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Published: 2002-04-12 00:00:00

The Waikato's coastal environment is potentially at risk from the introduction of new marine species, Environment Waikato's policy committee heard this week.

Coastal ecologist Dr Stephanie Turner said invasive marine species were one of the main threats to the marine environment, and a number of introduced species were already present in the Waikato Region. However unlike other threats to the coastal environment such as increased sediments, nutrients and contaminants, the effect of introduced marine organisms had been largely overlooked.

Scientists estimated that at least 160 marine plants and animals had been introduced to New Zealand’s coastal environment, with new ones arriving at about 1.5 a year. The largest number of organisms have come from Europe, Eastern Asia, tropical Indo-Pacific, Australia and North America. A number of species were also exported from New Zealand and established in other countries.

They could arrive naturally, on currents, attached to logs or swimming creatures, and through deliberate introduction, vessel fouling and in ballast water.

"There is ample evidence internationally that introduced marine species can cause serious impact on natural coastal ecosystems; commercial, recreational and customary fisheries; shipping; coastal recreation and amenity, and human health.

"Given New Zealand's reliance on international shipping, with more than 90 percent by volume of exports and imports being carried by sea, and the proximity of the Waikato Region to international ports, shipping lanes and potential sources of introduced marine organisms, the Region's coastal environment is at risk from the introduction of new marine species.”

New Zealanders were aware of the numerous plants and animals that had been introduced and become established on the land, and in lakes and streams, and of the effects they may have on native ecosystems,but were much less aware of introductions of plants and animals in the marine environment.

Often it was only when new arrivals in coastal areas had become well-established and reached considerable numbers that that they were noticed.