The global economic cost of sea lice to the salmonid farming industry

The economic cost of a problem may be the best metric for prioritizing research and management resources. Other metrics could be based on fish welfare, and risks or impacts of parasiticides on the environment, farm staff or the consumer; but these are not addressed here. Sea lice, ectoparasitic copepod crustaceans, are the most damaging parasite to the salmonid farming industry in both Europe and the Americas (Costello 2006). Despite major research efforts over 30 years, as evident from over 800 research publications, they remain a persistent problem. The damage includes the impact on the fish and the environment, and public perceptions of aquaculture (Costello 1993; Pike & Wadsworth1999; Costello, Grant, Davies, Cecchini, Papoutsoglou, Quigley & Saroglia 2001). However, their economic cost has only been estimated at national or regional scales. Here, published estimates of sea lice costs are presented to stimulate better estimates, and provide an estimate of sea lice costs to the world salmonid farming industry. Estimated costs of sea lice control were obtained from the literature (Table 1) and compared with the most recently available salmonid production statistics (Table 2). The salmonid data used included marine production of Atlantic salmon, Salmo salar L., Pacific salmon species, Oncorhynchus spp., sea trout, Salmo trutta L., and charr, Salvelinus alpinus (L.), from countries where sea lice have been reported to be a problem. Data were excluded for countries where sea lice have not been reported as a significant problem, namely Australia, Finland, France, Iceland, Japan, New Zealand and Sweden. To calculate costs per region, average costs from Table 1 were used for UK (Scotland), most recent cost for Norway, Norwegian cost for Faeroes, average of Atlantic Canada for all of Canada and USA, and only the full cost for Chile. These costs were then multiplied by the 2006 marine salmonid production to calculate costs per country and globally (Table 2). Costs of sea lice control are reported in the original currency but converted to cost per kilogram of fish produced by country. For comparative purposes, all values were converted to euros (€) in April 2008 to minimize the effect of recent changes in the value of the US$. Ten estimates of costs because of sea lice were obtained from eight publications for Canada, Chile, Ireland, Norway and Scotland (Table 1). However, what costs the estimates included was only reported in five publications. Whether costs varied between Pacific and Atlantic Canada, and what they were for the USA, were not available. The lowest and highest estimates vary by a factor of 100 for full lice costs, and by 1000 where lower estimates only considered treatment expenses. These differences reflect the different costs between parasiticides and for the same parasiticides between countries, and to a lesser extent price changes over time. Most estimates fell within the range of €0.1–0.2 kg fish produced annually. Journal of Fish Diseases 2009, 32, 115–118 doi:10.1111/j.1365-2761.2008.01011.x