Factor intensity and economic returns of alternate shrimp crop and shrimp-salt farming in the coastal areas of Bangladesh

The paper examines the factor intensity and economic returns of alternate shrimp-crop and shrimp-salt farming in the coastal areas of Bangladesh. Data were collected from 30 shrimp-crop and 30 shrimp-salt farmers, 30 shrimp farmers and 30 rice farmers from three selected coastal districts of Bangladesh. Cobb-Douglas production function model was used to determine the effect of various factors on alternate shrimp-crop farming. The chosen variables were stocking of juveniles, paddy seed, labour, fertilizers, feed and farm size of respective type of farming. The results indicated that the production function exhibited increasing remrns to scale for alternate shrimp-rice, alternate shrimp-salt and year round shrimp farming while it indicated decreasing returns for year round rice farming. Economic analysis of same system of farming indicated that higher amount of input use produced higher level of yield, gross return and net return for each type of production system.

An observation of performances in carp-prawn polyculture in respect of fingerlings size and water area

Performances of fingerling size and water area was studied. Seven species of fish included 25% of Hypophthalmichthys molitrix, 15% of Gada catla, 20% of Labeo rohita, 10% of Cirrhinus mrigala, 10% of Ctenophyringodon idella and 20% of Macrobrachium rosenbergii were stocked at the rate of 8,000 individual/ha along Barbodes gonionoms at 6.0g weight size with a stocking density of 2,000 indl./ ha. Survival of all species was in the range of 39.9 to 96.3% except M. rosenbergii The highest survival was obtained from L. rohita (96.3%) followed by C mrigala (96.0 %)., B. gonionotus (92.3%), C idella (90.6%), H. molitrix (84.0%), C cada (81.7%) respectively. While the survival of M. rosenbergiiwas 13.1%. The highest production of 4912 kg/ha/yr was obtained from the bigger ponds (0.4 ha) stocked with 20-32g size of fingerlings, while lowest production (3123 kg/ha/yr) from small pond (0.1 ha) stocked with 3-10 g fingerlings. Economic analysis shows the highest net profit in bigger ponds stocked with bigger fish seed.

Economic analysis of carp based culture technologies in selected areas of Bangladesh

Six carp based culture technologies such as, carp-pangas, carp polyculture, carp-golda, pangas monoculture, golda monoculture and nursery have been selected to determine the cost and returns of respective technologies in Bangladesh. The sample farmers selected for these technologies were 55, 100, 65, 50, 51 and 55 respectively and thus the total sample size stood at 376. The study covered 7 districts of Bangladesh, namely, Mymensingh, Bogra, Noakhali, Comilla, Jessore, Khulna and Bagerhat. Both primary and secondary data were used for this study. It was found that farmers used a good number of feeds for the selected technologies and they maintained no standard doses for them. Remarkable differences were found among the prices of different feeds and other inputs used for different technologies in different locations. Prices of all inputs were found to be increasing and this increase was more in recent years compared to previous years. Though all the technologies were found to be profitable, the feed situation was not satisfactory. Except rice polish all the local feeds showed deficit in supply to meet the national demand for the country. If this situation persists and no proper measures are taken to secure the local feed supply, the present development of supplementary feed-based aquaculture would be fully dependent on imported feeds and would not be sustainable in future. This study strongly suggests the corresponding authority to handle the matter with proper attention considering its significant livelihood impact on the economy of the country.

Stock assessment of the demersal offshore fishery resources off the Karnataka coast

The total biomass of the demersal stocks in the depth range of 30-200m between 12°401 and 15°N latitudes in the Indian Exclusive Economic Zone is estimated to be a:round 1,23,000 metric tons (t). There is scope for doubling the present catch of about 40,000 t from demersal resources by extending exploitation to 50-200m depth zone. About 78% of this increase is expected to come from four species, namely, Nemipterus japonicus, Priacanthus macracanthus, Saurida tumbil and Arius spp.

