bodyType

customContents

entityId

entityUuid

articlePageQuery

filter

article

articleBaseAdvertisingInfoArticle

articleListArticle

articleSeoArticle

helpersCheckIsPostiesArticle

hooksArticleAcknowledgementGateOverlayArticle

hooksTrackPageViewArticle

hooksContentInterestArticle

articleLinkingDataContent

articleSchemaContent

liveArticle

advertZone

sentiment

contentLock

topics

types

sections

moreOnThisArticles

urlAlias

commentCount

sponsorType

authorLocations

authors

paywallTypes

corrections

displaySlideShow

multimediaEmbed

printHeadline

seriesContainer

socialHeadline

headline

flag

firstTopic

glossary

flattenTypeIds

publishedDate

additionalInfoBoxes

images

image

relatedLinks

relatedNewsletters

__typename

createdDate

sponsor

factSheets

series

disableOffPlatformContent

published

updatedDate

summary

subHeadline

body

keywords

copyrighted

customTimezone

liveContents

SCMP Reporter

As fish farmers are bankrupted, with their lives' work lying belly-up, they are desperate to find the answer to what causes the red tides that have been plaguing Hong Kong's shores.

 No previous red tide has caused such massive fish mortality, closing beaches and leading to a ban on eating shellfish.

 Now scientists are working to find out why it happens and what solutions there are.

 International expert Don Anderson, of the world-famous Woods Hole Oceanographic Institute in Massachusetts, visited Hong Kong this weekend to study the current record red tide. He equates his job to that of a forensic scientist, piecing together bits of evidence to find out the situation.

 He has been researching the phenomena for 20 years, ever since a huge outbreak hit the New England coast where he was a student at the Massachusetts Institute of Technology.

 'It closed all the shellfish beds, it made the water red and it kept coming back for years afterwards. In fact, it has continued ever since,' he said before his arrival in the SAR.

 Scientists are not short of theories as to what causes red tides, but finding proof and a treatment is the difficult part.

 'People tend to lump these things together and treat red tide as if it is one organism,' he said.

 'There are just so many algae out there, but there are a few dozen that can cause these problems, such as producing toxins or growing to huge numbers killing fish, so it's not surprising that you could have a couple of these algae types hit you in a one- or two-month interval.'  However, people could also be making their own damaging contribution.

 Dr Anderson says that increasing reclamation in Hong Kong may be restricting proper flushing of the harbour water, leaving the cells that lead to algal blooms to settle and build up on the seabed.

 'Humans are doing these things without the knowledge of how they are affecting the oceans.'  For instance, he said, late Hong Kong scientist Catherine Lam had found a marked increase in red tide in Tolo Harbour, which was now used by researchers worldwide as a standard for algae research. She had found 69 incidents of the problem between 1980 and 1986.

 Pollution is another popular spectre, as the algae feast on the nitrogen nutrients coming from sewage, particularly the run-off from pig and chicken farms.

 But how, then, should scientists explain the red tides that occur in Norway, which has some of the cleanest water in the world? It can often be a particular set of circumstances, according to Dr Anderson. 'You need the right nutrients, winds, sunlight, currents to cause a red tide,' he said.

 Many methods are being tried to predict, control, deter and destroy red tides. In one scheme, Norwegian fish-farmers have built fish storage cages that they can tow to deeper waters when toxic algae strike.

 In some countries, Dr Anderson said, fish farmers were trained to look at the water with microscopes to detect and count the algae to supplement government statistics and give a better picture of the algae's distribution.

 And South Korean farmers have 'saved their fish farms two years running' by dropping clay into the water at a cost of US$1 million (HK$7.7 million) each year, he said.

 The natural clay is non-toxic to marine life but it sticks to the algae and drags them to the seabed, breaking up the algal blooms.

 In 1996, the farmers used 60,000 tonnes of clay over 100 square kilometres to control a red tide caused by the cochlodinium algae that threatened near-shore fish farms.

 But Dr Anderson was tentative about applying the clay process in the United States, as the full effects of clay sediment on the seabed were unknown.

 He criticised scientists for being too concerned with experimental results before trying things out: more practical solutions were needed, and he was open to learning of any treatment ideas, he said.

 One such scheme was that of Italian entrepreneur Guido Roman, who tried in vain to interest the Hong Kong Government in his enzyme seaweed product that he called Induced Enzymatic Complex (IEC), which he said was the answer to the SAR's red tide problem.

 Mr Roman is a partner in manufacturer Promos, which is based in Creazzo, Italy.

 'It is patented,' Mr Roman said, 'and has been endorsed by the Pasteur Institute in Paris.'  He uses IEC to treat seaweed taken from red tide-affected areas. The seaweed is stored in a warehouse for 15 days, where the enzymes in IEC work in tandem with the natural decomposition of the seaweed.

 After the biological process is completed, the seaweed is strewn on the red tide areas to attack the toxic algae on the non-treated seaweed.

 The treated seaweed disappears in two to three months, and the whole process is fully biodegradable, Mr Roman said.

 But Dr Anderson was concerned about the effect the enzyme solution could have on other marine life.

 'Solving it is one thing, managing it is another, and the best news for Hong Kong is that many countries around the world are fighting these problems and they have rather healthy aquaculture or fisheries industries, even though there is this threat, and it is because they manage it,' he said.

 'There are ways to monitor, control and detect. But you can't expect Hong Kong to do it instantly.'  Red tides are a worldwide problem and the effects on certain areas of the US have been disastrous for both the fishing and tourist industry.

 In Longboat Key, Florida, residents were hit by a siege of red tide lasting 18 months, ending in 1995.

 During that time many fish farmers and tour operators went bankrupt.



All at sea in the search for ways to turn red tide