What are Freshwater Mussels Worth?

Abstract

Historically, little thought was given to the value of freshwater mussels when making decisions that affected these animals and their habitats, even though these values may be considerable, and may be greatly changed by environmental alterations. Here, I review several kinds of values provided by freshwater mussels. Direct-use (market) values of mussels were substantial when the mussels were harvested to provide buttons and pearls, amounting to about $10 billion (2017 dollars) in the USA alone. Current harvests are much smaller but still valuable. Mussels also provide indirect-use value through the ecosystem functions that they provide (water clarification, nutrient cycling, pathogen suppression, etc.). The monetary value of these functions may be substantial, but has not yet been estimated. As interesting, rare creatures, freshwater mussels may also have existence value to society. This value probably is small at present, but could be increased greatly through outreach and education, as could their option and bequest values (the value of saving them for the future). The total value of a freshwater mussel community would be the sum of direct use, indirect use, existence, option, and bequest values, and has not yet been estimated for any real mussel community. Alternatively, one could calculate the replacement value of freshwater mussels (the cost of replacing a mussel community that was damaged or destroyed); procedures for estimating replacement costs have been published. Despite uncertainty about the precise value of freshwater mussels, it is clear that they have substantial value to humans, possibly many millions of dollars in individual ecosystems, which should be taken into account in environmental decision making. Mussel ecologists and biologists can play important roles in helping society better value freshwater mussels.