Chapter 6: Costs and Economic Valuation of Freshwater Mussel Kills
The total monetary damage from a mussel kill is made up of several primary components: ecological (ecosystem services), use (habitat for fish and other benthic organisms), and nonuse values (aesthetic appreciation), plus replacement costs (Southwick and Loftus 2003). Ecological, use, and nonuse values should be included as part of monetary damages whenever they can be reliably quantified. However, because information to accurately estimate ecological, use, and nonuse values for mussels are only occasionally available, the process presented in this chapter is based on using replacement costs as a conservative method to determine restitution for killed mussels.
The true costs associated with a mussel kill cannot be fully accounted for using replacement costs alone. Hatchery-raised mussels may not be equivalent (in terms of survivorship, genetic make-up, or the ecological services they provide) to native species killed, and habitat restoration may be needed to ensure the site can host viable mussel populations.
Until research can be conducted into the full range of values provided by mussels, the replacement costs presented in this chapter must be considered a conservative and minimum method of assigning restitution after mussel kills. Production cost data or life history data local to the mussel kill site, region, genera or species should be used in preference to the general economic data provided in this book.
These estimated replacement costs are not applicable when time and resources are available to develop more current and relevant estimates through the Natural Resource Damage Assessment (NRDA) process.
These estimated replacement costs do not account for species that require life history research before propagation can be successful, and/or species that may be considered exceptionally difficult to raise. Additional damages are warranted for such species because the costs listed in this document are averages and likely underestimate the true cost of replacing hard to propagate species. Likewise, if data exist demonstrating the mussel population impacted by a kill has unique traits uncommon in other areas, additional damages are warranted.