【明報專訊】◆ How did scalloped hammerhead sharks get their name?

Scalloped hammerhead sharks are named after their hammer-like head. The flat head allows them to turn and change direction quickly. As their eyes are located at the tip of the head, they can have a wide vision — up to 360 degree! Similar to other sharks and rays (鰩), they have special sensory organs (感應器官) that can detect weak electric currents (電流). These organs are spread over the bottom side of the head, helping them scan the environment and search for prey.

◆Are there sharks in Hong Kong?

In Hong Kong, there have been records of bamboo sharks (竹鯊), reef sharks (礁鯊), tiger sharks (虎鯊), and even whale sharks (鯨鯊), the largest fish species in the world! Worried about meeting sharks at the beach? Most of the public beaches in Hong Kong are equipped with shark nets, and these animals have no longer been common in recent years.

◆Why are sharks declining?

Scalloped hammerhead sharks are endangered. Like many other sharks, they are declining now because of overfishing. Due to the huge demand for shark fin (魚翅), they are caught in huge amounts commercially or even illegally. Hong Kong is one of the world's largest trading centre of shark fin. In 2012, around 1.3 to 2.7 million hammerhead sharks entered the Hong Kong market, some of which were transported to places around the world.

Sharks are top predators, which means they are at the top of the food chains (食物鏈) in the ocean. They not only control the number of other animals, but also balance the ecosystem (生態系統). Sharks usually have slow growth and low reproductive rates, so their numbers are dropping rapidly due to overfishing. This would affect the marine ecosystem.

◆Conservation work in Ocean Park

Ocean Park has been leading the trend in sustainable catering. Starting from 1995, Ocean Park had stopped providing shark fin for guests and staff. Since 2012, all the seafood offered in the park restaurants has been sustainable seafood (環保海鮮). In 2015, the Park launched Hong Kong's first sustainable fish balls, which are made with Pacific hake (無鬚鱈魚) certified by the Marine Stewardship Council (MSC) (海洋管理委員會).

( Let's support sustainable seafood and become responsible seafood lovers! )

(Text and photos: Ocean Park Hong Kong)

■Glossary

predator (n) 捕食者

detect (v) 察知

prey (n) 獵物

catering (n) 餐飲業

[Smarties' Power English 第199期]