Consecuencias de las especies introducidas

The introduction of alien species into a new environment can have serious negative consequences for the environment, for the economy and for human health.

Ecological impacts may include:

• Competing with native species for space and food
• Preying upon native species
• Altering habitat
• Altering environmental conditions (e.g. decreased water clarity)
• Altering the food web and the overall ecosystem
• Displacing native species, reducing native biodiversity and even causing local extinctions

Economic impacts may include:

• Reductions in fisheries production (including collapse of the fishery) due to competition, predation and/or displacement of the fishery species by the invading species, and/or through habitat/environmental changes caused by the invading species;
• Impacts on aquaculture (including closure of fish-farms), especially from introduced harmful algal blooms;
• Physical impacts on coastal infrastructure, facilities and industry, especially by fouling species;
• Reduction in the economy and efficiency of shipping due to fouling species;
• Impacts or even closure of recreational and tourism beaches and other coastal amenity sites due to invasive species (e.g. physical fouling of beaches and severe odours from algal blooms);
• Secondary economic impacts from human health impacts of introduced pathogens and toxic species, including increased monitoring, testing and diagnostic and treatment costs, and loss of social productivity due to illness and even death in affected persons;
• Secondary economic impacts from ecological impacts and biodiversity loss;
• The costs of responding to the problem, including research and development, monitoring, education, communication, regulation, compliance, management mitigation and control costs.

Human health impacts

• Given the magnitude of ongoing ballast water transfers, there is significant potential for large-scale movement of micro-organisms by ships.  This has received attention from both epidemiologists and invasion biologists.
• There is evidence that cholera epidemics can be directly associated with ballast water discharges (see Examples of IAS). While Vibrio cholerae and other pathogens are normal constituents of coastal waters, they do not ordinarily occur in high enough concentrations to cause human health problems. However, with expanding world trade and an increasing number of ships moving among international ports, the transfer of microbes could well be the most insidious threat related to ballast water discharge.
• In addition to bacteria and viruses, ballast water can also transfer a range of species of microalgae, including toxic species that may form harmful algae blooms or ‘red tides’. The public health impact of such outbreaks is well documented and includes paralytic shellfish poisoning, which can cause severe illness and even death in humans.

Fuente:http://globallast.imo.org/the-invasive-aquatic-species-2/