SOME BIOLOGICAL ASPECTS OF CASPIAN SEA CRAYFISH ASTACUS LEPTODUCTYLUS EICHWALDI IN BANDAR ANZALI COASTAL ZONE

Document Type : Research Paper

Authors

1 Anzali

2 Tehran

Abstract

Among crayfish species only Astacus leptoductylus eichwaldi Bott, 1950, is found in Bandar Anzali coastal area. The research survey carried out during 2001-2002, by designing twelve transects (transects coverd the depth of 35, 45, 55 and 65m). Foldable traps being used to catch crayfish. The maximum abundance of crayfish was caught at the depth of 40-60m. The average length and weight measured 125.6±0.2mm and 60.6±0.3g. The length and weight range were 72-169mm and 12.5-148g, respectively. Sex ratio during studying period favoured females with 1:0.86. The ovarian and pleopodal eggs calculated 308.98±10.62 and 255.54±10.87, respectively. The fecundity result obtained from A. leptoductylus eichwaldi population showed resemblance to its Turkmenistan counterpart. 
With the increae of weight in females the number of eggs in each gram of body weight (relative fecundity) is reduced. The breeding season in the studied area occured in 21th January to 22th July. First moulting in males happened in July and the second moulting which are simultaneous with females occured 11th-30th September. Length group 120-129mm were dominant in population and length frequency analysis showed six age groups among the crayfishes in studied area September. Length group 120-129 mm were dominant in population and length frequency analysis showed six age groups among the crayfishes in studied area. 
Average CPUE in the mentioned year was 2.54 individuals per trap per 24 hours. At present no harvest of crayfish taken-place, CPUE data showed that the density of crayfish between transects of 1-7 have been relatively considerable, and it is recommended that after carrying out stock assessment survey, the exploitation of caryfish resources can be programmed.

Keywords

Iranian Scientific Fisheries Journal
Volume 13, Issue 1
March and April 2004
Pages 129-148

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