New Zealand Self Drive Adventures

June 07, 2019

Fishing in NZ during a Beech mast mouse epidemic

The Beech mast (seeding) this season is predicted to be one of the larger and more widespread in recent times. Additionally, this is the second year in a row where this has occurred. Normally this only occurs once every 4 to 5 years. The result will be an excess of food available to mice and other rodents whose population increased last year and should soar this year. The biggest concentration of Beech is in Southland and some parts of Canterbury but there are Beech forests throughout the Central North Island as well.

Why bigger trout?

In seasons such as this, there will be a lot of mice and they will be on the move looking for food and mates. They often cross waterways looking for mates and they also bathe in streams and rivers but this happens mainly at night. During a “mouse year” trout often frequent shallow stretches of water at the beech forest edge from dusk onwards and gorge on mice. This has two impacts on trout; firstly, they can increase in size quickly and dramatically. Secondly, trout that are feeding on mice all night are much less active during the day while they digest larger than normal amounts of food.

Many of the rivers in NZ produce reasonably good numbers of trout that range from 5 – 7 pounds but only a few rivers regularly produce trout that reach double figures. In a mouse year the trout feeding on mice can increase their body weight by as much as a third. That means all those rivers with 5 – 7 pounders will produce a good number of much larger fish. During a mouse year there is a much greater chance of catching a trophy trout (10 pounds plus).

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Where, when and how to fish Fishing in the South Island at night in rivers and streams that are flanked by beech forest is the ultimate way to take advantage of this phenomenon. However; daytime fishing and fishing in the Central North Island shouldn’t be discounted.

Fishing with a mouse pattern can be exhilarating. Trout savagely attack to try and disable the mouse quickly. Fishing this way in the dark is unparalleled in terms of the thrill of the take. On the flip side, fishing in the dark can be dangerous for obvious reasons. Its important to scout the area before dark and ensure you know where you can and can’t put your feet. Fortunately, mice tend to bathe and cross at the spots that have the easiest and calmest water. If possible, plan your evening by picking a place that has good footing, no drop offs, forest close to the water and plenty of room to cast.

Check this clip out on youtube https://www.youtube.com/watch?v=ikoZ1xxPre4 or buy the DVD at https://swiftflyfishing.com/collections/dvds/products/once-in-a-blue-moon

Author: Dave Turner