739 resultados para Lake trout fisheries
Resumo:
Source of the Nile Fish farm (SON) is located in northern Lake Victoria close to the headwaters of the River Nile. The proprietors of the farm have established a collaborative agreement with the National Fisheries Resources Research Institute (NaFIRRI) to undertake quarterly environment monitoring surveys of the fish cage site at Bugungu in the Napoleon Gulf. This activity is a mandatory requirement of the National Environment Management Authority (NEMA) of Uganda. Therefore NAFIRRI undertakes monitoring surveys once every quarter covering selected physical‐chemical parameters including water column depth, water transparency, water column temperature, dissolved oxygen, pH, conductivity and nutrient status; algal, zooplankton, macro‐benthos and fish communities. While the first quarter survey of 2013 (January‐March) was missed out due to late decision, the second quarter monitoring survey was dully undertaken in May 2013 and a technical report was compiled and submitted to the client. The present report covers the third quarter survey (July‐September) undertaken in September 2013. Results/observations made are presented in this technical report along with a scientific interpretation and discussion of the results with reference to possible impacts of the cage facilities to the water environment quality and selected aquatic biota.
Resumo:
Source of the Nile Fish farm (SON) is located at Bugungu area in Napoleon Gulf, northern Lake Victoria. The proprietors of the farm requested NaFIRRI to provide technical assistance to undertake regular environment monitoring of the cage site as is mandatory under the NEMA conditions. NAFIRRI agreed to undertake regular environment surveys in the cage area covering selected physical‐chemical factors i.e. water column depth, water transparency, water column temperature, dissolved oxygen, pH, conductivity, redox potential and turbidity; nutrient status, algal and invertebrate communities (micro‐invertebrates/zooplankton and macro‐invertebrates/macro‐benthos) as well as fish community. The first year‐round quarterly surveys were completed for the year 2011. It was decided by SON management to change the frequency of the monitoring surveys to biannual starting in the year 2012 and the first such survey, which is the subject of this report, was undertaken in June 2012. Results/observations made are presented in this technical report along with a scientific interpretation and discussion of the results with reference to possible impacts of the cage facilities to the water environment and aquatic biota. SON
Resumo:
Source of the Nile Fish farm (SON) is located at Bugungu area in Napoleon Gulf, northern Lake Victoria. The proprietors of the farm and the National Fisheries Resources Research Institute (NaFIRRI) have an established collaborative arrangement where NaFIRRI provides technical back‐stopping to enable quarterly environment monitoring of the cage site as a mandatory requirement of the National Environment Management Authority (NEMA). The agreed study areas are selected physical‐chemical factors (water depth, water transparency/secchi depth, water temperature, dissolved oxygen, pH, conductivity, and nutrient status), algal community (including primary production), aquatic invertebrates (zooplankton and macro‐benthos) and the fish community. This report presents field observations made during the first quarter (January‐March) field survey undertaken during March 2014; along with scientific interpretation and discussion of the results in reference to possible impacts of the cage facility to the water environment quality and aquatic biota. The
Resumo:
Major histocompatibility complex genes are thought to be involved in allogeneic graft rejection but not many reports are available on their functional analysis in fish. Analysis of available sequences of MHC genes suggests functions in antigen presentation similar to those found in higher vertebrates. In mammals, the MHC class I and class II molecules are major determinants of allogeneic graft rejection due to their polymorphism in conjunction with their antigen presenting function. In fish, MHC class H molecules are found to be involved in rejection of allogeneic scale grafts. The present study was designed to investigate the involvement of MHC class I molecules in allograft rejection. Erythrocytes were collected from donors of rainbow trout expressed different class MHC class I alleles, stained with two dyes, mixed and grafted to the recipients that were of the same sibling group as the donors. The grafts were rejected by allogeneic recipients and the MHC class I linkage group was the major determinant for the rejection.
Resumo:
A laboratory based 2 x 2 factorial experiment was conducted to investigate the influences of dietary phosphorus and zinc levels on growth and bone mineralization in fingerlings of rainbow trout for 21 weeks. Two levels of phosphorus (19 and 30 mg/g) and two levels of zinc (55 and 103 Ag/g) in the dry diets were tested. Duplicate tanks of 30 rainbow trout (average weight 1.56 ± 0.24 g) per 60L glass tank were fed experimental diets three times a day to apparent satiation level at 15 to 24°C water temperature. The results of the present study demonstrated that dietary phosphorus supplementation influenced the growth and bone mineralization whereas zinc levels significantly (p<0.05) influenced bone mineralization in rainbow trout. Further investigations in this area with different size and age groups of this fish are broadly needed.
Resumo:
Gut contents of 120 Oxygaster bacaila fmm Kaptai Lake were studied. Index of preponderance (IP) indicated that 0. bacaila consumed highest amount of Insects (35.89%) and thus occupied the first position among the food items. Zooplankton (Rmifera and crustacea 31.79%) and the other food items found in the guts were algae (Chlorophyceae, Bacillariophyceae, Euglenophyceae and Cyanophyceae 24.51%). From the analysis of gut contents, this fish might be considered as omnivore as it consumed both animal and plant foods with higher preference for animal food. The feeding intensity of this fish is fairly high. Total length (TL) versus gut length (GL) relationship and their ratio were found to be GL = 0.57663 TLL04801 (r = 0.9963) and TL: GL = l: 0.7086 respectively.
