A fish and chip shop in Falmouth and a restaurant in St Ives have been praised for serving sustainable seafood.
Harbour Lights and Porthminster Beach Cafe were surveyed by Fish2Fork and given the restaurant guide's highest sustainable rating.
Fish2Fork said of 500 establishments surveyed in the UK, more than 45% had improved their rating since 2009.
Harbour Lights owner Pete Fraser said he felt a "moral obligation" to protect future fish stocks.
"I've got four kids so I feel a moral obligation to leave the planet as it was when I came into it, but if we continue to plunder the sea, that won't happen," he said.
Not only does Mr Fraser serve sustainable species, last week he took cod off his menu for a seven-day trial.
"It's our best seller, so most people thought I was either very brave or very stupid," he said.
"I was worried because we're in a difficult financial time, but I've had a lovely warm response and sales have increased significantly - up by about 30%.
"Amazingly, there were only three people who did a U-turn and walked out the shop because I had no cod."
Hake and haddock were the fish and chip shop's most popular choice last week.
Earlier this year, Harbour Lights was awarded the Marine Stewardship Council's certification.
Mr Fraser, who has been running the family business for the past 11 years, said people seemed far more willing to try different things.
"Five years ago I put pollock on the menu and I just couldn't sell it... then two years ago I had line-caught pollock and I couldn't get enough," he said.
Fish2Fork founder Charles Clover described the improvement he's seen in two years as "phenomenal".
"Even though a few have slipped back, they are outnumbered more than two-to-one by those who have grasped that sustainability is now important to consumers of seafood."
The Porthminster Beach Cafe said it uses local suppliers wherever possible, with the majority of its seafood coming from the South West, including St Ives, Newlyn, Looe and Mevagissey.
Mr Clover said the "quantum shift" in public awareness about sustainability had been helped by celebrity chefs including Raymond Blanc, Jamie Oliver and Hugh Fearnley-Whittingstall.
Mr Fraser said he was thrilled with the accolade.