Time lag between catching and curing of fish and its influence on the finished product. 1. Mackerel

A study is made to determine the maximum permissible time lag both under iced and not iced storage conditions between the catching of mackerel (Rastrelliger kanagurta) and its curing, so that the quality of the finished product is within tolerable limits. Based on physical, chemical, bacteriological and taste panel studies the maximum time lag permissible is fixed as 8hrs under not iced condition and 3 days under iced condition. Icing of fish is also found to affect the tasting qualities of the finished product.

High temperature processing of fish sausage 3. - Studies on some of the storage characteristics

The proximate composition of the high temperature processed fish sausage was found to be 14.56% protein, 4.65% fat, 69.14% moisture, 2.12% ash and 8.12% carbohydrate. The quality of the product during storage was assessed on the basis of the changes observed in the physical, chemical and microbiological parameters. The results of the different tests such as pH, volatile base nitrogen (VBN), trimethyl amine nitrogen (TMA-N) and jelly strength are summarized and discussed. The total bacterial load increased gradually during storage but was not proportional to the initial load.

Studies on dried/smoked barracuda

Physical, chemical and organoleptic characteristics of dried and smoked barracuda (Sphyraena spp.) during storage at ambient temperature are reported. Initial increase in total volatile basic nitrogen (TVBN) content after drying as well as smoking did not have any significant effect on the organoleptic qualities of the products. Smoking was found effective in delaying the onset of fungal attack and also in improving the organoleptic qualities.

Improvement in quality and shelf-life of whole dried prawns

A simple and effective method is suggested to improve the quality and shelf-life of commercial whole dried thelly prawns (Metapenaeus dobsoni). Treatment of whole prawns in 10% brine containing 0.1% citric acid for 20 min followed by drying in sun yield a product having good physical, chemical and organoleptic characteristics. Retardation of fungal incidence, reduction in total volatile nitrogen (TVBN) and improvement in flavour are some of the advantages of the treatment. The treated product has a shelf-life around 30 weeks compared to 20 weeks for untreated control and 7 weeks for commercial sample.

Benthic fauna and water quality in Gorganrood River, Iran

This present work study on water quality and benthic Macro invertebrate in Gorganrood, river. The research was carried out at 6 sampling site and the abundance and diversity of benthos were monitored along the length of river between 2007_2008_14 families were recorded in phyla, namely Annelidae, Mollusca,.... The greatest number of species was at 1 st station and the least number was at 6th station. The upper section supported more diverse community then the lower section. A low macro invertebrate abundance was observed during spring as a result of heavy rainfall and flood, and generally in all lowest section because of high valve of nitrogen and other nutrients. Water physiochemical parameters such as Phosphate, Nitrate,TPS and others were measured and water quality were studied through different indices such as saprobic system, Helsinhoff (FBI), BMWP and the results were compared and evaluated by physical chemical and parameters. The result indicated that the water quality in the up stream and the middle were good to fair, but the down stream qualities were pour at all sites.

Assessing potential of production in Lake Choghakhor

Phytoplankton productivity is the common and important factor being considered in determining the overall status of a given body of water. This is because they are found at the base of an energy or food chain, being the basic source of primary food in a given aquatic system. Hence, information on their contribution is essential in indicating how much biomass energy will be available to all other living resources in the system. Though the primary productivity of shallow lakes is characterized by mixed populations of phytoplankton and submersed aquatic vegetation in the open water. Lake Choghakhor, is a shallow lake, located in Chaharmahal-Bakhtiyari Province. This lake is the most important ecosystem in the region especially for waterfowl populations, has a recreational value and supports tourism and fisheries. During last decade Choghakhor has been influenced by some man-made impacts such as water level fluctuation, agricultural discharge and fish (Cyprinids) introduction causing a serious problem in its trophic states. So water quality for physical, chemical and biological was monitored in five sampling stations, from April 2003 to March 2004. As biological parameters we studied phytoplankton, epiphytic algae, and zooplankton and macrobenthose community structure. Chlorophyll a content for phytoplankton and epiphytes was measured to estimate production of these groups (biomass over time). Also we determined biomasses of submersed macrophytes and macrobenthose and primary production of phytoplankton (dark and light bottles technique) to estimate fish production. The results of this study showed Lake Choghakhor did not undergo stable thermal and oxygen stratification, and the lake water was mixed throughout the study (the lake mixing regime is polymictic). Now submerged plants especially Myriophyllum spicatum has covered almost the entire lake and dense macrophyte beds (Polygonom amphibium), located on the east southern end of the lake appear to act as a sink for these nutrients. Lake Choghakhor appeared to be in a macrophyte dominated clear water state with low TP (annual mean: 24± 15μg.l-1) and chlorophyll a (annual mean: 3±1.28μg.l-1) concentrations and very high Secchi depth. The grazing pressure of dominant pelagic filtering zooplankton Daphnia longespina did not seem to be significant in determining the low phytoplankton crop expressed as chlorophyll a. We expect that sequestering of nutrients by submerged plants and associated epiphytes are the dominant stabilizing mechanisms suppressing the phytoplankton crop of Lake Choghakhor.

