The bull shark's carcass was dragged ashore after it was found outside a shark net on Saturday afternoon.
No injury was found on the 70-centimeter long shark and there were no signs of decomposision.
The Leisure and Cultural Services Department called in the Agriculture, Fisheries and Conservation Department staff, who took away the shark.
Although a sign was put up saying the beach was closed, swimmers ignored it and went in the water yesterday.
One of them, Chan, said he wasn't worried.
"I would only swim inside the shark prevention net, and there have ben shark sightings for a long time," Chan said.
Another who had been swimming at the Cafeteria New Beach since 2014 said he has never seen big fish or even sharks at the beach.
"I never swim outside the shark barrier, therefore I am not at all worried about sharks," he said.
Marine ecologist Law Him-yan said based on the size and its exposed sex organs, he believes it was a young male bull shark.
"There have been recorded sightings of bull sharks in Hong Kong waters, and it might be the salinity of the water in Tuen Mun that attracts bull sharks to rest there," Law said.
"A young bull shark is not as dangerous as grown ones, and I believe it swam into Hong Kong waters from near the Zhujiang River, or lived near the waters in Tuen Mun soon after his birth and was waiting to swim back into the sea after it grew bigger," Law said.
However, he called on swimmers not to approach any bull sharks regardless of whether they were young or grown.
Ken Ching Sze-ho, founding chairman of Eco-Education and Resources Centre, said although sharks might be sighted in local waters, beaches managed by the LCSD have shark nets installed to safeguard swimmers' safety.
"But if swimmers opt to swim in waters without shark barriers, they should pay more attention to their own safety. If they encounter a shark, they should stay calm and stop any movement, until the shark swims away," Ching said.
Bull sharks, which can grow to two to three meters long and weigh 200 kilograms, are one of four most dangerous sharks in the world, as they start attacking humans with little provocation.
Sharks have been seen in waters near Tuen Mun from time to time, but it is extremely rare to find bull sharks in the SAR.
Swimmers found a dead 30cm milk shark at Golden Beach in Tuen Mun in June.
Authorities will not become involved in compiling a list of overseas medical schools from where Hong Kong graduates will be able to return to the SAR to practice, Secretary for Food and Health Sophia Chan Siu-chee said.
A 10-strong panel will decide on the list of less than 100 medical institutions, and Chan said she for one will not take part in the process.
In a post aimed at clearing misunderstandings on the administration's proposed Medical Registration (Amendment) Bill 2021, Chan said she will just urge panel members to hurry if they are slow in making decisions.
The panel will consist of the chairman of the Medical Council, the deans of medical schools at the University of Hong Kong and the Chinese University, and representatives from the Department of Health, the Hospital Authority and the Academy of Medicine. And four more will be appointed by the chief executive.
In response to criticism that the new bill could undercut the Medical Council's statutory power to regulate doctors' registrations, Chan noted that the council chairman and not more than three members will be on the panel.
"I must stress that non-locally trained doctors must still be registered at the council and be overseen by the council - like all the other local doctors," she said.
The proposed bill will require foreign-trained doctors who are SAR residents to work full time for one of the four public health-care institutions - the Hospital Authority, the Department of Health and the two medical schools - for five years after obtaining specialist qualifications.
Unlike the existing policy, overseas doctors will no longer be required to pass a licensing exam before they turn to private practice. The bill will allow them to skip the exam as long as they are rated satisfactory during their service at public organizations.
But doctors' groups have voiced concerns over assessment of the doctors' capabilities without an exam.
On that, Chan said many countries, including Singapore and Australia, have similar mechanisms to grant full licenses to non-locally trained doctors.
"The government does not wish to replace the current licensing exam system but to create a new path to let qualified, foreign-trained doctors serve in the public medical system, given they are ensured to be up to standard," she said.
And the format of the on-the-job assessment will be discussed among authorities and the four institutions.
Chan said the requirement for full registration of foreign-trained doctors is tougher than for graduates of local medical schools, who are automatically granted registration after completing an internship at a public institution.
Financial Secretary Paul Chan Mo-po and Chief Secretary for Administration Matthew Cheung Kin-chung also called in their blogs for public support for the bill.
They said manpower at the public medical system is tight, with a current shortage of 710 doctors and estimates the shortage will be 1,949 in 2040, so the bill is a solution to ease the staffing problem in the long run.
The broad terms of a trade deal between the UK and Australia have been agreed, the BBC understands, with a formal announcement expected on Tuesday.