著者
土居 隆秀 中村 智幸 横田 賢史 丸山 隆 渡邊 精一 野口 拓史 佐野 祐介 藤田 知文 TAKAHIDE DOI TOMOYUKi NAKAMURA MASASHI YOKOTA TAKASHI MARUYAMA SEIICHI WATANABE HIROFUMI NOGUCHI YUSUKE SANO TOMOFUMI FUJITA 栃木県水産試験場 (独)水産総合研究センター 東京海洋大学海洋生物資源学科 東京海洋大学海洋環境学科 東京海洋大学海洋生物資源学科 東京海洋大学海洋環境学科 東京海洋大学海洋環境学科 東京海洋大学海洋生物資源学科 Tochigi Prefectural Fisheries Experiment Station Freshwater Fisheries Research Division National Research Institute of FIsheries Science Department of Aquatic Biosciences Department of Marine Environmental Sciences Tokyo University of Marine Science and Technology Department of Aquatic Biosciences Department of Marine Environmental Sciences Tokyo University of Marine Science and Technology Department of Marine Environmental Sciences Tokyo University of Marine Science and Technology Department of Aquatic Biosciences
出版者
The Japanese Society of Fisheries Science
雑誌
日本水産学会誌 = Bulletin of the Japanese Society of Scientific Fisheries (ISSN:00215392)
巻号頁・発行日
vol.70, no.5, pp.706-713, 2004-09-15
参考文献数
28
被引用文献数
2 3

イワナ・ヤマメ養殖魚の小型魚と大型魚の釣獲放流後の死亡率と成長を実験池において調査した。餌釣り,毛鈎釣りともに,口腔にかかった鈎を除去した場合,いずれの魚種においても死亡率は低かった。餌釣りで口腔より奥にかかった鈎を除去した場合,イワナ小型魚とヤマメ大型魚では死亡率は高かった。口腔にかかった毛鈎を残留させた場合,イワナ大型魚では死亡率は高かった。死亡のほとんどが釣獲放流後14日以内に観察された。釣獲方法,鈎がかりの部位,鈎の処理方法は成長と肥満度に影響しなかった。Mortality and growth of Japanese charr Salvelinus leucomaenis and masu salmon Oncorhynchus masou masou after catch and release were examined in experimental ponds, using hatchery-reared fish divided into smaller (< 15 cm in total length) and larger (> 15 cm) size groups. When the hooks stuck in the mouth and were removed for both species, the mortality within 21 days after catch and release was low (O-15.0%) for each size and fishing gear (bait and fly-fishing, using barbed hooks). When hooks in bait fishing were removed from the esophagus, mortalities were relatively high (66.7% in the smaller sized charr and 45.0% in the larger sized salmon). All the fish of both species and both size groups were alive when the hooks in fly-fishing were removed from the mouth, however the mortality was relatively high (40.0%) when the hooks were not removed from the mouth of the larger sized charr. 0f all the fish that died, 63.0 and 98.1% died within 3 and 14 days after catch and release, respectively. There was no negative effect of the catch and release on the growth and condition factor of both species and both size groups. These results suggest that catch and release is effective for conserving Japanese charr and masu salmon populations in rivers and lakes when anglers pay attention to the removal of hooks.
著者
Kazuyoshi Nishijima Takashi Maruyama Mathias Graf
出版者
Japan Society of Hydrology and Water Resources (JSHWR) / Japanese Association of Groundwater Hydrology (JAGH) / Japanese Association of Hydrological Sciences (JAHS) / Japanese Society of Physical Hydrology (JSPH)
雑誌
Hydrological Research Letters (ISSN:18823416)
巻号頁・発行日
vol.6, pp.23-28, 2012 (Released:2012-03-13)
参考文献数
11
被引用文献数
17 21

