Effect of chilled sea water storage of oil sardine (Sardinella longiceps) on quality changes during frozen storage

The shelf-life of frozen oil sardine (Sardinella longiceps) can be improved by preserving the fish immediately after catch in chilled sea water before freezing. Delayed icing caused considerable deterioration in quality and reduced frozen shelf-life. Oil sardine preserved in chilled sea water were found to be suitable for freezing up to 5 days whereas iced samples could be frozen only up to 2 days.

A review of water year 1987 in northern California [abstract and figures]

EXTRACT (SEE PDF FOR FULL ABSTRACT): It seems that an average water year is a rare beast; 1987 was no exception. It turned out to be the ninth driest this century in Northern California's Sacramento River basin. I'd like to summarize for you some interesting facts about water year 1987 and how it affected rainfall, snowpack, runoff, and water storage in California.

Nutrient dynamics of seasonal tanks in the dry zone of Sri Lanka in relation to their hydrological regimes

Village tanks are put to a wide range of uses by the rural communities that depend on them for their survival. As the primacy of irrigation has decreased under these tanks due to a variety of climatic and economic reasons there is a need to reevaluate their use for other productive functions. The research presented in this paper is part of a programme investigating the potential to improve the management of living aquatic resources in order to bring benefits to the most marginal groups identified in upper watershed areas. Based on an improved typology of seasonal tanks, the seasonal changes and dynamics of various water quality parameters indicative of nutrient status and fisheries carrying capacity are compared over a period of one year. Indicators of Net (Primary) Productivity (NP): Rates of Dissolved Oxygen (DO) change, Total Suspended Solids (TSS): Total Suspended Volatile solids (TVSS) ratios are the parameters of principle interest. Based on these results a comparative analysis is made on two classes of ‘seasonal’ and ‘semi-seasonal’ tanks. Results indicate a broad correlation in each of these parameters with seasonal trends in tank hydrology. Highest productivity levels are associated with periods of declining water storage, whilst the lowest levels are associated with the periods of maximum water storage shortly after the NW monsoon. This variation is primarily attributed to dilution effects associated with depth and storage area. During the yala period, encroachment of the surface layer by several species of aquatic macrophyte also has progressively negative impacts on productivity. The most seasonal tanks show wider extremes in seasonal nutrient dynamics, overall, with less favourable conditions than the ‘semi-seasonal’ tanks. Never the less all the tanks can be considered as being highly productive with NP levels comparable to fertilised pond systems for much of the year. This indicates that nutrient status is not likely to be amongst the most important constraints to enhancing fish production. Other potential management improvements based on these results are discussed. [PDF contains 19 pages]

Integrating cultural, economic and environmental requirements for fish production in Borno State

The study examines the integration of cultural, economic and environmental requirements for fish production in Borno State, Nigeria. A reconnaissance survey was conducted transferring some selected Local Government Areas. 60 questionnaires were administered in the six Local Governments representing Southern Borno State with Biu and Shani, central Borno with Konduga & Jere and Northern Borno with Gubia and Kukawa respectively. There is no cultural constraint to fish production but about 63% prefers to invest in other farming activities than in fish farming. 33% are not aware that fish can be cultured apart from getting it from the wild. 35% have the impression that fish farming ventures can be handled by government only. The economic earnings for fish production are high especially in some parts of Northern Borno, but the Local market potentials throughout the state are great. Nigeria has suitable soil for ponds apart from few locations at the central and Northern Borno that are made by sandy soil. Numerous perennial and seasonal rivers, streams, lakes, pools and flood plains adequate for fish culture especially in Southern Borno exist. The mean annual rainfall can result in some water storage in ponds. In areas where the annual precipitation is less than 550mm, exist few flow boreholes with potentials for fish production. The temperature regime may support growth and survival of fish even during the hottest months of the year (March, April and May). With the understanding and manipulation of these requirements, fish production in Nigeria can be greatly enhanced

