Exploratory trawl fishing and ground fish resources along the Kerala coast and adjacent waters

The paper deals with exploratory fishing operations mainly trawling, conducted along Kerj^a Coast and adjacent waters since 1908. Early operations prior to 1950 demonstrated tlie occurrence of rich grounds for percoid fishes in the Cape Comorin area and good hand-line fkhiiig grounds off South Kerala Coast. Bull trawling in the Cannanore-Cape Comorin region by the vessels of the Deep Sea Fishing, Station of the Government of India showed that elasmobranchs and miscellaneous fish comprising small sciaenids, lizard fishes, flatheads, etc., were common for the area with a dominant catfish element in the Cannanoi«- Calicut sector, perch element south of AUeppey including Cape Comorin grounds and a transitional middle sector having a few catfishes and perches. Inshore otter trawl operations with medium-sized boats were increasingly carried out by the lndo>.Norwegian Project, Deep Sea Fishing Station and private agencies mainly centred around Coehin during; the last decade. Deep Sea Fishing Station operations in the region revealed a composition of about SO % miscellaaeous fish, 20-35% prawns, 8-14% Nemipterus japonicus, 6-14% elasmobranchs and 1-3% Laeiarius faciariiu. These operations showed the area between Calicut and Alleppey to be more productive, those off river and bar mouths yielding good quantity of prawns. The catch rate of prawns and fish increased steadily around Cochin from 1957 to 1961 and since then showed a slight decline. The picture is indicative of excessive fishing pressure over a limited area. This points to the necessity for even dispersal of fishing effort. Indo-Norwegian Project hand-line fishing operations provided considerable information regarding the 'Kalava' (Epinephelus spp.) resources of the rocky grounds on the continental shelf usually lying in 70-110 m depth zone off Kerala Coast. The occurrence of a variety of deep sea prawns, densely shoaling bathypelagic fishes like Cubiceps uatalensis, Chlorophthatmus spp., Antigonia spp., mid-water concentrations of balistids etc. have been found out along the Kerala Coast mainly by the fishing operations of the Indo-Norwegian Project. These as well as the "Kalava" resources could be better exploited with increased effort

The fishery, biology and stock assessment of jew fish resources of India

Sciaenids are one of the major component of the demersal trawl The total catch of this resource during 1990-94 period was 1.50,142 t contributing 8.86% to the demersal catch of India. A number of species are found in different states of India. Of which biological and stock assessment studies were made on eleven important species. Crustaceans and fish appear to be the chief food in Juvenile and adult stage respectively. Most of the species have a protracted spawning season. Among all the species studied the largest asymptotic length was estimated for O.ruber from Tuticorin and the smallest for J. sina from Cochin. The highest Z of 7.59 was recorded for K. axillaris from Chennai and the lowest was for O. cuvierifrom Mumbai. The average exploitation rate (E) and the Lc/ Lao was 0.62 and 0.53 respectively. The present yield is 91.222 t and the MSY is 1.42,613 t for all the species taken together. The exploitation rate for almost all the stocks in the states appears to be more than the optimum leve

Performance characteristics of positive and negative delayed feedback on chaotic dynamics of directly modulated InGaAsP semiconductor lasers

The chaotic dynamics of directly modulated semiconductor lasers with delayed optoelectronic feedback is studied numerically. The effects of positive and negative delayed optoelectronic feedback in producing chaotic outputs from such lasers with nonlinear gain reduction in its optimum value range is investigated using bifurcation diagrams. The results are confirmed by calculating the Lyapunov exponents. A negative delayed optoelectronic feedback configuration is found to be more effective in inducing chaotic dynamics to such systems with nonlinear gain reduction factor in the practical value range.Comment: 18 pages, 16 figures. To appear In Pramana - journal of physic

Total anomalous pulmonary venous drainage

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Surgical correction of anomalous pulmonary venous drainage. Mixed type-case report

This article does not have an abstract

Spectral Characterization of Laser Induced Plasma from Titanium Dioxide

Optical emission from TiO2 plasma, generated by a nanosecond laser is spectroscopically analysed. The main chemical species are identified and the spatio-temporal distribution of the plasma parameters such as electron temperature and density are characterized based on the study of spectral distribution of the line intensities and their broadening characteristics. The parameters of laser induced plasma vary quickly owing to its expansion at low background pressure and the possible deviations from local thermodynamic equilibrium conditions are tested to show its validity

Spectral Characterization of Laser Induced Plasma from Titanium Dioxide

Optical emission from TiO2 plasma, generated by a nanosecond laser is spectroscopically analysed. The main chemical species are identified and the spatio-temporal distribution of the plasma parameters such as electron temperature and density are characterized based on the study of spectral distribution of the line intensities and their broadening characteristics. The parameters of laser induced plasma vary quickly owing to its expansion at low background pressure and the possible deviations from local thermodynamic equilibrium conditions are tested to show its validity