XN000022-1988-06-03 — Page 7

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FRIDAY, JUNE 3, 1988

IN THE FORM OF A COMPUTER MODEL, IT AIMS TO

PROVIDE FORECASTS OF THE LIKELIHOOD OF OXYGEN DEPLETION IN THE WATERS WHICH MAY LEAD ΤΟ FISH KILLS, AND TO DETERMINE THE MAXIMUM LIMIT OF FISH STOCK AND ORGANIC LOADING IN THE FISH CULTURE ZONE.

CONDUCTED IN

AND

CONJUNCTION WITH THE UNIVERSITY'S CIVIL STRUCTURAL ENGINEERING DEPARTMENT, THE PROJECT WAS STARTED IN 1986 WHEN A COMPUTER MODEL WAS FORMULATED ΤΟ SIMULATE THE ECOLOGICAL CONDITIONS IN YUNG SHUE AU AS A TYPICAL FISH CULTURE ZONE LOCATED IN SHELTERED WATERS.

AFTER TWO YEARS OF EXTENSIVE RESEARCH AND FIELD WORK, THE COMPUTER MODEL DEVELOPED HAS BEEN FOUND TO BE ABLE TO PROVIDE FAIRLY ACCURATE PREDICTIONS OF THE CHANGES IN THE LEVEL OF DISSOLVED OXYGEN IN THE WATERS.

VERIFIED TO BE IN SATISFACTORY

THESE PREDICTIONS HAVE BEEN AGREEMENT WITH ACTUAL FIELD MEASUREMENTS.

THE SENIOR FISHERIES OFFICER OF THE AGRICULTURE AND FISHERIES DEPARTMENT, DR RUDOLF WU, TODAY (FRIDAY) DESCRIBED THE COMPUTER MODEL AS "A VERY EFFECTIVE SCIENTIFIC TOOL FOR MARICULTURE MANAGEMENT".

"THE DISSOLVED OXYGEN LEVEL IN THE WATERS IS MODELLED BY QUANTIFYING THE COMPLICATED INTERACTIONS OF A NUMBER OF BIOLOGICAL AND PHYSICAL FACTORS INCLUDING PHOTOSYNTHETIC PRODUCTION AND RESPIRATORY ACTIVITIES OF THE MARINE BIOTA, LIGHT INTENSITY, WATER TEMPERATURE, TIDAL FLUSHING AND WIND SPEED.

"BY FEEDING THE NECESSARY DATE INTO THE COMPUTER, THE MODEL ALSO HELPS TO DETERMINE THE CARRYING CAPACITY OF THE WATER BODY IN RELATION TO ORGANIC LOADING AND FISH STOCK DENSITY.'

.

THE MODEL HAS ALSO IDENTIFIED THAT ALGAL RESPIRATION, FISH RESPIRATION AND BOTTOM SEDIMENT RESPIRATION IN YUNG SHUF AU ARE UNEXPECTEDLY HIGH.

"COUPLED WITH ADVERSE METEOROLOGICAL CONDITIONS, SUCH HIGH OXYGEN CONSUMPTION RATES MAY CONTRIBUTE SIGNIFICANTLY TO MAJOR FISH KILLS, DR WU POINTED OUT.

НЕ SAID THAT THE COMPUTER MODEL COULD BE MODIFIED APPLICATION FOR USE IN OTHER FISH CULTURE ZONES IN THE TERRITORY.

FOR

THE RESEARCH TEAM FROM THE UNIVERSITY OF HONG KONG COMPRISES DR JOSEPH LEE AND PROFESSOR Y.K. CHEUNG. THEIR WORK WAS A GRANT AWARDED BY THE CROUCHER FOUNDATION.

SUPPORTED

BY

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