Resumo:
A study on the status of fisheries and environmental impact assessment (EIA) was conducted on Bashundhara Baridhara Housing Project (BBHP), Dhaka, Bangladesh for prediction and measure the effects of housing project related development activities that have already been implemented and planned for future implementation. The project is still under development phase and so far allotted 10,000 plots of different sizes. The study shows that the original water bodies and natural fish production there from have greatly declined due to earth filling carried out for development of land for the housing. The physico-chemical parameters of the existing water body within the project area were found to be suitable for fish farming in the estate. A number of economically important fish species are found available in the existing lake. However, the natural fisheries resources of the existing lake is under great stress due to the changes made in the ecosystem, siltation, construction of building and dumping of house building and household waste materials. This has caused some important fish species of the lake to become critically endangered and vulnerable which have been documented in this paper. Appropriate regulatory and mitigating measures with respect to water management, disposal of construction garbage and other biomedical toxic substances far away from the water bodies are required to be taken to keep the water safe and suitable for fish production as well as for multipurpose use of the lake water.
Resumo:
Growth, survival and food conversion ratio (FCR) of Cyprinus carpio in cages at different stocking density were studied in Kaptai lake. Fingerlings of common carp (12.47 ± 4.29 g) were stocked at 25/m2 , 50/m2 and 75/m2 each with replication in six floating net cages each of Sm x Sm x 4m and reared for 240 days. The growth rate was inversely related to the stocking density with the mean weights of 325.5 ± 11.74 g, 268.99± 8.44 g and 167.0 ± 11.66 g at low, medium and high densities, respectively. At harvest, standing crop biomass averaged 7 .82, 12.83 and 11.58 kg with the survival of 98.9%, 97.6% and 94.4% and food conversion ratios of 4.51, 3.82 and 4.21 for the above three densities, respectively. Weight gain and production at density 25 fish/m 2 were significantly different (p< 0.01) from other two densities. Water quality was not affected in the cages having different stocking densities.
Resumo:
The present study deals with the water quality and ichthyofauna of Sadatpur lake. Monthly changes in water quality parameters such as temperature, pH, dissolved oxygen (DO), total alkalinity, chlorides, sulphates, phosphates and nitrites have been studied for a period of one year beginning from January 2005 and were investigated to assess the suitability of this lake for fish and fisheries practices. All the physico-chemical parameters determined, revealed that the fluctuations in water temperature, pH, dissolved oxygen, alkalinity and nitrites, were within the desirable limits. On the other hand, chloride and sulphate were lower whereas phosphate was higher than the desirable limits. Altogether 24 fish species belonging to 17 genera and 2 orders were found to be present in the lake. Among fish species family Cyprinidae dominated the lake. The lake subsistence fishery served the need of local fishermen community.
Resumo:
Limnological factors of a sub-tropical lake Manchar were studied on seasonal basis. The mean values of various parameters were: transparency, (secchi disc reading): 90.5 cm, Orthophosphate: 0.257 mg/l, TDS: 3310,5 mg/l, Conductivity: 5232 µs/l, Total Chlorophyll (Planktonic): 31.3 µg/l Planktonic biomass: 5466 µg/l. Trophic state index (TSI) was calculated by using Carlson's (1977) equations. Mean TSI for transparency was 61, while for orthophosphate and chlorophyll, it was 82 and 64 respectively. TSI values indicate advanced eutrophic state of Manchar Lake. Morphoedaphic index (MEI) was also calculated on seasonal basis. The mean values were, TDS: 1103, conductivity: 1744, alkalinity: 60, transparency: 29 and biomass (plankton dry weight): 1746. Fish yield prediction for Manchar Lake (Z =3m, mean area=100 km²) was calculated by using MEI values. The results were quite different among various parameters. Conductivity (89.1mt/y), biomass (67.6 mt/y) and TDS (44.6 mt/y) were found to be good predictors of fish yield. Chlorophyll, transparency and alkalinity values gave very low estimate.
Resumo:
Nile perch (Mputa), Lates niloticus was introduced into Lakes Victoria and Kyoga from lake Albert to increase fish production of these lakes by feeding on and converting the small sized haplochromines (Nkejje) which were abundant in these lakes into a larger table fish. It was, however, feared that Nile perch would prey on and deplete stocks of the native fishes and affect fish species diversity. Nile perch became well established and is currently among the three most important commercial species. It is presently the most important export fish commodity from Uganda. Considerable changes have taken place in fishery yield, and in life history characteristics of the Nile perch itself since the predator got established in Lakes Victoria and Kyoga.
Resumo:
The Chilika Health report Card is based on three categories: water quality, fisheries and biodiversity.
