National Agricultural Research Organisation. Fisheries Resources Research Institute Annual Report 2000/2001

It is now clear that fisheries resources are among the key assets contributing to the national development objective of poverty eradication through providing food, employment, income and export earnings. It was recently reported in the papers that monthly fish exports had increased by 23% and fetched about US$ 10 Million during the month of November 2001 alone. This value may be underestimated as it is based solely on recorded exports from fish processing factories numbering 12. Although fisheries resources are renewable they can be depleted through unsustainable exploitation. It is therefore important to ensure that there is guided development and management of this asset so that it can continue contributing to the livelihood of the people who depend on it. Therefore, FIRRI contributes to the fisheries sub-sector developmental objective of ensuring increased and sustainable fishery production and utilization by providing information to guide sustainable management of capture fisheries resources and development of aquaculture.

National Agricultural Research Organisation. Fisheries Resources Research Institute Annual Report 2001-2002

Fisheries continue to be important in the national economy, especially as an export commodity. Fish exports increased from 15,876 tonnes valued at 34.4 million US$ in 2000 to 28,153 tonnes valued at 79.0 million US$ in 2001. Consequently information for sustainable exploitation and management of fish stocks is a priority. In order to fulfill this requirement, FIRRI has been implementing two research projects. The first project focuses on sustaining and increasing capture fisheries production through management of fish stocks, biodiversity and environment of aquatic systems. The second project focuses on increasing fish production through improved fry production and pond management and feeding of cultured species.

Fisheries research component implementation status 1997 -2001 and workplans 2001-2003

The report covers the status of: the economic and ecological values of Lake Victoria; priority issues; the vision of the Fisheries Research Component; the objectives of the Fisheries Research Component under LVEMP to generate, package and disseminate scientific knowledge and build capacity.

Effect of pond aeration on growth and survival of Penaeus monodon Fab.

The effect of paddle wheel aeration on shrimp growth and survival were studied at a commercial farm at Chandipur coast of Orissa, India, at different stocking densities of Penaeus monodon. Four different aeration patterns were adopted and evaluated. Influence of individual aeration pattern on average survival rate was not highly significant (p<0.05) at different stocking densities, while different aeration patterns had significant influence (p

The potential of mixed culture of freshwater giant prawn Macrobrachium rosenbergii de Man and tiger shrimp Penaeus monodon Fab. at Khulna region, Bangladesh

The freshwater giant prawn (golda), Macrobrachium rosenbergii and tiger shrimp (bagda), Penaeus monodon were stocked together with or without fin fishes at different stocking rates in semi-saline waters at Khulna region and their growth, survival, yield and costreturn analysis were made. Survival rate of golda and bagda ranged from 23.0 to 36.8% and 8.2 to 24%, respectively. The both species were significantly affected by their own stocking density. The average final weight of golda and bagda ranged from 62.4 to 73.3 g and 32.0 to 66.4 g. The bivariate analysis of average final weight of both golda and bagda revealed that golda positively and bagda negatively influenced by the total stocking density. However, the results of the individual sizes of both golda and bagda showed an increase in the proportions of smaller animals and a decrease in the proportion of larger ones with increasing stocking rates. The harvesting weights of all animals in the experimental ghers were in marketable sizes although their prices varied with the individual size. The total production comprised of both golda and bagda ranged from 514.6 to 952.8 kg ha·1, over a culture period of 10 months. Return on investment ranged from 51.0 to 125.7%.

Polyculture of freshwater prawn, Macrobrachium rosenbergii, de Man with carps: effects of prawn stocking density

Effects of three stocking densities, viz., 35, 50 and 65/decimal (1 decimal = 40.48 m2) of juvenile freshwater prawn (Macrobrachium rosenbergii) on prawn and fish production were tested in a polycuture system with silver carp (Hypophthalmichthys molitrix), catla (Catla catla), Grass carp (Ctenophmyngodon idella) and silver barb (Barbodes gonionotus). The fish stocking density was 19/decimal with the species combination of silver carp-10, catlac-6, grass carp-1 and silver barb-2. In a 8-month culture period, the prawn yield 423 ± 144 kg/ha was significantly lower (P< 0.5) with the prawn stocking density of 35/decimal than that of 548 ± 178 kg/ha and 662 ± 243 kg/ha with 50 and 65/decimal respectively. The fish production (1844-1891 kg/ha) did not differ significantly (p <0.05) among the three treatments indicating that prawn stocking densities had no influence on fish yield. The lower mean harvest weight (62 g) and survival rate (67 g) and higher yield (2.67 kg/decimal) with the highest stocking rate of prawn reveals that as density was increased, prawn survival and individual weight at harvest decreased but total yield increased.

