Publication Date:
2021-05-19
Description:
360 funnel traps were prepared as 30 in one row. They were bitted and located in different depths in sampling
sites. Two rows each composed of 30 traps were located by stone, linking rope and boat with 50 m distance in
sampling stations. The results showed that the average of total length of caught crayfish was 106.26±12.89 mm
and their mean weight was 38.79 ± 15.54 gr. The largest crayfish had 171 mm length and 216 g weight. Also
mean of total CPUE was 9.72±4.49 individuals in the study period. The evaluation by Schnabel approach
indicated that fluctuation range of freshwater crayfish biomass with more than 120mm length was 131-313 with
an average of 212.59 ±30.23 kilograms per ha. In this study freshwater crayfish biomass with more than 120mm
length was 247 × 10^3
kilograms. The Maximum Sustainable Yield (MSY) was estimated 83 × 10^3
kilograms. In
this study ّFecundity and biometry of crayfish (Astacus leptodactylus) was investigated during 2012-2013. The
results showed that the average of total length of caught crayfish was 106.26±12.89 mm and their mean weight
was 38.79 ± 15.54 gr. The largest crayfish had 171 mm length and 216 g weight. Mean number of ovarian and
pleopodal eggs were estimated at 286 ± 82 and 246.31 ± 80.41 eggs (with 95% confidence limits), respectively.
In this research, male to female ratio was obtained 1.21:1. The time of male moulting at 16° C was started from
April and was ended in the late May, when the water temperature reached to 18° C. The second moulting of
males and the first moulting of females was performed simultaneously in 18° C water temperature at September.
Reproduction of freshwater crayfish was started from November and continued to May of the next year.
Harvesting period was from May to late November.
Description:
Iranian Fisheries Science Research Institute
Description:
Published
Keywords:
Freshwater
;
Crayfish
;
Astacus leptodactylus
;
Fecundity
;
Biometry
;
Population changes
Repository Name:
AquaDocs
Type:
Report
,
Refereed
Format:
104pp.
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