Officials from King's Lynn Angling Association are set to lobby their MP over claims sections of the 1981 Wildlife and Countryside Act require anglers to kill all zander they catch.
It comes as EA officials say they won't enforce the law, because zander were lawfully stocked by their predecessors.
In today's Eastern Daily Press, journalist and predator angler Chris Bishop writes:
"Anglers in the Fens and further afield are unanimous about one thing. Zander need the same protection as any other species of predatory fish swimming in our waters.
"There's been no new ruling saying anyone's got to kill them. Natural England have recited a 21-year-old law no angler has ever taken a blind bit of notice of.
"No-one's ever been prosecuted for returning zander. And the Environment Agency says it has no plans to do so, because they were lawfully introduced by its predecessor.
"More worrying is the exception being made under the provisions of new national fisheries by-laws, governing fish removal. Zander are classed as an alien species.
"That doesn't mean there's a legal requirement to kill them, under this new legislation. But no limit's been placed on how many you can kill should you be so inclined. Club bailiffs fear this will undermine their efforts to police their waters.
"How we define alien is an important question. Peel this one back to its logical conclusion and we'd have to include carp - an alien species first brought to our shores by Medieval monks.
"Hundreds of years later, carp are part of the furniture, where fishing's concerned. Imagine Natural England saying you've got to bonk them on the head because their parentage gets a bit dubious if you go back far enough.
"Zander too have undoubtedly found their own niche and settled in alongside both their prey and fellow predators without upsetting the ecology of our rivers."
More here and here.