Dear MARMAM community,
My co-authors and I are pleased to share our new publication titled, Interchanges and movements of humpback whales in Japanese waters: Okinawa, Ogasawara, Amami, and Hokkaido using an automated matching system, which is now available in the open-access journal of PLOS ONE. by Nozomi Kobayashi, Satomi Kondo, Koki Tsujii, Katsuki Oki, Masami Hida, Haruna Okabe, Takashi Yoshikawa, Ryuta Ogawa, Chonho Lee, Naoto Higashi, Ryosuke Okamoto, Sachie Ozawa, Senzo Uchida, Yoko Mitani Abstract Humpback whales in the western North Pacific are considered endangered due to their small population size and lack of information. Although previous studies have reported interchanges between regions within a population, the relationship between the geographic regions of a population in Japan is poorly understood. Using 3,532 fluke photo IDs of unique individuals obtained from four areas in Japan: Hokkaido, six IDs (2009–2019); Ogasawara, 1,477 IDs, from two organizations (1) Everlasting nature of Asia (1987–2020) and (2) Ogasawara Whale Watching Association, (1990–2020); Amami, 373 IDs (1992–1994, 2005–2016); Okinawa, 1,676 IDs (1990–2018), interchanges were analyzed. The ID matchings were conducted using an automated system with an 80.9% matching accuracy. Interchange and within-region return indices were also calculated. As a result, number of matches and interchange indices follow locations, Hokkaido-Okinawa (3, 0.31), Amami-Ogasawara (36, 0.06), Amami-Okinawa (222, 0.37), and Okinawa-Ogasawara (225, 0.08), respectively. Interchange indices among Japanese areas were much higher than the indices between Ogasawara/Okinawa and Hawaii (0.01) and Mexico (0.00) reported in previous studies, indicating that the Japanese regions are utilized by the same population. At the same time, the frequency of interchanges among the three breeding areas vary, and the high within-region return indices in respective breeding areas suggest the site fidelity of the whales in each area at some level. These results indicate the existence of several groups within the population which are possibly be divided into at least two groups based on geographical features: one tend to utilize Ogasawara and the Mariana Archipelago; the other utilize Amami, Okinawa, and the Philippines, migrating along the Ryukyu and Philippine Trench. The matching results also suggest that Hokkaido is possibly be utilized as a corridor between northern feeding areas and southern breeding areas at least by individuals migrating to Okinawa area. The article is open-access, and full text PDF is available here: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0277761 Please feel free to contact us if you have questions! Warm regards, Nozomi Kobayashi -- ************************************************************* Nozomi Kobayashi, Ph. D. Chief Research Scientist Zoological Laboratory Okinawa Churashima Research Center Okinawa Churashima Foundation https://churashima.okinawa/en/ocrc/marine_organisms 小林希実 一般財団法人 沖縄美ら島財団 総合研究センター動物研究室 主任研究員 〒905-0206 沖縄県国頭郡本部町字石川888番地 TEL：0980-48-2266 FAX：0980-48-2200 E-mail：n-kobaya...@okichura.jp *************************************************************
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