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海産哺乳類を中心とした生態系モデリングのための数理統計学的研究
https://fra.repo.nii.ac.jp/records/2010805
https://fra.repo.nii.ac.jp/records/2010805ac6b4ea0-0c41-4914-8766-9b3e1905ad4b
| 名前 / ファイル | ライセンス | アクション |
|---|---|---|
fra_k_10_18.pdf (8.0 MB)
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| Item type | 紀要論文 / Departmental Bulletin Paper(1) | |||||
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| 公開日 | 2024-10-02 | |||||
| タイトル | ||||||
| タイトル | 海産哺乳類を中心とした生態系モデリングのための数理統計学的研究 | |||||
| 言語 | ja | |||||
| タイトル | ||||||
| タイトル | A statistical study for ecosystem modeling focused on marine mammals | |||||
| 言語 | en | |||||
| 言語 | ||||||
| 言語 | jpn | |||||
| キーワード | ||||||
| 言語 | en | |||||
| 主題Scheme | Other | |||||
| 主題 | abundance estimation; ecosystem modeling; marine mammals; prey preference; stock structure | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_6501 | |||||
| 資源タイプ | departmental bulletin paper | |||||
| アクセス権 | ||||||
| アクセス権 | open access | |||||
| アクセス権URI | http://purl.org/coar/access_right/c_abf2 | |||||
| 著者 |
岡村, 寛
× 岡村, 寛 |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | Most of cetacean species are highly migratory and difficult to keep in captivity so that it is not easy to grasp precise status of the populations. On the other hand, the limitation of the management based on single species has been recognized and the demand on the ecosystem-based population assessment and management has been increasing over the world. It is important to know the status of the population precisely and accurately as far as we can in ecosystem-based approach. To extract information efficiently from the data in which a lot of uncertainty exist and grasp the status of the population precisely and accurately, the use of statistical models is essential. This paper focuses on population assessment of marine mammals and develops some statistical models. Furthermore, the competition between marine mammals and fishery is investigated using an ecosystem model. Marine mammals are one of the important top-predators in an offshore ecosystem. The information on the distribution, migration, and stock structure is therefore indispensable to the construction of the offshore ecosystem model. In addition, the degree that the biological resource is affected by the catch greatly varies with the assumption of the stock structure in the procedure developed by the International Whaling Commission (IWC) for the management of large baleen whales. The regression analyses based on the generalized linear and additive models are useful for modeling the complicated phenomena such as the temporal-spatial structure of biological resources. In this paper, the spatial distribution and seasonal changes of the density of the western North Pacific minke whales was estimated using the generalized additive model so that there was no evidence that multiple stocks exist in the western North Pacific. On the other hand, the seasonal change of the density reproduced the aspect of migration of the minke whales well. The investigation of temporal-spatial distribution of biological resources using the regression models can be extensively useful for other species other than marine mammals. Line transect sampling is a standard method for estimating the population size of marine mammals. One of the important assumptions in standard line transect sampling is that all animals on the trackline are detected without fail. However, the surfacing-diving behavior of marine mammals for respiration and feeding can lead to failures in detection even if they are on the trackline. As a result, the population size tends to be underestimated. Although the underestimation of the population size brings conservative effect on single-species management, it leads to another problem in ecosystem approach because the impact by consumption of predator is underestimated. Conventional methods for estimating the detection probability on the trackline have several problems. The flexible method developed in this paper modified and improved such problems. Simulation studies showed that the method is promising. In addition, it was confirmed that the present method is able to be applied to real data sets using Antarctic minke whales data. The prey-predator interaction is extremely important in ecosystem modeling. If we can know preference of animals in laboratory, we can estimate diet composition of animals non-lethally by putting the information on the preference and the availability of animals obtained from sighting survey