The cost of non-native aquatic species introductions in Spain: fact or fiction?

The ecological and economic impact of non-native species introduction on local native biodiversity is often reported as undeniable scientific evidence on which to base management and sound policy. Here I used a combination of databases (Fishbase, FAO and IMPASSE) and an extensive review of existing literature to establish the proportion of non-native aquatic species introductions in Spain that are responsible for ecological and economic impacts. In Spain, aquaculture and angling are the two main ecosystem services responsible for introduction of non-native aquatic species. In total, forty two percent of all non-native aquatic introductions are intentional. Very little ecological impact resulting from these non-native species introductions has been demonstrated with some representing a benefit to Spanish ecosystem services. In 2007, the economic benefits to Spanish aquaculture arising from non-native aquatic species (n=9) was close to (sic)46.73 million (about U.S. $69 million) annually for an estimated average ecological risk for all introductions of 16.5% (SD= 26.85). These results must be seen in the context of other environmental factors such as habitat destruction, water abstraction and pollution from agricultural farming which represent major environmental pressures on Spanish aquatic fauna.