Composition of phytobenthos in 'lab-lab', a periphyton-based extensive aquaculture technology for milkfish in brackish water ponds
2006
Fortes, N.R. | Pinosa, L.A.G.
The species composition of phytoperiphyton present in a pond gradually filled with water to 5, 10, 15 and 30 cm was studied prior to stocking of milkfish during dry and wet periods. Periphyton (lab-lab) was allowed to grow on 24 artificial substrates set at regular distances in a 1000/sq m pond. Lab-lab that colonized the artificial substrate was collected, and that on the pond surrounding the substrate was scared off. The surface area sampled for lab-lab and its wet weight was taken. Simultaneously, water was collected for the analyses of physical, chemical and biologic parameters. Sampling was done biweekly, coinciding with 2 and 7 days' submergence at a desired depth, and before water level adjustment. Using a compound microscope, species were identified and counted using a haemacytometer for unicellular algae, and the Sedgwick Rafter and counting cell for filamentous and bigger algae. Major algae consisted of diatoms, blue-green algae, and green algae; with the diatoms dominating during the dry period, and the blue green algae during the wet period. Twenty-eight species were found during the dry period, and 25 during the wet period. Variation in species and density was observed each sampling, it was influenced by environmental conditions and the incoming water. There were lower counts and biomass during the wet period.
显示更多 [+] 显示较少 [-]