A red tide that started in the East China Sea three weeks ago has
grown to cover more than 1,500 square kilometers (579 square
miles), according to the
China
National Environmental Monitoring Center.
The red tide began off the coast of Zhoushan in east China's Zhejiang
Province on May 6, with a detected area of 300 square
kilometers (115.8 square miles), said the local marine
environmental monitoring station under the center Tuesday.
An
official with the station, surnamed Tang, noted Tuesday that the
red tide is the longest-lasting of the past 10 years and no
immediate end was in sight.
A
red tide is a dense population of microscopic organisms that breed
on the surface of salt water. These organisms, plentiful in number,
may suffocate fish by consuming nearly all the oxygen in the
water.
Most of the country's red tides occur in April and May and usually
last a week or two.
East China Sea areas suffered two large red tides in 2000,
measuring around 3,000 and 4,000 square kilometers (1,158 and 1,544
square miles) respectively and lasting a week, said Tang.
The actual coverage of the latest red tide is "surely larger than
the measured area," according to Tang.
In
recent years, Alexandrium sp. toxic organisms were found in the red
tides for the first time, according to Tang. But the latest red
tide was caused by the non-toxic organism Prorocentrum dentatum,
said Tang.
Tang said the increasing amount of farm pollutants and household
waste was a major reason for the frequency of red tides in the East
China Sea, in addition to industrial discharges.
He
said that no large-scale direct economic losses were being
predicted as a result of this month's red tide because it was not
near any fish farms. But the damage to the local marine environment
will be "enormous," Tang added.
Local media yesterday reported that fish farmers in Zhoushan had
taken precautions against the red tide invasion.
Some fish cages have been dropped into deeper water to avoid the
red tide, which usually occurs on the surface of the water, said
the reports.
To
cope with the increasing number of red tides, the State
Oceanographic Bureau is preparing to establish 10 red-tide
monitoring stations along the coast in northeast China's Liaoning
Province, north China's Hebei Province, east China's Zhejiang and
Fujian provinces and south China's Guangdong and Hainan provinces,
bureau press officer Wu Jingyou said yesterday.
The national monitoring network is due to be established by the end
of this year. It will provide better forecast services to local
fish farmers to prepare for red-tide invasions, according to
Wu.
Bureau statistics said the Chinese coast last year suffered 77
severe red tides, covering a total of more than 15,000 square
kilometers (5,790 square miles).
The East China Sea proved to be the most "disastrous" zone, with 27
red tides reported off Zhejiang Province last year.
(China
Daily May 29, 2002)