The processing of fish and other marine resources

The preservation of freshness in fish (commonly referred to as fish handling) and the conversion of fresh fish into other products can both be considered as methods of processing. In commercial practice, however, the term "processing" is confined to the conversion of fresh fish into other products.

A brief report on a survey of the fish and fisheries of the Tana river, with special reference to the probable effects of the proposed barrages

The construction of several barrages in order to develop the hydroelectric and irrigation potential of the Tana river has been proposed and the probable effects of these developments upon the fish and fisheries of the area' has been investigated. Briefly in the highest reaches the sport fishery will be unaffected, in the middle reaches the sparse subsistence fisheries will be only slightly inconvenienced but in the terminal reaches of the river the subsistence and commercial fishing enterprises are expected to be seriously reduced by the progressive re-regulation of river-flow. However each new dam will support a new and productive reservoir fishery and with proper development the annual yield of fish from the Tana basin is expected to increase considerably.

Processing and marketing of fish with special reference to export of pelagic fish and fish products

The paper describes the world tuna fishery, industry and markets and the trends for its future development. The prospects for developing a tuna export industry in Sri Lanka are discussed. Suggestions are given as to products composition, international co-operation and utilization of available processing facilities. The need for industry and export support is stressed, and it is concluded that preparations for the development should start well in time.

Bacterial flora associated with diseased fish and their antibiogram

Bacterial flora associated with tail rot/fin rot of Carassius auratus, Xiphophorus helleri and hemorrhagic ulcers of Clarias spp were studied. Sensitivity pattern of 33 isolates comprising Aeromonas spp, Pseudomonas spp and Gram-positive rods from diseased C. auratus, X. helleri and Clarias spp were screened against six broad-spectrum antibiotics viz. ciprofloxacin, chloramphenicol, co-trimoxazole, gentamycin, nitro-furantoin and oxytetracycline. Ciprofloxacin was the most effective in inhibiting bacteria at 0.05-0.10 µg/ml level. About 44% of Pseudomonas spp. was resistant to nitrofurantoin. Resistance to oxytetracycline was seen in 27% of Aeromonas spp Gram-positive rods were comparatively more resistant to antibiotics. The multiple antibiotic resistances were seen in 21% of the bacterial isolates of diseased fish.

An empirical study on income and efficiency of pond fish and nursery fish production in some selected areas of Pabna, Bangladesh

The study was designed to determine the costs, returns and relative profitability of pond fish and nursery fish production. In order to attain this objective, a total of 70 producers: 35 producing pond fish and 35 producing nursery fish were selected on the basis of purposive random sampling technique from 6 villages under two Upazilas (Sujanagar and Santhia) of Pabna district. It was estimated that per hectare per year gross cost of pond fish production was Tk 65,918 while gross return and net return were Tk 91,707 and Tk 25,789 respectively. Per hectare per year gross cost of nursery fish production was Tk 87,489 while gross return and net return were Tk 1,39,272 and Tk 51,783 respectively. The findings revealed that nursery fish production was more profitable than pond fish production. Cobb-Douglas production function was applied to realize the specific effect of the factors on pond fish and nursery fish production. It was observed that most of the included variables had significant impact on pond fish and nursery fish production. Out of five variables included in the function, all the variables had positive impact on return from pond fish production but stock value of pond, material cost and pond area had positive impact on return from nursery fish production.

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.

Flavour components of some processed. fish and fishery products of Japan

A study was conducted to examine the flavour components of some processed fish and fishery products of Japan by gas chromatography-mass spectrometry (GC-MS). In brief the method was to absorb the headspace volatiles at 70°C into the fused silica fibre of needle of the solid phase micro extraction fibre. The absorbed components were injected to the GC-MS. The components were identified by computer matching with library database as well as by authentic standard components. In general the number of flavour components were higher in the processed fish and fishery products (except frozen prawn) than that of the raw fish and prawn. The concentration (quantity) of the f1avour components in processed fish and fishery products was much higher than that of the raw fish and prawn. Smoked salmon and baked salmon possessed double number of flavour components than that of the raw salmon. Smoking resulted the highest number of flavour components followed by baking (grilling) and canning, surimi products (kamaboko and chikuwa), drying and lastly salting. However, freezing and frozen storage resulted loss of flavour components in prawn.

Feasibility of bi-culture of mud crab (Scylla serrata) and shrimp (Penaeus monodon)

