Brown Bullhead Catfish code of Practise

A guide to reducing the risk of catfish being introduced to new areas

MFish has prepared this Code of Practice to reduce the risks of catfish being taken accidentally and introduced to new areas. Fishers can unintentionally take catfish when fishing for other species like eels.

Putting the Code of Practice into use will help reduce the impacts of catfish on native New Zealand freshwater species and the aquatic environment.

Catfish Background

Brown bullhead catfish (Ameiurus nebulosus) were introduced to New Zealand in 1877. Having been introduced into the Auckland region, their numbers have grown significantly, mainly in the northern part of the North Island. Catfish are now widespread in the Waikato River system including Lake Taupo, where they are present in large numbers. They are also found in one isolated area on the West Coast of the South Island. Further spread of this species is highly undesirable.
 
Catfish are a problem in New Zealand because they damage the environment by eating small native fish and their eggs. They also compete for food with other native species, including freshwater crayfish. Catfish stir up mud which reduces water quality for other animals and plants.
 
Catfish are robust fish with whisker-like barbels on their heads and sharp spines on their fins. They prefer slow flowing streams and the edges of lakes. They often live among water plants. They grow up to about 2 kg in New Zealand. Catfish can survive in a wide range of temperatures and poor water quality.
They can also survive for a long time out of water and can be difficult to kill.

Catfish Laws

1. If a non-commercial fisher catches a catfish, the fisher must kill it immediately. The penalty for possessing live catfish for non-commercial fishers is $750. (Fisheries (Amateur Fishing) Regulations 1986)

2. The sale of live catfish is prohibited. Commercial fishers must kill all catfish before selling them to a licensed fish receiver. The penalty for a commercial fisher selling live catfish is a fine of up to $20,000. (Fisheries (Commercial Fishing) Regulations 2001)
3. An authorisation is required to release any live animals or plants into any freshwater area. Failure to have an authorisation could mean a fine of up to $5000. (Conservation Act 1987)
   

CODE OF PRACTICE

CHECK, CLEAN, DRY .... stop the spread

FOR NON-COMMERCIAL FISHERS

Check, clean, dry. Remove all catfish, larvae and eggs from vehicles, boat trailers and fishing gear before leaving boat ramps.

Check, clean, dry. Remove all aquatic life including clumps of weed and algae from vehicles, boat trailers and fishing gear before leaving boat ramps.

Clean all your freshwater fishing gear in salt baths, including fyke nets and hïnaki. Salt water will kill freshwater fish, including catfish (see salt bath protocol in this pamphlet).

FOR COMMERCIAL FISHERS

Check, clean, dry. Remove all catfish, larvae and eggs from vehicles, boat trailers and fishing gear before leaving boat ramps.

Check, clean, dry. Remove all aquatic life including clumps of weed and algae from vehicles, boat trailers and fishing gear before leaving boat ramps.

Clean all your freshwater fishing gear in salt baths, including fyke nets and hïnaki (see salt bath protocol in this pamphlet).

Use covered or secure bins or tanks when you transport catfish to a licensed fish receiver to ensure no catfish can escape.

Commercial fishers are required to kill all catfish before sale to a licensed fish receiver. If possible, commercial fishers should kill all catfish caught immediately, even those that they do not intend to sell.

SALT BATH PROTOCOL

Materials required

• A drum or water trough large enough to soak your nets in.
• A container to measure the salt and water (eg. a bucket).
• Standard table or agricultural salt.
• Fresh water (or sea water).

Procedure

1. Make up a salt bath by adding 1 part salt to 14 parts fresh water by volume to a drum or trough that is big enough to soak the nets in.
2. Mix until all the salt has dissolved. This will usually take less than 5 minutes, longer in cooler temperatures.
3. Soak nets in the salt water solution for 1 hour or more.
4. It is advisable to rinse fishing gear in fresh water after salt bath treatment.
5. Nets can be reused immediately or stored for later use in the normal way.

Reuse, safety and disposal of treatment solution

The salt water solution can be reused many times as long as the salt is not diluted by putting very wet nets into the solution. Try to drain nets as much as possible to avoid diluting the bath. If in doubt, add further salt to the bath or mix a fresh solution.

Sea water may be used in place of freshwater to form part of the solution. Sea water already contains salt so you will need only need to add 1 part salt to 28 parts seawater to obtain the right concentration. Brackish water from estuaries will not be salty enough and should be treated as freshwater.

Further dilute the salt solution when you dispose of the salt bath, to prevent damage to the aquatic environment.

Remember!

• To be 100% effective in killing catfish, fishing gear must be treated in salt baths of 1 part salt to 14 parts water, for at least 1 hour.
• Each time you fish in a different river catchment there is the potential to transfer catfish. You should treat fishing gear in salt baths before fishing in the next river catchment.
• Treatment of fishing gear in salt baths is also 100% effective in killing other problem species including koi carp, gambusia (mosquito fish) and the freshwater invasive alga didymo.
• If no salt is available fishing gear can be cleaned in 5% dishwashing liquid solution or hot water above 45 degrees. Gear can be dried for 48 hours to have similar cleaning effects.

 Download Brown Bullhead Catfish Code of Practise Brochure (PDF 292kb)