Marine Protected Area, which encompasses the areas of Whale Sound, Magellan Strait, and Charles Islands off Carlos III Island (53°37′S, 72°21′W). The feeding concentration of humpback whales in the Strait of Magellan can be considered a seasonal subpopulation of the Stock G. Humpbacks have been systematically studied for 18 consecutive feeding seasons from 1999 to 2016 in the strait, with approximately 85% site fidelity (Gibbons et al ; Capella et al , ). Presently, 177 individuals have been identified from photographs of their unique natural marks and pigmentation and scars on the ventral fluke and dorsal fin (Katona and Whitehead ), and a seasonal abundance of about 120 individuals is estimated (Capella et al ), representing about 2.5% and 1.7%, respectively, of estimated population for Stock G (Félix et al ).…”

“…We evaluated the initial behavioral response, healing process, survival rates, and short‐term reproductive behavior and success of 7 percutaneous‐tagged whales incidentally monitored for 4–10 years. We obtained nearly 2 decades of sighting records from each individual's annual visits to the feeding ground in the Magellan Strait (Capella et al ), which provided a unique opportunity for the assessment of animal welfare.…”

Movements and Timing of Humpback Whales (Megaptera novaeangliae) Within the Breeding Region of the Eastern South Pacific

“…The connectivity between some feeding and breeding grounds has been demonstrated through photoidentification (Stone et al, 1990;Stevick et al, 2004;Acevedo et al, 2007;Rasmussen et al, 2007;Capella et al, 2008) and to a lesser extent with genetics (Caballero et al, 2001;Félix et al, 2012). In addition, regional movements of five individuals and a migratory path used by one humpback whale from the breeding region to feeding grounds has been recently characterized via satellite tracking (Félix & Guzmán, 2014).…”