Rules & regulations
Check, clean and dry to avoid spreading didymo
Anglers can help reduce the liklihood of didymo spreading
- Always check, clean and dry equipment before
using it again
- Don't use the same equipment on different
waterways without checking cleaning and drying
- Using rubber-soled boots (felt-soled footwear
is banned from 1 October 2008)
- Bringing only clean fishing equipment into
- Being informed about didymo: see
Didymo biosecurity alert
|Check, clean and dry
Before you leave a river or lake, check items
and leave debris at site. If you find any later, treat and put in
rubbish. Do not wash down drains.
Biosecurity New Zealand website advises that there are
several ways to kill didymo. Choose the most practical treatment
for your situation which will not adversely affect your gear.
- Non-absorbent items
Detergent: Soak or spray all surfaces for at least one
minute in 5% dishwashing detergent or nappy cleaner (two large
cups or 500 mls with water added to make 10 litres); or
Bleach: Soak or spray all surfaces for at least one
minute in 2% household bleach (one small cup or 200 mls with water
added to make 10 litres); or
Hot water: Soak for at least one minute in very hot water
kept above 60 °C (hotter than most tap water) or for at least
20 minutes in hot water kept above 45 °C (uncomfortable to
- Absorbent items
Absorbent items require longer soaking times to allow thorough
Hot water: soak for at least 40 minutes in hot water
kept above 45 °C; OR
Hot water plus detergent: soak for 30 minutes in hot
water kept above 45 °C containing 5% dishwashing detergent
or nappy cleaner; OR
Freezing: Freezing until solid
Freezing any item until solid will also kill didymo.
Drying will kill didymo, but slightly moist didymo
can survive for months. To ensure didymo cells are dead by drying,
the item must be completely dry to the touch, inside and out, then
left dry for at least another 48 hours before use.
Relying on ambient drying as a stand-alone treatment
for decontaminating highly absorbent risk goods is not recommended
in situations where use between waterways is frequent (daily, weekly
or even monthly).
Drying should only be relied upon as a decontamination
treatment if great care is taken to actively and completely dry
the material (such as by using a heat source where temperatures
around the felt are assured of reaching 30 °C). Once the material
appears dry, complete dryness must be confirmed by a tactile inspection
of the base of the fibres. Once completely dry, items must remain
dry for at least 48 hours before use in another waterway.
|Use rubber soled boots
A ban applies to using using
felt-soled waders or footwear incorporating or having attached a
sole of felted, matted or woven fibrous material when sports fishing.
Instead of felt-soled boots or waders, Fish &
Game New Zealand recommend using rubber-soled alternatives that
dry rapidly and are easily cleaned.
Banned felt-soled boots
Bringing fishing equipment into
To slow the spread of the
invasive alga didymo, in New Zealand waterways, MAF Biosecurity
New Zealand requires all used freshwater fishing equipment brought
into New Zealand to be clean and dry. Read
For more information
information about didymo, please see:
Scierra Ipac wading boots
Didymo growth in the Hawea River, Central Otago.
Photo: Glenn Maclean, DOC