HONG KONG—Hong Kong and mainland authorities have seized about $540,000 worth of smuggled Australian lobsters believed to be bound for the mainland, after China restricted imports of the crustacean amid escalating tensions with Australia. Hong Kong authorities said at a news conference Friday that its customs and Chinese law enforcement agencies confiscated about 11,650 pounds of lobsters and arrested 13 people. The seizure came after a recent surge in the import volume of Australian lobsters to Hong Kong, after China imposed an unofficial ban on the imports late last year. Officials said monthly imports of Australian lobster to Hong Kong have since more than doubled. China’s lobster ban came after the Australian government pushed for an international investigation into the origins of COVID-19. China has since blocked trade on other Australian imports, such as wine, barley, cotton, and coal. “We believe that smuggling syndicates might make use of improper means …