Sunday, February 24, 2008

World's coastal waters - Invasion problem

According to the newest Nature Conservancy study 48 % of the world's coasts are being colonized by foreign aquatic species that are changing current aquatic ecosystems. Many of these invading species are considered to be extremely harmful when introduced to a new landscape, freshwater system or ocean region.

Famous San Francisco bay is world's most invaded area, with 85 invasive species in its waters, of which 66 percent are considered harmful. These new species disrupt food chain in these ecosystems since these new areas new often lack natural competitors and predators.

According to some estimations, about10,000 species are estimated to be in transit at any one time, with many of then being invasive species traveling by thousands of vessels cross our oceans and invading different aquatic ecosystems.

Once these invaders settle in these new ecosystems it is almost impossible to remove them and the only real solution is prevention of their arrival in these ecosystems. These invaders are not only dangerous by ecological point of view but are also damaging economy and US for instance spends about $120 billion annually to control and repair damage that was caused by these invaders.

Among these invading species most notable are: Chinese mitten crab (Delta and San Francisco Bay), tropical seaweed Caulerpa (Mediterranean and Australia), Comb jellyfish (Caspian sea and Black sea) and many other alien algae.

All these marine invading species are showing no mercy to species that live in these areas and if further introduction of these organisms continue this will affect the biodiversity of many ecosystems and cause extinction of many species because of the disorder in the food chain.

How big is this problem? The best would be to quote Jennifer Molnar, lead author of the study, "Assessing the Global Threat of Invasive Species to Marine Biodiversity" that said: "The scale of this problem is vast."

San Francisco bay - Aquatic ecosystem invaded by foreign species, especially Chinese mitten crab.

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