Age and growth of Lactarius lactarius (Bloch & Schneider, 1801) from Karnataka, south-west coast of India

Age and growth of Lactarius lactarius was studied separately for males and females from the Karnataka coast using monthly length composition data collected from three major fish landing centres viz., Mangalore, Malpe and Karwar. The growth of L. lactarius was studied from length frequency data by ELEFAN I programme, and also by modal progression analysis using Gulland and Holt (1959) model after separating the modes using Bhattacharya (1967) method. The growth parameters estimated for males were: Lα = 240 mm, K = 1.01yr-1 and t0 = -0.0151; for females: Lα = 285 mm, K = 0.91 yr-1 and t0 = -0.0183 and for unsexed fishes (juveniles, males and females pooled) were: Lα = 294 mm, K = 0.84 yr-1 and t0 = -0.0215. The recruitment pattern showed two recruitment pulses every year, the major one during March and the minor one during June-August. The von Bertalanffy growth formula fitted to L. lactarius indicated the fish to attain a length of 168 mm at the end of 1 year, 240 mm at the end of 2 years and 271 mm at the end of 3 years of its life. The estimated life span appears to be 3.57 years

Studies on the Age, Growth and Mortality Rates of Indian Oil Sardine, Sardinella longiceps Valenciennes, 1847 off Oman Sea, Muscat, Sultanate of Oman

Investigations have been carried out on the age, growth and mortality of sardine Sardinella longiceps based on the length frequency data. The hypothetical asymptotic length (L∞) and growth coefficient (K) were estimated as 220.3 mm and 1.209 yr-1 respectively. The species grows from 155 and 200 mm at the end of 1 and 2 years of life. The life span appeared to be around 2 years of species life. The total (Z), natural (M) and fishing (F) mortalities were represented as 4.11 yr-1, 2.21 yr-1 and 1.91 yr-1 respectively. The exploitation rate (E) was 0.46. The exploitation rate suggested that the stock was below the optimum level of exploitation. As a management plan, there is a need to increase the fishing scale and protecting spawning season to maintain sustainability over time. Keywords: The Hypothetical Asymptotic Length; Growth Coefficient; Mortalities; Exploitation Rate; Sustainability

Catches of mechanised boats at Madras in 1971-72

Fish catches by the mechanised vessels operated at Madras were estimated for the years 1971-72. The fishery, species composition and seasonal fluctuation in these tw

Catch trend of the commercial trawl fisheries of Rameswaram

The present report summarises the catch details of some of the commercially important fishes landed by the trawlers operating from Rameswaram during the years 1980 and 1981. The silverbellies, formed the major group, indicating the availability of silverbellies in large quantities throughout the year, followed by Elasmobranchs and Penaeid prawns in the landings. Quarterrwise landings of trawlnets and monthwise landings of prawns and other groups were portrayed

Maturation and spawning of the whitefish, Lactarius lactarius (Bloch and Schneider, 1801) (Family Lactariidae) along the Karnataka coast, India

Maturation and spawning of the whitefish, Lactarius lactarius was studied by collecting samples from Mangalore, Malpe and Karwar landing centres. Monthly Gonado-Somatic Index values of males and females were found to increase from August and reach the highest in February indicating breeding activities. The Kn values showed an increasing trend from October reaching a minor peak in February which coincides with the peak spawning.. Higher percentage of fully mature testes and ovaries occurred during November-April indicating peak spawning activities. Kn values were the lowest in the length group 130-139 mm for both males and females. Length at first maturity was determined as 131 mm for males and 133 mm females. Sex ratio indicates dominance of males up to 155 mm and females were present above 215 mm only. Fecundity varied from 7,042 to 53,275 eggs. Relationship of fecundity to ovary weight, body weight and total length exhibited a linear trend

