حضور دریادلان را گرامی میداریم
مطالب خواندنی در باره دریا،دریانوردی، فرهنگي و زيست محيطي
قالب وبلاگ

Cross Boundary Impacts and Red Tides

 

The Major Events of Red Tide in 1998 and the Mitigation of CBI

There are two major events that affect the marine biological resources.  The bleaching of the corals due to abnormally high sea surface temperature, and the much higher rate of occurrence of red tides.
The bleaching of corals is definitely a cross boundary impacts, but it may not be connected to any single economic activity, nor t to any single economy.  It may even be natural variation.

Most of the red tide events are very localized and there is no interaction between two regions.  Reported events in APEC are:

  1. Canada
    Salmon Loss to Algal Blooms. In early September 1997, International Aqua Foods Ltd. announced that it had lost some of its salmon inventory at 4 Vancouver Island, BC, salmon farm sites near Tofino and Coal Harbor due to severe algal blooms. Six additional BC farm sites were unaffected>
  2. China
    massive Red Tide event in Bohai.  It was found in mid-September of 1998.  The affected area is nearly 3000 km*km, according to the State Oceanic Administration.
  3. Japan
    Japan Oysters Suffer Mass Death From 'Red Tide"
  4. (Fox News On-Line, 98/10/26)
    TOKYO — A red tide of poisonous algae is devastating some of Japan's main oyster breeding grounds and threatening winter supplies of the succulent shellfish.
    Fisheries officials in western Japan's Hiroshima Prefecture said Monday that the algae bloom, known as "red tide'' because it turns the sea a reddish-brown, was cutting a swathe through the local oyster industry. "In some areas, we found that 80 to 90 percent of the oysters were dead,'' said one official.
    Experts said the particular kind of algae bloom which has stained Hiroshima Bay this year prefers warm and salty water and that an unusually low number of typhoons had raised water temperature and salt levels in Japan's seas. "We've experienced red tide in the past, but not where it covered almost the entire Hiroshima Bay,'' the fisheries official said.
    Half of the oysters supplied to Japanese markets in the winter come from Hiroshima. Officials said the oyster cultivators had no really effective way of protecting their oysters from the deadly algae bloom except to move them to safer waters — which were becoming increasingly scarce. "My oysters for the next season have also died off. I don't know what to do,'' Kyodo news agency quoted one Hiroshima oyster cultivator as saying.
     
  5. Hong Kong, China
    The Hong Kong government circulated a health warning to call attention to the fish poisoning.  By mid-January 1998, a total of 69 suspected ciguatera (fish poisoning) cases had been reported in Hong Kong, compared to 95 cases for the entire 1997 year. this concern.
  6. [Reuters]
  7. New Zealand
    SEA LION EPIDEMIC, JANUARY- FEBRUARY 1998 
    The final tally of dead pups on 20 February was 1606 (53%). This is a minimum estimate because on the final count on Dundas, 700 pups were unaccounted for. They presumably had either dispersed away from the island or had died and were washed out to sea.  
    There is a possibility that an algal bloom occurred in the Auckland Islands region during January 1998. Landsat imagery, provided by the NZ National Institute of Water and Atmospheric Research, shows high chlorophyll concentrations in surface water layers around the Auckland Islands in January . However, it is not known whether this phenomenon is a regular or a rare occurrence in that subantarctic region. Coincidentally, there were red tides at other locations around the New Zealand mainland between January and March that caused clinical illness in people and was the likely cause of fish, sea bird, and fur seal deaths in affected areas.  (from http://www.massey.ac.nz/ %7Ewwvet/SEALION.HTM)
  8. United States
    Environmental authorities said Monday that 162 dolphins found dead on Gulf of California beaches earlier this year died from red tide, a naturally occurring toxic algae.  Investigators in the northern state of Sinaloa said they have largely discounted hypotheses that toxic wastes or chemical markers used by drug traffickers could have caused the deaths.  "It can now be affirmed that the deaths were not caused by a spill of toxic substances," the Sinaloa Committee for Natural Resource Emergencies said in a report published by the Mexico City daily Reforma.  The report says the dolphins, four whales and one sea lion, found dead in January and February, probably swam through a red-tide bloom in the open ocean, with their bodies washing ashore near the state capital of Culiacan. The Sinaloa coast is a main route for drug traffickers, who occasionally drop hipments at sea and mark them with a phosphorescent, cyanide-based chemical. Final results of an investigation should be available within two weeks.
  9. (April 7, 1997, Associated Press)


