Publication Date:
2021-05-19
Description:
During last two decades 200 millions of kutum fingerlings were released into the Caspian Sea Rivers annually.
Morpholine as retrieving agent were used by many researchers for homing of fishes. To understand the effects of
morpholine on fisheries return of kutum fishes a project with use of tagging method was approved in2004 and
its first phase started in 2005. Brooders were selected from Khoshkrud River and breeding were done in shahid
ansari hatchery, Rasht. Totally 15930 fishes were subjected for this study. 5480 fingerlings (4-5g.) were used for
determining the dose effects of morpholine (3 treatments 5x10*-2,5x10*-5 ,5x10*-7 mg/lit) in return rate and
homing of fishes. Results revealed that there were significant differences between kutum return rate exposed
with 5x10*-5 mg/lit (0.62 %) with other treatments i.e. : 5x10*-7 ، (0.15%) and 5x10*-2 (0.37%) during the
experimented period(P〈0.001). To determine the critical period for imprinting of morpholine 10450 kutum
fishes were exposed to 5x10*-5 mg/lit of morpholine in different growth stages(yolk sac fry ,active fry, 2-3-g.
fingerlings , 4-5 g. fingerling ).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 experiment(P〈0.001). There were significant difference in sex
ratio [M(1.42): F(1)] in recaptured kutums in khoshkrud river( x2=6.4 α= 0.05 df= 1).Recapturing rate were 6.7
% compare to recapture rate during last 5 year(5%) revealed that morpholine can be use for return rate enhancing
of kutum.
Description:
Iranian Fisheries Science Research Institute
Description:
Published
Keywords:
Kutum
;
Tagging
;
Return rate
;
Morpholine
;
Rutilus frisii kutum
;
Fingerlings
;
Imprinting
Repository Name:
AquaDocs
Type:
Report
,
Refereed
Format:
80pp.
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