A preliminary account of the fisheries of Vizhinjam

As a part of the research programme of the Central Marine Fisheries Research Station, it was decided in 1948 to conduct a survey of the Indian coastline to estimate the marine fish landing s,and to find out the types of fish stocks available. As very little work (Bal and Banerji, 1951) has been done in the past regarding the fishery resources of our country, a preliminary survey was found essential before embarking on the final programme. With this in view, the author conducted a preliminary survey in 1949 to ascertain the number of fishing villages, boats, nets and fishermen along the coastal strip extending from Cape Comorin in the south to Ponnani River in Malabar District in the north. Based on the data thus collected, the final design to estimate the landings was made. Initially five observation centres, Blangad in South Malabar, Narakkal and Malippuram in Trichur District, Wadi in Quilon District, and Vizhingam in Trivandrum District, of the erstwhile Travancore-Cochin State, were selected. Regular observations were taken at these centres in 1950. From 1951 onwards observations were restricted to two centres, Narakkal and Vizhingam, and from January 1953 to August 1954 observations were confined to Vizhingam alone. From September 1954 onwards two more centres. Cape Comorin and Wadi, were also included for the estimation of fish landings. As Vizhingam is a very important fishing centre, and as data for five consecutive years were available it was decided to embody the observations in the present paper as suggested by Dr. N. K. Panikkar, the then Chief Research Officer, Central Marine Fisheries Research Station, Mandapam Camp

Pearl and Chank Fisheries - A New Outlook in Survey and Fishing

The Gulf of Mannar and the Palk Bay Zones of the east coast of the Madras state, particularly the area from Rameshwaram to Manapad, are of very great fishing importance as far as the pearl and chank fisheries are concerned. The submarine plateau of the inshore areas of the sea here affords excellent habitat for the growth of the shell fish, Xnrcvs pyrum (Linn.) (the sacred chank) and Pivcunla jucaia (Gould) (the pearl oyster). Chank fishing and pearl fishing in this zone had been conducted from time immemorial under the control of the State. All along the stretch of the sea-bottom, extensive, flat rocky patches occur at a distance of 8-12 miles from the shore within 7-12 fathoms, separated from one another and surrounded by equally extensive patches of fine sandy areas at the same or slightly deeper zones. Whereas the chanks prefer fine and soft sandy areas called locally 'Poochi-manal' or 'pirals' as their abode, the oysters are sedentary and are attached to hard rocky substrata called'Pa ar'. Occasionally tfe one is found in the natural habitat of the other. There are more than 65 well known'Paars' (rocky sea-bottom) and lesser in number of good chank grounds in the Gulf of Mannar known to fisherman by their depth and location fixed by land bearings. The sea bottrm on Palk Bay side is not rocky, at the same time less shallow also. The chanks rrowing in this zone are classified as 'Patti' variety which is priced less than the 'Jadhi' variety fished from Rameshwaram to Tiruchendur. The differentiation between these two lie in the latter being elongate, elegantly formed, comparatively narrower and with well balanced spire whereas the former is with a short spire. The Tirunelveli and Ramanathapuram chanks now constitute the bulk to meet the demand from Bengal for chank bangle industry

AirCode: Unobtrusive Physical Tags for Digital Fabrication

We present AirCode, a technique that allows the user to tag physically fabricated objects with given information. An AirCode tag consists of a group of carefully designed air pockets placed beneath the object surface. These air pockets are easily produced during the fabrication process of the object, without any additional material or postprocessing. Meanwhile, the air pockets affect only the scattering light transport under the surface, and thus are hard to notice to our naked eyes. But, by using a computational imaging method, the tags become detectable. We present a tool that automates the design of air pockets for the user to encode information. AirCode system also allows the user to retrieve the information from captured images via a robust decoding algorithm. We demonstrate our tagging technique with applications for metadata embedding, robotic grasping, as well as conveying object affordances.Comment: ACM UIST 2017 Technical Paper

Free diving in Indian waters

The story of man's adventure into the sea and his dreams of exploring the underwater world is as old as time itself and a glance through the pages of history will show the various attempts made by him to surmount the difficulties in remaining under water for considerable periods

Oyster culture- Status and prospects

Most scientific studies on oyster resources, biology and farming have been carried out in the twentieth century. New approaches to our understanding of the intricate pattern of the oyster behaviour in respect of feeding, reproduction, larval development and disease control have enabled scientists to plan and undertake highly successful oyster farming in recent years. This is not only the situation in advanced countries but has become a distinct possibility in India. Scientists of the Central Marine Fisheries Research Institute have achieved remarkable success by carrying out extensive investigations relating to the breeding and farming of the edible oyster during the past one decade. In addition to the evaluation of the potentialities of natural resources in several zones of Indian coastal waters, estuaries and backwaters, suitable technologies for oyster farming and hatchery production of oyster seed have been developed by the CMFRI. It would only be a matter of time before commercial farming of the edible oyster takes place in the country

Oyster farming

Large quantities of the edible oyster, Crassostrea madrasensis (Fig. 1) growing wildly in most of the tidal creeks and estuarine regions along the east coast of India, are allowed to perish un-exploring the great strides made in this venture by developed nations. The Central Marine Fisheries Research Institute focused its attention in developing systems for the culture of edible bivalves, identifying edible oyster farming and mussel farming as priority areas for Research and Development. Evaluation of the resources potential, identification of suitable water spread and areas for culture, evolving proper techniques to collect required seed for farming, introducing an appropriate method of farming and establishing a model farm formed the broad objectives of the project initiated in 1975 on edible oyster culture. By employing suitable method for spat collection and providing better growing conditions for the seed so collected it appeared distinctly possible to raise large number of oysters achieving faster growth rate and better meat yield. Weighing the pros and cons of the different systems of oyster culture followed in other countries and bearing in mind the local conditions, it was decided to experiment with the 'rack' system of culture

Pearl culture

Most scientific studies on oyster resources, biology and farming have been carried out in the twentieth century. New approaches to our understanding of the intricate pattern of the oyster behaviour in respect of feeding, reproduction, larval development and disease control have enabled scientists to plan and undertake highly successful oyster farming in recent years. This is not only the situation in advanced countries but has become a distinct possibility in India. Scientists of the Central Marine Fisheries Research Institute have achieved remarkable success by carrying out extensive investigations relating to the breeding and farming of the edible oyster during the past one decade. In addition to the evaluation of the potentialities of natural resources in several zones of Indian coastal waters, estuaries and backwaters, suitable technologies for oyster farming and hatchery production of oyster seed have been developed by the CMFRI. It would only be a matter of time before commercial farming of the edible oyster takes place in the country

Studies on Raschel knotless netting

Production of knotless webbings is of recent origin in India. An attempt has been made to evaluate the quality of the product consequent to its introduction in the fishing industry. A method has been presented to fix up yarn specification for Raschel knotless nettings equivalent to a given knotted netting

Underwater ecological observations in the Gulf of Mannar, off Tuticorin-II. The Occurrence of the Synaptid Chondrocloea along with the Massive Sponge, Petrosia

In this paper an interesting instance of association between a sponge and a synaptid, which was observed during the course of our underwater dives with SCUBA is recorded. The rocky patches of the sea bottom off Tuticorin exhibited certain sharacteristic fauna depending on the depth and locality. For instance, the shorepvard rocky floor in the 10-13 metre range was characterized by, amongst other things, the small and medium sized sponges firmly attached to the substratum and Ivas conspicuous by the absence of the massive sponge of the genus Petrosla