An evaluation of alternative estimates of demand for and benefits from Oregon salmon sport fishing

Graduation date: 1985The main objective of this study was to estimate the demand for and net economic benefits from Oregon salmon sport fishing. The travel cost method was used as the primary technique for demand analysis. Several empirical estimates of consumer surplus per trip and per fish were obtained from different estimation methods. The differences in net economic benefits among different versions of the travel cost method were assessed. Empirical results indicated that the individual observation approaches produced higher consumer surplus estimates than the zone average approach when reported travel costs were used. These higher estimates of net economic benefits are believed to be due in part to the bias caused by travel cost measurement error. However, this problem of bias was dealt with by using the instrumental variable approach. Higher estimates of net economic benefits also resulted from the use of unadjusted individual observations (UIO) for fitting the recreational demand function because this approach does not account for the declining participation rates for the more distant zones. Therefore, it is recommended that the individual observations be adjusted to a per capita basis, or that the probability of participation be linked to the UIO estimates of demand in order to compute valid estimates of net economic benefits. A quality variable was incorporated into regional and hedonic travel cost models. Average and marginal values of the primary site and substitutes sites thus were directly derived from the demand equations. Estimates of total and average consumer surpluses computed from the traditional travel cost model were changed very little with the addition of the substitute and quality variables in the more completely specified regional travel cost models. This finding indicates that the traditional travel cost model may be basically robust for estimating total and average consumer surplus. However, additional research on other recreational activities is needed to see if estimates of total consumer surplus from the traditional travel cost model always remain relatively stable when quality and substitute variables are included in a regional travel cost type of specification. Unfortunately, the numerical estimates of value per trip and per fish from the hedonic travel cost model were rather unstable and should be considered somewhat questionable for this study. Similarly, the estimates of marginal values per fish from the regional travel cost model did not seem very reasonable, being only about one-fourth of the average value per fish. Therefore, it appears that the more complex regional and hedonic travel cost models require more and better quality data to yield more accurate estimates of marginal values per fish