Experimental formulation of an anti fouling paint with tributyl tin oxide as toxic pigment

Results of the experimental formulation of an antifouling paint incorporating TBTO as toxic pigment are presented in this paper. Of the various resins tested, namely, phenolic, cashew nut shell liquid (CNSL), epoxy linseed oil with rosin and limed rosin, the paint composition with limed rosin gave the critical leaching rate of TBTO. Acid alkali test showed dissolution of matrix and visible migration of toxin to the surface. Accelerated corrosion tests had not recorded any signs of corrosion in panels painted with or without barrier coat. Raft exposure studies indicated that the new formulation could resist fouling accumulation on painted panels for 9 months

Satellite based potential fishing zone (PFZ) advisories - acceptance levels and benefits derived by the user community along the Kerala coast

Intensive validation studies of potential fishing zone (PFZ) advisories generated using integration of ocean colour monitor (OCM) derived chlorophyll concentration and advanced very high resolution radiometer (AVHRR) derived sea surface temperatures (SST) were undertaken by the Indian National Centre for Ocean Information Services (INCOIS) along Kerala coast during the period 2003-2011. There is a positive relationship between PFZ advisories and occurrence/abundance of commercially important pelagic fishes such as oilsardine, Indian mackerel, anchovies, carangids and coastal tunas. Fishing operations undertaken on or closer to dates on which related SST/chlorophyll images have been received yielded positive results. As the gap increases, the yield within PFZ is likely to come down unless the features remain more or less in the same location as revealed by succeeding satellite imagery. The present paper revealed that the fish catch (CPUE) and net profit earned are higher within PFZ compared to the results of operations outside PFZ. The usefulness of PFZ advisories, the only short term marine fishery forecast available in the country for fisherfolk towards obtaining comparatively higher catch per unit effort for the above mentioned major pelagics is proved beyond doubt from the results of more than 100 controlled experiments conducted within and outside PFZ with identical fishing gear along Kerala coast

Mixed farming or polyculture

In Kerala, nearly 75-80% of the population consume fish and their annual per capita consumption rate is about 13 kg. The rate of fish consumption is likely to go up due to increased awareness about fish as a source of cheap and highly nutritious but harmless food item. Hence there is every need to augment fish production not only to meet our food requirements but also to increase foreign exchange earnings. The current level of fish production is inadequate to fulfil all these needs. An analysis of the trend of fish production during the past few years indicates that there may not be any significant improvement in it in the coming years. In this context, measures to increase fish production are to be thought of Aquaculture is the only way to achieve this. In Kerala at present aquaculture is restricted to backwaters and inland waterbodies. In order to enhance fish production, farming of fish and other species of aquatic organisms is to be extended to inshore coastal waters for which suitable farming methods are to be adopted

Studies on the influence of moisture and specific gravity on the strength properties of mango wood (Mangifera indica)

Influence of moisture and specific gravity on the strength of mango wood is discussed. The co-efficient of correlation between specific gravity and breaking strength was found to be non-significant. The relation of strength and moisture was found to be highly significant. The mean strength values indicated a reduction in strength when the moisture increased from 8.5 to 18.8%. However no appreciable difference in strength values could be observed when moisture increased above 37%. The strength-moisture relationship is a straight line, passing approximately through the fibre saturation point. By using the exponential formula, the breaking strength corresponding to any moisture level between zero and fibre saturation can be determined

സമ്മിശ്ര മത്സ്യകൃഷി (Mixed farming or Polyculture)

The rate of fish consumption is likely to go up due to increased awareness about fish as a source of cheap and highly nutritious but harmless food item. Hence there is every need to augment fish production not only to meet our food requirements but also to increase foreign exchange earnings. The current level of fish production is inadequate to fulfil all these needs. An analysis of the trend of fish production during the past few years indicates that there may not be any significant improvement in it in the coming years. In this context, measures to increase fish production are to be thought of Aquaculture is the only way to achieve this. In Kerala at present aquaculture is restricted to backwaters and inland waterbodies. In order to enhance fish production, farming of fish and other species of aquatic organisms is to be extended to inshore coastal waters for which suitable farming methods are to be adopted

Broodstock development and spawning in Penaeus indicus

Among cultivable native species, Penaeus indicus occupies an important position due to its tolerance to wide range of salinity, fast growtK compatibility in high density culture, wide distribution and demand in export market. P. indicus broodstock can be developed using adults collected from the wild or from grow out ponds or by reusing healthy females after spawning in the hatchery. The size of prawn used for broodstock development should preferably be above 145 mmT.L. (20 g) for females and 140 mm T.L. (17 g)for males. Pens, cages, tanks with or without flow through system, recirculation system etc. are in vogue for broodstock development. 1001 tanks with in situ biological filter is used for the brood stock development in CMFRI. Stocking density of prawns per cubic meter (sex ratio I : Ij was found ideal. Three tanks of the above size can meet the broodstock requirements of a hatchery of 18 million capacity. Unilateral eyestalk ablation of females proved to be effective. Electrocautery apparatus was usedfor this purpose. Experiments also revealed that unablated P. indicus, can also be induced to mature and spawn by environmental and feed manipulation. Unablated P. indicus maintained in recirculation system and fed with intertidal oligochaetes, clam and squid meat attained maturity and spawned repeatedly over a prolonged period. Maintaining the pH of water between 8-8.2 and controlling the light intensity in broodstock tanks found to fasten maturation

On the importance of ship-bottom fouling by marine organisms: a techno-economic survey

A high attention has been paid for constant research on the preservation of materials in the marine environment. This includes all phases of design, development, applied engineering and economics which may influence the construction and operation of ships and underwater installations

Length-weight relationship and relative condition factor of Stolephorus commersonii (Lacepede, 1803) exploited along Kerala coast

The length-weight relationship and relative condition factor of Stolephorus commersonii was calculated to assess the significance of allometric factor and the well being. The study was carried out by using the data collected from ring seine and purse seine catches during the year 2010-2011. The length of species in catches ranged from 5 to 14.6 cm with a mean length of 9.24 ± 1.83 cm and the weight ranged from 1 to 25g with an average weight of 6.64 ± 3.96 g. Length-weight relationship calculated for male, female and pooled are W = 0.0070 L3.02, W = 0. 00756 L2.99 and W = 0. 0073 L3.006 respectively. The relative condition factor (Kn) estimated separately for male and female showed monthly fluctuation. The highest Kn values were observed in February and August and the lowest in June for both the sexes