EFFECT OF USING PERIPHYTON SUBSTRATE (BAMBOO STEMS) ON WATER QUALITY,EFFECT PHYTOPLANKTON, ZOOPLANKTON, PERIPHYTON AND GROWTH PERFORMANCE FOR DIFFERENT FISH SPECIES IN POLYCULTURE IN EARTHEN PONDS
Ahmed A. Hassan and Hosam M. Agouz
Department of Aquaculture, Central Laboratory for Aquaculture Research, Abbassa, Abo-Hammad, Sharkia Governorate, Egypt.
Received 28/ 1/ 2010 Accepted 25/ 2/ 2010
Abstract
A polyculture trial was conducted in earthen ponds at Kafer El-Sheikh Governorate – Egypt to compare traditional aquaculture techniques. The study was carried out in fifteen earthen ponds (1000m2 each ) with five treatments each in three replicates: traditional fertilization with bamboo (Bambusa sp.) substrate; traditional fertilization without substrate; mineral with substrate; mineral without substrate and control treatment (artificial feed only). The total number of different fish species per pond were 3000, 750,500,500 and 250 for tilapia, mullet,common carp, silver carp,and catfish, respectively in each pond.
Nile tilapia (Oreochromis niloticus) 60% mixed sex, common carp (Cyprinus carpio) 10%, silver carp (Hypophthalmichtys molitrix) 10%, mullet (Mugel cephalus) 15% and catfish (Clarias gariepinus) 5% (mean body weight 10 ±1.1g) were stocked at 20000fish/feddan. Grow-out duration was 150 days. Water quality, phytoplankton; zooplankton and periphyton were monitored throughout the experiment. Significantly higher concentrations of nitrogen compounds (NH4, NH3, NO2 and NO3) were recorded in traditional and mineral fertilization without substrate than with substrate treatments and feed only. Dissolved oxygen significantly increased in substrate treatments than others due to the consumption by phytoplankton. The chlorophyl- a concentration of pond water was significantly higher in the traditional and mineral fertilization treatments without substrate than in the other treatments. The net primary productivity (NPP) and gross primary productivity (GPP) significantly increased in traditional fertilizers with and without substrate treatments than in mineral fertilizers with and without substrate and feed only. Periphyton significantly increased NPN and GPP. The pheophytin-a chlorophyll-a total number of phytoplankton and zooplankton significantly increased in traditional and mineral fertilization treatments without substrate than in with substrate treatments. Dry matter content increased significantly with depth up to 50 cm, and then decreased gradually to the end. Periphyton chlorophyll a concentrations per unit surface area were significantly different among the substrate depths and decreased with increasing water depth.
The total fish production was 3245, 2932, 2499, 2146 and 2002 kg/ feddan for traditional with and without substrate treatments; mineral fertilizer with and without substrate and feed only, respectively. The fish production was significantly higher in substrate treatment than without substrate treatments and feed only treatments. Survival rate was significantly increased in substrate treatments (traditional and mineral fertilization) than in without substrate (traditional and mineral fertilization) and feed only. The bamboo substrate improved water quality, survival rate and total production of fish.
The stomach
of silver carp had significant increased of phytoplankton than others content and than others fish species. Also, catfish, tilapia and mullet had significant increaseof zooplankton, detritus and insects than other fish species.
Key Words:
Periphyton, Water quality, Phytoplankton, Zooplankton, Growth performance, Fish species,Fresh water.
