Residents in South Korea are reluctant to purchase seafood at local fish markets over concerns about Japan's ongoing nuclear-contaminated water release at Fukushima, China Media Group (CMG) reported on Sunday.

Large amounts of groupers have died in fish farms in the country's Yeosu City due to stagnant sales and increasing water temperature, according to the report.

More than 1 million fish are dead in the city, taking up 20 percent of the total feeding amount, and amounting to losses equivalent to $11.6 million, CMG reported.

Japan's decision to dump the radioactive water has cast a shadow over South Korea's seafood industry. The price of the grouper has dived more than 30 percent compared to the period before Japan started releasing the water.

A local specialty known as Niphon spinosus - a type of sea bass consumed for high-end sashimi in Jeju Island, has lost its attraction with its auction price slumping by 60 percent year on year. Many seaside cities have also lost group orders of sashimi, according to CMG.

A survey conducted by Gallup Korea suggests more than seven out of 10 Koreans are concerned that the release of wastewater from Fukushima could pollute Korean waters and seafood.

Merchants at Seoul's Noryangjin Fisheries Wholesale Market have struggled to assure the products' safety.

"This is the worst that I've ever seen," a vendor who has worked at the market for over 20 years complained, according to The Korea Times.

"There are so few people coming here that it's ridiculous. We're receiving not even half of the customers we used to see," the vendor said.

Some vendors have started labeling the origin of their seafood to dispel the customers' fears that seafood could be contaminated by the radioactive water.

"Several visitors asked me when and where the fish was caught," another vendor said. She also mentioned people are inclined to buy frozen fish were caught before the wastewater release.

Japan started releasing nuclear-contaminated water from the crippled Fukushima Daiichi Nuclear Power Plant into the Pacific Ocean on August 24, despite raging opposition at home and abroad.

The radioactive water has been diluted as planned before being discharged via an underwater tunnel one kilometer from the plant, according to the plant operator Tokyo Electric Power Company, though proofs supporting its claim remain unclear. 

It is estimated that it would take 30 years for all the stored nuclear-contaminated water to be released into the ocean.