Observations on changes in the major protein nitrogen fraction of prawns and sardines during ice storage

Changes in the major protein nitrogen fractions (sarcoplasmic, myofibrillar, stroma) have been studied in two species of prawns and in oil sardine held in ice storage. Myofibrillar proteins were observed to get denatured at a rapid rate as determined by salt extractability method. The sarcoplasmic proteins were not denatured to any considerable extent. With sardine however, the extraction of myofibrillar proteins was inhibited rather in the uniced condition itself presumably owing to the presence of free fatty acids.

Preliminary observations on the effect of electrical seine on fish catch

Forty-six experiments were done with the electric seine in 24 tanks with a.c. and interrupted a.c. The source of electrical energy was a 3 Kw a.c. generator of water-cooled diesel engine. A control seining without applying electricity was conducted for every experiment with electric "seine" to have a comparison for the efficiency of electric "seine" over control ones. Electric seine was found to have an increased catch over control seining both in numbers and in weight. Electric seine with two electrodes was found to have better effect over three electrodes. Benthic fishes like Cirrhina mrigala, Notopterus notopterus, Cyprinus carpio, Glassogobius giuris, Ophicephalus sp. and Mystus sp. were found to be more sensitive in electric "seine". Increased catch of small fishes like C. mrigala, N, notopterus and Ophicephalus sp. has been observed in electrical "seine" in addition to larger ones.

Some observations on the performance of 10.5 m mid-water trawl operated off Veraval

The communication presents the results of fishing trials conducted off Veraval with a 10.5 m four-seam unequal paneled mid-water trawl with vertically curved otter boards. The design and structural details of net and otter boards are described in detail. Particulars such as the fish caught during experimentation, horizontal spread of the net as well as towing resistance offered in action are also incorporated.

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.

Ice storage characteristics of fresh and brined shark fillets

Ice storage characteristics of fresh and brined fillets from fresh shark (Carcharias melanopterus) were studied in and out of contact with ice for more than two weeks. Changes occurring in biochemical constituents, physical qualities and bacterial counts of the fillets are reported. Shelf life of brined fillets out of contact with ice was considerably longer than that of control samples tinder similar conditions. Icing of shark fillets is suggested as a method for the removal of urea on a commercial scale.

Further investigations on the relative efficiency of different shaped otter boards

Horizontal curved, vertical curved and V-shaped otter boards were studied to compare their relative efficiency under identical fishing conditions. The gear operated with V-shaped otter boards performed well followed by the gear fitted with horizontal curved boards. Vertical curved boards were found to be comparatively less efficient, but with slight modification, can be used advantageously for bottom and off bottom fishes. Fishing at various depths with horizontal curved and V-shaped otter boards at different scope ratios showed better performance of horizontal curved boards at a scope ratio of 1:6 and V-shaped otter boards at a scope ratio of 1:5.

Preservation of Bombay duck (Harpodon nehereus) and Rohu (Labeo rohita) by gamma irradiation

The gamma irradiation procedures for preservation of Bombay duck and rohu were studied in collaboration with Bhabha Atomic Research Centre, Bombay. Irradiation at 0.1 M rad extended the storage life of Bombay duck to 20-22 days at 0-2°C due to partial destruction of spoilage organisms as against rapid deterioration of un-irradiated samples within 5-6 days. In the case of the fresh water fish, rohu, the storage life was enhanced by about 7-10 days by the same dose of irradiation over the control under identical storage condition. In all the cases, empirical relations were worked out between organoleptic rating and total volatile nitrogen.

Canning of smoked dhoma (Sciaenid sp.)

A process for the preparation of a wholesome smoked and canned product from dhoma (Sciaenid sp.) is discussed. The dressed dhoma is cold blanched in 15% brine containing 0.5% potash alum and 0.2% citric acid and smoked for 120 minutes at 45 ± 5°C. The smoked fish after filling in cans is precooked at 0.35 kg/sq.cm steam pressure for 50 minutes in inverted position, filled with hot refined groundnut oil, sealed and processed for 60 minutes at 0.7 kg/sq.cm steam pressure.

Investigations on long distance transportation of fish. 3. Field trials with a dismantlable insulated galvanised iron container

The paper communicates the results of field trials conducted with a dismantlable insulated galvanised iron container designed and fabricated by the first two authors in their laboratory. Different varieties of fishes and different types of packing, namely, fresh iced, chilled iced and frozen were employed in the transportation experiments which were conducted from Kakinada to Howrah, Kakinada to New Delhi and Paradeep to Howrah. In all the experiments the container performed exceedingly well and has still remained in very trim condition.

On the trend of prawn catch off Paradeep

The distribution and landings of important varieties of prawns off Paradeep coast, Orissa, in relation to the climatic and hydrographic conditions from 1970-1976 are presented. The prawn fishery as a whole, showed a quadrennial cycle along the coast. The post-monsoon migration of all varieties of prawns along the coast directly depends on the annual precipitation. Temperature gradient, fluctuations in salinity and southerly wind in the Bay of Bengal influence the migration of the different species of prawns.

Enteropathogenic E. coli and other coliforms in marine fish

One hundred and twenty six samples of marine fish (96 from landing centre and 30 from retail market) and swabs from deck surfaces of 34 fishing boats were examined for coliforms including enteropathogenic E. Coli. Forty out of 96 fish samples from landing centre, 24 out of 30 from retail market and 11 out of 34 fishing boats revealed coliforms. On further tests, 5, 7 and 4 coliform isolates from the three groups respectively were found to be E. coli. Two of the E. coli. isolated, one from sciaenids and one from cat fish, were found to be enteropathogenic serotypes 055 and 0111. Enteropathogenic serotypes of E. coli are reported from sciaenids and cat fish for the first time in this country.

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.

Some biochemical constituents and the calorific values of different regions of the body musculature of pond murrel Channa punctatus Bloch

A study of the distribution of some chemical constituents in the musculature of Channa punctatus Bloch showed it to be fairly heterogeneous. The increase in the levels of protein, fat, ash, total carbohydrates, glycogen, RNA, DNA and cholesterol towards the posterior region of the fillet was the result of increase in the number of cells per unit weight of the sample and in the concentration of myocommata. The distribution of water in the musculature was inversely related to that of the fat. The concentration of protein appeared to be associated with the RNA level. The posterior region of the fillet exhibited more calorific value than the anterior region.

Selectivity of gill nets for Hilsa toli and Pampus argentus

Fishing conducted off Saurashtra coast during 1971-74 with 27 units of nylon gill nets using 210/2/3, 210/3/3 and 210/4/3 twines with 51, 57 and 63 mm bar mesh and 0.70, 0 60 and 0.50 hanging coefficients have helped in standardizing an optimum gear for exploitation of commercial size group of Hilsa toli and Pampus argenteus. Gill nets of 210/2/3 with 51 mm bar mesh and 0.60 hanging coefficient for Hilsa toli and 210/2/3 with 63 mm bar and 0.60 hanging coefficient for Pampus argenteus are recommended for the commercial exploitation of these two species of fishes.

Portable electronic warp load meter

A portable type warp load meter has been developed for the use in fishing trawlers. The instrument enables to monitor the warp load in fishing trawlers accurately and easily without disturbing the routine fishing operations. The instrument can be used in several other places like cranes, bollard tests for marine engines, dry docks etc. especially when the operation has to be conducted easily without disturbing the load system. The information displayed in micro ammeter in the range 0 to 1000 kg can be fed to continuous recorders for detailed analysis and permanent records.