Fisheries studies on Lake George and Kazinga Channel: first quarter final report June/July 2001

FIRRI surveyed the fisheries of Lake George and Kazinga Channel between 20th June and 20th July 2001. This was the second survey FIRRI has conducted for the ILM project on the water system. The first survey was conducted during November 2000. These data, the analyses and accompanying reports contribute to baseline information for the fishery being collected with the support of ILM that is required for lakewide planning and management. Eight fish landing sites (6 on Lake George) namely; Kahendero, Hamukungu, Kasenyi, Kashaka, Mahyoro, Kayinja (2 on Kazinga Channel) namely; Katunguru -K and B fall within the focus of ILM and were surveyed during November 2000 and June/July 2001 over a three day period at each landing site in 2001 (Mahyoro 2 days). In November 2000, each landing was sampled once. FIRRI conducted a rapid FS and concurrently a CAS. All results are reported by landing site and then summed up (Global) for 8 sites on Lake George and Kazinga Channel.

Examining the possibilty of multiplication and breeding of (Schizothorav [sic] zarudnyi) in order to restoration of regional aquatics reservations of Hamoon Lake and taking its advantag [sic] for aquaculture

Schizothorax zarudnvi, is an endemic fish of east country waters. (Triple lagoons of Hamoon and relevant water resources) that in the world it is reported in this resource specially. This fish named Hamoon mahi is one of the most economically valuable species in this region. Because of the recent years droughts, Hamoon logoon has been drive since 2000. Also, semi-wells (a semi natural resource) were affected drastically by recent drought years and their volume reduced to nearly one third of their real volume and resulted in changing at growth and reproduction physiology process in Schizothorax zanidnyi, brood stocks. Beginning of this project was done from October 2003. It's field studies begun (brood catching) since November 2001 by two methods including entangling gairs and at semi wells of Sistan that (Beach seine) had maximum rate of preparing qualified brood stocks. Broods transferred to Cyprinidea reproduction work shop of Zahak and after taking primary measures they stored in to the edaphic pools. Increasing the success safety factor (coefficient) for artificial reproduction of Sthizothorax zarudnyi , identifying the appropriate tune for Hormonal acceptance (physiological preparation of broods) is needed , so this important work was done regularly by histological studies and GSI measurements since November. Highest GSI rates of females (%80.51) and highest IV stage abundance of sexual maturity (%l 00) were observed an march. On the base of this date, Hormone therapy was done on broods on march. The used hormones are as follows Hypophysis. extraction, GnRHa and Anti Dopamin at the dozes of 3-6 ml, 20-30kg and 10-15 ml per kg body weight respectively and 2-3 times from 11-12-80 they were injected. Injected broods kept in to two circumstances, flow-through (rounded pool) and stagnant systems. In stagnant system 14 and 19 individuals of female and male (Schizothorax zauiulnri) broods, respectively injected in 11th, 15111, 19th, and 24th of march 1380. Non of the injected broods in 11 and 15 and 19th march (in stagnant Condition) answered to Hormone therapy. After final injection broods had general less activity and a few of them died. Mean temperature of brood pond waters (daily) which were injected. Fluctuated between 10-25-13. 63°c but injected broods on 24th march had different characteristics. They had pale color and had few fecundity. In this stage of injection they hadn't any successful vulation. After injection, Mean daily water temperature was 15, 88-17, 54°c. In Flowing system, 13-16 individual of males and females respectively were injected on 15th, 19th, 22th and 23th march. None of injected producers on 15th and 19th march with mean daily water temperature of 10, 25-12°c were prepared for spawning but injected producers on 22nd an 23th march with mean daily water temperature of 13.5-1 rc responded about 75-100 percent. (Schizothorax zarudnyi) brood stocks were prepared for spawning after 353-428 hours/day from final injection. Diameter of obtained eggs (before fertilization) was between 1.9-2.3 min and of fertilized eggs was 3.8mm. Fertilized eggs of (Schizothorax zarudnyi) were hatched after 6-7 days with mean water temperature of 17.08°c. Mean length of on one day larvae was 9.47 mm. Larvae was 9.47 mm. Larvae adsorbed the whole yolk sac after , 5-6 days at 17- 1°c and were prepared for releasing in to edaphic pools. Because of the lack of necessary and complementary facilities in the region , they had to release them in to veniros and growing them for 8 days. At the end of 18th day , 35000 larvae (at first) released into an edaphic pond with a volume of 150m2. After growing them for one moth , mean length and weight of new hatched larvae was 29.41 mm and 1.12►r , respectively. With respect to results of this investigation , artificial reproduction of (Schizothorax zarudnyi) Can be possible at 14-17°C and flowing water with Hormonal treatment. It -s breeding has increased development than other cultural specious in the region. Due to high economical value of this specious in Sistan and ti-s specialization east waters of Iran and having high resistance and proper growth There is a need of it's development and reproduction and culture in fish culture fanns (edaphic ponds• two-purpose pools) at the region and country.