Mangroves: The Roots of the Ocean

Mangroves may not be as sexy as coral reefs but they’re just as important to the overall health of the ocean. Read on to find out why.

Mangroves may not be as sexy as coral reefs but they’re just as important to the overall health of the ocean. Read on to find out why.

Why are mangroves important?

Mangroves are quite literally the roots of the ocean. Three-quarters of all tropical fish species are born within mangrove forests, whose branches provide shelter and protection for the juvenile fish and some sharks. As nurseries, mangroves are vital not only to the health of coral reefs but also to commercial fisheries. There are 110 species of mangrove, and they grow only in tropical regions. Mangroves add an estimated $186 million per year to the global total of goods and services. This includes the production of timber and plant products for local communities and also products for trade within the international marketplace.

Mangroves offer environmental benefits as well. These forests provide coastal protection against wind and wave action, such as tsunamis. In a time of more severe weather patterns, mangroves are key to our continued survival as we urbanize coastal areas.

Mangroves also trap sediments. By doing so, they prevent coral reefs from becoming silted. They also break down pollution from agricultural activities. Mangrove forests can store 50 times more carbon in their soils as defined by area than tropical forests, and 10 times more carbon than temperate forests. The decomposed leaf litter from mangrove forests provides nutrients for phytoplankton to grow as well. This is the base of all ocean ecosystems. In effect, mangroves support the entire food web that humans rely upon.

What are the threats to mangroves?

Mangroves are disappearing at a rate of 1 percent every year. Aquaculture, coastal development, agriculture, unsustainable fishing and pollution are mostly to blame. We have already lost over half of the world’s original mangrove forest area, which scientists estimate at almost 80 million acres.

Most of this loss has occurred within the last 20 years. Shrimp farming is a significant threat to the survival of the remaining forests. The United States, Japan, Canada and Europe are the main shrimp consumers. The high demand for shrimp and the profitability of shrimp farming has led to extensive removal of mangrove forests to create shrimp farms in recent years. Shrimp producers only use the pools within shrimp farms for short periods of time before they deforest other areas for use. Producers often abandon the pools due to pollution and disease. In the end, they’ve laid waste to extensive areas of deforested land for this trade, which results in the long-term loss of mangroves.

Why does this matter to scuba divers?

Put simply, if we want to continue diving on clean and healthy coral reefs around the world, then we need to protect mangrove forests. Without mangroves, there will be considerably fewer fish, sharks and other marine species that hold such appeal for divers. That is of course putting aside the value of mangroves for the health of the oceans and for the tourism industry, of which scuba diving is a significant part. As ocean users, it is our responsibility to do all that we can to protect and care for the environment around us. 

What can we do to help?

As consumers, an obvious, and easy, change is to stop eating shrimp entirely. Much wild-caught shrimp is netted via trawler, which exacts a terrible environmental toll as well. If you must eat seafood, only consume sustainably caught fish. If the demand disappears, the market collapses and mangrove forests marked for shrimp farms will no longer be destroyed.

Many countries and agencies produce guides to assist people in making sustainable choices as consumers of fish and seafood. These guides explain which fish species you should and should not eat. The guides take fishing methods and the health of different fish stocks into consideration. It’s easy to get informed, make educated choices and use your power as a consumer to effect change.

A number of conservation organizations around the globe are also tackling the loss of mangroves by planting new mangrove forests, and by educating local communities. Projects Abroad is one such organization. It welcomes volunteers on their Fiji project to assist in mangrove reforestation and to dive with bull sharks and enjoy the local reefs.

Mangroves, although they may not be as sexy as coral reefs, are just as important. So next time you pass a mangrove forest on the way to a dive site, remember what you can do to ensure its continued survival.