海洋理工学会誌
Online ISSN : 2188-3262
Print ISSN : 1341-2752
ISSN-L : 1341-2752
10 巻 , 2 号
選択された号の論文の9件中1~9を表示しています
原著
  • 佐々木 保徳, 岩崎 杉紀, 中村 敏明, 角田 晋也, 中田 喜三郎
    2004 年 10 巻 2 号 p. 1-18
    発行日: 2004年
    公開日: 2019/02/16
    ジャーナル フリー
    本論文は,海氷上の積雪層内におけるマイクロ波放射の伝播過程に対し雪氷学的パラメーターが及ぼす影響を推定するための方法を議論している。議論はリモートセンシングにより正確な測定が可能な唯一の物理量である表面輝度温度の実測値に基づき行われている。6.7GHzと18.6GHzにおいて行ったマイクロ波測定では,海氷上の積雪層から放射されるマイクロ波は多重散乱効果のためほぼLambertian(すなわち等方性)であることがわかっている。そこで著者らは,この等方性放射が積雪層内全体にわたって生じていると仮定し,積雪層内を伝播するマイクロ波放射に対して積雪層が及ぼす効果の推定を行うため,P.KubelkaとC.Munkにより提案された“二流理論”を応用した。その結果,この理論から6.7GHzと18.6GHzにおける後方散乱,吸収,全消散などの係数値の推定ができた。さらに,これら の値を用いることにより,積雪層がマイクロ波の伝播過程に及ぼすすべての効果の推定も積雪層全体にわたり可能となった。
  • 本田 是人, 石田 基雄, 家田 喜一, 武田 和也, 山口 安幸, 鈴木 輝明
    2004 年 10 巻 2 号 p. 19-33
    発行日: 2004年
    公開日: 2019/02/16
    ジャーナル フリー
    The possibility of using granulated blast furnace slag was investigated in the present study, because in the near future it may become more difficult to obtain marine sand on a massive scale. Granulated blast furnace slag is a by-product from the manufacturing of iron. It can act as an alternative material to marine sand for constructing artificial tidal flats and shallows. This studies were conducted at a Tidal Flat Mesocosm System (5m x 8m) which can reproduce physical conditions of a tidal flat such as tidal level, tidal current, wave and wind. The effect of five kinds of granulated blast furnace slag, including mixture by natural sand was assessed on the basis of the structure of benthic community, and larval settlement, post-settlement survival of the Japanese Littleneck Clam, Ruditapes philippinarum. The effects were compared to five different kinds of natural sand. There was no significant difference in the benthic community such as bacteria, meiobenthos and macrobenthos between the blast furnace slag group and the natural sand group. On the other hand, there was no significant difference in the larval settlement and post-settlement survival of Ruditapes philippinarum between the granulated blast furnace slag group and the natural sand group. From the results of these two experiments, the possibility to used the granulated blast furnace slag as an alternative material to marine sand was suggested.
速報
  • 中田 聡史, 石原 靖文, 原島 省
    2004 年 10 巻 2 号 p. 35-49
    発行日: 2004年
    公開日: 2019/02/16
    ジャーナル フリー
    The Sekisei Lagoon surrounded by the Yaeyama archipelago is one of coral reef areas in Japan. However, it has been partly damaged due to several causes. It is important to note that the transport of coral eggs and larvae by the flow from the source area, that is less damaged, will contribute to the recruitment and recovery of the damaged area. Our goal is to identify the trajectory coral eggs and larvae from the source area to the recruitment area based on the modeling of physical circumstances including the flow and dispersion. It will help ascertain the protec tive area and clarify the restoration process of damaged coral reefs. As the first step, we examine a flow pattern in summer in the Sekisei Lagoon using a numerical simulation of a multi-level hydrostatic model with a two-stepped Nested area. We focus on the flow pattern both of the whole Sekisei Lagoon and the part around Kuroshima, which locates in the southern part of this lagoon. The model is driven by the averaged wind stress in summer and the M2 tidal component. The results show that the northward current about lOcm/s, which basically follows the wind direction, dominates along the eastern coast of Kuroshima and a weak flow exists the southeastern side of Kuroshima.
