Biodeterioration of cellulose materials in Karingote, Nileswaram, Kavvayi and Ramapuram Backwater systems of Kerala

The hydrographic conditions prevailing in an estuarine system along the southwest coast of India are described. The nature of destruction of timber in these backwaters has been examined in detail which revealed the existence of 8 species of shipworms, 2 species each of pholads and isopods. The shipworms are represented by Dicyathifer manni, Lyrodus pedicellatus, Teredo furcifera, T. clappi, Nausitora dunlopei, Bankia carinata, B. campanellata; the pholads by Martesia striata and M. (Purticoma) nairi; and the isopods by Sphaeroma terebrans and S. annandalei. The incidence and relative abundance of these pests are discussed in relation to the salinity profile of the estuary.

Technical terms in fishing gear materials and gear fabrication

Papers dealing with technical terms in fisheries science are few. This paper however, covers only one or two aspects of the subject, namely fishing gear materials and fishing gear fabrication. Similar papers on other aspects are also planned. Short explanations or descriptions are also given wherever considered necessary.

A survey of process hygiene in the Sri Lankan prawn industry. 1. Hygiene status of raw materials and products

A survey of processing hygiene in the Sri Lankan prawn industry has shown that the incoming raw material has extremely high bacterial loadings; about 50% of samples analysed had a total count in excess of 10,000,000/g. Although beheading reduces the count, ineffective temperature control during processing means that the final total count of raw, shell-on, P.U.D. and P.A.D. prawns, as well as cooked prawns, is in excess of 1,000,000/g. - the maximum level specified by many importing countries.

Investigations on wooden floating materials: the loss of buoyancy under continuous immersion in water and the rate of its redemption by drying

A wooden fishing float under immersion in water for long periods is liable to absorb water, the quantity of water absorbed possibly being dependent upon the physical factors like the specific gravity and the inherent property of the material, the time of soaking and the pressure acting on it. Consequently a wooden float is likely to become heavy and loss its original buoyancy. However, when the float is removed from water and dried, the lost buoyancy is regained on complete drying. The present paper is an attempt to elucidate these two important characteristics of some of the chief wooden floating materials used on the West Coast of India.

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.

A wider choice of construction materials for the modern fishing boats

An account of fishing vessel construction materials is given, with information on essential features, and a material account. Materials discussed in detail are steel, wood, aluminium, glass reinforced plastic, and ferro-cement.

Selection of materials for marine instruments

The paper describes the selection of materials for the reliable operation of oceanographic instruments. For selecting the material, raft immersion tests were carried out for one year. Results of the tests are presented. Comparisons between metals were discussed.