Mice theory for fat fish gains traction

BY BLAIR ENSOR

Two Australian tourists have landed two monster brown trout within a stone's throw of one another as speculation about the "year of the mouse" hots up in the Nelson Marlborough Fish and Game district.

Australian husband and wife team Keith and Mary Crane, from Sydney, caught the super trophies, both 5.3kg, 20 metres apart, on nymphs last Wednesday.

Strike Adventure guide Tony Entwistle, who would not disclose where the monsters were caught, said Mr and Mrs Crane were both very skilful anglers who had travelled to New Zealand for the last 24 years to fish.

Mrs Crane had previously caught a 4.8kg (10.5lb) fish, but it was Mr Crane's first "double-digit" trophy.

"A big fish like that only has to shake his head and he'll break the line," said Mr Entwistle.

"If they were humans they would be berated by the health professionals as being obese, and yet trout fishermen find these fish attractive."

The catch fuels rumours that large mouse populations prompted by a partial beech mast are producing very large trout this season.

Mr Entwistle said he was sceptical about the theory, but said there were big fish spread throughout the Nelson Marlborough Fish and Game district.

"The longer I fish the less I know.

"We have seen years of the mouse before when there's a lot more of these fish."

He said a really good year-class had survived last season, but "the mice have certainly augmented the diet of some fish and that's helped them sustain their size".

Fish and Game Nelson-Marlborough regional manager Neil Deans said he was very pleased with how the season had gone to date with fish in good condition.

Mr Deans said "freshes" or regular rainfall and good hatches of insects and invertebrates had kept fish well fed.

"Quite sustainable conditions for the fish are unpleasant for us."

Mr Deans said mice were the explanation for large fish.

"If they start feeding on these things it's not surprising they put on the beef quickly."

Trout could only get up to a certain size by feeding on small invertebrates, but to get any bigger they needed to feed on something with a bit more energy in it like small fish, mice or large invertebrates.

"I don't know what goes through the minds of rodents to drive them into rivers, but if they go into the water they are vulnerable."

Mr Deans said fishermen needed to be quick to take advantage of the large fish because the mouse population would "eat itself out of house and home" and head into decline shortly.

- The Marlborough Express