  • 山岸 祐希子, 荒井 修亮, 光永 靖, 三田村 啓理, Viputhanumas Thavee
    2004 年 10 巻 2 号 p. 51-57
    発行日: 2004年
    公開日: 2019/02/16
    ジャーナル フリー
    In order to recover both data loggers and stomach contents of fishes, a new device, automatic fish recapture system (AFR system) was developed. The system can force to surface a free swimming fish at a preset time. We carried out two recapturing experiments on Mekong giant catfish in the Mae peum reservoir, Phayao, Thailand and successfully recovered one catfish and attached data loggers. Furthermore, we obtained data showed vertical movement and stomach contents as well as the AFR system.
講座
総説・展望
  • 澤田 好史
    2004 年 10 巻 2 号 p. 75-85
    発行日: 2004年
    公開日: 2019/02/16
    ジャーナル フリー
    Tuna aquaculture is currently dependent on the wild capture of juveniles for production. The development of hatchery technology for the Pacific bluefin and other tunas would be a major step forward in improving sustainability of their aquaculture. The present study overviews the technology in the life cycle comple tion of the Pacific bluefin tuna (PBT) Thunnus orientalis (Temminck et Schlegel) under aquaculture conditions in Kinki University, and the problems to be solved for the establishment of tuna hatchery technology. PBT juveniles were wild-caught in 1987 when they were several months old, and reared to maturity. Fertilized eggs were obtained from these fish in 1995 and 1996, and were used for a mass rearing experiment. Resulting juveniles (the artificially hatched first generation) were reared to maturity and spontaneously spawned on 23 June 2002. Over the summer of 2002, 1.63 million eggs from these fish were used for a mass rearing experiment, and 17,307 juveniles were produced and transferred to an open sea net cage. Of these artificially hatched second generation PBT, 1,000 grew to approximately 105 cm TL and 18 kg BW in 24 months. This procedure means the completion of PBT life cycle under aquaculture conditions which firstly attained among large tuna species. The problems awaiting solution in PBT hatchery production are their unpredictable spawning in captivity, to improve survival during the first 10 days posthatch, to reduce cannibalism in larval and juvenile stages, and to solve collision problem causing high mortality during juvenile stage.
  • 藤原 正夢
    2004 年 10 巻 2 号 p. 87-91
    発行日: 2004年
    公開日: 2019/02/16
    ジャーナル フリー
    The cockles, Fulvia mutica, caught in Miyazu Bay, Kunda Bay and Maizuru Bay, Kyoto prefecture, grow up nearly 10 cm of shell height that is about 1.5 times as big as cockles caught in other sea area. Individual numbers of the cockles caught in Kyoto prefecture, however, have fluctuated from 0 to 60,000 and in recent years the number is less than 10,000. In order to increase the yield of cockle, we have established the methods for seed production and cultivation of cockle. Furthermore, we tried to develop the breeding technique of cockle. In the present study, it was cleared that the shell length and weight of whole body of Fl hybrid were significantly larger than those of inbred parents.
  • 益田 玲爾
    2004 年 10 巻 2 号 p. 93-100
    発行日: 2004年
    公開日: 2019/02/16
    ジャーナル フリー
    Fish Psychology is a research field that deals with the behavior and ecology of fishes through an approach of experimental psychology. ”How do fish maintain a school?” ”How smart can fish be?” Research is often based on questions that arise from direct observation during diving census. Rearing experiments are then related to the function and mechanism of behavior with emphasis on their ontogeny. We aim to apply the achievement of fish psychology to human psychology as well as sustainable fishery management. In this review I presented the results of bi-monthly diving census conducted for three consecutive years, as well as that conducted in dawn, noon, dusk, and midnight. Then more experimental studies on the develop ment of schooling behavior in Carangid fishes are introduced. Ontogenetic changes of learning capability in fishes are also demonstrated.
  • 橋本 民雄
    2004 年 10 巻 2 号 p. 101-108
    発行日: 2004年
    公開日: 2019/02/16
    ジャーナル フリー
    The TraceFish was proposed by EU in November, 2002 through the discussion of two years. The concept and the implementation method of TraceFish are excellent, though there are remaining both an excess and deficiency in information. The many exporters to EU will adopt TraceFish. In Japan, testing of traceability adopted by some enterprises can apply to only internal circle between a producer and a shop, not universal system at all. In short, the system applied by large supermarket is a kind of tool for sorting out incapable suppliers. The movement of the de facto standard plan is still under proceeding, because there are neither a group nor an enterprise that takes the initiative at all, modeling the compound circulation is difficult each fish species and various commercial practices are varied in accordance to each region. The enterprises hope for the standard of marine products traceability.
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