Technical report on the environmental monitoring of the cage area at the Source of the Nile (SON) Fish Farm for quarter 4: October-December 2011

Source of the Nile Fish farm (SON) is located at Bugungu area in Napoleon Gulf, northern Lake Victoria. The proprietors of the farm requested for technical assistance of NaFIRRI to undertake regular environment monitoring of the cage site as is mandatory under the NEMA conditions. As the SON is a key collaborator/client of the institute, NAFIRRI agreed to undertake the assignment subject to facilitation by the client. The institute agreed to conduct quarterly surveys of key environmental parameters at the site including selected physical-chemical and biological factors, nutrient status, column depth, water transparency and sedimentation. Samples and field measurements were to be taken at 3 sites: within and/or close to the fish cages (WIC), upstream (USC) and downstream (DSC) of the cages. The first environmental monitoring survey was undertaken in February 2011; the second in May 2011 and the third in September 2011. The surveys cover physical-chemical parameters, nutrient status, invertebrate and fish communities. The present report presents field observations made for the fourth quarter survey undertaken in November 2011 and provides a scientific interpretation and discussion of the results with reference to possible impacts of the cage facilities to the water environment and the different aquatic biota at and around the cage site including natural fish communities.

Technical report on the environmental monitoring of the cage area at the Source of the Nile (SON) Cage Fish Farm for quarter 4: October-December 2015

Source of the Nile (SON) Cage Fish farm is located at Bugungu in Napoleon Gulf, northern Lake Victoria, near the headwaters of the River Nile. NaFIRRI has, through a Public-Private collaborative partnership with SON management, undertaken quarterly monitoring of the cage fish farm since 2011. The objective of the environment monitoring is to track possible environment and biological changes as a result of fish cage operations in the area. The agreed study areas cover selected physical-chemical parameters i.e. water depth, transparency, column temperature, dissolved oxygen, pH and conductivity; nutrient status; and biological parameters i.e. algae, zooplankton, macro-benthos and fish communities. The fourth quarter survey, which is the subject of this report was undertaken during December 2015. 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. The present report presents field observations made for the fourth quarter survey undertaken in December 2015 and provides a scientific interpretation and discussion of the results with reference to possible impacts of the cage facilities to the water environment and the different aquatic biota in and around the fish cage site.

Technical report on the environmental monitoring of the cage area at the Source of the Nile (SON) Fish Farm for quarter 2: April-June 2015

Source of the Nile Fish farm (SON) is located at Bugungu area in Napoleon Gulf, northern Lake Victoria. The proprietors of the farm have a collaborative arrangement with NaFIRRI to undertake quarterly environment monitoring of the cage site as is mandatory under the NEMA conditions. The monitoring surveys cover selected physical-chemical factors i.e. water column depth, water transparency, water column temperature, dissolved oxygen, pH and conductivity; nutrient status, algal and invertebrate communities (micro-invertebrates/zooplankton and macroinvertebrates/ macro-benthos) as well as fish community. The second quarter survey for the calendar year 2015, which is the subject of this report, was undertaken in June 2015. 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.

Report of the baseline survey undertaken on the Chinese cage site in Napoleon Gulf, Northern Lake Victoria, 12 March 2012

The government of the People's Republic of China through a 2007 agreement with the Government of the Republic of Uganda, has establishment of an Agricultural Technology Demonstration Center (ATDC). The first phase covering the building of aquaculture infrastructure at Kajjansi ARDC is complete and the second operation phase has started in which facilities for cage culture have been set up in the Napoleon gulf, northern Lake Victoria near Jinja. The cage facility is aimed at boosting fish farming within the lake as a diversification to the traditional pond fish culture technology. NaFIRRI scientists as well as Chinese experts undertook a baseline survey in the chosen cage site on 12 March 2012. The survey covered determination of water depth, water transparency, measurement of selected physical-chemical parameters (temperature,dissolved oxygen, conductivity and pH; determination of the nutrient status and study of algae, invertebrate and fish communities at the site. Materials and methodologies used in the survey were based on the Standard Operating Procedures (SOPs) of NaFIRRI. The study area was divided into three study sites. Site 1 (upstream) was at 8.9 metre depth while site 2 (proposed cage site) and site 3 (downstream) were 6 and 4.3 metres deep respectively. Water transparency was lowest at site 1 (1.58 m) and highest at site 3 (1.64 m). Dissolved oxygen at the three sites ranged from 6.0 to 8 mg/I. Water temperature profiles fluctuated within narrow limits between 26.5 and 27.5 DC. Measurements of pH were between 7 (neutral) and 8 (alkaline) while electrical conductivity was between 98 and 101 uS/em. These observed physical-chemical parameters at the study site were considered suitable for cage fish rearing purposes. Nitrite-nitrogen levels varied within narrow limits from 0.043 to 0.0453 mgtl. Similarly, Ammonia-nitrogen varied between 0.015 and 0.0185 mg/1. Soluble reactive phosphorus (SRP) level was highest at site 3 (O.012mgll) compared to that at sites 1 and 2 (0.009mgll). Total suspended solids (TSS) were higher at site 1 (83.3mgll), thereafter decreasing to lower levels at sites 2 (24.8mgtl) and 3 (19.8mgl) respectively. The nutrient level results observed here all fall below the maximum permissible limits by NEMA and therefore the site is recommended for cage culture The algal community was constituted by four major groups: Blue greens,Greens, Cryptophytes, and Diatoms with blue greens as the common and dominant group. High algal biomass (19944961 ugtL) of the dominant blue green algae was observed at site 1 compared site 2 and 3 (58655.2 & 27487. 7 ugtL) respectively. Occurrence of toxicin producing algae: microsytis and cylindrospermopsis in the proposed cage area was considered to be of not much significance as their concentrations were below harmful levels. However, monitoring their presence, biomass and seasonality will be critical in order to follow when and where they occur and at what time of the year for ease of management of the cages