日本ベントス学会誌
Online ISSN : 1883-891X
Print ISSN : 1345-112X
ISSN-L : 1345-112X
61 巻
選択された号の論文の12件中1~12を表示しています
  • 淀 真理, 渡部 哲也, 中西 夕香, 酒野 光世, 木邑 聡美, 野元 彰人, 和田 恵次
    2006 年 61 巻 p. 2-7
    発行日: 2006/07/28
    公開日: 2009/08/07
    ジャーナル フリー
    Abundances and size structures of crabs of the genus Ocypode were investigated seasonally from 2000 to 2003 in Nakusanohama-beach, Wakayama, middle Japan. One temperate species, Ocypode stimpsoni, and two subtropical species, O. sinensis and O. ceratophthalma, were collected, with the number being largest in O. ceratophthalma and smallest in O. sinensis. Ocypode stimpsoni was dominant among the crabs collected from spring to summer, whereas O. ceratophthalma was dominant from summer to autumn. In O. stimpsoni, collected crabs were mostly large-sized, with few newly-settled small crabs, throughout the year. In O. ceratophthalma, newly-settled small crabs occurred from June through August and grew up to be middle-sized in the late autumn, but did not attain the matured size and notoverwinter. Newly-settled small O. sinensis occurred from July to November, and some of them overwintered and attained the mature size in the next year. Judging from the seasonal pattern of population structures of O. stimpsoni and O. ceratophthalma and widely overlapped habitats between the two species, it was assumed that abundance of O. stimpsoni was negatively influenced by O. ceratophthalma.
  • 大野 恭子, 和田 恵次, 鎌田 磨人
    2006 年 61 巻 p. 8-15
    発行日: 2006/07/28
    公開日: 2009/08/07
    ジャーナル フリー
    A field study was conducted for spatial distribution and movements of burrow locations of the fiddler crab Uca arcuata in the estuary of the Katsuura River, Tokushima Prefecture, western Japan. The crabs inhabited the upper intertidal zone of reed (Phragmites australis) marshes to bare mud flat. Large crabs were found widely throughout the distributional range, whereas small crabs and ovigerous females tended to occur in the upper area of the habitat, near the lower edge of reed marsh. In the non-breeding season both males and females foraged in similar frequency in all areas of the habitat. In the breeding season, however, males foraged less frequently than females, and exhibited waving display more frequently in the upper non-vegetated area than in other areas. A tracking survey of marked crabs for 28 days revealed that the males held the same burrows for average 4.7 days with the maximum 16 days and females for average 5.5 days with the maximum 14 days. The movement distances of the burrow locations by each crab were less than 4m.
  • 川井 唯史, 長澤 和也
    2006 年 61 巻 p. 16-20
    発行日: 2006/07/28
    公開日: 2009/08/07
    ジャーナル フリー
    Pelseneeria castanea is a small parasitic snail found on the sea urchin Strongylocentrotus nudes in Japan. From 100 to 282 individuals of S. nudus were collected at intervals of one to four months from June, 2001, to September, 2003, in coastal waters of the Sea of Japan at Tomari in the Shiribeshi District of western Hokkaido, Japan, in order to determine the body size and age of infected hosts, the breeding season of P. castanea, and annual and seasonal changes in infection level. Snails were observed only on small-sized S. nudus of less than 50 mm in test diameter. Infected hosts were all one or two years old in 2001 and one to four years old in 2002. No snails were found on urchins aged three to eight years hosts in 2001, nor on those aged five to eight years in 2002. It thus appears that P. castanea infects smaller and younger S. nudus and induces the mortality of infected hosts. The highest prevalences of infection each year were 94.7% in September, 2001, 16.4% in November, 2002, and 10.6% in June, 2003. Mean intensity of infection sharply increased in spring and summer and reached the highest level in autumn, but declined abruptly in early winter to the lowest level in late winter. Frequency of occurrence of urchins with snail egg capsules showed a similar trend. Egg capsules were most frequently found from August to November, which indicates that this is the breeding season of P. castanea.