Resumo:
The present research was done with the aim of studing the effects of some medicinal plant essential oils against Lactococcus garvieae and on some spoilage indexes in rainbow trout fillets in 4°C during 18 days. Essential oils of Mentha longifola (20, 40 and 80 μg g-1), Satureja bachtiarica (0.125, 0.25 and 0.50 μg g-1) and Satrureja khuzestanica (0.06, 0.12, 0.25 and 0.50 μg g-1) were used for this study. According to the results, the highest and the lowest microbial load were observed in control group and the groups contained 80 and 40 μg g-1 of Mentha longifola, respectively (P≤0.05). The spoilage indexes were increased after 18 days showing a statistical difference for protein, fat, TVN, FFA and TBA (P≤0.05). The most and the least changes were observed in the the control group and the fillets containing 80 μg g-1 of Mentha longifola, respectively (P≤0.05). The results indicated that, in comparison with control group, using herbal essential oils leads to reduction of Lactococcus garvieae population and spoilage process of the fillets through decreasing in TVN, FFA and TBA. Meanwhile, Mentha longifola having 80 μg g-1 was found to be more effective
Resumo:
For study the genetic diversity of Caspian brown trout population in five rivers in the southern part of Caspian Sea in Iran 182 number generators in the fall and winter of 1390 were collected in Chalus, Sardab Rud, Cheshmeh Kileh, Kargan Rud and Astara rivers. Then about 3-5 g of soft and fresh tissue from the bottom fin fish removed and were fixed in ethanol 96°. Genomic DNA was extracted by using ammonium acetate, then quantity and quality of the extracted DNA were determined by using spectrophotometry and horizontal electrophoresis in 1% agarose gel. The polymerase chain reaction was performed by using 16 SSR primers and sequencing primers (D-Loop) and the quality of PCR products amplified by SSR method were performed by using horizontal electrophoresis in 2% agarose gel. Alleles and their sizes were determined by using vertical electrophoresis in 6% polyacrylamide gel and silver nitrate staining method. Gel images were recorded by gel documentarian, the bands were scored by using Photo- Capt software and statistical analysis was performed by using Gene Alex and Pop Gene software. Also the PCR sequencing products after quality assessment by usinghorizontal electrophoresis in 1.5% agarose gel were purified and sent to South Korea Bioneer Corporation for sequencing. Sequencing was performed by chain termination method and the statistical analysis was performed by using Bio- Edit, Mega, Arlequin and DNA SP software. The SSR method, 5 pairs of primers produced polymorphic bands and the average real and effective number of alleles were calculated 5.60±1.83 and 3.87±1.46 in the Cheshmeh Kileh river and 7.60±1.75 and 5.48±1.32 in the Karganrud river and the mean observed and expected heterozygosity were calculated 0.44 ±0.15 and 0.52 ±0.16 in the Cheshmeh Kileh river and 0.50 ±0.11 and 0.70±0.13 in the Karganrud river. Analysis of Molecular Variance results showed that significant differences in genetic diversity between and within populations and between and within individuals in the studied rivers (P<0.01). The sequencing method identified 35 different haplotype, the highest number of polymorphic position (251) and haplotype (14) were observed in the Chalus river. The highest mean observed number of alleles (2.24±0.48) was calculated in the Sardabrud river, the highest mean observed heterozygosity (1.00±0.03) was calculated in the Chalus river and the highest mean nucleotide diversity (0.13±0.07) was observed in the Sardabrud river and mean haplotype diversity was obtained (1) in three studied rivers. The overall results show that there are no same population of this fish in the studied rivers and Karganrud and Chalus rivers in the SSR and sequencing methods had the highest levels of genetic diversity.
Resumo:
In this study, Iranian and French male and female Oncorhynchus mykiss broodstocks were divided into two groups 50 and 24 respectively in Research center of genetic and breeding of coldwater fishes, Yasouj, Iran and the genetic structure of them was investigated using 6 microsatellite markers. Then 19 morphometric and 5 meristic of broodstock were measured and compared in two populations. Along with broodstock maturation, fertilization 1:1(female:male) were randomly assigned and occurred in 25 of 12 Iranian and French treatment respectively. Reproductive parameters were recorded for the whole family. Average number of observed alleles in Iranian and French stocks was 6.68 and 6.83, respectively. Average number of effective alleles in Iranian and French stocks was 3.13 and 3.45 respectively. Fixation index Fst was calculated based on allelic frequency between two stocks was 0.058 with significant difference between 2 stocks. Morphometric analysis showed significant difference between two stocks in 8 characteristics. Meristic characters was without significant difference in broodstock groups. Eyed percentage for french broodstock calculated zero and deleted. Fertilization rate (100-0), the eyed percentage (98- 0), The hatch rate (98-0), the average fecundity 4114.708, the average eggs size 4.88 mm, Survival in the first three months 19-73% calculated for Iranian broodstocks. Considering the quality of eggs and larvae at different stages and selection between the different family and the within family remained 10 treatments and are kept as future broodstocks. The relationship between fecundity - egg size, fecundity - weight , fecundity - length, egg size- weight was performed using regression. The results showed that Fecundity was influenced more by weight and productive length. The research is beginning to ID the broodstock in our country.