Risk prediction in life insurance industry using supervised learning algorithms

Risk assessment is a crucial element in the life insurance business to classify the applicants. Companies perform underwriting process to make decisions on applications and to price policies accordingly. With the increase in the amount of data and advances in data analytics, the underwriting process can be automated for faster processing of applications. This research aims at providing solutions to enhance risk assessment among life insurance firms using predictive analytics. The real world dataset with over hundred attributes (anonymized) has been used to conduct the analysis. The dimensionality reduction has been performed to choose prominent attributes that can improve the prediction power of the models. The data dimension has been reduced by feature selection techniques and feature extraction namely, Correlation-Based Feature Selection (CFS) and Principal Components Analysis (PCA). Machine learning algorithms, namely Multiple Linear Regression, Artificial Neural Network, REPTree and Random Tree classifiers were implemented on the dataset to predict the risk level of applicants.Findings revealed that REPTree algorithm showed the highest performance with the lowest mean absolute error (MAE) value of 1.5285 and lowest root-mean-squared error (RMSE) value of 2.027 for the CFS method, whereas Multiple Linear Regression showed the best performance for the PCA with the lowest MAE and RMSE values of 1.6396 and 2.0659, respectively, as compared to the other models

ENHANCED PRODUCTION OF PSORALEN THROUGH ELICITORS TREATMENT IN ADVENTITIOUS ROOT CULTURE OF PSORALEA CORYLIFOLIA L.

Objective: The present study aimed to determine the effect of two elicitors namely Methyl Jasmonate (MeJ) and Salicylic acid (SA) on adventitious root production of Psoralea corylifolia L. as the elicitors and at different concentrations.Methods: Adventitious roots of P. corylifolia L. were treated with different concentration of elicitors such as MeJ (10, 20, 30 and 40 µM/l) and SA (50, 100, 150 and 200 µM/l) to enhance the psoralen contents. After the treatment, psoralen content was analyzed through the analytical HPLC experiments (Methanol: Water (50:50) at 0.8 ml/min-1 flow rate and the injection volume as 20 µl).Results: MeJ and SA treatments at the concentrations of 30 µM/l and 150 µM/l respectively were found to increase the net wet weight of adventitious root production to 8 fold at 8 hours of elicitor treatment periods. Further, the quantity of psoralen was determined from the elicitors (MeJ and SA) treated roots and mother plant through the analytical HPLC experiments in order to estimate the psoralen content and it was found as 3.73 mg/ml, 0.015 mg/ml and 0.56 mg/ml respectively.Conclusion: In the present study we achieved enhanced production of psoralen through abiotic elicitors (MeJ and SA) treatment and concluded that the MeJ at 30 µM/l concentration shows significant enhancement of psoralen production.Â

Dorab fishery of Gulf of Mannar waters and population characteristics of the species Chirocentrus dorab (Forsskal, 1775) and Chirocentrus nudus Swainson, 1839

Dorab (wolf-herrings) fishery of Gulf of Mannar and species diversity, biology as well as population characteristics of the species, Chirocentrus dorab (Forsskal, 1775) and Chirocentrus nudus Swainson, 1839 were studied to understand the dynamics of the resource, evaluate extent of their exploitation and to propose appropriate strategies for sustaining the stock and yield. Almost all gears operating along the coast exploit dorabs. About 1,142 t dorabs were landed annually during the period. Fishery was supported by two species dominated by C. dorab. Growth estimates indicated that both species grow much faster than the earlier estimates from the same region. Stock assessment shows that both species were under heavy fishing pressure and subjected to overexploitation resulting in low production below the MSY level. Strategies for enhancing stock and yield are discussed

Snake mackerel fishery of the Tuticorin coast of Gulf of Mannar with emphasis on population characteristics of the sackfish, Neoepinnula orientalis (Gilchrist & von Bonde 1924)

Snake mackerels form by-catch in deep sea trawls and gillnets with an annual average production of 106 t during 2004 - 2006 in Tuticorin area. Fishery occurred almost round the year with peak during November - March. Fishery and biology of the dominant species, Neoepinnula orientalis was monitored during 2004 - 2005. Peak spawning and recruitment of the species was during December - March period. Growth parameters, L∝ and K are estimated as 31.6 cm and 0.68/year respectively. K value indicates that fish growth is relatively slow. Natural mortality estimate (M) is 1.38, total mortality (Z) 1.59 and fishing mortality (F) 0.21. The exploitation ratio (E) is low being 0.132. These estimates indicate that the stock is at its early stage of exploitation and have large scope for future commercial exploitation. As a preliminary step in this direction, the extent of stock abundance, biomass and distribution of the stock needs to be assessed. Being a slow growing species in cold habitat, considerably long time is required for stock multiplication. These factors have to be taken into consideration while planning for exploitation of snake mackerels in future