太平洋のトップ捕食者のバイオマス,サイズ,トロフィック状態
John Sibert1, John Hampton, Pierre Kleiber
1Joint Institute for Marine and Atmospheric Research, University of Hawaii, Honolulu, HI 96822, USA. sibert@hawaii.edu
まとめ
太平洋の漁業は,1950年以来,5千万トンのトンネと捕食動物を漁獲した. 大魚の数は減少したものの,全体的なバイオマスは健全であり,生態系に重大な影響があるが,壊滅的な影響ではないことを示している.
科学分野:
- マリン・バイオロジー マリン・バイオロジー
- 漁業 科学 漁業 科学
- エコシステムのダイナミクス
背景:
- 太平洋の漁業は,1950年以来,5千万トン以上のトンネや主要な捕食動物を漁獲しています.
- 人口バイオマスの大幅な減少と海洋の食物連鎖の崩壊に関する懸念がある.
研究 の 目的:
- 1950年から2004年までの太平洋のトンネ漁業が,人口バイオマスと人口規模構造に及ぼす影響を推定する.
- pelagicの生態系内のトップレベルの捕食者への影響を評価する.
主な方法:
- 1950年から2004年にかけての太平洋のトンネルの漁業に関する利用可能なすべてのデータの分析.
- 人口のバイオマスとサイズ構造に対する漁業の影響の推定.
- 捕獲量と人口のトロフィックレベルの変化の評価.
主要な成果:
- トナ種の現在のバイオマスは,未漁獲レベルの36%から91%の範囲で,管理目標を達成しています.
- 大型魚 (175cm以上) の割合は,人口の5%から約1%に減少しました.
- 漁獲のトロフィックレベルはわずかに低下したが,全体的なトロフィックレベルには大きな変化はなかった.
結論:
- 漁業は太平洋のトップレベルの捕食者に対して,実質的な,しかし壊滅的な影響を及ぼしていません.
- 太平洋の生態系に対する全体的な影響は軽微であるように思われる.
- 現在のバイオマスレベルは,大きな漁業圧力にもかかわらず,これらの魚群の回復力を示唆しています.
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