Certain issues are basic to the study of environmental science, such as the importance of learning to sustain our environmental resources so that they will be available in the future.  

A CLOSER LOOK: Determining the Carrying Capacity of Chinook Salmon  

The problem of determining carrying capacity is illustrated by the history of commercial fishing of chinook salmon in the Columbia River of the Pacific Northwest.  The number of salmon caught there during the period 1866-1966 on an annual basis fluctuated significantly, stablizing during different periods - between 1890 and 1920, and at much lower levels during the 1960s.  During these periods it may have been concluded by wildlife managers that catch levels at the time were sustainable at those levels.  This illustrates the difficulty in determining a truly sustainable harvest.