Posted: Feb. 22, 2012, 11:50 a.m. EST
By John Dawes
Red lobster, fairy moss, water hyacinth, lionfish, goldfish, carp, pumpkinseed, caulerpa, mosquito fish, water lettuce, salvinia, apple snails…they all have one thing in common: they are regarded as invasive, or potentially invasive, alien species in numerous countries and regions outside their natural range. And these are only some of the well-known species within the ornamental aquatic industry. Add all the others and we are talking hundreds--or thousands--of such species.
One country taking recent action regarding these species is Spain. After several years of consultation (in which the Spanish pet industry association, Asociación Española de Distribuidores de Productos para Animales de Compañía, played an integral part) the country’s Council of Ministers approved in November 2011 a Royal Decree regulating a list and catalogue of Spain’s invasive alien species. Such species are considered some of the most important threats to the conservation of Spain’s biodiversity and its autochthonous species, and as the cause of major damage to agricultural, livestock and forestry production.
In total, the list includes 200 species, some in a catalogue and others within a listing. Those that appear in the catalogue are exotic species for which “scientific and technical information exists indicating that they constitute a serious threat to autochthonous species, habitats or ecosystems, agriculture or economic resources associated with the use of the country’s natural heritage.”
The beautiful but highly invasive water lettuce(Pistia stratiotes) is included in the Catalogue of Spanish Invasive Alien Species.Photo by John Dawes
Species included in the listing are those that are “susceptible” to becoming a serious threat through competition with autochthonous wild species, or to their genetic purity, or to ecological equilibria, or their exhibiting invasive potential.
Thus, water hyacinth (Eichhornia crassipes), water lettuce (Pistia stratiotes), red lionfish (Pterois volitans), red lobster or Louisiana red swamp crayfish (Procambarus clarkii) and all the others mentioned above--as well as additional species--appear in the catalogue, with two important exceptions: the goldfish (Carassius auratus) and the carp, including koi (Cyprinus carpio), which are included in the listing.
Three other fish species in trade—the guppy (Poecilia reticulata), the silver or tinfoil barb (Barbonymus schwanenfeldii), and the dojo or Japanese weather loach (Misgurnus anguillicaudatus)—are also included in the listing, but not in the catalogue. This indicates that, while they are thought to meet the above susceptibility and potentiality criteria, they are not (at least, not yet) sufficiently well documented to warrant their inclusion in the catalogue.
For the most part, the catalogue and listing’s content seem quite reasonable. Nonetheless, several inclusions seem somewhat anomalous. It’s not that they don’t have the potential to become invasive, but is this true throughout Spanish inland waterways and/or coasts?
Take the silver or tinfoil barb, for example. Its temperature range is usually given as 71 to 77 degrees Fahrenheit. I live in southern Spain, about the warmest region of the country (with the exception of the Canary Islands) and, as I write these lines, the temperature of the water in my pond is already down to around 57 to 59 degrees at night. In a few weeks’ time, it will be down to 50 degrees or even lower. No tinfoil barb can withstand such temperatures.
Neither can guppies. The dojo, on the other hand, will: its broad temperature range being 41 to 77 degrees.
To my knowledge, there are no populations of tinfoil barbs in Spain, although the species was introduced into Italy, but has not become established. With regard to the guppy, there’s only one population in Spain, and this is in a thermal spa resort in Montanejos, Castellón. So, we are not talking about species with the potential to invade all Spanish waters, by any stretch of the imagination.
Perhaps the most surprising inclusion in the catalogue is the red lionfish (Pterois volitans). I say this because, while we know this species has become widespread in some United States’ waters along the Atlantic coast, there are no records of it having been introduced into any other regions of the world. Although its temperature range is regarded as tropical, specimens have been spotted in water as cool as 56 degrees (unpublished document). Whether it can survive indefinitely at this temperature, and breed, is a different matter altogether.
The second species reported from the eastern coast of the U.S. is the very similar P. miles--the devil firefish. Genetic analysis carried out on both species has revealed that the vast majority of exotic lionfish in U.S. waters is P. volitans with a small number of P. miles.
Several questions arise from the above. Is there really a justifiable case for including P. volitans in the catalogue, or even the listing? If so, why is P. miles not included?
The Royal Decree is still in its infancy, of course, and revisions may occur in due course. However, as things stand at the moment, “The inclusion of a species in the Catalogue…carries with it generic prohibition with regard to the possession, transport and commercialization of living or dead specimens, their remains or propagules (plant material used for propagation purposes), including external trade.”
We’ll just have to wait and see. <HOME>
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