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11.
Arsenic, cadmium, chromium, and copper concentrations of the Pacific oyster,Crassostrea gigas, purchased from four different markets were determined in this project. In general, gill tissue had the highest proportion
of metal contents (34%–67%) when compared with other tissue parts (mantle, viscera, and adductor muscle), except for arsenic,
which showed the highest level in adductor muscle (44%). Smaller oysters (longitudinal length of soft body part less than
6 cm) had higher metal levels than larger ones (longitudinal length of soft body part more than 6 cm), except copper. None
of the four metals examined showed an obvious seasonal trend, although cadmium levels seemed to be higher in autumn and winter
months. Arsenic, cadmium, and copper levels in oysters purchased from different markets and different months obtained in the
present study were higher when compared with past reports. Cadmium levels, as high as 10.98 mg/kg (dry weight basis) have
been obtained. This approaches the safety limit that may be hazardous to human health. Continual monitoring of cadmium and
other trace metals of toxicological significance to man in Hong Kong seafood is recommended. 相似文献
12.
Accounting for the mismanagement of tropical nearshore fisheries 总被引:2,自引:0,他引:2
The underlying reason for the mismanagement of tropical nearshore fisheries is the implementation of policies and programs
based on Western models and approaches, coupled with an inability and/or unwillingness to consider non-Western alternatives
of empirically proven value. Such attitudes are embedded in donor and development agency behavior, and are demonstrated by
the temperate bias in conventional approaches to fisheries education and management, with a corresponding lack of understanding
of tropical milieux, and in the persistence of various prejudices. Adaptive Management, The Ecosystem Approach, Local Knowledge,
and Protected Areas are discussed from the perspectives of Western models and pre-existing Pacific Island systems as alternative
models. Given the parlous condition of the global environment and resources, the best non-Western pre-existing models and
Western approaches must be blended to provide sustainable solutions.
相似文献
Francis R. HickeyEmail: |
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16.
北太平洋柔鱼渔场时空分布与海洋环境要素的研究 总被引:9,自引:0,他引:9
根据2010 年7~9月和2011年7~10月“舟渔1301#” 2个航次的北太平洋柔鱼渔场海上调查资料,利用渔获生产数据?海况天气数据以及同期的卫星遥感获取的海表面温度(SST) ?海表盐度(SSS)及叶绿素a (Chl-a)浓度和海流等数据,分析柔鱼的中心渔场分布与海洋环境的变动关系.研究结果显示:整个调查期间渔获频次在SST和Chl-a因子上均呈正态分布,渔场高产的最适SST范围为18~20℃, 最适SSS范围为33.60‰~34.80‰, 最适Chl-a浓度范围为0.08~0.24mg/m3,其中SST与柔鱼渔场之间有较好的匹配关系,中心渔场通常位于18~20℃的等温线附近,且位置一般出现在冷水团和暖水团交汇区的冷水团一侧;中心渔场位于亲潮和黑潮交汇混合区的向北一侧,离交汇地带的距离较近,而且随着时间的推移,渔汛期间中心渔场的位置逐步往其向西北方向移动.总体上多个环境因子皆可作为确定潜在中心渔场的指标,但以海表水温为最佳,另外辅助寒?暖流的交汇情况以及Chl-a浓度?天气海况等因素来综合分析,判断渔场的中心位置会更准确. 相似文献
17.
于2018年10月9日~11月1日采集西太平洋表层海水,通过营养盐添加船基培养实验,研究了不同营养盐条件下浮游植物的生长及其释放挥发性卤代烃(VHCs)含量的动态变化规律.结果表明,与对照组相比,氮磷营养盐的添加对叶绿素a(Chl-a)的含量和三氯乙烯(C2HCl3),四氯乙烯(C2Cl4),一氯二溴甲烷(CHBr2Cl),三溴甲烷(CHBr3)的释放量表现出显著促进作用,但促进程度与添加氮磷营养盐的浓度及比值密切相关.高浓度氮更有利于浮游植物的生长及C2HCl3和C2Cl4的释放.N/P比符合Redfield比值更有利于CHBr2Cl和CHBr3的释放.相比NO3--N,NH4+-N的添加更有利于4种VHCs释放. 相似文献
18.