A study on the feasibility of bi-culture of mud crab (Scylla serrata) and shrimp (Penaeus monodon) in brackishwater earthen ponds (0.1 ha each) was carried out for a period of five months (March-August). Nursed shrimp juvenile (ABL:· 3.36±0.23 em and ABW: 0.26±0.04 g) and crab juvenile (ACL: 2.61±0.22 cm, ACW: 4.63±0.11 cm and ABW: 43±2.64 g) were stocked following the experimental design of shrimp 2/m2 (Treatment-1), shrimp 2/m2 and mud crab l/m2 (Treatment-2) and shrimp 2/m2 and mud crab 0.5/m2 (Treatment-3). Crabs were fed with chopped trash tilapia @ 10~5%, while shrimp were fed with Saudi-Bangla shrimp feed @ 3~5% of biomass twice daily. Significantly (p<0.05) higher specific growth rate (SGR) of shrimp and mud crab was 1.86% (g/day) in T2 and 0.83% (g/day) in T3, respectively. The survival of shrimp and mud crab also varied significantly (p<0.05) with a higher mean value of74.63% in Tl and 51.04% in T3, respectively. The production of shrimp (424.09 kg/ha) was significantly (p<0.05) higher in Tl and that of mud crab (568.80 kg/ha) in T2. Significantly (p<0.05) highest total production of 871.29 kg!ha was in T2 followed by 708.52 kg/ha in T3 and 424.09 kg/ha in Tl. The results indicate that mud crab can be cultured at a stocking rate of 1/m2 together with shrimp at 2/m2 •

Consumption pattern and consumer preference for value-added fish and fish products in north zone of India

Present paper attempts to analyze consumption pattern and consumer preferences towards value-added fish and fish products in north zone of India. Results reveal that socio economic variables affect consumption of value-added fish and fish products. A total of 49 percent respondents were of middle age group (35 to 50 years). All were literates except 7% from the rural area. All were purchasing fish at least once in 15 days. A total of 90% respondents in rural, 11% in semi urban and 50% in urban area were unaware of value-added fish and fish products. About 10% of respondents had consumed it, out of which most were from urban area. Demand analysis by Cobb Douglas (CD) Demand function revealed that when price of fish, price of the substitutes, income of family and family size were used as independent variables, variation in demand of fish explained by CD Demand function was about 39% in urban area, 24% in semi urban area and 22% in rural area. From Garette ranking technique major problems in fish consumption found were irregular supply, lack of fresh fish, high price and presence of bones in fish. While lack of awareness, unavailability, no preference and unacceptable taste were major problems for consumption of value-added fish and fish products.

Population dynamics of a cladoceran zooplankter, Daphnia magna, in two poultry-cum-fish (duck-fish and chicken-fish) integrated ponds

The population dynamics of Daphnia magna was studied in two integrated fish-cum-poultry ponds (duck-fish and chicken-fish). The seasonal changes in the population of D. magna were recorded. Peak population of the zooplankter was recorded in the month of January in both ponds. The birth rate (b), growth rate (r) and death rate {d) of D. magna were studied in field as well as in the laboratory. Three temperatures and three different food concentrations were selected for laboratory study. The maximum values of (b) and (r) were recorded during December-January in field. Under laboratory conditions, highest birth and death rate occurred at lowest temperature (15 °C). Both food and temperature were found to affect the population dynamics of the species; longest life span and maximum population were recorded at lowest temperature and maximum food concentration.

Activation mechanism of pre-phenoloxidase in lobster and shrimp

Phenoloxidase in shrimp and lobster is shown to exist in latent form which could be activated by trypsin and by an endogenous enzyme with tryptic activity. On Sephadex G-100 gel, three isoenzymes, differing in molecular weights, were isolated from naturally activated lobster shell extracts. Mechanism of activation of ptephenoloxidase involving limited proteolysis by the activating enzyme to form isoenzymes has been proposed.

Adoption, productivity and profitability of rice-fish and fingerling culture in three selected districts of Bangladesh

The study aimed to investigate the productivity and profitability of rice-fish farming. It also determined the factors affecting rice-fish and fingerling production in Bangladesh. Among the total respondents about 55% were involved in rice-fish farming, 37% in pond fish culture and rest 9% in fish nursery. Integrated rice-fish farming contributed about 83% of the annual farm income in Comilla while it was about 20% in both Kishoregonj and Chandpur districts. Among the different farming systems integrated rice-fish culture and rearing fingerlings in the nursery pond were more profitable at the farm level. Farmers earned a net return of Tk. 49,714/ha from integrated fish culture with boro rice while the net return of boro rice-alone was only Tk. 11,179/ha. This indicated that farmer could earn 218% higher net return from integrated rice-fish farming than that of boro rice only farming. Moreover, integrated rice-fish culture also reduced pesticides cost to about 77% and weeding cost to about 51% in boro season. Fingerling nursing earned highest net returns among the three technologies.

Filleting of fish and utilization of filleting waste

A manual method of filleting of different varieties of fishes yields of skin-on and skinless fillets that can be obtained from them, levels of recovery of picked meat from the filleting waste and the utilization of the latter for the production of fish meal have been reported in this communication. The compositions of meal thus prepared are also given.

Studies on aminotransferase enzymes in fish and shellfish

The distribution of aspartate aminotransferase (AAT) and alanine aminotransferase (ALAT) activities in the skeletal muscle of several fish species is reported. AAT activity is found higher than ALAT activity and that the red muscle has higher aminotransferase activity than the white muscle. It is observed that 2-oxoglutaric acid has a wider scope as an amino group acceptor than pyruvic acid in the skeletal muscle of fish. The significance of transamination& in fish is discussed.

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.