Homayoon Hosseinzadeh Sahafi; Hossein Abdolhai1; Mohammad Hossein Toloee; Javad Sayadfar
Volume 10, Issue 3 , September 2012, , Pages 14-22
Abstract
Morpholine as retrieving agent has been used by many researchers for homing of fish.Brooders were selected from Khoshkrud River and breeding was done in Shahid Ansari hatchery, Rasht in 2005. To determine the critical period for imprinting of morpholine 10450 kutum fish were exposed to 10×5-5 mg/lit ...
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Morpholine as retrieving agent has been used by many researchers for homing of fish.Brooders were selected from Khoshkrud River and breeding was done in Shahid Ansari hatchery, Rasht in 2005. To determine the critical period for imprinting of morpholine 10450 kutum fish were exposed to 10×5-5 mg/lit of morpholine in different stages(yolk sac fry ,active fry, 2-3-g fingerlings , 4-5 g fingerlings )and released into Khoshkrud river.The return rate of released fish were studied and recorded in2008 .Results showed significant difference between kutum return rate in active fry stage(1 %) compare to other stages i.e. , yolk sac fry (0.23%) , 2-3- g. fingerling(0.23%) , 4-5 g. fingerling (0.26%) and control(0.13) during the tree years of study period(P<0.001). There was significant difference in sex ratio [M(1.42): F(1)] in recaptured fish in Khoshkrud river( x2=6.4 α= 0.05 df= 1).Higher recapturing rate of 6.7 % recorded in the present study compared to recapture rate of 5% reported during last 5 years, revealed that morpholine can be used for return rate enhancing of kutum fish.