ducted once per month, four times in a year, in Japan. In that case, it can be represented the abundance and the species of organisms in the field, but does not evaluate the role of organisms in a natural situation. If the qualitative and quantitative estimation are considered for the evaluation of environmental effects, biological monitoring measures must correspond with the time-space scale of natural mechanism which want to analyze in the wide spectrum. Because in general, marine organisms are inherent genetically, physiologically. metabolically, ecologically and other characteristics having a given time-space scale. Volta and Servida (1992) reviewed the nature of indicators in the Environmental Impact Assessment Process. The sampling design for the biological parameters may define the qualitative level of evaluation.
Marine organisms will affect the changes in the physical and chemical environment of water and sediment. Sensitivity and tolerance to these changes varies considerably from species to species. For example. some species are very sensitive to temperature. salinity, the dissolved oxygen level and so on. Thus, at first, the sampling design for biological parameters must define the phenomena and species-, population-community- and ecosystem- scale that assume the effect on organisms in development. Biological measurements by a given scale must be design to reveal the relationships between physiological and ecological function and environmental parameters in laboratory experiments. Thus, we must find a transformation that accepts the empirical relations for the model.
An estuary and coastal waters were pointed out as inherently variable in time and space since the 1980s (Wolf. 1986). Spatial and temporal variability of organisms, on the other hand, are very important subjects making up sampling schemes. Moreover, in general. geographic. temporal. spatial and process variability having in nature have problems an evaluating the environmental impacts. We show the several examples for the natural fluctuations ranges as follows: the effect by freshwater discharge in a week is shown in Fig. 2 (Ishikawa, 1982), the annual change of temperature in which a semi-closed bay system is affected by a regional climatological pattern is shown in Fig. 3 (Ishikawa, 1996) and the distribution of benthic organisms with environmental gradients is shown in
Fig. 4 (Ishikawa, 1989).
Moreover, the results in the study on the environ- mental impact assessment seen as being the unreliable if it can estimate the empirical relational function using the experiment and the numerical model. With regard to the unreliability, it was pointed out importance in the Basic Environment Law in Japan (EA,1996). That is, as the results of monitoring have included both the natural fluctuations and the effects of development, evaluation of environmental impacts enable to spend time over the understanding effects sufficiently and to use the information that are available in the literature and the model.
4. Concluding Remarks
Relations between environmental impact and marine organisms needs a quantitative approach to be able to success the sustainable development in coastal waters management. Recently, the Environment Agency of Japan pointed out the unreliability and the theme on accuracy and the staff for biology in the environmental impact study. Biological response to environmental impact happens the wide spectrum in physiological and ecological functions, so biological monitoring measures must correspond with the given time-space scale of natural mechanism. For the evaluation of environmental impact. it is desire to conduct the development of experimental technique and collect biological basic data for the object.
