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Threats
Marine invasive
(non-indigenous) species are generally understudied; few countries in
and around the Pacific have extensively researched on this threat.
However, where documented, the scientific literature acknowledges that
invasives pose a very serious ecological and economic threat. For
example, the Micronesia Challenge—a regional initiative—recognizes the
need across those islands to focus on marine invasive species control,
among other sustainable marine policies. Marine invasives travel in a
number of ways. First, they can be unwitting stowaways on ships engaged
in trans-Pacific routes. Ballast water, taken on board at port before a
voyage, takes with it marine organisms. When the cargo is unloaded at
the destination, the ship also deposits the surviving species. Ship
hull fouling, boring, dry and semi-dry ballast, and water ballast have
transported hundreds of exotic species around the Pacific. The second
vector for marine invasive species is stocking; aquaculture, for
example, may introduce non-natives into new areas.
Environmental & Socioeconomic Impacts
Marine invasive species, if they can survive in their new environment,
can negatively affect native species and the existing "host" ecosystem.
While not all marine invasives from shipping or stocking harm their new
environment, many establish their own populations and cause biological
invasions of native species. These invasive populations may then
compete with native species for habitat and food or introduce diseases,
leading to the depletion of native populations and altering the
functions of entire ecosystems. Introduced toxic dinoflagellates, for
example, have caused red tides and harmful algal blooms that can impair
or even kill shellfish, fish, sea birds, and people. Already disturbed
habitats are most prone to such invasions.
Marine invasives can be costly to human society as well. Species introduced through ballast water or aquaculture can affect fisheries or other aquaculture operations by competing for food or introducing deadly pathogens. The mass mortalities of farmed or native fish species can lead to abrupt production declines, thereby reducing fisheries livelihoods and creating food insecurity. The total economic losses from marine invasives can approach billions of dollars per year throughout the Pacific region.
Click here for key readings about invasive species' threat to and impact on the Pacific Ocean.
