A dark shroud was cast over the annual cross-harbor swim in Hong Kong after a 46-year-old man was pulled from the water unconscious and later announced dead.
A woman thought to be in her 60s was also separately rescued and is reported to be in intensive care in hospital.
The 1.5 kilometer race, which attracts world-class international competitors, saw around 3,000 people swim between two piers on opposite sides of Hong Kong's famous harbor – an increase of 500 from the previous year.
Local broadcaster RTHK reported there were just 120 lifeguards at the event, only 10 more than in 2015. The international criteria requires a one-to-ten lifeguard-to-swimmer ratio.
However, the president of the Hong Kong Amateur Swimming Association, Ronnie Wong, defended the number of lifeguards, telling local media the number assigned had been sufficient.
"We are very saddened by the news and will do whatever possible to help his family get through this difficult time," Ronnie Wong told the South China Morning Post.
The event is split into two categories – racing and recreational groups – both the dead man and the hospitalized woman had been competing in the latter, which is for slower swimmers.
The annual race was first held 110 years ago, but was halted in 1978 as water quality deteriorated.
The event was revived in 2011, with organizers insisting the water had improved although some environmental groups warned there were still high bacteria levels present.
The weather for this year's swim was warm and sunny, but some competitors reported strong currents in the harbor.
American swimmer Charles Peterson won the men's title in just 16 minutes 44 seconds, while Rio Olympics 10km open water gold medalist Sharon van Rouwendaal from the Netherlands secured the women's crown.