海湾网箱渔场老化特征分析

ANALYSING ON THE DEGRADATIONAL CHARATERISTICS OF CAGED FISH CULTURE OF A BAY

以珠江口牛头岛深湾作为周年逐月监测点，采用点面结合的方法，同时对大亚湾和珠江口几个开发网箱养鱼多年的海湾作季度调查。通过渔场水质、沉积物的环境要素监测，发现海湾网箱渔场使用多年以后由于有机污染严重，沉积硫化物含量比湾外自然沉积高１０多倍，在夏季小潮期，深湾下层水体溶氧量平均值仅为３．５８ｍｇ／Ｌ，最低值为１．３６ｍｇ／Ｌ。认为沉积硫化物高和下层水体溶氧低是渔场老化的特征。

From 1991 to 1993, we did monthly survey on Shen Bay of Niutou Island located at Zhujiang Estuary and quarterly survey on other several new caged fish grounds located at Daya Bay and Zhujiang Estuary. From the data of the water qualities and the sediment we got, we found that after years fish culturing, Shen Bay was serious polluted by organic. Its sulfide of sediment was 10 times high as that out of the Bay. During summer low tide period, its average of DO in lower water body was 3.58mg/L, the lowest was only 1.36mg/L. So, we considered that high sulphide of sediment and low DO of the lower water bady were the main degradational properties of caged fish culture in a bay.