Following the release of 36,000 salmon smolt from the Mt Cook Alpine Salmon hatchery at Ohau 18 months ago, anglers have reported being able to hook a fish on every cast at some spots on the Tekapo and Ohau canals.
However, Central South Island Fish and Game field officer Graeme Hughes said the easy fishing had resulted in more people fishing illegally and ignoring the two-salmon quota.
Mr Hughes said since December, 18 offence notices had been handed out to anglers on the Pukaki and Tekapo canals.
He said most of the offence notices were issued for fishing without a licence, but there had also been a lot of instances of people using ''the wrong bait and wrong methods''.
Ohau A in particular, was a ''hot-spot'' for landing fish, he said.
''There appears to be one heck of a lot of fish being caught.
''People hear about these easy fish and they go up there with the wrong type of gear.''
However, he said, the situation had resulted in shouting matches and ''unpleasant situations'', when rule-breakers had been confronted by law-abiding anglers fishing on the same stretches of water.
''Where you get a time of plenty you get a time of greed, and that's what annoys people who are sticking to the rules and only taking two, when they are looking at people taking more than two.''
As a result, Fish and Game would have rangers patrolling the canals to make sure people were ''playing the game'', he said.
Mt Cook Alpine Salmon chief executive Geoff Matthews said the release of salmon was part of the fishery's commitment to the community and environment, and although regular releases to restock local lakes and rivers would continue, he urged anglers to obey the law.
''There is beautiful fishing on the Ohau A canal. They're not the big monsters that you get on the Ohau C, but there are beautiful fish out there.
''There is enough for everyone to go round,'' he said.
''We release those fish in conjunction with Fish and Game and Meridian, and we released them for recreational fishing, but people have got to obey the recreational fishing laws - simple as that.''
