"0ctober 1, 1979 to September 30, 1980." "We continued our studies on the clam resources in Oregon's estuaries. Our objectives were: (1) to monitor the commercial harvest of subtidal clams in Yaquina and Coos bays and evaluate the effects of mechanical harvest on subtidal clam populations and habitat; (2) to calculate natural mortality of gaper clams in Yaquina Bay and; (3) to monitor growth of laboratory reared Manila littleneck clams released in Netarts Bay." (from the Introduction)