What is an endangered species worth? Threshold costs for protecting imperilled fishes in Canada

The protection of imperilled fish species is increasingly urgent given ongoing fisheries declines and the degradation of aquatic habitats. In Canada, threatened aquatic species were less likely than terrestrial species to be listed under the Species at Risk Act (SARA), the main legal instrument for bestowing protection, in the early years of the Act's implementation. In this paper, the existence of economic thresholds that might have hampered the protection of Canadian marine and freshwater fishes is examined. The analysis of the socio-economic data used to inform listing decisions about threatened fish taxa over the past decade reveals that the likelihood of being listed declines non-linearly with increasing estimated costs of protection but does not vary with proposed threat status. The estimated threshold cost (i.e., the point at which the likelihood of not being listed=0.5) was ∼$5,000,000 (∼$1,400,000 to ∼$31,400,000, 95% CI) per decade for freshwater species but only ∼$90,000 ($∼50,000 to ∼$140,000, 95% CI) per decade for marine fish taxa. In fact, no marine fish species with an anticipated cost of listing greater than zero was listed for protection. The presence of existing management legislation and qualitative statements about negative impacts of listing on exploitation generally led to denying protection to marine but not to freshwater species. These findings highlight both a large and inconsistent emphasis on costs of protection in SARA listing decisions, to the detriment of marine fish species.