Fisherman Jake Robson finds 400 rounds of ammo in Edwardes Lake, Reservoir

A fisherman has made an explosive discovery at a lake in Melbourne’s north that has baffled local police and left many unanswered questions.

A hobby fisherman has made shock discovery at a lake in Melbourne’s northern suburbs which has left local police scratching their heads.

Jake Robson, a magnet fishing hobbyist, reeled in about 400 rounds of ammunition secured inside plastic bags from Edwardes Lake near Leamington St on November 12.

Mr Robson said the find was a “really big shock”.

“You don't think you’ll pull out 200 rounds of bullets in one bag and then another 200 in another bag,” he said.

Inside the bags was a weighted exercise vest, which was how the magnet was able to pull the bullets out of the water.

The live ammunition was found in a bag that has been weighted down in a Reservoir lake.

Mr Robson said it was puzzling to find the bullets at the bottom of the lake.

“There‘s no really good reason to hide those bullets … everyone knows that if you’ve got them and you no longer have a licence, you could just turn them in,” he said.

“What are you led to believe, when they’re thrown in the water?

“Who knows what else is in there?”

It’s not the first time Mr Robson’s fishing equipment has pulled in something unique at the lake; in the past he has found vials of unidentified drugs, a cash register, commercial cigarette cabinets and what he believed to be a CCTV hard drive.

Police attended the scene and seized the ammunition and drug material, one officer speculating there was about $1000 worth of ammunition.

“(The police) were shocked, they said it was a first … (they’d never) been called out to a park to retrieve bullets from a creek,” Mr Robson said.

Mr Robson said he’d noticed people “hovering” nearby where he was using magnets to fish at the lake and asking questions about what he’d found.

“It’s a bit weird,” he said.

“One person, when I found the cash register, was really deterring me from looking in that location … then they sat in the car and watched me for two hours.”

“I was thinking ‘Am I not supposed to find something here?

“I assume there’s plenty more to be found.’’

Victoria Police confirmed it was making inquiries into who owned the ammunition.