What is a mangrove?
Mangroves are one of the rarer of
the forest types in the world. Along tropical and subtropical sheltered
coasts, the mangrove is the most common ecosystem encountered.
Found below the high tide level, mangroves are wetland ecosystems, consisting
of plants and animals that are able to survive when the ground is submerged.
Mangroves are classified into two types:
Mangrove forests remain
waterlogged throughout the year. The soils consist of organic ooze
with a high sulfur content. Because of the waterlogged conditions,
the soil is also anaerobic, without access to oxygen. Plants must
adapt in special ways to survive this environment. Prop roots are
a common sight among mangroves. The main body of the tree is suspended
above the water, supported by the prop roots. Small roots known as
pneumatophores branch off of the submerged roots and rise to the surface,
creating a source of oxygen for the plants in the anaerobic environment.
Fringe mangrove vegetation species have also developed methods to remove
salt from their tissues.
Fringe mangroves---found between the ocean and the
land in saline conditions
Riverine mangroves--found along river edges in freshwater
One of the most productive
ecosystems in the world, mangrove forests provide many services beyond
their intrinsic beauty. They serve many functions to fisheries, creating
shelters for spawning, hatching, and feeding. Many other wildlife
species also call the mangrove forests home. The shoreline is protected
by mangroves, which stabilize the coast and absorb incoming waves.
Water is filtered through the submerged roots as it passes through the
mangrove. Timber has been harvested for many years from the forests.
What is Aquaculture?
is essentially the farming of aquatic species. For thousands of years,
aquaculture has been used in Asia to provide a food source for many people.
Today aquaculture is an expanding industry, providing an increasing percentage
of the annual fish production. The industry is booming across the
world, with particular success in southeast Asian countries, Costa Rica,
and the United States. Shrimp, salmon, tilapia, and several other
species are common products of aquaculture.
explain the current upward trend aquaculture has experienced:
What is the Problem?
The growth of human population has greatly increased
the demand for food.
Due to overfishing, the production of the world's
catch fisheries is plummeting.
Pollution has increased consumer awareness of food
origin, increasing demand for more controlled and known growing conditions.
Aquaculture is a very efficient method of producing
food---a small space can produce a large amount of food.
problem is that in many areas, mangroves are being converted to fish and
shrimp ponds for aquaculture. This practice has led to the destruction
of an enormous amount of the world's mangrove forests in nations such as
India, Thailand, Costa Rica, and Ecuador. Environmentalists argue
that the mangroves should be protected, especially considering that mangroves
were not abundant to begin with. When the mangroves are destroyed
for aquaculture, the many various services these ecosystems provide are
traded for a single service. Besides killing the mangroves, if not
properly sustained, aquaculture can create many more problems for the surrounding
Proponents of aquaculture
in mangroves maintain that the benefits outweigh the costs. They
argue that the practice creates a vital food source that will become more
and more necessary as the catch fisheries continue to be over exploited.
Also noted is that since it often occurs in low-income areas, aquaculture
brings much-needed income to the people of the area.
Accidental introduction of exotic species
Introduction of diseases into the environment
In rebuttal, defenders
of the mangroves point out that in many cases, the owners of the aquaculture
farms are foreigners to the country. The profits made by the farm
are subsequently shipped out of the country rather than into the economy
of the producing country. The food produced, like the revenue, is
also often shipped out to other countries, leaving the workers and their
families struggling to put food on their own tables. The process
of replacing mangrove forests with aquaculture ponds thus presents both
environmental and socio-economic difficulties.
What is Being Done?
Many countries have
recognized that their mangrove forests are valuable when kept intact.
In 1971, the
Ramsar Convention on Wetlands was held in Ramsar,
Iran, where mangroves were included in protection actions agreed upon by
several countries. Several non-government organizations (NGO's) have
reached agreements to urge governments to improve their practices to protect
mangroves, such as the Choluteca Declaration on Unsustainable Shrimp Aquaculture,
signed by 21 NGO's and community organizations from North America, Europe,
Asia, and Latin America in October of 1996. So far, a number of international
environmental pacts have been made, but enforcement of these policies is
weak, as with any international agreement.
Some aquaculture companies
have recognized the problems the industry creates for mangroves.
ZB Industries argues
that mangroves are not even suitable for shrimp farming, due to the high
sulfur content of the soils. As increased knowledge of the situation
spreads, more governments and other groups will join in the fight, and
hopefully action will be taken.
Who to Contact:
For More Information:
In order to express
your opinion on the subject of the battle between mangroves and aquaculture,