  • 大野 恭子, 和田 恵次, 鎌田 磨人
    2006 年 61 巻 p. 21-25
    発行日: 2006/07/28
    公開日: 2009/08/07
    ジャーナル フリー
    The influence of reed marshes on the distribution of the fiddler crab Uca arcuata was examined by means of field experiments in the salt marsh of the estuary of the Katsuura River, Tokushima Prefecture, western Japan. When pots with reeds and pots without reeds were set out with 6 replicates on a tidal flat during the recruitment season, the number of recruits in the pots did not differ between the two treatments. When aboveground reeds were removed from some areas of the marsh, the number of recruits was greater there than in the intact area, while abundance of adult crabs showed no difference. When juveniles were introduced into a box with mud only and into a box with mud and reeds, all of which were set out on the tidal flat, more of the juveniles survived in a box without reeds than in the box with reeds. These results suggest that reed marshes have a negative effect on the distribution of juveniles, while no effect on the distribution of adult crabs in their habitat.
  • 合田 幸子, 大森 浩二, 柳沢 康信
    2006 年 61 巻 p. 26-39
    発行日: 2006/07/28
    公開日: 2009/08/07
    ジャーナル フリー
    Helice tridens and Chasmagnathus convexus are grapsid crabs living in tidal flats . Both species construct burrows in the upper intertidal and supratidal zones, although they use also waterside areas in lower tidal zones during low tide. In this study, temporal variations in above-ground density and food items of the two species in different habitats (i.e., burrow areas and waterside areas) were investigated in the Shigenobu and Awai River estuaries of Ehime Prefecture, southwestern Japan, to examine the crabs' seasonal and diel activity patterns in relation to their food habits . Monthly investigations showed that above-ground densities of both species increased from spring and peaked in summer, and the densities were positively correlated with underground temperature. Diel activity patterns differed between the two species. Chasmagnathus convexus tended to be nocturnally active in both burrow and waterside areas . On the other hand, H. tridens exhibited high diurnal activity in their burrow areas during cool seasons (March, October), while at other times they tended to be active nocturnally in both the burrow and waterside areas . Helice tridens consumed various food items such as surface sediment, macroalgae, reeds, and macrozoobenthos. These crabs mainly consumed surface sediment in burrow areas, whereas they frequently consumed macroalgae in waterside areas, where their foraging activity was greater. Food and habitat use of C. convexus differed from those of H . tridens; they primarily consumed reeds in burrow areas and rarely foraged in waterside areas. Overall results suggest that the differences in diel activity pattern between the two species are related to their different food habits and spatial variation in food availability.
  • 門谷 茂, 平川 和正
    2006 年 61 巻 p. 40
    発行日: 2006/07/28
    公開日: 2009/08/07
    ジャーナル フリー
  • 品田 晃良
    2006 年 61 巻 p. 41-44
    発行日: 2006/07/28
    公開日: 2009/08/07
    ジャーナル フリー
    Effect of temperature and food concentration on the growth of bottom cultured Japanese scallop Mizuhopecten yessoensis, was investigated in the coastal area of northeastern part of Hokkaido, Japan. Fourteen years from 1992 to 2005 were distinguished into good growth years and bad growth years by yield rates of adductor muscle. Although water temperature was not different between good and bad growth years significantly, chlorophyll a concentrations in spring were significantly higher in good growth years than in bad growth years. The predictive model for bad growth years was constructed by spring temperature and chlorophyll a data. The appropriate logistic regression model was selected by AIC method, so that the model using spring chlorophyll a data was adapted. These results suggest that low food concentration in spring causes bad growth to bottom cultured Japanese scallop.
  • 宮園 章
    2006 年 61 巻 p. 45-52
    発行日: 2006/07/28
    公開日: 2009/08/07
    ジャーナル フリー
    Hanging culture of Japanese scallops (Mizuhopecten yessoensis) constitutes the most important fishery in Funka Bay, located in the southeastern part of Hokkaido, Japan. Scallop culture started in the early 1970s and developed into an important industry involving scallop processing and distribution not only as locally important industries, but also as a pillar of the Hokkaido economy. The carrying capacity of scallops cultured in Funka Bay was estimated in 1977-1978 for the first time; after that, however, cultured scallop production continued to increase year by year owing to failure to control on the basis of this estimate. At present, scallop production far exceeds the carrying capacity. The carrying capacity model used to calculate that early estimate was based on the difference between food production and food consumption in the scallop culture area. Controllability of product size and quarity is a marked characteristic of mariculture. I have incorporated the idea into the old 1977-78 model. A new model proposed herein will be useful as educational tools for businesses involved in scallop culture. The huge number of scallops hanging in the coastal area, where their culture areas occupy 19% of the total area of Funka Bay, undoutedly has important ecosystem-level effects in the bay. We need to assess the ecosystem-level effects of the scallop culture and devise a new standard of carrying capacity estimation in order to improve the sustainability of this fishery.
