Introduced fish species have not received much attention until recently. The identification in March 2006 of a known invasive fish species, Tilapia, in a fresh water lake on San Cristóbal was probably a deliberate introduction for the purpose of fish farming. Tilapia has caused ecological problems to many places where it has been introduced. Its impact on the lake’s ecosystem is not yet known but expected to be devastating.
Until recently the issue of introduced species in the marine environment was greatly undervalued. It has been estimated that, worldwide, 3,000 different species (including fish, bivalves such as mussels, and seaweed) are dumped in foreign ports every day from ballast tanks of cargo ships.
The Galapagos Marine Reserve was created in 1998. Due to the confluence of warm and cold surface currents and deep, cold upwelling waters around the Galapagos archipelago, the Marine Reserve is host to a range of endemic marine species. The introduced species can profoundly affect the ecological processes in marine ecosystems. Research in the Marine Reserve is relatively new and it is not known how many species there are introduced, or potentially invasive. Funding at present does not allow for any research in this area.
Fortunately there is now growing awareness of the problem and the need to take action, with the development of strategies for managing the main vectors of dispersion, via ballast water, bilge water and hull fouling. Bilge water and ballast water are considered to be low risk. Most boats operate almost exclusively within the Marine Reserve and relatively few pass through, although this may be changing. Cargo ships enter the Marine Reserve full and return to the continent empty and therefore take on ballast, and do not discharge it while in Galapagos. Hull fouling is probably the highest risk, as boats (tourist yachts and cargo boats) travel between the continent and the archipelago.