Willingness to pay for ecosystem services of open oceans by choice-based conjoint analysis: A case study of Japanese residents

• Conducted conjoint analysis of marginal WTP for open ocean ecosystem service (OPES).
• Explored Japanese residents' marginal WTP for three key OPES.
• Found discrepancies between results of conjoint analysis and alternative methods.
• Despite Japan's social homogeneity, considerable regional variation exists in WTP.
• Identified two factors (gender, income) that influence the marginal WTP for OPES.

Today, greater attention has never been dedicated to the challenges of a changing climate and efforts to explore and utilize the open ocean. A range of different valuation data are needed in order to accurately assess the tradeoffs of different management regimes. Nevertheless, many aspects of the open ocean remain unstudied, and few case studies have been conducted on the valuation of the open ocean.This study explores the monetary value of open ocean ecosystem service (OPES) using conjoint analysis. A choice experiment with 814 Japanese respondents was conducted to elicit the marginal willingness to pay (WTP) of respondents for three main OPES: fish production, carbon dioxide absorption, and water purification. The case study in Japan found a 1% marginal WTP for fish production, carbon dioxide absorption, and water purification of open oceans with respective average per capita values of USD .06, .19 and .16 per year. We also found variation across different prefecture in WTP trends for the three OPES, implying the influence of traditional food culture, mass media and natural hazards. Differences in WTP trends were also found to depend on income level and gender. The case study included respondents across five income levels. Positive correlations can be observed between marginal WTP and income levels for each of the three OPES. In addition, female respondents were found to have a higher WTP than male respondents for improving each of the three OPES. Therefore, when formulating ecosystem-based management policies related to the open oceans, it is necessary to consider differences in WTP based on region, income, gender and other relative specific factors. This will aide in consensus-building and maximizing cost-benefit outcomes.