Experiments on preservation and weathering of net twines

Koura (1963) reporting the results of the comparative studies on different preservation methods of cotton twines stated that "by the difference of rotting in the different waters, not ever one method may be the most economical one". The observations were simultaneously made at Alexandria in Egypt in the sub-tropical region and Cuxhaven in the estuary of the River Elbe in the temperate zone. The course of weathering and effect of immersion in water of man-made fibres have also been mentioned in this communication. Subsequently work on similar lines were extended to Cochin in the tropical region with Cuxhaven and Hamburg as the other places of observation and the results of these studies are presented in this paper.

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.

Tensile strength properties of polyethylene netting twines under exposure to out-door and artificial UV radiation

Photodegradation of three types of polyethylene twines namely, polyethylene fibrillated tape twine, polyethylene flat tape twine and polyethylene monofilament twines were studied by exposing them to sunlight and artificial UV radiation. The percentage residual strength varied in the samples, the monofilament with the highest residual strength followed by fibrillated tape twine and flat tape twine. A plot of the difference between the breaking strengths of the fibrillated tape twine and the mono filament twines against any given period of exposure exhibited a linear relationship

Marketing of fishing gear materials and fishing gear making in parts of Kainji Lake basin

The importance of fishing gear in fishing cannot be over-emphasized; as without it fish cannot be obtained. The method used to catch fish affects the condition in which the product is landed. This means that a bad-catching method would produced bad fish to the consumer. To achieve the goal of self-sufficiency in fish production in Nigeria, there is need to address the lingering problems of fishing gear and craft technology, especially in terms of availability of materials and their cost. The sale and making of fishing gear materials are two areas of fisheries, which are yet to be exploited by the general public as forms of businesses for livelihood. The study is conducted in villages around the lower part of Kainji Lake, towards the dam, including New Bussa. It reveals that only the fishermen themselves are involved in making their own fishing gears while those involved in the selling of fishing gear materials like the sheet netting, ropes, twines, floats, sinkers etc are business men and women who may not have any experience of fishing. Also considered in the study is the art of making fishing crafts like the canoe and gourd. Very few entrepreneurs are involved and they are so skilled that each is specialized in the making of only one kind of craft or gear

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.

Preservation of cotton fish net twines by tanning 1. Optimum concentration of tanning

Samples of tannin-containing preservatives used by fishermen in India for treating cotton nets were collected and qualitative and quantitative characterisation of the tannins made. The concentrations of different tannins required to impart optimum periods of preservation to the net were worked out and found to be 2% in 8 out of 10 materials studied.

Preservation of cotton fish net twines by tanning 2. Fixation of tannin

Fixative behaviour of tannin belonging to three functional groups was stud1ed m deta1l using copper sulphate and potassium dichromate as oxidising agents.