Anglers are calling for tougher measures, including ring-fencing of the world-class Taupo-Tongariro fishery, to stop the invasive algae didymo spreading from the South Island.
"A clear Government policy that effectively ring-fences the North Island to protect the valuable freshwater resource is needed as soon as possible," Federation of Freshwater Anglers president Ian Rodger said yesterday.
Live didymo cells were "aquatic hitchhikers" he said, adding they had spread out of control through the South Island. They survived weeks in damp or wet fishing gear, clothing, kayaks, boats and particularly felt-soled wading boots.
Mr Rodger said stronger and more effective measures were needed in light of the recent "wake up call" when dead didymo cells were found in four Central Plateau rivers, including the Tongariro.
In the end, the National Institute of Water & Atmospheric Research last month owned up to the cells coming from contaminated water quality sampling containers brought up from Christchurch.
Subsequent sampling found no further didymo cells in the rivers but Mr Rodger said it was disturbing that there was not a "full alert, full surveillance, right from the start".
The federation had been urging more public signage about the risk of spreading didymo and greater biosecurity detection measures at the inter-island ferry terminals.
"While we have been heartened by action recently taken by MAF Biosecurity New Zealand in this direction we still consider it inadequate.
"Anglers have tended to be blamed for the spread of didymo. We fully accept that as freshwater anglers we must act responsibly.
"However we would ask that others who use freshwater for recreation do likewise.
"The fact is there are many other potential didymo carriers, from kayaks to trailer boats, trampers and four-wheel-drive vehicles."
Mr Rodger said a second layer of control around the Taupo catchment was warranted because of the fishery's importance for recreation and tourism and could be imposed through the border control measures of the Biosecurity Act.
Biosecurity New Zealand and recreational groups have been pushing the message of "check, clean and dry" for equipment.
The South Island is a controlled area which means freshwater gear has to be cleaned when leaving any river.
In Fiordland, any person wanting to fish there must obtain a special authorisation called a "controlled fishery licence" from Fish and Game.
All gear is required to be cleaned at an approved cleaning station within 48 hours of departure for the trip. Anglers are also required to have a "clean gear certificate" in addition to a full season sports fishing licence.
In the upper South Island, the waters of the tourist attraction Te Waikoropupu Springs have been closed to fishing and diving since January 2007.
Yet didymo continues to spread. The most recent discovery was on December 11 in the Rangitata Diversion Race in Canterbury.
Biosecurity Didymo Response Manager Chris Bicknell said the North Island was already ring-fenced by making the South island a controlled area.
"All practical and reasonable measures are being taken to make sure it does not move across the buffer of Cook Strait," said Mr Bicknell.
Biosecurity had two teams working at ferry terminals on either side of the strait to check for craft and equipment used in South Island waters and if necessary to clean them on the spot.
He said all anglers received information about the pest with their fishing licences and simulated alerts for didymo held in different regions had also raised awareness of the risk.
He supported Fish and Game's proposal of a ban on the use of felt-soled boots in the new fishing season.
What the New Zealand Federation of Freshwater Anglers is demanding:
* Ring-fencing the North Island by extending the amendment to the Import Health Standards announced by Biosecurity NZ in September;
* Ring-fencing the Taupo Catchment Fishery;
* Introducing a Clean Gear Licence for ALL freshwater anglers (as in parts of Southland) and for all vehicles, boats, equipment and kayaks using same;
* Imposing restrictions on the use and importation of felt-soled boots;
* Launching a NZ-wide high profile awareness campaign that covers all present and future incursions. (In addition to the very successful 'check-clean-dry' MAF/BNZ didymo campaign.)By Wayne Thompson Email Wayne