Column set gill net fishing in Gobindsagar reservoir

Previous authors observed the influence of temperature variations in movement of fishes and noticed better catches in bottom set nets during summer in Tungabhadra reservoir. The present account reports on similar observations in Gobindsagar reservoir.

A note on the comparative catch efficiency of nylon over cotton gill nets in reservoir fishing

The authors conducted a series of experiments to evaluate the relative efficiency of nylon over cotton in tropical waters, particularly in reservoir fishing. The experiments were conducted in the Gobindsagar reservoir (Himachal Pradesh/Punjab). The nets made with both materials were identical in essential details like twine size, mesh size, number of floats arid sinkers and hanging coefficients.

Technological aspects of preservation and processing of edible shell fishes IV. Comparative efficiency of different glazes in the preservation of frozen crab meat

The present work was undertaken to enlighten upon the comparative efficiency of different glazes in improving the quality of frozen crab meat (Scylla Serrata).

On the comparative efficiency of trawls made of cotton, polyethylene and combination of both the materials

The merits and demerits of cotton, polyethylene and combination of the two materials ascertained on the basis of cost, wear and tear, maintenance, total catch and qualitative analysis of the catch are discussed by making comparative fishing experiments with the three trawl gears made of these materials. The study can be concluded with a suggestion for switching over to polyethylene twisted monofilaments for better, in case of bottom trawls without in any way adversely affecting the catch of shrimps and at the same time for enhanced fish catch. Even though the combination net is found to be equal in efficiency as the polyethylene net this idea cannot be conveniently adopted from the point of view of economy.

Catch efficiency and selective action of coloured gill nets

Information on the catch efficiency and selective action of coloured gill nets in relation to the reservoir fishes of India are lacking. Authors, in the present studies have attempted to evaluate the comparative catch efficiency of gill nets of four shades viz. yellow, orange, green and blue over the colourless ones, by conducting fishing experiments, in the Govindsagar reservoir. Attempts have also been made to study the preference shown to colours by the four major species of fishes of the reservoir.

Comparative efficiency of frame nets and trammel nets

Fishing experiments were conducted simultaneously with frame nets and trammel nets in the Hirakud Reservoir and the results indicated the relative superiority of frame nets, whose catch rate was two times more than that of the trammel nets.

Comparative efficiency of trawls made of nylon, polyethylene monofilament and tape twines

Results of comparative fishing operations conducted with three nets of identical design made of nylon, twisted polyethylene monofilament and high density polyethylene (HDPE) tape twines are presented in this communication. Since the tape net recorded the highest prawn and fish catch, monofilament and nylon following in order, it can be recommended to the fishing industry as one of the cheapest and effective fishing materials evolved for trawl fabrication.

Double-rig shrimp trawling, its rigging, comparative efficiency and economics

A radical and revolutionary change from the hitherto employed shrimp trawling is reported for better productivity and economy in deep sea trawling with medium and large vessels. Studies carried out off Veraval with a 13.7 m. four seam shrimp trawl as conventional single-rig and two 6.8 m four seam shrimp trawls as double-rig from a 15.2 m fishing vessel showed an increase of 98% shrimp catch by double-rig over single-rig at 86.3 % of the power utilised by the latter. It has also been worked out, theoretically, how better this available power can be utilised for further improvement of catch. An increase of 15% head rope length in case of double-rig over the optimum single-rig gear of any vessel is recommended.

One-boat midwater trawling with unequal panelled trawl

Results of the comparative efficiency studies with 10.5 m equal panelled and 10.3 m unequal panelled midwater trawls operated from 10.9 m wooden trawler are presented. Out of the two nets, the latter proved to be relatively good for the capture of off bottom and column fishes like pomfrets, seer, lactarius, catfish, silver bar, ribbon fish and an increase of 84.4% in total catch was observed.

The effect of increase in the number of fishing trips on the economic efficiency of 9.82 m and 11 m fishing trawlers along Kerala coast

Cost-benefit analysis of a 9.82 m and 11 m fishing trawlers based on the number of fishing trips is presented. The number of fishing trips per year determines the profit and loss of the trawler. With the increase in the number of fishing trips, the profit also increase for both the sizes of trawlers. The minimum quantity of prawn and fish to be landed for 0-20% profit for varying number of fishing trips are worked out. The break-even for 9.82 and 11m trawlers was observed to be 185 and 210 fishing trips respectively during 1980-81.

Studies on the effect of colour of webbing on the efficiency of gill nets for hilsa and pomfret off Veraval

Influence of colour of webbing on the catch of gill nets for commercially important hilsa (Hilsa toli and Hilsa ilisha) and pomfret (Pampus argenteus and Parastromateus niger) has been studied in the coastal waters off Veraval. Among the colours tested yellow and white are recommended for hilsa and pomfret gear. Influence of fishing depth, surface water temperature and turbidity on catch are also discussed.

On the problem of nonadditivity in two-way analysis of variance of data for comparing the efficiency of fishing gears

To bring out the relative efficiency of various types of fishing gears, in the analysis of catch data, a combination of Tukey's test, consequent transformation and graphical analysis for outlier elimination has been introduced, which can be advantageously used for applying ANOVA techniques, Application of these procedures to actual sets of data showed that nonadditivity in the data was caused by either the presence of outliers, or the absence of a suitable transformation or both. As a corollary, the concurrent model: X sub(ij) = µ + α sub(i) + β sub(j) + λ α sub(i) β sub(j) + E sub(ij) adequately fits the data.

On the comparative efficiency of "V" shaped and rectangular flat otter boards for trawling off Veraval, north west coast of India

V shaped all steel boards, with their inherent stability to tide over obstacles and mud, interchangeability of starboard and portside boards are found to be superior to conventional flat rectangular boards for bottom trawling. These are cheaper in construction, offer less resistance and give longer service. Comparative trials with the two types of boards showed significant difference in tension between the boards but not in catch or horizontal opening.

Effect of hanging coefficient on the efficiency of frame net

Comparative fishing experiments with frame nets of 0.4 and 0.5 hanging coefficients were conducted. Results indicate that net with hanging coefficient of 0.4 as more effective for better catch.

Efficiency of two designs of trawls in Hirakud Reservoir

High opening trawl was found to be effective for the exploitation of bottom and off bottom fishes from Hirakud reservoir compared to bulged belly trawl.