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.

Evolution of suitable trawl nets for medium size trawlers - 1: Comparative fishing efficiency between 32 m bulged belly, long wing and four panel trawls

Comparative studies of the efficiency of 32 m bulged belly, long wing and four panel trawls have shown that the bulged belly trawl to be superior to the other nets in catching bottom fishes and column fishes. 40% of the bottom fishes and 48% of the column fishes were caught by the bulged belly trawl. However, for prawn catch, the long wing trawl appears to be better as it landed 52% of the total prawn catch of the three nets. Bulged belly trawl was found to be next only to long wing trawl in this respect.

Parallel twin-body trawl for shrimps, its design and efficiency

Comparative studies with a new 17 m parallel twin-body trawl and a 17 m bulged belly trawl conducted off Cochin during 1974-77 are reported. The parallel twin body trawl showed an increase of 28% in catch over that of bulged belly with a break up of 39.9% and 23.1 % for prawns and fishes respectively. The increase in catch is attributed to the extra wide mouth opening (26.6 %) of the parallel twin-body trawl. Parallel twin-body trawl had 8.96% lesser resistance which resulted in lower utilization of horse power.

A hierarchical approach coupled with coarse DEM information for improving the efficiency and accuracy of forest mapping over very rugged terrains

Forest mapping over mountainous terrains is difficult because of high relief Although digital elevation models (DEMs) are often useful to improve mapping accuracy, high quality DEMs are seldom available over large areas, especially in developing countries

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.

On the design, operation and efficiency of 11 m dual purpose trawl for small machanised [i.e. mechanised] boats

Preliminary midwater fishing trials were conducted off Cochin with an 11m dual purpose trawl during the monsoon months when the prawns were available in the column layers. Further, with a view to assess its suitability as bottom trawl, the gear with suitable modifications in the rigging was towed in comparison with a 15m bottom trawl along the depth ranges of 5-10m and 10-20m and the fishing operations were found satisfactory.

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.