One of the key ecotourism attractions is "mangrove forests". One may have heard about the sheer importance of mangrove forests to an ecosystem, but why is it like that?
Distinct from their woody relatives, mangroves, often rooted underwater, thrive in salty sediments. They are usually found along shores, brackish rivers and estuaries in the tropics and subtropics. To adapt to such a harsh environment, mangroves have evolved complex aerial root systems sticking out of mud like little chimneys. These root systems have become a safe haven for a diverse array of small marine animals. During high tide, mangrove forests play the role of a shelter, offering abundant food, such as planktons including various algae and larvae of marine animals, thereby serving as a fish nursery ground. As for the juvenile fish, their survival rate is greatly enhanced, paving the way for their entry into the sea "full of potential danger" when they reach maturity.
Despite being a concrete jungle, Hong Kong is home to the "hidden treasures" along many shorelines. Dozens of and even over a hundred juvenile fish are often spotted swimming near the mangrove in Shui Hau, perhaps just around your feet. The more common species recorded in the area include Jarbua Terapon (Terapon jarbua), Common Silver-biddy (Gerres oyena) and Mangrove Snapper (Lutjanus argentimaculatus). These juvenile fish skillfully take advantage of their pale-coloured bodies in camouflage to hide in between mangroves, in a bid to avoid their predators such as carnivorous fish and birds. They also follow the principle of "numerical superiority" by developing the habit of swimming in the same direction in groups, while living in the complex mangrove aerial root system areas to reduce the chances of being eaten.
The mangrove ecosystem is without a shadow of doubt a paradise for juvenile fish. Yet, what else animals do you think are fond of dwelling here? Snails, crabs, or birds? Why not explore at your leisure and find the answers yourselves? So the next time you hear someone mention the "sheer importance of mangrove forests to an ecosystem", maybe you know how to elaborate on that, with a view to disseminating the message of conserving mangrove forests to all corners of the society.