Bartail flathead

Abstract: During this study from December 2009 to November 2011, 469 p. indicus fish was caught and their weights and lengths were measured. Total number of caught fishes included, 248 males, 198 females and 23 immature fishes. The Mean, maximum and minimum total lengths were 353±180, 1886 mm and 57 mm respectively. The Mean, maximum and minimum total weight for this species was 384±130g, 600 and 140 g respectively. The length-weight relation were calculated as W=0.000009 FL (n=248, R =0.83) for males, 2.95 2 W=0.000005FL (n=198, R = 0.82) for females and W=0.000004FL (n=469, R =0.86) for total fishes. Verifying 3.07 2 3.10 2 calculated b with 3, using Students t-test there was significant difference between calculated b and 3 (P<0.05), growth pattern is allometric. The mean values of condition factor (K) and Hepatosomatic Index (HIS) was 0.71± 0.14, 1.23±0.65 in male specimens and 0.75± 0.15, 1.32± 0.70 for female specimens. The highest values of K and HIS were observed in November, January and the lowest were in March, June. The mean value of Gonadosomatic Index (GSI) for the male and female were 0.52 ± 0.39 and 1.41 ± 0.62 respectively. For both sexes, the highest GSI values were observed in April and the lowest were in November. Mean GSI value and maturity stages indicated that spawning time were occurred during April to May. The mean size at first sexual maturity (Lm) was 283mm for males and 310 mm for females.

Abstract: Platycephalus indicus (bartail flathead) is dominant species of Platycephalidae family in Iran's southern waters, especially Khuzestan province and mainly is captured by bottom trawl and gillnet. The population biology of this species in the northwest waters of Persian Gulf (Iran) was investigated to derive information required for its management. Parameter values of the von Bertalanffy growth Function fit to size at length frequency data (males and females combined) were: k = 0.5year −1 , L∞ = 62.16 cm, to = −0.26 years. The estimated valve of total mortality, natural mortality, fishing mortality and Exploitation ratio (males and females com- bined) was: Z= 2.59 year -1 , M= 0.77 year -1 , F= 1.82 year -1 and E= 0.70, respectively. Exploita- tion rate, U and Annual total stock at beginning of year were 0.64 and 1194 T respectively. Annual average standing stock, b= 420 T, MSY= 544 T and MCY=362 T were estimated re- spectively. Result in this study showed exploitation ratio the bartail flathead stock is lower MSY and upper MCY. The results of the study highlight critical resource base issues and pro- vide the direction for the future management of this species in the northwest waters of Persian Gulf.