Endangered freshwater and marine environments and conservation of coral reefs

Abstract

Freshwater Environments In all phases of his evolution, man has depended on water for existence. His gradual progress has been closely associated with rivers and lakes. And yet, para- doxically, he has always abused this gift from nature regarding any waterway as a convenient outlet for his garbage, sewage and urban waste. To this he has added more recently his highly toxic industrial effluent. Chemical Pollution Man's first move to deliberately poison water was probably to supplement his food supply. For centuries the extract from derris root has been a traditional method of killing fish in Asia. Recently such excessively toxic chemicals as Endrin and Dieldrex have been used with devastating results. Rivers and streams, confined as they are by land, are particularly susceptible to toxic materials. The effects of such poisons are never restricted to the area of application but are moved downstream by the current for great distances. Endrin is especially toxic, killing not only the type of fish the fisherman desires but all life in the path of its drift. Furthermore, rivers move as a single mass of water, while fish and other aquatic life remain stationary within their particular territory; thus bulk applications of poison will move undiluted through considerable stretches of the river environment before it becomes harmless. When applied to small ponds and lakes such toxins will diffuse throughout the whole area rendering it totally barren.