Why might licensed divers choose to dive in an aquarium in preference to the open sea, you may well wonder? Certainly, that was the question that popped into our heads when we heard about Ocean Park's new Grand Aquarium Scuba Diving programme.

Shirley Wong Pui-ling, programme director, has the answer in a word: "biodiversity". Where else in Hong Kong waters can you see as diverse and concentrated a range of marine animals as the 450 species in Ocean Park's 5.2-million-litre aquarium?

Says Wong: "The biodiversity divers can encounter [here] is unique and excites even the most experienced divers. [The new programme] is conducted in the deep-water area [of the aquarium], where the participants can meet the bigger fish and sharks, including our manta ray and hammerhead sharks."

Other species likely to be encountered in the three-hour programme include the zebra shark, nurse shark and giant grouper.

Lest the word "shark" cause alarm, divers are given safety briefings prior to taking the plunge and later a tour of the food preparation room, which should settle any lingering fears that the predators are ever allowed to go hungry. Also included in the programme are visits to the coral culture room and giant viewing panel.

"Through the programme, we deliver the message of being a responsible diver and encourage participation in marine conservation activities like reef surveys and clean-ups at the sea bottom. We hope it will reinforce an appreciation of and encourage further commitment and action towards care and respect for the ocean," Wong says.

Ocean Park's Grand Aquarium Scuba Diving programme was launched yesterday and will be offered every Saturday at 2pm and 5pm. Participants must be 15 or above and licensed scuba divers. All equipment is provided and the cost, together with park admission, is HK$2,180. Five per cent of the proceeds go to Ocean Park Conservation Foundation. Advance booking is required. For inquires, call 3923 2328.