Studies on the interaction between shellfish long-line culture and environment in Sungo Bay

Field experiments were carried out from June to October of 2003 and March of 2004 to monitor some environmental factors such as water velocity, pH, dissolved oxygen inside and outside scallop culture lantern net and longline culture area by using YSI6600 water quality monitoring instrument, SD6000 automatic water velocity and gypsum in Sungo Bay. The results showed: (1) the average seawater velocity inside the lease area were decreased from 7.505.29 to 5.283.23 cms-1, decreased by 29.6%. And the average chlorophyll a concentration was decreased from 2.48 to 1.19 gL-1, decreased by 52%. (2) The average chlorophyll a concentration was 4.13 and 4.60 gL-1 respectively for the water samples inside and outside the lantern nets at the beginning, but decreased to 1.57 and 4.20 gL-1 respectively in the end. pH kept stabile outside the lantern nets, but it declined continuously inside, and reached the lowest value (7.46) in September. During the blooming period of fouling organisms, there was significant difference of dissolved oxygen outside and inside the nets. Compare to 7.04 mgL-1 outside the lantern nets, the dissolved oxygen inside is only 5.13 mgL-1, decreased by 27.1%.