タイトル |
イワナの資源管理 |
担当機関 |
秋田県水産振興センター |
研究期間 |
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研究担当者 |
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発行年度 |
2003 |
背景・ねらい |
ねらい: 生態系の保全に配慮したイワナ資源の管理手法及び増殖技術を開発する。 成果の特徴:
- 稚魚はカバー(遮へい物)を有する岸際の、主として流速5cm以下の緩流域で認められることから(図1、図2)、このような場所は稚魚の成育場所として保全していく必要がある。
- イワナの産卵床は川幅が2~3mの小支川に多く見られることから(図3)、産卵遡上を妨げる河川工作物の設置は避けるべきである。
- 調査河川では、在来種であるイワナと放流由来であるヤマメが混生していた。両者は、餌料や生息場所を巡って競合関係にあると考えられることから、ヤマメは本来の生息域である堰堤より下流域を生息域とし、それより上流域はイワナの生息を優先する。
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- 調査した支川では0.08~0.11尾/m2の密度でイワナの成魚が生息しており(表1)、種苗放流によって資源を増大させるほどではない。しかしながら、禁漁区であるこの支川を解禁した場合、遊漁による影響はかなり大きいものと考えられる。ここではむしろ、生息環境や産卵環境の整備などにより自然繁殖の促進を図りながら、今後も禁漁区として管理していく方が有効である。
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成果の活用面・留意点 |
各河川に固有の遺伝資源を持つとされるイワナ個体群の増殖及び資源管理対策に利用できる。
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図表1 |
![229463-1.png](https://s3-agre-content.s3.ap-northeast-1.amazonaws.com/assets/images/seika_chart/229463-1.png?X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEGsaDmFwLW5vcnRoZWFzdC0xIkYwRAIgSHhNBla5aEqpQQs%2BtgVc9inB%2FbLC%2FsOYgavEWpg4TfgCICQx%2BWsRyHlAXEymxUiYnfbT9G1%2Bfp57SOeZVIiHjGOPKpAECCQQAhoMNTMyMzMxMDcyMDQxIgx68HDNE9YkK6a7DaIq7QMzZFCvWIGXKkDj86%2B8r3%2Bv3v1qTKO4GyF4UdmYlCHN30dH5RDTqmcCWAhm0iA8aFcTYNZqR%2Fo37ngN9mccleSqjdBE8SvmCnPJDV%2BXhe45yP8jNfNppeGGobuTmX%2FB6XvgpVqdLgYEu03uoJKhG6AZYNxAzyP4TBF%2FNMRanG5S%2B%2FTyaJnKtwaShJ7OK1mtCd%2FwGDUVThq8P6n%2BiNWk7TZLl24D9Gq0VYtTAL%2BfN3ldtFy3Qb0GZiyhLSeObUVyGRE8OcZx4yCD6CUUxL7UWp%2F%2F8nbzxrPPHuiVuoqjDM0G7Gi4ZGVeI1gG9W%2ByLKxuFZ%2FTTrG%2ByF%2FGgnTP6TdN3ZBfMV2LL2x7NEUGSZ2VxK1P7jdJmdMcYyTG8IJYzxh1GiCkwdLNgbuQU%2F6vTONX5W%2BnLnn15h%2B2Qc3H2k8hgAGV5ZVrI%2FCc2Ss3HE%2Bs2GHtqTLg%2Bn%2FP%2BafeUZEXU3xpMdFkBqqlQaYZYzWts4Vmw6jEKo%2BsBJr64p2BWbpOJY1GkJoxwslIgsebDP04XqCuBafcMEBKg5OguRnXp%2Bl78RokkecVcrY%2Ba8Js%2F3wlh2CY4wLSkp5lfdBvBoLf4t229X0wmr9L0YneerCcMOeKgjE0aQTs7TWIUTgRQbP9VKHGl2UhZ9oe2cS4FUPQkGhvMMv3%2FbMGOqcBd3KSu%2BwUhczuYXOOlONashc8UCP7juAX1jo4LvTE%2Fm0yrwW%2BNBlIWOnyigYx3zh4AnibHrzbq5nq1bBC8Fieop1OKSWl2UhV0MUcfCn3wfMphFMmoqdu51NoWSHZjSGqzfKa26rat9AOM%2FjuK75RCVG%2F3Ge5EnFjv9XoPN%2BiPdQVA%2BFTyO2V8YeWiTl1pb4sDWmbVC%2BBcxN4T37LYDZaBhuBTdksvD0%3D&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=ASIAXX4LHRIU3PX5ATAH%2F20240629%2Fap-northeast-1%2Fs3%2Faws4_request&X-Amz-Date=20240629T032405Z&X-Amz-SignedHeaders=host&X-Amz-Expires=1800&X-Amz-Signature=3ab255716c9c1967e9bfc0cd7fa77f66211d1e937805de2391c9e346c8c900e8) |
