In the past, water temperature has been utilized in combination with some measure of fishing effort in the development of economic estimator or predictor equations for the yield of the lobster Homarus americanus. The hypothesis that the inshore lobster fishery in the United States has been overfished since the end of World War II to the point where increases in fishing effort since that time have had only minor effects on the yields was examined. It was shown that suitable yield prediction equations could be developed using only lagged and present temperatures as the independent variables. Comparisons were made of equations developed for the Maine fishery and sections of the Canadian fishery. Further analyses were done comparing equations developed using winter vs. summer temperatures and surface vs. bottom temperatures.