Symbioses between dinoflagellates in the genus Symbiodinium (commonly referred to as zooxanthellae) and scleractinian corals are an essential feature for the maintenance of coral reefs.
The fine-scale diversity and population structure of the zooxanthellae inhabiting the coral Pocillopora meandrina, a major reef building species in Polynesia, was examined. We used two polymorphic microsatellites to study seven populations
from the South Pacific, whose host structuring has been previously investigated. The symbionts of P. meandrina showed high levels of diversity, with more than one zooxanthella genotype being identified in most of the host individuals.
Genetic differentiation between symbiont populations was detected at a large scale (2,000 km) between the Tonga and the Society
Archipelagos. Within the Society Archipelago, the two most remote populations (Tahiti and Bora-Bora; 200 km apart) were only
weakly differentiated from each other. Statistical tests demonstrated that the symbiont genetic structure was not correlated
with that of its host, suggesting that dispersal of the symbionts, whether they are transported within a host larva or free
in the water, depends mainly on distance and water currents. In addition, the data suggests that hosts may acquire new symbionts
after maternal transmission, possibly following a disturbance event. Lastly, the weak differentiation between symbiont populations
of P. verrucosa and P. meandrina, both from Moorea, indicated that there was some host-symbiont fine-scale specificity detectable at the genetic resolution
offered by microsatellites. 相似文献
19.
Jinfan Duan John Selker Gordon E. Grant 《Journal of the American Water Resources Association》1998,34(3):617-627
ABSTRACT: Recent work has found that a one-parameter Weibull model of wet day precipitation amount based on the Weibull distribution provides a better fit to historical daily precipitation data for eastern U.S. sites than other one-parameter models. The general two-parameter Weibull distribution was compared in this study to other widely used distributions for describing the distribution of daily precipitation event sizes at 99 sites from the U.S. Pacific Northwest. Surprisingly little performance was sacrificed by reducing the two-parameter Weibull to a single-parameter distribution. Advantages of the single-parameter model included requiring only the mean wet day precipitation amount for calibration, invertibility for simulation purposes, and ease of analytical manipulation. The fit of the single-parameter Weibull to the 99 stations included in this study was significantly better than other single-parameter models tested, and performed as well as the widely endorsed, more cumbersome, two-parameter gamma model. Both the one-and two-parameter Weibull distributions are shown to have b-moments that are consistent with historical precipitation data, while the ratio of b-skew and b-variance in the gamma model is inconsistent with the historical recerd by this measure. In addition, it was found that the two-parameter gamma distribution was better fit using the method of moments estimators than maximum likelihood estimates. These findings suggested that the distribution in precipitation among sites in the Pacific Northwest with dramatically different settings are nearly identical if expressed in proportion to the mean site event size. 相似文献
20.
James D. Proctor 《Environmental management》1998,22(3):347-358
/ Public participation in environmental management decisions has frequently led to conflict. This paper examines the role of environmental values in fueling these conflicts, based on a data base and sample content analysis of written public comments solicited in 1994 regarding the highly contentious Clinton Forest Plan (also known as Option 9) proposed for management of federal forests in the US Pacific Northwest. The analysis considered whether those respondents favoring more versus less environmental protection than was offered in Option 9 held entirely different values, identifying which antagonistic values appeared to be most fundamental and where (if at all) values consensus occurred. It also compared values emanating from respondents within and outside the affected region, although few major differences were detected in this regard. Results suggest that strong values differences did exist among those preferring greater versus less environmental protection, in particular as concerned the extent, form, and spatial and temporal scope of justification of their positions, their ideas of forests, and the appropriate role of people in forest management. Disagreement concerned far more than purely environmental values: a major point of difference involved human benefits and harms of the proposed forest plan. Indeed, both sides' positions were overridingly anthropocentric and consequentialist-a values orientation that almost inevitably spells conflict in light of the commonly differentiated social impacts of environmental management decisions. Although public involvement in environmental management thus cannot be expected to lead to a clear and consensual social directive, the Pacific Northwest case suggests that viable environmental management solutions that take this range of values into account can still be crafted.KEY WORDS: Environmental values; Public participation; Clinton Forest Plan; Pacific Northwest 相似文献