International Journal of Fisheries and Aquatic Studies
2015, Vol. 2, Issue 5, Part D
Age and growth of red toothed triggerfish Odonus niger (Ruppell, 1836) (Family: Balistidae) off Thoothukudi, Southeast coast of India (08° 53.6’N 78° 16’E and 08° 53.8’N 78° 32’E) – (36 M)Author(s):
T. Vaitheeswaran, S. Malathi, K. Prabakar, N. Neethiselvan, V. K. VenkataramaniAbstract:
Fishery resources, being renewable, have to be exploited in such a way that reaping of maximum sustainable yield (MSY) is possible without affecting the stocks. For such an effective exploitation, size of stocks is to be determined for obtaining their MSY. Its distribution was recorded up to 36 m depth between 08° 53.6’N lat. 78° 16’E long and 08° 53.8’N lat. 78° 32’E long, 38 miles from Thoothukudi fishing harbour, southeast coast of India. The regression equation calculated for female was Log W = -2.8161 + 2.2508 Log L, and for male was Log W = -2.6605 + 2.1601 Log L by40. The slope value (b) estimated for Balistoides viridescens of both sexes was found to be 1.0541. The slope value (b) estimated for Balistoides viridescens male was found to be 1.4070 and for female 1.2257. The asymptotic length (L∞) of O. niger was higher for females 283.90 and the value of K was 0.75. The t0 value was estimated at 0.002. The summer point ts value was 0.30. The length base index of growth performance index (Phi prime) Pφ was 4.781. The regression equations calculated for female was Log W = -0.4394 + 1.2257 Log L, and for male Log W = -0.7044 + 1.407041. The natural mortality (M), fishing mortality (F) and total mortality (Z) were estimated at 0.80, 0.27 and 1.07, respectively. The present level of exploitation rate and exploitation ratio (F/Z) is estimated at 0.25. Heavy fishing pressure on the length group 6 to 31.5 cm revealed that O. niger in Thoothukudi waters suffer due to recruitment overfishing. The total stock, average annual stock and maximum sustainable yield were estimated at 1,25,392.028 tonnes, 3134.8007 tonnes and 1,161.3730 tonnes respectively. This red toothed was found to have two recruitment seasons, one major season, during November and a minor season during April. The estimated life span appears to be 2.5 years.Pages: 204-209 | 818 Views 5 DownloadsDownload Full Article:
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T. Vaitheeswaran, S. Malathi, K. Prabakar, N. Neethiselvan, V. K. Venkataramani. Age and growth of red toothed triggerfish Odonus niger (Ruppell, 1836) (Family: Balistidae) off Thoothukudi, Southeast coast of India (08° 53.6’N 78° 16’E and 08° 53.8’N 78° 32’E) – (36 M). International Journal of Fisheries and Aquatic Studies. 2015; 2(5): 204-209.