Preventing the spread of invasive marine species

Aquatic Invasive Species (AIS) are aquatic organisms that establish and reproduce rapidly outside their native range and threaten natural ecosystems, human health and the economy.   Invasive species are also called alien, nuisance or exotic species.

AIS threaten the diversity or abundance of native species through competition for resources, predation, parasitism, interbreeding with native populations, transmitting diseases, or causing physical or chemical changes to the invaded habitat. With the onset of climate change, it is anticipated that species will be introduced to non-native habitats as their range expands, and associated ecosystem impacts will be experienced in new locations.  Through their impacts on natural ecosystems, water delivery and flood protection systems, AIS may also negatively affect human health and/or the economy.  Examples of direct impact to human activities include the clogging of navigable waterways and water delivery systems, weakening flood control structures, introducing diseases to marine life (especially those that are raised or harvested commercially), and diminishing sportfish populations.

A large population of aquatic invasive species can start from a very small number of individuals, and those individuals can be difficult to see, so they may easily go unnoticed.  The tiny young of invasive shellfish, or a fragment of an aquatic weed can be enough to start off a population that will ultimately become a multimillion dollar headache for the state.  However, these populations do not grow from a few individuals to damaging levels overnight, and if populations are detected early enough, there is a good likelihood that they can be eliminated before they cause damage and huge population control costs.  Early detection and rapid response are the most effective and cost efficient responses to invasive species introductions. Ideally, minimizing AIS introductions through preventative measures will reduce the need for these responses.

California’s current management of AIS in marine and coastal ecosystems is focused on preventing introductions of AIS from commercial shipping – both ballast water and hull fouling.  Invasive species are also introduced from other pathways such as commercial fishing; recreational boating; intentional and accidental releases of aquaculture species, aquarium specimens or bait; and other means. Foreign invaders such as the green crab, zebra mussel and Pacific jellyfish have displaced native species and diminished biodiversity, resulting in significant economic impacts and fundamental disruptions of coastal and fresh water ecosystems.

In 2005, the OPC provided $110,000 to the San Francisco Estuary Project and coordination to complete the California Aquatic Invasive Species Management Plan (appendices).  OPC is now working with state agencies and other partners on implementing the plan, which identifies the actions that need to be taken to minimize the harmful environmental, economic, and human health impacts of AIS in California.  OPC is focused on the following actions to support implementation of the plan:

If these core actions can be accomplished, it will provide a basis for pursuing the larger list of AIS management priorities in the future.


Council Documents
Staff Recommendation to fund research on aquatic invasive species vector risk assessments

Staff Recommendation to fund completion of the AIS Plan

Categories: Sustainable Fisheries and Marine Ecosystems