A note on the shallow ponds on the gravel ridge of Epping Forest, Essex

In a recent study in Freshwater Forum on Speakman's Pond (also known as Nursery Pond) the impression was given that it had been a permanent water-filled pond which had recently dried out due to exceptionally low rainfall. In fact, Nursery Pond was created by the extraction of gravel and was never more than 50 cm deep, until the creation of trenches in 1989 to provide a refuge for aquatic life. The Nursery Pond followed a seasonal pattern of filling with winter rain and slowly drying out between 1940 to 1970. It had no established aquatic vegetation, no fish, and only rarely amphibians. Permanent water was present only from about 1979 until 1995 due to leakage from a Thames water storage reservoir.

Fish and fisheries in the Sesan River Basin: catchment baseline, fisheries section

The present report was prepared for the Water and Food Challenge Program project “Optimizing the management of a cascade of reservoirs at the catchment level” (MK3). It constitutes the baseline assessment of fish and fisheries in the Sesan River Basin. The objective of the MK3 project is to contribute knowledge and recommendations so that cascades of reservoirs corresponding to hydropower dams in the Mekong Basin are managed in ways that are more fair and equitable for all water users. This project seeks to understand at the catchment scale the cumulative upstream and downstream consequences of management decisions taken for multiple reservoirs. Revised rules for water storage infrastructure management will in particular take into account fisheries and agricultural potential as well as hydropower gen

The storage of red snapper (Lutjanus spp.) in ice, chilled sea water and chilled fresh water

The results are given of trials conducted to determine the effect on quality of holding fish (Lutjanus species) in chilled freshwater and also to compare the quality loss of fish stored in chilled seawater and chilled freshwater and in ice. No adverse effects were observed when storing in chilled freshwater apart from loss of external appearance after 6 days storage; taste panel tests showed acceptable conditions up to 15 days. Chilled seawater is unsuitable for storage as it spoils the intake of salt from the medium, making the flesh unpalatable.

Studies on frozen storage characteristics of fillets from six species of fresh water fishes

Frozen storage characteristics of fillets from six major species of fresh water fishes namely, Labeo rohita, Catla catla, Cirrhina mrigala, Labeo calbasu, Mystus seenghala, and Wallago attu are reported. The biochemical, bacteriological and organoleptic changes in the frozen fillets during storage at -18°C have been followed systematically. Compared to the two species of fresh water cat fishes, the four species of carps studied, had a slightly better storage life. From the organoleptic point of view, fillets of Cirrhina mrigala had the best shelf life.

Interim report on surface water resources of Baker County, Florida

The principal sources of surface-water supplies inBaker County are the St. Marys River and its tributaries. However, the flow of many of the small tributaries is intermittent, and without storage they are not dependable sources of supply during sustained periods of deficient rainfall. Of the six stream-gaging stations in Baker County for which complete records are available, one has been in operation for 31 years and provides a long-term record upon which to base correlative estimates for extending the short-term records at the other stations. All available streamflow data to 1957 have been summarized in graphic or tabular form. The hydrologic balance between minimum streamflows and increased evaporation losses afforded by potential shallow reservoirs provides design criteria for determining the maximum surface area of effective reservoir that can be created at a selected site within Baker County. This information has been presented in graphic and tabular form in the report. (PDF has 37 pages.)

A tool for better management of water quality during periods of algal blooms: the case of the River Oise

Like other rivers in the Paris area, the Oise is subject to important seasonal algal blooms. This eutrophication generates notable problems for the production of drinking-water from a treatment plant on the river at Méry. A mathematical model has been developed to simulate variation in water quality in a pre-treatment storage basin, and another model is currently being adapted to model the River Oise. Integration of the two models should provide a comprehensive tool for predicting variations of phytoplankton and water-quality parameters associated with algal blooms. This will be a decision-aid for optimizing control of the treatment process for providing potable water.

