Length-weight relationships of commercially important marine fishes and shellfishes of the southern coast of Karnataka, India

The parameters of the length-weight relationship of the form W = aLb are presented for 51 species of commercially important marine fishes and shellfishes caught along the southern coast of Karnataka, India. Samples from commercial (trawl, purse seines, gill nets) and artisanal gears were taken during August 1999 to May 2001. The ‘b’ value ranged between 1.942 and 3.616 with a mean of 2.80, standard deviation of 0.32, and mode of 3

Length-weight relationships of commercially important marine fishes and shellfishes of the southern coast of Karnataka, India

The parameters of the length-weight relationship of the form W = aLb are presented for 51 species of commercially important marine fishes and shellfishes caught along the southern coast of Karnataka, India. Samples from commercial (trawl, purse seines, gill nets) and artisanal gears were taken during August 1999 to May 2001. The ‘b’ value ranged between 1.942 and 3.616 with a mean of 2.80, standard deviation of 0.32, and mode of 3.Length-weight relationships, Marine fish, Shellfish, Stock assessment, India, Karnataka,

Marine fisheries of Karnataka State, India

This contribution provides an overview of the marine capture fisheries off the coast of Karnataka State, India. It covers the main fisheries and fishing gears, production trends (by main species /groups and gears), assessment results and fisheries management. Marine fisheries production in the State increased from about 57,000 t/year during the 1950s to a peak of about 250,000 in 1989, declining to about 150,000 t/year by 1995. Substantive changes have been noted in dominant gears and species groups contributing to the catch between 1980-84 and 1990-95. Results of assessments indicate that many commercially important stocks are overfished, thus requiring a reduction in fishing effort

Population dynamics and stock assessment of spadenose shark Scoliodon laticaudus Muller and Henle 1839 along Gujarat coast of India

423-433Stock assessment of Scoliodon laticaudus Muller and Henle, 1839 was made along with analysis of its few biological characteristics from its commercial landings during 2012-2016 from Gujarat waters of India to understand the population dynamics and stock status of the species. The average annual landing of the species was 5442 t, which constituted about 67% of the total shark landings at Gujarat coast. L∞, K and t0 were estimated as 75.53 cm and 0.54/yr, and -0.4 yr, respectively. Total mortality rate, fishing mortality rate and natural mortality rate were estimated as 1.95 yr-1, 1.04 yr-1 and 0.91 yr-1, respectively. The length at capture (Lc50) and length at maturity (Lm50) were 39.74 cm and 35.79 cm, respectively, which indicate that most of the sharks are exploited after attaining the sexual maturity. Length-weight relationship showed that the growth was isometric. The species was a continuous breeder and showed peak recruitment during September. The current exploitation ratio (Ecur) was found to be 0.53, which is lower than E0.1 estimated for the species using Beverton and Holt yield per recruit analysis. Thompson and Bell prediction model showed that maximum sustainable yield for S. laticaudus could be obtained by increasing fishing effort by almost 2.4 times higher than the present level which would deplete the spawning stock biomass (SSB) to 20%. Maximum economic yield could be obtained by increasing the fishing effort by 1.8 times which would also decrease the SSB, but to a comparatively safer 26.5% level. Considering 30% SSB as a precautionary management reference point, the effort could be increased by 50% exclusively for the sharks to increase the yield and revenue from fishery while maintain SSB at a safer 30% level

<smarttagtype namespaceuri="urn:schemas-microsoft-com:office:smarttags" name="place" downloadurl="http://www.5iantlavalamp.com/"> Prediction and modelling of marine fishery yields from the Arabian Sea off Karnataka using Ecosim </smarttagtype>

69-76 Ecosim simulation exercise was carried out for predicting over 10 years the changes in fishery yields in the multi-species and multi-gear marine fisheries of the Arabian Sea off Karnataka. The present study elucidates that in all the gears (multiday and single day trawl; purse seine, drift gillnet, hook and line and artisanal) the key resources such as mackerel, sardines, seerfishes, tunas, sharks and skates and rays showed rapid decline in yields within 5 years due to a consistent increase in fishing effort (@ 17% per annum). The shrimp yields showed an increasing trend in trawls as they seem able to sustain the high fishing pressure as long as their predators are also harvested. In all gears excepting hook and line, there is no ecological and economic advantage in increasing the fishing effort. Also increasing the effort can result in rapid declines of many important marine resources. This will have a serious effect on the ecosystem functioning. Attempt has been made to model changes in the marine ecosystem due to fishing as part of the effort to move towards ecosystem based fisheries management. This is the pioneer effort for the same. </smarttagtype

<span style="font-size:11.0pt;mso-bidi-font-size: 10.0pt;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-GB;mso-fareast-language:EN-US;mso-bidi-language:AR-SA" lang="EN-GB">Observations on the utilization of the biochemical constituents during maturation of the butterfish <i style="mso-bidi-font-style:normal">Scatophagus argus</i> (L.1766) from Palk Bay, south east coast of India</span>

75-81Observations on the utilization of biochemical constituents of various tissues viz. liver, muscle and gonads of butterfish Scatophagus argus (L. 1766) with respect to sex and maturity stages were made from Mandapam water in Palk Bay. Investigation revealed that moisture content of muscle, liver and gonad in male and female butterfish was more or less same in all the stages with very little difference of 1-2% in both sexes. An inverse relationship of moisture content with carbohydrate and lipid was recorded in muscle, liver and gonad irrespective of their development stages. Protein level in muscle, liver and ovary of female and in testis of male decreased during maturation process. Muscle and liver carbohydrate content in female and male decreased indicating utilization of carbohydrate during maturation and spawning. In female, higher caloric value was recorded in stage I for both muscle and liver tissues while in ovary it was in stage IV whereas in male higher caloric values in muscle, liver and gonad were registered in stage VII

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