A non-typical red tide event happened in the Hong Kong waters that wiped out half of the farmed fish in 1998.  According to Reuters (1998.4.17):


"HONG KONG CALLS IN EXPERTS TO TACKLE 'RED TIDE'
Hong Kong said today it will bring in "red tide" experts to prevent a repeat of the algae bloom that has crippled its fish farming industry, and workers battled to clear local waters of thousands of rotting fish.
The government will bring together experts on "red tide" and satellite technology, both locally and from the mainland, and seek views from overseas experts, a spokesman said, adding that experts from the Hong Kong Observatory also would be approached.
An invasion of algae bloom has killed at least 1,500 tons of farmed fish over the past week, equal to half the entire amount produced in Hong Kong waters last year.
"We have arranged to meet both local and mainland experts," the Agriculture and Fisheries Department spokesman said.
"We will also contact overseas experts to solicit their views on how to improve monitoring systems and set up an early warning system," the spokesman told Reuters. He did not have details on when the meeting would be held.
This particular algae attack has been fatal to fish because it invades their gills, suffocating them. Made up of microscopic organisms, the algae multiplies rapidly and turns swathes of sea a reddish brown.
Fish farmers estimate they have lost at least HK$250 million (US$32.3 million) from the algae attack, and many blame the government for not having warned them early enough.  The government's estimate of the loss, however, is HK$80 million.
Environmental groups are pressing the government to do more to fight pollution, which they say is a key reason for the more frequent occurrences of red tide in Hong Kong in recent years.
The meeting of experts will address the pollution issue, other sources said. The government has deployed dozens of workers and a flotilla of ships and waterborne bulldozers since Sunday to collect the dead fish, fearing they may cause serious pollution if left to rot in the water as the weather gets warmer.  The clean-up has been painstaking and slow.
Many of the fish farms have been abandoned as farmers try to catch up on lost sleep of several days and nights, when they tried in vain to save their stock from the killer algae.
"Many fish farmers are not at the farms and we are trying to locate them so that we can collect the dead fish," the government spokesman said.  By late Thursday, 500 tons of dead fish had been collected and dumped in landfills.
 

In terms of mitigation of the red tide event, there is no proven methods that are successfully applied.  A non-profit organization named START (Solutions To Avoid Red Tide) suggested that:
"The use of certain types of common clay (in liquid or powdered form) has been successful in stopping red tide blooms in the Orient. This possible solution must be thoroughly tested by scientists in American waters on American red tide species. Also useful might be a trial use of "booms" (similar to the ones used to contain oil spills) to keep dead fish from washing ashore and blanketing our beaches and bays. A limited effort could be made to consider chemicals and application procedures that are already accepted for controlling aquatic weeds and pests, carefully evaluating the risks to other organisms.
Biological controls in the form of a virus, parasite or bacteria should be studied and the risks assessed. Many of these organisms already exist in our waters and could potentially be exploited to control blooms." 

In terms of mitigation of health hazards from the red tide events, a common measure is put out warning to the public on fishing.  Hong Kong Government did one step ahead by actively collecting the dead fish and dumped them in the landfills.

The real solution may come after we know how did this red tide happen?  There is no doubt that the nutrient level was too high, there are blooming of toxin-producing algae.  But,
(1) where is the source of these nutrients? Natural processes or man-made?  If it is man-made, then who did it?
(2) Where is the source of these algae?  How to prevent it from importing by the ship ballast water?  How to suppress it from blooming in the local water?
No one has the answer so far, but we do hope to have some progress in the coming year through scientific and technological cooperation among scientists of APEC members
 

[ ] [ ] [ مدیر ] [ ]
.: Weblog Themes By WeblogSkin :.
درباره وبلاگ

با سلام، بیائید زمین را پاک بداریم dear all, lets care more about our environment
نويسندگان
صفحات اختصاصی
امکانات وب




برای نمایش تصاویر گالری كلیك كنید


کد گالری

IS
ابزار پرش به بالا