together. Preference for multiple food items can be measured in the laboratory by choice tests like cafeteria trials, in which an animal is initially offered a variety of foods that are equally available at the same time. However, the results of the multiple-choice experiments can be affected by many factors such as placement, amounts of foods, and the length of time that the experimental animal is permitted to eat. An alternative way to determine multiple-preference is to repeat a series of paired comparisons. The paired comparisons have an advantage over the multiple-choice tests because the design of each trial is simpler so that the conditions of the experiment can be easily controlled. The data collected from paired comparisons can be analyzed with the Bradley-Terry model. However, conventional Bradley-Terry model has some defects; for instance, it is not able to deal with the amount of consumption. This paper proposes a modification of the estimation method used in the Bradley-terry model. The maximum likelihood estimation based on a binomial distribution in the original model is replaced with the nonlinear least squares method. Furthermore, some simple methods to estimate the precision of parameters and to test several hypotheses on preferences are provided. The methods were applied to the analysis of food preference of a captive northern fur seal. The comparison between the method and the conventional Bradley-Terry model indicated that the statistical power of the method can be higher than the conventional one. Finally, the ecosystem model off Sanriku area using Ecopath was constructed and the competition between consumption of whales and fishery was investigated by Ecosim. The strong competition was found under the setting of a certain parameter. The precise estimation of parameters and the appropriate incorporation of uncertainty are extremely important because the results are sensitive to the input parameters. The statistical models developed in this paper gave improvements upon the previous ones in some ways. The population trajectory predicted from the ecosystem model tends to depend much on input parameter estimates. Therefore, the importance of estimation of the parameters used in ecosystem models will be increasing in the future. In the problems such as wildlife and ecosystem conservation, and a food shortage, reasonable assessment and management of aquatic resources is still more important. To construct ecosystem models incorporating uncertainty appropriately and making the best use of information the data have at the maximum is a big theme to be attained in the twenty one century. | |||||
| 言語 | en | |||||
| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | 多くの鯨類のように，高度回遊性を持ち，飼育の困難な生物の正確な資源状態を知ることは容易ではない。一方で近年，単一種に基づいた生物種の管理の限界が認識され，生態系全体を考慮した資源評価・管理への需要が高まってきている。生態系モデルは一般に多くの不確実性を被るので，生態系を考慮したアプローチでは，各生物の資源状態をできるだけ正確で精度良く把握する必要がある。また，不確実性の大きいデータから効率よく情報を引き出し，生物資源の状態を正しく把握するためには，統計モデルの活用が重要となる。本論文の構成は次の通りである。第 1 章では，過去の海産哺乳類の資源評価・管理の歴史と現状，および近年の水産資源に対する生態系モデル研究の概要を述べた。第 2 章では，鯨類資源の分布・系群構造把握のための共変量モデルの開発と北太平洋ミンククジラへの適用を行った。北太平洋ミンククジラの空間的な分布，季節的な変動を推定した結果，複数系群が存在するという証拠は得られなかった。密度の季節変動は，ミンククジラの回遊の様子をよく再現しており，本方法の有効性が確認された。回帰モデルを利用した時空間分布の把握は，他の水産資源の分布・回遊の把握にも有効に働くと考えられ，本方法を広く水産生物の動態の分析に応用することが可能である。第 3 章では，目視調査線上の見落とし率の補正を含む新しい個体数推定法の開発を行い，シミュレーションや実際のデータへの適用により本方法の有効性を確認した。従来の調査線上の発見確率推定法では，発見したクジラの追跡などの調査デザインの変更や，潜水時間に関する外部データの必要性，情報の不完全な使用，近似尤度の使用などいくつかの問題点があった。そのような問題点を改良・修正することにより，柔軟で一般化した推定量を与える方法を開発した。第 4 章では，鰭脚類の実験データから，定量的に動物の嗜好性を調べる方法の開発を行った。従来のモデルでは，消費量の情報を直接扱えない，1 種類の餌のみが利用される全勝データを扱えないなどの欠点により，検出力の低下，偏りの問題が想定されるが，それらの欠点を解消した方法を開発した。さらにパラメータの精度と嗜好性に関するいくつかの仮説を検定するためのシンプルな方法を提示した。第 5 章では，生態系モデル・エコパスを三陸生態系に適用し，鯨類と漁業の競合関係の検証を行った。パラメータの設定によっては，競合関係の存在が支持され，パラメータの精度の良い推定，不確実性の取り込みの重要性が確認された。最後に，第 6 章において，本論文で開発した統計モデルの長所・短所，生態系モデル開発の重要性および将来の展望について議論した。 | |||||
| 言語 | ja | |||||
| 書誌情報 |
ja : 水産総合研究センター研究報告 en : Bulletin of Fisheries Research Agency 巻 10, p. 18-100, ページ数 83, 発行日 2004-03 |
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| 出版者 | ||||||
| 出版者 | 水産総合研究センター | |||||
| 言語 | ja | |||||
| ISSN | ||||||
| 収録物識別子タイプ | PISSN | |||||
| 収録物識別子 | 1346-9894 | |||||
| 書誌レコードID | ||||||
| 収録物識別子タイプ | NCID | |||||
| 収録物識別子 | AA11589591 | |||||
| 情報源 | ||||||
| 識別子タイプ | Local | |||||
| 関連識別子 | fra_k_10_18 | |||||
| 関連サイト | ||||||
| 識別子タイプ | URI | |||||
| 関連識別子 | https://agriknowledge.affrc.go.jp/RN/2010692577 | |||||
| 関連名称 | 日本農学文献記事索引（AgriKnowledge） | |||||
| 著者版フラグ | ||||||
| 出版タイプ | VoR | |||||
| 出版タイプResource | http://purl.org/coar/version/c_970fb48d4fbd8a85 | |||||
