Changes in the numbers of spotted seals (<i>Phoca largha</i>) in Bakkai port and on Yagishiri Island in Hokkaido, Japan from 2003 to 2009

DOI Web Site
  • Kato Mio
    Laboratory of Aquatic Management, Department of Aqua-Bioscience and Industry, Faculty of Bioindustry, Tokyo University of Agriculture
  • Kobayashi Mari
    Laboratory of Aquatic Management, Department of Aqua-Bioscience and Industry, Faculty of Bioindustry, Tokyo University of Agriculture NPO Marine Wildlife Center of JAPAN
  • Ito Miyuki
    Free investigators of Bakkai village
  • Kono Yasuo
    Free investigators of Yagishiri Island

Bibliographic Information

Other Title
  • 北海道稚内市抜海港および焼尻島の2003年から2009年におけるゴマフアザラシの個体数変動
  • ホッカイドウ ワッカナイシ バツ カイコウ オヨビ ヤギシリトウ ノ 2003ネン カラ 2009ネン ニ オケル ゴマフアザラシ ノ コタイスウ ヘンドウ

Search this article

Abstract

<p>In this study, we analyzed annual and seasonal changes in the numbers of spotted seals (Phoca largha) hauled out in the area around Bakkai and Yagishiri in the Japan Sea from 2003 to 2009, for the first time. The number of animals observed tended to increase over the years at both sites, but the increment was bigger in Bakkai than Yagishiri. This is thought to be due to spatial differences among the haul-out sites, with the former location having a larger area. In addition, seasonal changes in the numbers of seals were different; there was a single peak in Bakkai observed in winter, while Yagishiri had two peaks, one during winter and the other in spring. These seasonal changes are thought to be related to changes in the distribution of sea-ice in the Okhotsk Sea. Because adult seals are known to migrate to sea-ice areas to breed after winter, the seals counted in Yagishiri during spring reflect the number of sub-adults staying in this region.</p>

Journal

Keywords

Details 詳細情報について

Report a problem

Back to top