Publication Date:
2021-05-19
Description:
The aim of this project is to study the growth and age structure in the Caspian trout, comparison with other
coldwater species and check the trend of these parameters in recent years. This study was conducted during 2013
till 2015. Totally, 43 specimens for back calculation and 101 specimens for biometrical study of the Caspian
trout have been caught in two month period. Biometric parameters such as length, weight and age of the fish
were recorded. Base on Back calculation method in 1393, the average length of fish at ages 1, 2 and 3 years old
were 18.98 ± 3.5, 30.5 ± 7.24 and 41.7 ± 9.1 cm. So these age groups are under the adult age and don’t
approaching to near the beach and rivers for spawning behavior. Therefore, these length groups cannot be
observed in catch composition.
The result showed, the mean of gonad weight in this fish was about 11 percent of total weight and number of
eggs per gram of gonad calculated about 10.8 numbers.
Minimum age and maximum age of this species determined 4 years and 7 years (mean = 5.6) and the most
frequency allocated to 5 age group and the frequency of 6 and 7 years has been remarkable.
The average length of salmon was 69.2 ± 6.2 cm (minimum 57 and maximum 81 cm) and the average weight
was measured 3323 ± 677 g (2400 to 5600 g) in the catch composition. Growth parameters such as k, L∞ and ø’
was measured 0.18, 104 cm and 3.289 respectively. The amount of b for relation length and weight was 2.9
which imply negative allometry. L∞ and growth coefficient (K) on the Caspian trout were acceptable range, that
it shows good growth the fish in the sea water.
Most of the fishes were catched from Cheshmehkileh River.
As at present Shilat uses just the broods of the Tonekaboon region for restocking of this species, we recommend
using the broods of the western region separately for rehabilitation of the stocks of this region.
Description:
Iranian Fisheries Science Research Institute
Description:
Published
Keywords:
Caspian trout
;
Salmo trutta caspius
;
Age
;
Growth
;
Growth performance
;
Composition
Repository Name:
AquaDocs
Type:
Report
,
Refereed
Format:
46pp.
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