Last updated October 2026
The Waikato River at Mercer and Tuakau is big river fishing south-east of Pukekohe. Fish & Game names two of its favourite coarse fishing spots here: Les Batkin Reserve on River Road in Tuakau, and the western shore either side of the Mercer Bridge.
The lower river holds high numbers of rudd, catfish and koi carp, plenty of perch, and brown trout that move down the river after spawning. It is open all year to fly, spin and bait. Catfish must be killed when caught, and a live koi must never be kept.
At a Glance
- Location
- Les Batkin Reserve, River Road, Tuakau; and the western bank either side of the Mercer Bridge
- Type
- Wide lowland river with backwaters
- Main species
- Rudd, catfish and koi carp (high numbers), perch, brown trout
- Method
- Fly, spin and bait
- Season
- Open all year
- Licence
- Fish & Game licence for trout, rudd, perch and tench; none needed for koi, catfish or goldfish
- Best time
- Summer for rudd; winter for trout, early morning and the hour after dusk
- Boat ramp
- Les Batkin Reserve, River Road, Tuakau
- Pest fish
- Kill catfish on capture; never hold a live koi
- Flow
- Check Waikato Regional Council river levels after rain
Flow and clarity move the fishing: trout fish best in winter when the river runs clearest, rudd in summer, and high, dirty water after rain calls for bigger, darker lures.
More About The Waikato River at Mercer and Tuakau
Below Karapiro Dam the Waikato runs as a broad lowland river, on its way to the sea past Mercer and Tuakau. Fish & Game says the river from Karapiro to the sea holds high numbers of rudd, catfish and koi carp. Perch are plentiful too, and brown trout are found throughout the river.
At Mercer the road bridge crosses from the village to the western bank. From above, a backwater opens off the western side just north of the bridge, with farm drains running into it, while State Highway 1 and the railway follow the eastern bank. Fish & Game’s favoured water is that western shore, either side of the bridge.
Downstream at Tuakau, River Road runs beside the river from the town towards the Tuakau Bridge, and Les Batkin Reserve on River Road has a council boat ramp. Further down again, Fish & Game also rates the back-channels near Hoods Landing.
Catfish, brown bullheads, were first recorded in Lake Taupō in 1985 and have spread down the Waikato River since. Waikato Regional Council says they compete for food on the river bed and, in big numbers, stir up sediment and worsen water quality.
How to Fish the Waikato River at Mercer and Tuakau
Coarse fish
- Rudd: extremely abundant, and best targeted in summer. Use a light float, hooks from size 10 to 14, and bread or corn.
- Perch: plentiful. Light tackle with soft baits of 5 to 7 cm works well.
- Koi carp and catfish: both common in the lower river. Neither needs a licence, and the rules below apply to both.
Brown trout
Fish & Game says brown trout, usually around 1.5 kg, drop downstream to feed after spawning in April and May and stay in the river until December. Winter brings the clearest water, and early morning and the hour after dusk are the most productive times.
- Trolling: productive in the lower reaches. Use 4 to 5 kg nylon and a three-way swivel with a sinker bumping the bottom, with a black Toby of 10 or 12 g or a Tasmanian Devil or Cobra, and follow the deeper, faster channels.
- Spinning: soft baits with a T or paddle tail, a black Toby, a copper Zed or a red Veltic. Go larger and darker when the water is high.
- Fly: wet flies usually do better than nymphs or dries. Rabbit flies in olive green or black work well, and a big black rabbit suits night fishing or coloured water.
- Bait: smelt or worm is popular, especially with young anglers.
Rules and Safety
Licences and methods
- Licence: you need a Fish & Game licence to fish for trout, rudd, perch or tench. Koi carp, catfish and goldfish need none, but if you catch a licensed species without a licence, return it quickly.
- Rules: this stretch comes under the general Auckland/Waikato river rules: open all year to fly, spin and bait. You may fish for coarse fish anywhere sports fishing is allowed.
- Coarse fishing waters: the nearby Mangatāwhiri River, from the State Highway 2 bridge to where it joins the Waikato, and the Whangamarino River are listed coarse fishing waters with their own tackle and bait rules.
- Limits: bag limits for trout and coarse fish are set in the Auckland/Waikato regulations; read the current brochure before you keep fish.
Pest fish
- Catfish: a pest species in New Zealand. Under the Fisheries Regulations 2013 they cannot be spread and must be killed when caught. Handle them carefully: the dorsal and pectoral fins carry sharp spines.
- Koi carp: a noxious fish. It is illegal to have a live koi in your possession, and fines can be heavy.
- No moving water or fish: never use fish taken from another water as bait, and never carry water, bait buckets or live wells from one waterway to another.
On the bank
- The Waikato is a big, moving river. Fish from the bank, keep children back from the edge, and stay off the water when it is high after rain.
- Keep clear of the Les Batkin Reserve ramp while boats are launching.
- Felt-soled waders are banned for sports fishing.
Getting There and Facilities
- Tuakau: Les Batkin Reserve is on River Road, which follows the river below the town. The reserve has a Waikato District Council boat ramp.
- Mercer: cross the Mercer Bridge from the village to the western bank and fish the shore either side of the bridge.
- Bait and tackle: buy bread, corn, worms and lures in town before you go.
Useful Links
Fish & Game: Auckland/Waikato coarse fishing waters: coarse species and access points on the lower Waikato.
Waikato Regional Council: brown bullhead catfish: why catfish are a pest and what to do with one.
Auckland/Waikato regulations 2026 to 2027: seasons, methods, coarse fishing waters and limits.
Common Questions
Where can I fish the Waikato River near Tuakau?
Les Batkin Reserve on River Road, Tuakau, is one of Fish & Game’s favoured access points, and it has a boat ramp.
Where do people fish at Mercer?
On the western shore either side of the Mercer Bridge.
What can I catch in the Waikato River at Mercer?
Rudd, catfish and koi carp in high numbers, plus perch and brown trout.
Do I need a licence?
Yes for trout, rudd, perch and tench. No for koi carp, catfish and goldfish.
What should I do with a catfish?
Kill it. Catfish are a pest that must be killed on capture and cannot be spread. Watch out for the sharp fin spines.
Can I keep a koi carp alive?
No. Koi are a noxious fish, and having a live one is illegal.
What bait catches rudd?
Bread or corn on a size 10 to 14 hook under a light float, best in summer.
When are trout in the lower Waikato?
Brown trout move downstream after spawning in April and May and stay until December. Winter has the clearest water.
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