Photo‐identification matches of humpback whales (Megaptera novaeangliae) from feeding areas in Russian Far East seas and breeding grounds in the North Pacific

Abstract

Humpback whales migrate seasonally from high latitude feeding areas to lower latitude breeding areas for mating and calving. In 2004-2006, a North Pacific basin-wide study called SPLASH was conducted as an international collaboration among various groups of researchers. The Russian Far East consists of multiple high latitude feeding areas and during SPLASH, 102 whales were identified and compared to catalogs from breeding areas. Our goal in this study was to further investigate the migratory destinations of whales from the Russian Far East using a total of 1,459 photographs of whales identified from 2004 to 2014. We compared the latest Russian catalog with the SPLASH catalog from wintering areas (2004)(2005)(2006) and with two additional regional catalogs from Okinawa (1989Okinawa ( -2006 and the northern Philippines (2000Philippines ( -2006. We found a total of 152 matches: 106 with Asian, 35 with Hawaiian, and 11 with Mexican breeding grounds. The match rate was higher in mainland Kamchatka and consisted mostly of whales from the Asian breeding ground. In the Commander Islands, the proportion of whales from Asia was twice that of Hawaii and six times higher than Mexico. The total match rate was low, supporting the hypothesis of some undiscovered humpback whale breeding location in the North Pacific.

Convergence and divergence of songs suggests ongoing, but annually variable, mixing of humpback whale populations throughout the North Pacific

“…This study, along with previous song comparison studies, indicates that populations of humpback whales throughout the North Pacific mix on an ongoing basis, and have done so for as long as we have studied them. Photo-identification matches and satellite tagging clearly indicate the potential for ocean-wide mixing, with individuals on one feeding ground migrating to different winter assembly locations; individuals changing their winter destination year to year - and even one record of multiple crossings of the Pacific from Asia to the North American coast 32–42 . However, to date the import of this mixing has often been minimized, as separate North Pacific ‘stocks’ were designated 29,33,40 .…”

Interchange and movements of humpback whales (Megaptera novaeangliae) between western North Pacific winter breeding grounds in northern Luzon, Philippines and Okinawa, Japan

“…Hence, the researchers concluded that these whales must be going to a previously unsampled wintering ground (Baker et al, 2013;Barlow et al, 2011;Calambokidis et al, 2008). This hypothesis was further supported by Titova et al (2018) who found a low overall match rate of individual whales from Russia and the Aleutians to any of the wintering grounds in the North Pacific.…”

“…Although it has been demonstrated in previous work based on photo-identification and genetic studies that the Philippines, Okinawa and Ogasawara are winter breeding destinations for humpback whales in the western North Pacific (Baker et al, 2008;Calambokidis et al, 2008;Titova et al, 2018;Witteveen et al, 2009), the SPLASH study postulated the existence of a second unknown breeding population. The SPLASH data indicated that the whales feeding from the Aleutians and Bering Islands were not well represented in any of the wintering grounds surveyed during their study.…”

“…Humpback whales (Megaptera novaeangliae) are widely distributed in oceans worldwide and migrate from higher latitude feeding grounds in the summer to lower latitude breeding grounds in the winter (Baker et al, 1986;Chittleborough, 1965;Clapham and Mead, 1999;Dawbin, 1966;Katona and Beard, 1990). In the North Pacific, the summer feeding range of humpback whales spans the Okhotsk Sea, Commander Islands, Chukotka Peninsula, Kamchatka, Russia, Aleutian-Bering Sea, Gulf of Alaska, southeast Alaska and North British Columbia, Washington/South British Columbia, California-Oregon coast and waters off California (Calambokidis et al, 2008;Calambokidis et al, 1996;Titova et al, 2018). Five winter breeding grounds are now known in the North Pacific (Calambokidis et al, 2008): in the western North Pacific: (1) the waters of Ogasawara (Bonin Islands) and Okinawa (Ryukyu) in Japan and the Babuyan Islands, northern Philippines, referred to as the Asian breeding ground; (2) a second western North Pacific population whose location is unknown, which is believed to migrate through Ogasawara (Bettridge et al, 2015); in the central North Pacific; (3) around the waters of the main Hawaiian Islands or the Hawaiian breeding ground; in the eastern North Pacific; (4) the Mexican breeding ground which includes the Revillagigedo Islands, Baja, California and the coast of mainland Mexico; and (5) the Central American breeding ground, off the waters of southern Mexico to Costa Rica (Craig and Herman, 1997;Darling and Mori, 1993;Herman, 1980;Herman and Antinoja, 1977;Nishiwaki, 1966;Titova et al, 2018;Urban and Aguayo, 1987) (Fig.…”

Tracking North Pacific Humpback Whales To Unravel Their Basin-Wide Movements

“…Thus, satellite tracking has thus demonstrated the connection between Hawaii, the Aleutian Islands, and the Bering Sea with unprecedented detail (see also Kennedy et al 2014), supporting the treatment of the Aleutians and the Bering Sea together for abundance estimation (Wade et al 2016, Wade 2017. Interestingly, results from photo-ID and genetic studies of humpback whales in eastern Russia indicate a high degree of separation between the Commander Islands (at the western end of the Aleutians), the east side of Kamchatka Peninsula, and the Gulf of Anadyr, despite their geographic proximity (Calambokidis et al 2008, Titova et al 2017, Richard et al 2018. However, the satellite tracking data from 1997 and 2018 indicated that whales from Hawaii may visit several of these areas, even within the same feeding season.…”