  • 神山 孝史, 山内 洋幸, 岩井 拓郎
    2006 年 61 巻 p. 53-58
    発行日: 2006/07/28
    公開日: 2009/08/07
    ジャーナル フリー
    Aquaculture of the Pacific oyster Crassostrea gigas is one of important fisheries industries in Japan. Since production of cultured oysters mainly depends on the natural productivity of the ecosystem, information on the mechanism of the lower trophic ecosystem in oyster farming areas is essential to sustain the high productivity of oyster aquaculture. In the present study, characteristics of environmental conditions, primary production and the grazing loss by microzooplankton in an oyster farming area in Oginohama Bay (Miyagi Prefecture), Japan, were clarified by partly comparing with data in Hiroshima Bay. Then, based on accumulated data, carbon energy flow from primary production through the planktonic food chain to oysters were estimated. In Oginohama Bay, occurrence of phytoplankton blooms in spring and autumn, low concentration of nutrients in early summer, and high abundance of microzooplankton in early spring and late summer were observed. Among environmental parameters in the bay, the annual mean temperature, nutrient concentration and abundances of prey organisms for oysters were lower and salinity was higher than the values in Hiroshima Bay. Primary production in Oginohama Bay was high in spring and autumn, and low in summer and winter. Low primary production in summer was probably due to low nutrient concentrations. Grazing loss of phytoplankton by microzooplankton often exceeded the primary production in summer. The annual production of oyster and plankton components and estimated energy flow between them showed that the transfer efficiency from primary production to oyster production was ca. 4% and also implies that the energy flow from microzooplankton to oysters is an important pathway as well as that from phytoplankton.
  • 山口 一岩, 堤 裕昭, 佃 政則, 柴沼 成一郎, 山田 俊郎, 門谷 茂
    2006 年 61 巻 p. 59-65
    発行日: 2006/07/28
    公開日: 2010/02/05
    ジャーナル フリー
    The dominant food sources of benthic suspension feeding bivalves living in shallow coastal areas have been known to be phytoplankton and microphytobenthos. However, there has been considerable debate over which is the primary food source. In this paper, we reviewed previous studies that deal with microalgae (i.e. phytoplankton and microphytobenthos) as a food source for benthic suspension feeding bivalves living in shallow coastal areas. Results of previous studies examining the stable carbon isotope composition of the cockle, Cerastoderme edule, in various coastal areas showed that the main food source for C. edule varied spatially. We estimated the main food source for the clam, Ruditapes philippinarum, on a tidal flat at the mouth of the Midori River. We concluded that R. philippinarum was predominantly feeding on the microphytobenthos. In our sampling station, the annual mean micropytobenthos biomass of the sediment was 30.2±10.2 mgChl-a m-2; this was approximately three times higher than that of phytoplankton in the overlying water column. The high biomass of the microphytobenthos coupled with high tidal and turbulent flow at the mouth of the Midori River results in resuspension and high relative abundance of the microphytobenthos to the overlying phytoplankton. This resuspension provides access to the microphytobenthos as the dominant food for R. philippinarum. To clarify whether the relative importance of phytoplankton and microphytobenthos as food for benthic suspension feeding bivalves living in shallow coastal areas, we need to understand the environmental factors influencing their main food source; additional case studies in this regard is necessary.
  • 大島 ゆう子, 岸 道郎, 向井 宏
    2006 年 61 巻 p. 66-76
    発行日: 2006/07/28
    公開日: 2009/08/07
    ジャーナル フリー
    Bivalve has an important role in the marine ecosystem of Akkeshi estuary, which is located in eastern Hokkaido, Japan. To discuss the role of benthos and epiphyte on the material cycle in this area, we modified a three-dimensional physical-biological coupled model (MK-3). The ecosystem model includes eelgrasses, epiphytes, oysters and clams together with phytoplankton, zooplankton, POM and DOM and is based on nitrogen and phosphorus cycles. A physical model was forced by M2 tide. In this area, the role of clams on the material cycle is much larger than that of oysters, and epiphytes uptake nutrient twice as large as phytoplankton. We estimated nutrient release from sediment was smaller than previous estimation in sensitivity analysis, and we found that eelgrasses and epiphytes had an important role in supply for the food of clams and oysters.
  • 2006 年 61 巻 p. 79-81
    発行日: 2006/07/28
    公開日: 2009/08/07
    ジャーナル フリー
feedback
Top