Population dynamics and stock assessment of the common carp (Cyprinus carpio) in Iranian waters of the Caspian Sea

In order to come up with the responsible fishing pattern of common carp, there was a need to identify some of the biological characteristics and stock assessment of carp in Iranian waters of the Caspian Sea .The fork length ,weight ,age ,growth parameters of von bertalanffy and mortality rates of common carp were estimated from oct 2006 to sept 2007.Based on the exponential relationship between length and weight in the size range 6.3-65.6 cm ,b was calculated 2.895, 2.843 and 2.925 respectively for combined sexes ,males and females. The mean condition factor was 1.9 which is close to the ideal condition.The results from measuring 3170 specimens ,were showed the first fork length of maturity was 30 cm for males and 32 cm for females. The results indicated that females were predominate and sex ratio was 0.66:1 (M:F) and chi-squares analysis showeda significant difference between males and females.(p<0.05).Length infinity and growth coefficient were calculated by three different methods as below: Length frequency analysis : k=0.17 L∞ =68.04 Age-Length Key k=0.15 L∞ =74.25 Back calculation : k=0.14 L∞ =68.4 The mortality parameters and exploitation rate were estimated as below : Z=0.73 per year M=0.31 per year F=0.42 per year E=0.56 Refer to amount of common carp catch in 2007 -08 ,biomass was calculated 9640.2 tones by jone's cohort analysis and MSY 2374.5 tones.According to analysis ,the number of common carp in the distribution area (Iranian part of the Caspian Sea ) was estimated 24 millions in the 2006-07.

Investigation on the ecological impact of constructing and activities of petrochemical industries of petrochemical special economic zone of Mahshahr on the abundance and diversity of macrobenthic fauna in Jafari Creek, north-west of the Persian Gulf

The impact of Petrochemical Special Economic Zone (PETZONE) activities on the health status of Jafari Creek was studied by assessing the changes in macroinvertebrate assemblages in nine sites during September 2006- January 2008. Furthermore to evaluate the ecological status of the Jafari Creek the WFD indices (i.e. AMBI, M-AMBI) were used. The relationship between spatial pattern of macro invertebrate assemblages and ambient factors (i.e. water temperature, salinity, pH, dissolved oxygen, turbidity, electrical conductivity, total dissolved solid, total hardness, total nitrogen, ammonia, total phosphorous, chemical oxygen demand, biological oxygen demand, sediment grain size distribution, sediment organic content, heavy metals contents) was measured. Background Enrichment indices, Contamination factor and Contamination degree, were used to assess the health status in the study area based on Nickel, Lead, Cadmium and Mercury contents of the sediments. The macrobenthic communities had a low diversity and were dominated by opportunistic taxa, and the AMBI and M-AMBI indices need to be calibrated before using in Persian Gulf and its coastal waters. The BIO-ENV analysis identified pH, dissolved oxygen, TDS, and the total organic content of sediments as the major environmental variables influencing the infaunal pattern. This suggests that management should attempt to ensure minimal disturbance to environmental variables underlying the spatial variation in macroinvertebrate assemblages. Background Enrichment indices showed that the health of Jafari Creek has declined over time due to the constant discharge of heavy metals to the Creek system. Furthermore WQS index shows that the quality condition of the water column in Jafari Creek, regard to the calculated number (3) is week. These indices also identified a significant degree of pollution in the study area. The decrease in the ecological potential of Jafari Creek was best highlighted by the alteration in macrobenthic assemblages.

Dispersion, population dynamics and stock assessment of Caspian Sea prawns, genus Palaemon in Guilan Province coastal waters

