Study of the Dynamic Density and Diversity of Plankton at Different Brackishwater Pond Managements in Gresik, East Java

The success of fish and shrimp farming is strongly influenced by the improvement of water quality, which is measurable from physical, chemical and biological parameters. Biological parameter refers to the presence or absence of plankton. Plankton is a microscopic- sized organism whose life drifts with the current. Plankton has a favorable type of group, and this type of adverse group is affected in pond production. A way to understand the group, the density and diversity of plankton in a pond one of them is to know the management of ponds, both traditional ponds and semi-intensive ponds. This research was conducted in traditional pond of Pandanan village and Tambak Semi Intensive Village of Ambeng-ambeng Gresik, East Java. It aimed to find out the dynamics of density and plankton diversity with different management. The method employed was survey method, which is is a research method aimed to describe the phenomena that exist regardless the time of occurrence. The results were presented in descriptive form. The result of total density of plankton of traditional pond was about 102-793 ind / l, while semi intensive density of total plankton density reached 59-980 ind / l. The results of traditional ponds diversity index ranged from 0.119 to 0.159 ind / l in semi intensive ponds 0.121-0.159 ind / l. Traditional fish dominance index values ranged from 0.1 to-0.338ind / l, and semi intensive ponds ranged from 0.172-0.558 ind / l. The nitrogen values of traditional and semi-intensive ponds were 0.042 - 0.314 mg / l and 0.048 - 0.224 mg / l respectively. The result of measurement of phosphorus value of traditional pond successively ranged from 0,02 to 0,042 mg / l and 0,007 - 0,031 mg / l for semi-intensive pond. The result of measurement of N / P ratio of traditional ponds consecutively ranged between 3,545 and 8 mg /, and semi intensive pond fpr 4,272 - 9.857 mg / l. The results of water quality assessment increased and decreased in the value of dissolved oxygen, ranging between 3.28 and 5.32 mg / l for traditional ponds and 5-8.25 mg /1 for semi-intensive ponds. The pH of traditional pond ranged from 6 to 7.89 and 7 to 9.2 for semi-intensive ponds. The temperature of traditional ponds ranged between 28 and 31°C and semi intensive pond at 29-31°C. Research has been done to conclude that.