Economic Valuation of Ecosystem Services Provided by Nereocystis luetkeana in Puget Sound.

Abstract

Bull kelp (Nereocystis luetkeana) is known to provide ecosystem services to Puget Sound in the State of Washington including support of food webs and fisheries, nutrient cycling, mitigation of storm surge and coastal erosion, and cultural services. However, the economic value of these services is largely unknown, making it difficult to conceptualize and communicate the benefits of bull kelp and to justify conservation and restoration investments. This study estimates the contribution of bull kelp to Puget Sound in the form of provisioning services by salmon and herring fisheries and regulating services by temporary nitrate removal. I combined a literature-derived habitat dependency index, a value that represents the proportion of a species’ life history that is dependent on bull kelp, with public data to 1) simulate the value of the annual contribution by the current areal extent of bull kelp to non-tribal fisheries and 2) estimate the value of temporary nitrate removal. The contribution of bull kelp to commercial salmon and herring fisheries is valued at $2.6M ± 0.5M, the contribution to recreational salmon fisheries is valued at $2.1M ± 0.2M, and temporary nitrate removal is valued at $3.1M ± 1M. This means the State of Washington would lose $7.8M ± 1.7M per year if there were a total loss of bull kelp in Puget Sound from current levels. This value, when combined with estimates of the economic value of other ecosystem services, can inform conservation spending decisions for bull kelp conservation in Puget Sound. This study also provides a foundation for valuing other ecosystem services provided by bull kelp in the region and emphasizes the need for additional data collection with which to improve estimates.