Police Scotland are also concerned and they handed out specially-designed leaflets at Harlaw Reservoir above Balerno during a recent water safety day.
The leaflets clearly detailed that poaching is against the Salmon and Freshwater Fisheries (Consolidation) Act 2003.
And they stressed that fishing at Harlaw is a water that can only be accessed by members and season ticket holders plus those with day tickets.
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The leaflet added: "It is an offence to fish here without legal right or written permission."
And it stressed: "Water bailiffs and police patrol this area and the loch has regular anti-poaching patrols."
Anybody found to be fishing illegally may be prosecuted and their equipment siezed and the leaflet added: "If in doubt, members should report any suspicious behaviour to Police Scotland by dialing 101."
Gangs using vans and lights have been noted at night at the reservoir this season, hence the increase in policing.
And Robert Ross, company secretary of Malleny Angling, who administer the water and part of neighbouring Threipmuir, said that a number of people, some camping overnight, have been caught this season using bait and spinning equipment to tempt fish.
Harlaw, he stressed, is fly fishing only and no float tubes or boat fishing is allowed and anglers can only take part in their sport from 7am to dusk. No night fishing of any description is permitted.
Ross said: "Poaching is a real concern to us as a committee and for our members and season ticket holders. They, plus day ticket buyers, pay for the privilege of fishing here and taking fish illegally means others are depriving them.
"We regularly re-stock the water to main a good head of fish to provide good sport for those who pay to come here. Some of the fishing this year has been exceptional and catch returns by those who fish legally have been good so it is incredibly frustrating when people flout the rules for their own or commercial benefit."
He added: "Two groups have already been caught by the police and cautioned pending possible prosecution with all fishing tackle confiscated."
Jock Callison, who founded the competition when he owned Stenhouse Fishery near Burntisland, handed over the silverware.
And Davies also took home £400 in cash, £200 of Snowbee vouchers, a £50 Fishing Megastore voucher, a £50 Blob and Buzzer voucher and £50 Flybox voucher plus a goodie bag. He bagged four fish early in shallow water on dries at the West End of the loch and kept catching.
Connor Wales, the Scottish youth team captain, had a great start, picking up four fish in shallow water at the East End of the loch. He was close behind with eight fish for 16lb 8oz. Now he represents Scotland in the forthcoming Home International in Ireland.
He bagged £200 in cash, a £100 Snowbee voucher, a £30 Fishing Megastore voucher, a £30 Blob and Buzzer voucher and Flybox goodie bag.
Two anglers netted six fish each but a rainbow of 3lb 2oz, the heaviest fish caught on the day, edged it for Ronnie Couper. His bag weight was 14lb 4oz.
Ronnie pocketed £100 in cash, a £75 Snowbee voucher, a £20 Fishing Megastore voucher, £20 Blob and Buzzer voucher and Flybox goodie bag.
Couper, after a slow start, changed tactics to a small booby on a midge tip line and reaped immediate rewards.
He also received the Gary Johnson Memorial Salver for the heaviest fish in the final presented by Gary's son Danny. That brought him a further £50 worth of Snowbee vouchers.
Brian Sutherland was fourth only eight ounces behind with his six fish tipping the scales for 13lb 12oz and he also lost out on the heaviest fish by one ounce.
Fifth with four fish for 9lb 10oz was Scott Mudie and sixth Darren McPherson with three fish weighing 7lb 6oz.
Paul Merrifield was seventh and Craig McGurk eighth. Both men had three fish each for 7lb but Merrifield landed his fish first.
Johny Whitlam, who had the lowest bag weight at the scales of 1lg 12oz, was also awarded a prize in the final which took place three months after the first heat at Stenhouse.
Conditions on the morning for the 24 qualifiers were considered ideal with a gentle south-east breeze and cloud cover.
The boats split across the water with eight going left from the pier and targeting the area from the Dam Wall across to The Shallows. The other four boats went to the far bank and drifted down to the area behind The Island.
Sam Davis headed to the far bank he struck early with a fish after only 15 minutes. This turned out to be the quickest of the day. He picked up a pack of Iain Barr flies.
Fish could be seen moving throughout the day and anglers said that if you could get in front of them, then they were often obliging, but only if your presentation was correct.
The wind freshened in the afternoon and anglers said this appeared to slow down almost all of the catch rates. A number of anglers cursed their luck at losing hard-fighting fish, some on the rim of the net.