Metallothionein as an indicator of water quality: assessment of the bioavailability of cadmium, copper, mercury and zinc in aquatic animals at the cellular level

The study of metallothioneins (MTs) has greatly improved our understanding of body burdens, metal storage and detoxification in aquatic organisms subjected to contamination by the toxic heavy metals, Cd, Cu, Hg and Zn. These studies have shown that in certain organisms MT status can be used to assess impact of these metals at the cellular level and, whilst validation is currently limited to a few examples, this stress response may be linked to higher levels of organisation, thus indicating its potential for environmental quality assessment. Molluscs, such as Mytilus spp., and several commonly occurring teleost species, are the most promising of the indicator species tested. Natural variability of MT levels caused by the organism's size, condition, age, position in the sexual cycle, temperature and various stressors, can lead to difficulties in interpretation of field data as a definitive response-indicator of metal contamination unless a critical appraisal of these variables is available. From laboratory and field studies these data are almost complete for teleost fish. Whilst for molluscs much of this information is lacking, when suitable controls are utilised and MT measurements are combined with observations of metal partitioning, current studies indicate that they are nevertheless a powerful tool in the interpretation of impact, and may prove useful in water quality assessment.

Freshwater biology and water supply in Britain

This paper is designed to give a general account of freshwater biology as it bears on waterworks practice. Most water that is used for consumption will commonly go through a storage reservoir. Here special reference is given to the biological relations in standing waters, the biological control of water supplies, methods of plankton estimation, the biology of slow sand filtration and the use of algicides.

Phosphate treatment of frozen prawns. Pt 2. Frozen storage characteristics of prawn meat treated with polyphosphates

This communication reports the changes in physical, organoleptic and biochemical characteristics of prawn meat dip-treated with alkaline and neutral solutions of polyphosphates during frozen storage. Results are presented on changes in thawed and cooked yields, water extractable nitrogen, non-protein nitrogen, free amino-nitrogen, salt solubility, myosin and moisture in the muscle and loss of soluble nitrogenous constituents in thaw drip during frozen storage up to seven months. The salt solubility remained unchanged during storage in samples treated with neutral polyphosphate solutions and the organoleptic quality was superior to control sample. It is concluded that dip treatment with neutralized solutions of tripolyphosphate not only maintains correct drained weight and improves cooked yield during prolonged frozen storage but also protects the frozen product from denaturation as measured by the salt solubility of the proteins.

Technological aspects of processing of edible mussels, clams and crabs. Pt. 1. Spoilage during ice storage

Rate and pattern of spoilage of some of the economically important edible species of shell fishes Mytilus edulis (Mussel), Villorita cornucopia (Clam), Neptunus pelagicus (Crab) and Scylla serrata (Crab) have been discussed in this communication. Chemical indices used for objective evaluation of quality were water extractable nitrogen (WEN), non-protein nitrogen (NPN), free α-amino nitrogen (α - NH2 -N), glycogen, lactic acid and inorganic phosphorus in addition to the subjective tests. No significant difference in the spoilage pattern of the species during ice storage was observed and these species could be preserved in ice in organoleptic acceptable condition up to 8 days, 9 days, 8 days and 11 days respectively.

Preparation of pasteurized fish ball in curry and its storage study at 0 to 2°C

Fish ball in curry was prepared as per the standardized method and recipe, pasteurized and subjected to storage at 0 to 2°C in a domestic refrigerator. The curry prepared with tomato at a level of 20% of onion was found to be suitable organoleptically. A level of 3% of spice mixture improved the taste of curry. Fish balls prepared with concentrated curry paste and oil at a level of 0.5% was found to be suitable organoleptically. Curry prepared by adding oil at the rate of 3% scored high values for all attributes as compared to other levels. Curry prepared by diluting curry paste with water at rate of 20% had been adjudged the best as compared to other water levels. Fish ball in curry with a 50 : 50 ratio pasteurized at 85°C for five minutes had scored higher values under organoleptic evaluation. It was observed that the product was acceptable organoleptically up to the 12th day when stored at 0 to 2°C.