The relationship between aquatic biota and water quality in Feitsui Reservoir
Date Issued
2015
Date
2015
Author(s)
Lin, Yi-Ping
Abstract
In recent year, millions of dollars are invested for lake and reservoir restoration. The classical biomanipulation method have been well developed in temperate regions since 1975. And the non-classical biomanipulation is used in tropical regions. Taiwan is subject to both tropical and temperate climatic influence. There was no feasible biomanipulation method yet. Feitsui Reservoir is the second largest reservoir in Taiwan. It supplies our domestic water of taipei-keelung metropolitan area. We analyzed the correlation between water quality, algae, zooplanktons and fishes in the reservoir to find the feasible biomanipulation strategy and target species. The water quality of B,C region were oligotrophic, but the A region was mesotrophic. In A region, the relationship between zooplanktons and algae showed a postive mild-moderately correlation (0.1≦R2<0.6). Even though the sizes of zooplankton were less than 3 mm), the grazing activities of cladocerans and copepods could inhibit algal biomass effectively when the fish density was low. This indicated that a classical biomanipulation could be implemented in A region. In the major fish species, tilapia and common carp showed bad effect to water quality.The results showed a negative mild-moderately correlations between those fishes and water clarity. Redfin culter make no siginificant effect to water quality. The bighead carp community was steady these years. The percentage of blue-green algae intake of bighead carp was proportional to algal biomass (R2≧6.0). It indicates that bighead carp had the potential to be a target species for preventing blue-green algae density in B,C region of Taipei Feitsui Reservoir. Due to the differences of depth and animal composition between A, B and C regions, two different methods of biomanipulation can be taken. In A region, enhancing of the grazing activity of zooplanktons can lead to successful classical biomanipulation. In B,C regions, we can increase the bighead carp stock up to the effective density indicated by previous studies. Bighead carp can prevent the eutrophication in reservoir.
Subjects
Feitsui Reservoir
biomanipulation
water quality
planktivorous fish
eutrophication
Type
thesis