2.1 Study area and period A study was carried out to explore the existence of spawning ground in Surma and Kushiara river for a period of four months during April to July 2015. Four (04) sampling points were selected from different suitable location of Surma and Kushiara river site with the help of local Upazila Fisheries Office, Fishermen Community and other stakeholders. The selected sampling sites were Hetimganj and Atgram point in Surma river; and Bhadeswar and Monumukh point in Kushiara river.
2.2 Natural fish spawn collection The Indian major carp spawn fishing gear that has traditionally been used in the two major river systems (Ganges-Padma and Bhrhamaputra-Jamuna) is a funnel-shaped fixed net, popularly called ‘Savar net’. This is a type of set bag net specially designed to fix the net at the shallow, gently sloping shoreline of the rivers, where the depth of water is negotiable without any aid. The ‘Savar net’ is usually small, with a collection pocket at the tail end. The net is made of a fine mesh that traps tiny eggs or spawn that drift with the water flow during the monsoon months. The upper edge of the tail bag is kept about 4–5 cm above the water surface to prevent the escape of spawn (Figure 2).
The savar net has a wide mouth (anterior opening) and a small tail (posterior) opening. The mouth has two lateral extensions, each 6'-2" long and 2' wide (deep). The tail opening is round and it has 9" diameter. Its edge is stitched in a ring of split bamboo. The tail bag is a receptacle, which collects spawn trapped in the net. It is rectangular in shape made of gamcha (local cloth) or other finely woven cloth.
2.3 Collection and transportation of fish seed samples The research was conducted by setting up two ‘Savar net’ at each sampling point for the collection of fish seed sample. The sampling works was done by a skilled fisherman at each site in Surma and Kushiara rivers through a collection of fish seed sample. The sampling net was observed four times in a day at 6 hours interval. Fish seed sample were collected at six hours interval from the sampling points and samples were collected through oxygen bag. The collected samples were transferred and stocked immediately in a small pond (1 decimal) at the Fish Seed Multiplication Farm (FSMF), Golapganj. For ponds were used separately for four sampling sites.
2.4 Spawn rearing and species identification: The collected samples were reared for a period of 15 days for species identification. The fish seeds were reared properly for 15 days with the necessary management technique. After 15 days, the sizes of the fish spawn were about 2.5-3.0 cm and they were easily identified. The identification of fish species was done by visual investigation.
2.5 Water quality parameters: Water quality parameters such as water temperature, turbidity, pH, dissolved oxygen (DO), acidity, alkalinity, ammonia, CO2, chloride, hardness, nitrate, TDS were estimated at a monthly intervals from 09.00 to 10.00 am. Water temperature was recorded with a Celsius thermometer, and turbidity was measured with a Secchi disc of 20-cm diameter. Dissolved oxygen, pH and other parameters were measured by digital HANNA instruments. The Enumerator (MS student) was involved there closely with each sampling site for sample collection and other activities. Technical supports and laboratory facilities were provided from the Department of Fish Biology and Genetics, Sylhet Agricultural University.
2.6 Data processing and analysis The collected data were summarized and scrutinized carefully before the actual tabulation. For processing and analysis purposes, MS Excel and SPSS have been used.