Coastal Aquaculture Research Institute, Department of Fisheries
Graduate School of Biosphere Sciences, Hiroshima University
Laboratory of Environmental Conservation, Graduate School of Kuroshio Science (GRAKUS), Kochi University
抄録
Effects of nutrient load from feeds on shrimp production was investigated in two intensive shrimp ponds (A6 and D2) in terms of eutrophication process and changes in community structure of living organisms in the ponds. Our results found that, although feeding was not much different, a practice for A6 was failed regarding shrimp production (48kg/pond), while that for D2 was successful producing 946kg/pond. Chlorophyll a concentrations varied within the range of 10.3-108μg/l in A6 and 16-266μg/l in D2, indicating that the eutrophication status in D2 was higher than in A6. Water quality parameter indicated low concentration of dissolved phosphorus in A6 probably due to the DOP sink to the bottom sediment of high N/P ratio at the beginning which resulted in decrease of N/P ratio of sediment and deficiency of P (high N/P ratio) in water column that disfavored by phytoplankton. The concentrations of N and P were gradually increased in D2 resulting in lowering of N/P ratio to close to the Redfield ratio and the correspondence increasing of phytoplankton biomass and community succession. The appearance of Noctiluca for almost 2 months during the middle period of shrimp culture was also the possible cause of stress to shrimps and resulting in low production in A6. The success of production in D2 may relate to the appearance of Oscillatoria that was the successive group after short appearance of Gymnodinium may imply nitrogen fixation occurring during the end of culture. In addition, our results may indicate the present of nano-phytoplankton that contributed to the high chlorophyll a concentration during the last period of shrimp culture. The importance of controlling community of living organisms and some countermeasures were discussed in this paper.
雑誌名
Coastal marine science
巻
30
号
1
ページ
91 - 99
発行年
2006-04-28
ISSN
13493000
書誌レコードID
AA11957899
フォーマット
application/pdf
日本十進分類法
452
出版者
International Coastal Research Center, Ocean Research Institute, the University of Tokyo
Importance of controlling community structure of living organisms in intensive shrimp culture ponds
KJ00004354587.pdf
(912.63KB)
