A plague of marine pests could invade Auckland’s bays unless Auckland Council makes better plans to tackle the problem, says Forest & Bird.
The environmental organisation has filed an appeal in the Environment Court to try to get the council to take a stronger line against marine pests.
Forest & Bird Auckland regional manager Nick Beveridge is concerned that the council’s regional pest plan fails to include requirements for the council to control existing marine pests.
“A proper programme of marine pest control needs to be included, or marine pests could spiral out of control,” says Mr Beveridge.
“Like any pests, they can displace native species, because they compete with native sea life for habitat and food.”
Marine pests can cause environmental and economic harm by eating native and farmed fish and shellfish, fouling boat hulls, spreading diseases, and releasing toxins.
“They pose a really high risk to the sustainability of our fisheries and marine biodiversity,” says Mr Beveridge.
One example of a marine pest posing a serious threat to Auckland beaches is the Australian droplet tunicate. It can smother entire beaches in white or cream-coloured cylindrical tubes that are almost impossible to get rid of once they are established.
This pest has spread quickly in Northland and has been spotted in three parts of Auckland - Mahurangi Harbour, Sandspit and Oakura Bay on Waiheke Island.
The Australian droplet tunicate takes over the habitat of native species and destroys marine farms.
Forest & Bird wants this tunicate and six other marine pests that have already entered New Zealand waters to be targeted by the council in control programmes.
These include Asian paddle crabs, Japanese mantis shrimps, Mediterranean fanworms, styela and pyura sea squirts, and undaria seaweed.
Restrictions on selling these pests should also be imposed, says Mr Beveridge.
The council’s pest management plan doesn’t include strong enough rules to stop new marine pests from becoming established around Auckland’s coastlines, he says.
Many marine pests attach themselves to boats and they can be captured in bilge waters. This means commercial and recreational vessels sailing between regions can easily introduce new marine pests into harbours that were previously free of them.
“We need to do everything we can to prevent new pests from being introduced and to stop them spreading from Auckland to other areas," Mr Beveridge says.
Forest & Bird is calling for the council to require boat owners to clean marine pests from their hulls before entering Auckland waters and before sailing between different parts of Auckland region.
Management plans for marine pests should be required from those carrying out high risk activities, such as dredging, marine farming, commercial fishing, tourism charters, and marine construction, Mr Beveridge says.
Northland Regional Council recently adopted a regional pest and marine pathway management plan with clear guidelines to stop new marine pests and prevent the spread of existing pests, he says.
“We want Auckland to get on board and offer the same level of control for marine pests as Northland."
Forest & Bird has also joined an appeal by Keith Salmon from Le Roys Bush and Little Shoal Bay Reserves Charitable Trust against Auckland Council’s pest management plan.
This appeal calls for the council to take a tougher stance on weed control.
Mr Salmon says landowners throughout Auckland should be required to eradicate highly invasive weeds, such as moth plant, woolly nightshade and climbing asparagus. The council should impose fines on landowners who fail to comply with requirements to remove pest plants, he says.
Mr Salmon’s appeal asks the council to include several parks in its weed control programmes that have been left out.
For further comment, contact Nick Beveridge on 09 302 3901 or email n.beveridge@forestandbird.org.nz.
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