No.189 研究課題 / Project
多摩川河口干潟における地形・潮位と生物行動の関連性の研究 ― 上げ潮・満潮・下げ潮時の干潟の魅力を探るStudy on the Relationships among Water Level, Tidal Range and Biological Behavior in the Tidal Flat of the Tama River Estuary| 一般研究 General Research |
No.189 |
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| 代表研究者 Principal Investigator |
五明 美智男 Michio Gomyo |
| 所属（採択当時） Affiliation |
特定非営利活動法人 海つくり研究会 理事 Director, Association for Shore Environment Creation |
| 研究内容要約 Research Summary |
本研究では，上げ潮・満潮・下げ潮時の見方・歩き方・ふれあい方・楽しみ方を工夫し干潮の新たな魅力を発見することを目的として，干潟の魅力の扱われ方を既往資料並びに現地踏査から整理するとともに，水の流動・水位・地形・生物に着目した調査を前報と同じ多摩川河口干潟において実施する．特に，干潮時の生物の行動と比べ，干潮時以外の潮位での生物行動はあまり知られていないことから，特定の場所において干潮から満潮の潮位変化に合わせた生物行動を把握することには意義がある．特に，江戸前の代表ともいえるマハゼや，近年遡上量が増加しているアユなどにとっての干潟の役割も注目されるところである．従来の底生系の生物調査に対し，水系の生物調査を実施することで，干潮時以外の干潟の魅力を探り環境学習の素材の可能性に言及することを具体的な成果目標として研究を進める． 今回の研究における稚仔魚調査区域は100m オーダーの空間スケールである．この程度であれば，調査に慣れたスタッフによって稚仔魚採集を行い，干出する平坦部と干潟斜面部での底生系，水系の生物の相違あるいは多様性を体感するプログラムが可能と考えられる．季節的には，底生生物の活動が活発となる春季が良いが，季節ごとに異なる稚仔魚が出現することから野鳥観察との組み合わせも有効である．なお，稚仔魚の同定，特にハゼ類の同定は大変難しいが，前掲のような標本ならびに成魚の生態写真などを用意しておくことで，ある程度の対応はできるものと考えられる． This study aims at discovering the new charms of low tide by finding better ways to enjoy the view of rising tides, high tides, and falling tides, to walk in them, to touch them, and to enjoy them. We will gather existing materials and field findings on the appeal of tidal flat, and at the same time, conduct surveys on the water flow, water level, topography, and living organisms of a tidal flat at the estuary of the Tama River, the same place we did the previous survey. Compared to the behavior of living organisms at low tide, which is well known, their behavior at other tide levels is hardly known. Therefore, it is meaningful to study the behavior of living organisms in accordance with the changes in water level from low tide to high tide at a specific site. The role of low tide is especially notable in the spiny goby, Acanthogobius flavimanus, which is representative of the Tokyo area, and in ayu, Plecoglossus altivelis altivelis, the number of which swimming up the river has increased in recent years. By studying the living organisms in the water system, as opposed to conducting a conventional study of the living organisms in the benthic system, we hope to illustrate the appeals of tidal flats at tidal levels other than the low tide, and to use the findings as possible environmental study materials. With this in mind, we would like to carry on our survey. For this study, the area where fish larvae and juveniles are surveyed is 100 m long. At this scale, the staff members, who are used to conducting surveys, can collect the small fish and put together a program to experience the differences and diversity of living organisms in the water system and in the benthic system at the dry areas and slopes of the tidal flat. The spring season is optimal since the benthic organisms are most active at this time; however, since different kinds of fish larvae and juveniles appear in different seasons, it is a good idea to also combine bird watching with our other activities. The identification of fish larvae and juveniles, especially the identification of family of gobies, is very difficult. By preparing specimens and obtaining photos of the adult fish in advance, as mentioned above, we are sure we can manage to carry on our study. |
| 共同研究者 Collaborators |
木村 尚（海辺つくり研究会事務局） 玉上 和範（東亜建設工業） |
| 研究全文 Full Text |
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