Biological aspects, population dynamics and stock assessment of the Caspian Sea prawns Palaemon adspersus and Palaemon eleganse were investigated in Guilan coastal water of the Caspian Sea. Sampling was done monthly with a bottom trawl with mesh size of 3 mm in cod end in 0 - 5 m and 5 - 10 m depth in areas as Astra, Shafa Roud, Anzali, Chonchanan Chamkhaleh and Chaboksar during year 2002. Results of one year sampling showed that mean total length of Palaemon adspersus (pooled data) was 39.9±6.84 mm (X±SD) and mean wiegth was 1.133±0.67 g. The mean total length of females and males was 41.6±7.5 mm and 37.9±5.2 mm respectively and mean weight for the mentioned sexes was 1.353±0.65 g and 0.868±0.38 g respectively. There was significant differences in mean length and weight of females and males (P<0.05). The mean total annual sex ratio of males: females for this species was 1.4 and this sex ratio deviated significantly from 1:1 (X2, P<0.05) and biased towards males in the population of this species. The spawning season of Palaemon adspersus begins in April and ends in September with a peak in June . Mean fecundity of this species was 1994.5 ± 506.6 . The growth coefficients Loo and K for females were estimated as 58.5 mm and 2.3 /Year and for males as 55.9 mm and 2.6 /year respectively . The mean CPUA ( catch / Km2 ) for this species was 9.99 ± 33.2 kg / km2 and the correspondance biomass was calculated as 5067.7 kg in 0 - 10 m depth . The mean total length of Palaemon elegans (pooled data ) was 27.5 ± 5.7 mm (X±S.D) and mm and 24.01±4.18 mm respectively and mean weight for the mentioned sexes were was 0.553 ± 0.3 g and 0.237±0.15 g respectively. There was significant differences in mean length and weight of females and males (P<0.05). The mean total annual sex ratio of males:females for this species was 0.57 and in this species also sex ratio differed significantly from 1:1 (X2, P<0.05) and skewed towards females in the population of this species. The spawning season of Palaemon elegans extended from May to September with a peak in July . Mean fecundity of this species was 642.7±313.4. The growth coefficients LOO and K for females were estimated as 42.119 mm and 2.40 /Year and 33.87 mm and 2.50 /year for males respectively. The mean. CPUA ( catch/ Km2 ) for this species was 0.75±3.86 kg/km2 and the correspondance biomass was calculated as 382.1 kg in 0-10 m depth .

A study on stock enhancement/restocking of the Kyoga basin lakes

Increased management attention to the fisheries tn Uganda is fuelled by five major factors:socio-economic demands, human population increase,stock depletion, biodiversity loss and,environmental degradation.Fish exports from Uganda to overseas and regional markets have rapidly increased since the mid 1990s and it is estimated that total exports are worth at least US$ 200m three quarters of the value due mostly to Nile perch exports to overseas markets.Exports to regional markets are dominated by variously processed tilapia "mukene" (Rastrineobo/a argentea),Nile perch "angara"(A/estes baremose) and cat fishes.Virtually all major water bodies contribute to this trade. A combinatilm of exports and an increased human population has seen the per capita fish consumption in Uganda drop from 15kg in the early 1990s to almost 10kg by 2005.this figure is below the WHO recommended fish protein intake of 17kg. the apparent fish gap in a liberalised economic framework has stimulated interest in commercial fish farming

Report of Lake Wamala fisheries frame survey 2012

Lake Wamala, a small lake (180 km2) located in Central Uganda and believed to have been part of the main Lake Victoria and only got separated about 4000 years ago, has already undergone different levels of fisheries evolution that warrant using it as a case study to inform changes in other systems. Using resources provided by the Lake Victoria Environmental Management Project (LVEMP) II, under the Applied Research Facility, we evaluated the fishing inputs, socio-economic infrastructure and analyzed trends in fishery benefits to guide evolution of management advice. A frame survey was conducted on the entire lake (13th - 23rd March 2012) enumerating all fishing factors and enlisting available and accessible socio-economic infrastructure along the shores of the lake. The lake traverses districts (Gomba, Mityana, and Mubende) with its largest portion lying in Mityana. There are 26 established fish landing sites and about 600 fishers with a similar number of boats on the lake. The total number of boats on the lake is almost equal to the number of fishers; illustrating the common type (paracute) and size (Small, about 4 m) of boats and hence a fishing crew structure of one fisher per boat. Main fishing gears are Gillnets targeting the tilapia (Ngege) and long line hooks (Protperus, Mamba, and Clarias, Male). Almost equal number of boats used the two main gears on the lake (about 300 each). 97% of the gill nets on the lake are small (3.5” (8.9 cm – 4.5” – 11.4 cm) stretched mesh size while 98% of the hoots are large (< size 10). The implication is gill net fishers target small tilapia while long line fishers aim at the large mamba and male. Generally the lake has poor socio-economic infrastructure compared to other lakes of Uganda probably due to its geo-morphological setting. The lakes fishing factors have continued to expand with the ever increasing population. There may be need to check the continued entry into the fisheries especially if the increasing effort does not translate into increase in fishery yield.