Operators of fishing trawlers have run out of time to register their vessels as the government attempts to clean up the industry, says Prime Minister Prayut Chan-o-cha.
He turned down requests Tuesday by trawler operators to delay by three months the measures against illegal, unreported and unregulated (IUU) fishing.
The operators had been warned to comply with the regulations for several months ahead of the start date, which falls today, but they failed to take proper action, Gen Prayut said.
By Tuesday, operators were required to register their trawlers, and ensure their fishing gear was up to standard, or face legal action.
The crackdown follows the European Union's (EU) yellow card, or final warning, against IUU fishing practices, which it said Thailand must correct, or face a ban on seafood exports to EU countries.
"I've given them a chance to comply [with the regulations] for some time. How many grace periods do we have to grant them? It can't be like this forever. We gave them several months," Gen Prayut said.
The operators of about 3,000 medium-sized trawlers in 22 coastal provinces have been keeping their vessels in port rather than heading out to fish as the new measures take effect.
The resulting drop in seafood supply is forcing major seafood markets in several provinces to close, said Mongkol Sukcharoenkana, vice-president of the National Fisheries Association of Thailand.