From the Times of India: Mangroves under threat from shrimp farms, UN study says
OSLO: Valuable mangrove forests that protect coastlines, sustain
sealife and help slow climate change are being wrecked by the spread of
shrimp and fish farms, a UN-backed study showed on Wednesday.
About a fifth of mangroves worldwide have been lost since 1980, mostly
because of clearance to make way for the farms which often get choked
with waste, antibiotics and fertilizers, according to the study.
Intact mangroves were almost always more valuable than shrimp farms, said its authors, who drew on forestry and conservation expertise from several UN organizations.
Mangroves â€” trees and shrubs that grow in salty coastal sediment â€”
can be found in 123 nations in the tropics and sub-tropics and cover an
area slightly larger than Nepal. They are nurseries for wild fish
stocks, sources of wood for building and serve as buffers to storm
They absorb carbon dioxide, the main greenhouse gas from
burning of fossil fuels, and store it in their roots. And their growth
can help counteract the effects of rising sea levels as it elevates
"There is an opportunity for many countries to go for
restoration of mangroves," Hanneke Van Lavieren, lead author of the
study at the UN University's Institute for Water, Environment and Health
(UNWEH), told Reuters.
"Mangroves can be seen as a key ecosystem for food security in the world," she said.
Many of the shrimp farms are in southeast Asian nations. World
production surged to about 2.8 million tonnes in 2008 from about 500,000
two decades earlier, mostly in China, Thailand and Indonesia.
The fish farmers are often encouraged by subsidies to expand, even
though other lucrative businesses depend on mangroves for their own
Wild prawns caught off Australia's Northern Territories
and Queensland, for instance, rely on mangroves to grow and are one of
the country's most valuable fisheries, earning almost $72 million a
year, the report said.
Protecting almost 12,000 hectares (30,000
acres) of mangroves in Vietnam cost about $1 million but saved more than
$7 million on dyke maintenance, it said.
Countries such as
Australia and Brazil had been good at preserving their mangroves while
nations including Indonesia, China and Vietnam had lost big tracts and
projects to restore them needed more support.
Zafar Adeel, head of UNWEH, suggested that people could also choose to avoid buying shrimps raised in farms.
"We as consumers internationally play a big role," he said. "For the
first time in human history about half the global population is living
in coastal areas. The stresses are going to be higher."