A restaurant supplier has warned pickers to steer clear of Shoreham Beach Local Nature Reserve after a ticking-off from police.
But Mike de Stroumillo, from restaurant supply company Mash, said communities should make more of their thriving natural sea kale by licensing its picking.
Police were called after men were seen bundling the gourmet plant on the beach into bin bags, believed to be sold on to various high-end London restaurants.
Mr de Stroumillo, whose London-based company buys sea kale from pickers, said: “I have said it is a no-go area.
“I cannot tell what they have picked from there but I said if I hear of anybody being stopped or get any more reports then I will stop buying from them altogether, whether they pick from Shoreham or anywhere else.”
He added the vegetable, which tastes like a cross between cabbage and asparagus, was in demand as part of a wider trend for foraged food.
It normally sells to restaurants for about £15 per kilo, he added, and Shoreham was “missing a trick” in a possible trade.
He said: “What they could be doing is issuing licences to pickers, for example at £50-a-day, and that could go towards the running of the beach or the nature reserve.
“They can also then vet who picks and on which days they pick.”
He said picking for eating did not damage the plant as only two to three leaves were taken, adding it “encourages natural growth”.
Liza McKinney, Adur councillor for Shoreham Beach, said she wanted signs to be put up on the beach warning people they should not pick the kale.
She said pickers had not returned since Monday and local residents were being “vigilant”.
She said: “We don’t want to lose any part of the nature reserve.”
A police spokesman said Shoreham Beach was protected under the Wildlife and Countryside Act and kale must not be picked without the permission of the landowner.
He added: “On July 23 three people were seen cutting and collecting plants in the reserve and putting them into binbags to sell to a business in London.
“The business has since been contacted and warned that its suppliers must not forage on the beach as it is protected.”