33
3.4.2 Data collecting
In analyzing and discussing the issues in this research requires data that consists of two data sources, namely:
primary data and secondary data.
1.
Primary data is collected by the investigator through field survey. Such data are in raw form and must be refined before use. These data can be
gathered internally or externally though surveys, observations, experiments, and simulation.
2.
Secondary data is extracted from the existing published or unpublished sources, that is from the data already collected by others. Before the use
of secondary data, in example, other persons data, we must properly scrutinize and edit them to find whether these data are: reliable,
suitable, and adequate.
3.4.3 Processing of Risco Data
The experimental research is a systematic and scientific approach to research in which the researcher manipulates one or more variables, and controls
and measures any change in other variables. Experiments are conducted to be able to predict phenomenons. Typically, an experiment is constructed to be able to
explain some kind of causation. The case study is the most flexible of all research designs, allowing the researcher to retain the holistic characteristics of real-life
events while investigating empirical events Yin, 1984. There was several experiment design in RISCO project, in every station;
we have a cage of oyster which is showed in figure 19.
34
The observations of this research have been conducted monthly 8 surveys in May until December 2010, which are:
1. 3 and 4 May 2010 2. 31 May and 1 June 2010
3. 5 and 6 July 2010 4. 2 and 3 August 2010
5. 30 and 31 August 2010 6. 27 and 28 September 2010
7. 4 and 5 November 2010 8. 13 and 14 December 2010
Each month, there are several analyses which have been done, such as: 1. Analysis of pathology OsHV
1
and vibrio 2. Analysis of sediment granulometry
3. Analysis of hydrology such as temperature, salinity, oxygen, chlorophyll a, turbidity and suspended matter, and
4. Oyster growth and mortality Spat and Adult
Here, we focus on the fourth, especially on mortality of oyster. In each
station, we counted the number of predators starfishes and gastropods on the
Figure 19. Experimental Design of Oyster Culture
Surface water
On-bottom of the sea
35
cage and in each bag we calculated the numbers of dead oysters then we took sampling of 30 living oysters for growth and pathology analysis. In each dead
oyster, we also observed the boring oyster by oyster drill and parasitism by Polydora. We did the same thing from April to December 2010
and sometimes we added several oysters at each station, in case of there was huge death oysters,
approximately 50-100 oysters.
4 Results
4.1 The Predators in the Quiberon Bay
Kategori