図表2 |
![229463-2.png](https://s3-agre-content.s3.ap-northeast-1.amazonaws.com/assets/images/seika_chart/229463-2.png?X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEGsaDmFwLW5vcnRoZWFzdC0xIkYwRAIgSHhNBla5aEqpQQs%2BtgVc9inB%2FbLC%2FsOYgavEWpg4TfgCICQx%2BWsRyHlAXEymxUiYnfbT9G1%2Bfp57SOeZVIiHjGOPKpAECCQQAhoMNTMyMzMxMDcyMDQxIgx68HDNE9YkK6a7DaIq7QMzZFCvWIGXKkDj86%2B8r3%2Bv3v1qTKO4GyF4UdmYlCHN30dH5RDTqmcCWAhm0iA8aFcTYNZqR%2Fo37ngN9mccleSqjdBE8SvmCnPJDV%2BXhe45yP8jNfNppeGGobuTmX%2FB6XvgpVqdLgYEu03uoJKhG6AZYNxAzyP4TBF%2FNMRanG5S%2B%2FTyaJnKtwaShJ7OK1mtCd%2FwGDUVThq8P6n%2BiNWk7TZLl24D9Gq0VYtTAL%2BfN3ldtFy3Qb0GZiyhLSeObUVyGRE8OcZx4yCD6CUUxL7UWp%2F%2F8nbzxrPPHuiVuoqjDM0G7Gi4ZGVeI1gG9W%2ByLKxuFZ%2FTTrG%2ByF%2FGgnTP6TdN3ZBfMV2LL2x7NEUGSZ2VxK1P7jdJmdMcYyTG8IJYzxh1GiCkwdLNgbuQU%2F6vTONX5W%2BnLnn15h%2B2Qc3H2k8hgAGV5ZVrI%2FCc2Ss3HE%2Bs2GHtqTLg%2Bn%2FP%2BafeUZEXU3xpMdFkBqqlQaYZYzWts4Vmw6jEKo%2BsBJr64p2BWbpOJY1GkJoxwslIgsebDP04XqCuBafcMEBKg5OguRnXp%2Bl78RokkecVcrY%2Ba8Js%2F3wlh2CY4wLSkp5lfdBvBoLf4t229X0wmr9L0YneerCcMOeKgjE0aQTs7TWIUTgRQbP9VKHGl2UhZ9oe2cS4FUPQkGhvMMv3%2FbMGOqcBd3KSu%2BwUhczuYXOOlONashc8UCP7juAX1jo4LvTE%2Fm0yrwW%2BNBlIWOnyigYx3zh4AnibHrzbq5nq1bBC8Fieop1OKSWl2UhV0MUcfCn3wfMphFMmoqdu51NoWSHZjSGqzfKa26rat9AOM%2FjuK75RCVG%2F3Ge5EnFjv9XoPN%2BiPdQVA%2BFTyO2V8YeWiTl1pb4sDWmbVC%2BBcxN4T37LYDZaBhuBTdksvD0%3D&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=ASIAXX4LHRIU3PX5ATAH%2F20240629%2Fap-northeast-1%2Fs3%2Faws4_request&X-Amz-Date=20240629T032405Z&X-Amz-SignedHeaders=host&X-Amz-Expires=1800&X-Amz-Signature=7e5714746ef793de820b60dc81522686f91b24c4c335656e289c99515672489e) |
図表3 |
![229463-3.png](https://s3-agre-content.s3.ap-northeast-1.amazonaws.com/assets/images/seika_chart/229463-3.png?X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEGsaDmFwLW5vcnRoZWFzdC0xIkYwRAIgSHhNBla5aEqpQQs%2BtgVc9inB%2FbLC%2FsOYgavEWpg4TfgCICQx%2BWsRyHlAXEymxUiYnfbT9G1%2Bfp57SOeZVIiHjGOPKpAECCQQAhoMNTMyMzMxMDcyMDQxIgx68HDNE9YkK6a7DaIq7QMzZFCvWIGXKkDj86%2B8r3%2Bv3v1qTKO4GyF4UdmYlCHN30dH5RDTqmcCWAhm0iA8aFcTYNZqR%2Fo37ngN9mccleSqjdBE8SvmCnPJDV%2BXhe45yP8jNfNppeGGobuTmX%2FB6XvgpVqdLgYEu03uoJKhG6AZYNxAzyP4TBF%2FNMRanG5S%2B%2FTyaJnKtwaShJ7OK1mtCd%2FwGDUVThq8P6n%2BiNWk7TZLl24D9Gq0VYtTAL%2BfN3ldtFy3Qb0GZiyhLSeObUVyGRE8OcZx4yCD6CUUxL7UWp%2F%2F8nbzxrPPHuiVuoqjDM0G7Gi4ZGVeI1gG9W%2ByLKxuFZ%2FTTrG%2ByF%2FGgnTP6TdN3ZBfMV2LL2x7NEUGSZ2VxK1P7jdJmdMcYyTG8IJYzxh1GiCkwdLNgbuQU%2F6vTONX5W%2BnLnn15h%2B2Qc3H2k8hgAGV5ZVrI%2FCc2Ss3HE%2Bs2GHtqTLg%2Bn%2FP%2BafeUZEXU3xpMdFkBqqlQaYZYzWts4Vmw6jEKo%2BsBJr64p2BWbpOJY1GkJoxwslIgsebDP04XqCuBafcMEBKg5OguRnXp%2Bl78RokkecVcrY%2Ba8Js%2F3wlh2CY4wLSkp5lfdBvBoLf4t229X0wmr9L0YneerCcMOeKgjE0aQTs7TWIUTgRQbP9VKHGl2UhZ9oe2cS4FUPQkGhvMMv3%2FbMGOqcBd3KSu%2BwUhczuYXOOlONashc8UCP7juAX1jo4LvTE%2Fm0yrwW%2BNBlIWOnyigYx3zh4AnibHrzbq5nq1bBC8Fieop1OKSWl2UhV0MUcfCn3wfMphFMmoqdu51NoWSHZjSGqzfKa26rat9AOM%2FjuK75RCVG%2F3Ge5EnFjv9XoPN%2BiPdQVA%2BFTyO2V8YeWiTl1pb4sDWmbVC%2BBcxN4T37LYDZaBhuBTdksvD0%3D&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=ASIAXX4LHRIU3PX5ATAH%2F20240629%2Fap-northeast-1%2Fs3%2Faws4_request&X-Amz-Date=20240629T032405Z&X-Amz-SignedHeaders=host&X-Amz-Expires=1800&X-Amz-Signature=992cee58ffa4c318cdbf7449f72abcdbdad5d015fb66b13171ae431d6129fb82) |
図表4 |
![229463-4.png](https://s3-agre-content.s3.ap-northeast-1.amazonaws.com/assets/images/seika_chart/229463-4.png?X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Security-Token=IQoJb3JpZ2luX2VjEGsaDmFwLW5vcnRoZWFzdC0xIkYwRAIgSHhNBla5aEqpQQs%2BtgVc9inB%2FbLC%2FsOYgavEWpg4TfgCICQx%2BWsRyHlAXEymxUiYnfbT9G1%2Bfp57SOeZVIiHjGOPKpAECCQQAhoMNTMyMzMxMDcyMDQxIgx68HDNE9YkK6a7DaIq7QMzZFCvWIGXKkDj86%2B8r3%2Bv3v1qTKO4GyF4UdmYlCHN30dH5RDTqmcCWAhm0iA8aFcTYNZqR%2Fo37ngN9mccleSqjdBE8SvmCnPJDV%2BXhe45yP8jNfNppeGGobuTmX%2FB6XvgpVqdLgYEu03uoJKhG6AZYNxAzyP4TBF%2FNMRanG5S%2B%2FTyaJnKtwaShJ7OK1mtCd%2FwGDUVThq8P6n%2BiNWk7TZLl24D9Gq0VYtTAL%2BfN3ldtFy3Qb0GZiyhLSeObUVyGRE8OcZx4yCD6CUUxL7UWp%2F%2F8nbzxrPPHuiVuoqjDM0G7Gi4ZGVeI1gG9W%2ByLKxuFZ%2FTTrG%2ByF%2FGgnTP6TdN3ZBfMV2LL2x7NEUGSZ2VxK1P7jdJmdMcYyTG8IJYzxh1GiCkwdLNgbuQU%2F6vTONX5W%2BnLnn15h%2B2Qc3H2k8hgAGV5ZVrI%2FCc2Ss3HE%2Bs2GHtqTLg%2Bn%2FP%2BafeUZEXU3xpMdFkBqqlQaYZYzWts4Vmw6jEKo%2BsBJr64p2BWbpOJY1GkJoxwslIgsebDP04XqCuBafcMEBKg5OguRnXp%2Bl78RokkecVcrY%2Ba8Js%2F3wlh2CY4wLSkp5lfdBvBoLf4t229X0wmr9L0YneerCcMOeKgjE0aQTs7TWIUTgRQbP9VKHGl2UhZ9oe2cS4FUPQkGhvMMv3%2FbMGOqcBd3KSu%2BwUhczuYXOOlONashc8UCP7juAX1jo4LvTE%2Fm0yrwW%2BNBlIWOnyigYx3zh4AnibHrzbq5nq1bBC8Fieop1OKSWl2UhV0MUcfCn3wfMphFMmoqdu51NoWSHZjSGqzfKa26rat9AOM%2FjuK75RCVG%2F3Ge5EnFjv9XoPN%2BiPdQVA%2BFTyO2V8YeWiTl1pb4sDWmbVC%2BBcxN4T37LYDZaBhuBTdksvD0%3D&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=ASIAXX4LHRIU3PX5ATAH%2F20240629%2Fap-northeast-1%2Fs3%2Faws4_request&X-Amz-Date=20240629T032405Z&X-Amz-SignedHeaders=host&X-Amz-Expires=1800&X-Amz-Signature=39a0cf8d78aba04f1a20bef43052e386d7efffb0f5692771965ef50919c43940) |
カテゴリ |
遺伝資源
繁殖性改善
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