Population dynamics of red-toothed triggerfish Odonus niger (Ruppell, 1836) along southwest coast of India

The red toothed trigger fish Odonus niger (Ruppell, 1836) contributed up to 96.5% to the total catch of the exploratory trawler operating in the Wadge bank. The catch rate was 2.26 t hr -1 . Its distribution was recorded up to 130 m depth between 7° N and 10° N Lat., 75° E and 77° E Long. Length (mm) - weight (g) relationship of this species was estimated as W = 0.0002 L 2.5218 . The von Bertalanffy equation was derived as L t = 33 (1-e -0.78 (t + 0.214) ). The natural mortality (M), fishing mortality (F) and total mortality (Z) were estimated as 1.48, 1.32 and 2.80, respectively. The exploitation ratio (E) was 0.47. The mean length at first capture (Lc) was estimated as 16.4 cm. Recruitment of this species was observed during February - April, and the peak was in March. Virtual Population Analysis showed that the mortality was more in the size group of 23 cm.