|What impact do they have?
Marine pests can have severe ecological and economic impacts. For example, they can take over large areas of habitat to the detriment of native species. Some prey directly on native species or compete with them for food.
Pest species can also cause considerable economic damage. Infestations of marine pests can impact on marine industries, such as aquaculture, commercial and recreational fishing and boating, tourism and even international and domestic shipping. Some marine pests, such as toxic dinoflagellates, can threaten public health.
Some pests like European fan worm form a 'carpet' on the seabed, smothering native species for food and space and altering the marine habitat to suit themselves.
Some pests, like the northern Pacific seastar prey on native species depleting aquaculture and fishery operations.
Some pests may infest the shoreline to such an extent that the area becomes unattractive and its value as an amenity is reduced. Some crabs canburrows into the shore causing erosion. They can also damage fishing gear and affect aquaculture operations and also hosts parasites like liver fluke which is harmful to human health.
Some pests will encrust structures such as jetties and marinas, long lines used in aquaculture or industrial water intake pipes.
Marine pests can damage engines by clogging cooling water intakes resulting in engine overheating.
The build up of up of marine biofouling on vessel hulls slows down the vessel and increases fuel consumption. The antifouling coating of this yacht is at the end of its effective life and biofouling has accumulated to a level where the yacht may inadvertently be harbouring marine pests.
Some pests are microscopic organisms that in high levels are toxic to humans. Shellfish feed by filtering such organisms from the water and can accumulate them in high levels when the right conditions exist. This has a double effect, creating human health issues as well as causing the affected shellfish beds to be closed down and loss of income for the operator.