Whitebaiters urged to ‘check, clean, dry’ gear

15 August 2007

Whitebaiters urged to ‘check, clean, dry’ their gear

Whitebaiters are reminded to clean nets and other gear to prevent the spread of aquatic pests and the invasive algae didymo into Wellington region waterways during the whitebait season, which begins here today (August 15) and continues until the end of November.

Didymo(Didymosphenia geminata) has not yet been found in North Island rivers but has been confirmed in the South Island, in waterways in Southland, Otago, Canterbury, the West Coast, and Tasman. The Department of Conservation, which manages the whitebait fishery, is appealing to whitebaiters to “clean, check and dry” their equipment when moving between waterways, to protect rivers, including whitebait habitat, against fresh water weeds and didymo.

Didymo is a nuisance alga which can cover river bottoms with unusually large mats which can shred and float downstream, clogging water intakes and fishing nets.

“Didymo is a single-celled micro-organism that can spread between waterways by the movement of water, equipment, clothing and any other damp item,” DOC Wellington-based freshwater pest awareness officer David Moss said.

“Because it’s so hard to detect it’s important to thoroughly clean fishing gear using the approved cleaning methods,” Mr Moss said.

He said other pest species (such as pest fish and aquatic weeds) are present in some North Island waterways and can also have negative impacts on whitebait.

“Before leaving a waterway, items should be checked for clumps of algae or other matter and any debris found left at the waterway. Whitebait nets, including corners, should be thoroughly checked and cleaned of debris.”
MAF Biosecurity New Zealand didymo programme response manager Chris Bicknell said all waterways should be treated as if they are infected with didymo as it is difficult to detect when not in bloom. and all gear should be cleaned before it is used elsewhere.
“We need everybody to do their bit to protect our freshwater environments against didymo and other aquatic pests.”
He said there were several cleaning options available for whitebaiters and they should choose the most practical option for their situation.-

* Nets and other items made of absorbent material can be decontaminated by soaking in a 5 percent solution of dishwashing liquid or nappy cleaner for as long as it takes to thoroughly saturate the item, plus for at least an additional minute to kill didymo cells trapped deep within the cracks, crevices and absorbent parts of the item. Non-absorbent items such as tyres, trailers and buckets can be soaked or sprayed with the above cleaning solutions for at least one minute.

* Dilute seawater such as found in whitebaiting areas is ineffective at killing didymo. Whitebaiters who prefer to decontaminate their gear with salt should use a 2% by volume salt solution (saltier than seawater) prepared by adding one small cup (200 mls) of table salt to water to make 10 litres. Soak for as long as it takes to thoroughly saturate the item, plus for at least an additional ten minutes.

* Other options for decontaminating gear include soaking in hot water kept above 45 °C for at least 20 minutes (longer for absorbent items), freezing until solid or drying. Although drying will kill didymo, slightly moist didymo can live for months. To ensure didymo cells are dead by drying, the entire item must be completely dry to the touch, inside and out, then left dry for at least 48 hours before use.

If cleaning or drying is not practical, whitebaiters must restrict their gear to a single waterway.

More information on didymo and approved cleaning methods can be found on the MAF Biosecurity New Zealand website www.biosecurity.govt.nz.

The whitebait season lasts until 30 November everywhere except the West Coast of the South Island, where the season ends on the 14 November. Fishing is permitted only between 5 am and 8 pm or between 6 am and 9 p.m. when daylight saving comes into effect in October.

The regulations provide for fines of up to $5,000, so fishers should be aware of what is permitted.

Information on whitebaiting regulations and whitebait and other native fish species can be found on the DOC website: www.doc.govt.nz . Pamphlets outlining information on the regulations can be obtained from DOC offices and sports shops

ENDS

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