This paper performs a quantitative impact assessment of the climate change on typhoon wind risk, focusing on residential buildings in Japan. The risk is assessed based on (1) the typhoon event set extracted from the simulation by the super-high resolution atmospheric general circulation model developed within the KAKUSHIN program; (2) the probabilistic typhoon modeling scheme developed by our group; (3) a fragility model empirically estimated on the basis of the damage report of typhoon Songda in 2004 and the reproduced wind field by a mesoscale meteorological model; JMA-NHM. The main results are that in the future (2075–2099) at most locations of Japan: (1) extreme wind events (10-minute sustained wind speed exceeding 30 m/s) are more likely to occur; (2) the median of the annual maximum wind speed decreases; (3) the expected number of damaged residential buildings decreases, assuming that the profile of the building portfolio remains unchanged. Based on these results, the assumptions and inputs to the assessment are critically reviewed. Thereby, the needs of further research efforts toward more credible and comprehensive assessment are addressed.
著者
Takashi Maruyama Eriko Tomokiyo Junji Maeda
出版者
水文・水資源学会/日本地下水学会/日本水文科学会/陸水物理研究会
雑誌
Hydrological Research Letters (ISSN:18823416)
巻号頁・発行日
vol.4, pp.40-44, 2010 (Released:2010-04-09)
参考文献数
4
被引用文献数
1 4

The strong wind field caused by Typhoon Songda, which passed through Kyushu in Japan in 2004, was simulated numerically. A non-hydrostatic mesoscale model was used for the numerical simulation. The simulated wind field was compared with the observed wind field in terms of wind speeds and directions, which were measured by the wind observation network, NeWMeK. It was found that the temporal variation of the calculated wind speeds at 1 km hori-zontal mesh grids correspond to the average of the observed wind speeds over a ten to fifteen minute time period. The temporal variation of the calculated wind directions showed good agreement with the observations. The maximum values of the calculated wind speeds were highly correlated to the maximum values of the observed wind speeds. The applicability of the mesoscale model for the wind hazard assessment of buildings was examined, and it was found that the maximum values of the calculated wind speeds at higher altitudes showed higher correlations with the rates of damaged houses caused by Typhoon Songda.
著者
久保田 仁志 中村 智幸 丸山 隆 渡邊 精一 Hitoshi Kubota Tomoyuki Nakamura Takashi Maruyama Seiichi Watanabe 栃木県水産試験場 独立行政法人水産総合研究センター中央水産研究所水面利用部 東京水産大学海洋環境学科 東京水産大学資源育成学科 Tochigi Prefectural Fisheries Experiment Station Freshwater Fisheries and Environment Division National Research Institute of Fisheries Science Department of Ocean Sciences Tokyo University of Fisheries Department of Aquatic Biosciences Tokyo University of Fisheries
出版者
The Japanese Society of Fisheries Science
雑誌
日本水産学会誌 = Bulletin of the Japanese Society of Scientific Fisheries (ISSN:00215392)
巻号頁・発行日
vol.67, no.4, pp.703-709, 2001-07-15
参考文献数
19
被引用文献数
5 9

1993年6月&acd;1995年11月にかけて, 利根川水系鬼怒川の小支流において, イワナ, ヤマメの生息数, 当歳魚の移動分散, 成長の季節変化を調査した。3ヶ年の総採捕個体のうち, イワナは81.4%(1073個体中873個体), ヤマメは98.8%(244個体中241個体)が当歳魚であった。ヤマメ当歳魚は2月から採捕され, 8月以降はほとんど採捕されなかった。これに対して, イワナ当歳魚は3月から採捕され, 6月以降は1回の調査あたりの採捕数の変化はなかった。一方, 1995年に鬼怒川本流で採捕調査を行ったところ, 採捕された当歳魚のうちイワナが8.0%, ヤマメが92.0%を占め, ヤマメ当歳魚が優占した。以上の結果から, 小支流は特にイワナ当歳魚にとって重要な成育場所であると考えられた。We investigated the seasonal changes in number, dispersal and growth of juvenile Japanese charr Salvelinus leucomaenis and masu salmon Oncorhynchus masou masou in the Karatakisawa Stream, a small tributary of the Kinu River in central Japan. 873 (81.4%) of a total 1073 charr caught by monthly sampling from 1993 to 1995 were age-0,and 241 (98.8%) of a total 244 salmon were age-0. Most of the newly emerged age-0 salmon were caught in the spring of 1995. They shifted downstream, and the number of fish decreased markedly by early summer. The number of the age-0 charr caught at any sampling from any month did not decrease until the end of autumn, although the distribution of the age-0 charr shifted downstream. In contrast, of a total 387 age-0 fish captured by samplings in the adjacent Kinu River in 1995,356 (92.0%) were salmon, whereas only 31 (8.0%) were charr. These results suggest that small tributaries play an important role as nursery habitats, especially for Japanese charr.