Application of count models in estimating recreational values of pond aquaculture

With the rapid development of the third industry, recreational fishery has become one of significant sectors of fishery economy in China. At the same time, the increasing investment in the recent decade on the recreational fishery has made this industry more valuable in Shanghai. The literatures show that there are a few researches focused on the recreational values of pond aquaculture ecosystems, and the suitability of methods and models which may be used to analyze these values should be estimated. Owing to the lag of researches on the estimation methods, these eco-service values were not scientifically explained. Based on the investigation in Qingpu, Jiading and Fengxian, three suburban districts of Shanghai, this paper estimated the recreational values of the pond aquaculture ecosystems in these areas with count models of individual travel cost method (ITCM). The effectiveness of Poisson Model and Negative Binomial Regression Model were compared. The estimated value of the pond aquaculture ecosystems in Qingpu District this time and those results of former studies in the same area was also compared to analyze the stability of individual travel cost method (ITCM) and the zone travel cost method (ZTCM). The results showed that: ① estimated values of pond aquaculture ecosystems were sensitive to the models used, Negative Binomial Regression Model was more effective than Poisson Model when the data had discrete characteristics; ② it was feasible to use the estimated values by individual travel cost method and zone travel cost method as the upper and lower limits of pond aquaculture ecosystem services values respectively, the ratio of the values estimated by the two methods was 4.98︰1; ③ the recreational values in the three districts were approximately 20 863.34 Yuan·hm^-2·a ^-1, 57 997.03 Yuan·hm^-2·a ^-1 and 522.73 Yuan·hm^-2·a ^-1, respectively. The results suggest that stakeholders should recognize the existence and importance of these types of ecosystem services values, support the development of recreational fishery, protect the pond aquaculture ecosystems, and make full use of these ecosystems to promote the sustainable development of tour industry and aquaculture and increase fish farmers' income in these areas.