Publication Date:
2021-05-19
Description:
The recirculation of inorganic nutrients orthophosphate and nitrate in relation with productivity in sturgeon rearing ponds was studied through two rearing periods at the Shahid Beheshti Hatchery. The first rearing period commenced on May 24, 1998 and ended on July 26, 1998 whereas the second rearing period commenced on May 16, 1999 and ended on June 26, 1999. Four earthen ponds with a surface area of 2 hectares each were used in this studied of which three ponds (number 25, 26 and 27) were considered experimental ponds and one pond (number 24) was used as the control. Results obtained in the first rearing period indicate that the fertilization program employed in this study was suitable to maintain the productivity of experimental ponds. Growth rates in fingerlings also indicate a rapid increase in growth during the first few weeks of rearing. However unfavorable conditions encountered at the end of the rearing period (increase in water temperature, decrease in dissolved oxygen concentrations, deterioration of water quality etc.,) lead to decrease in food consumption by fingerlings that ultimately resulted in decrease in growth and survival rate of fingerlings (survival rate 60 % in first year). On the basis of the results obtained in the first year, measures were taken to and increase the biomass of benthic organisms in the rearing ponds. The biomass of benthic organisms in experimental ponds increased from a maximum of 2.1 g m-2 in the first year to a maximum of 189 g mo in the second year. However despite the management policies employed to maintain productivity and meet the food requirements of A. persicus fingerlings, water scarcity that prevailed in the entire region lead to an increase in water temperature, decrease in dissolved oxygen concentrations, over growth of aquatic vegetation and thus survival rate of fingerlings dropped to less than 40 % in the second year. Results obtained from scientific studies reveal that increase in pond productivity does not depend on basic knowledge alone. Techniques involved in pond management that provide suitable conditions required for fish culture such as stock assessment* basic control of fish growth, proper utilization of food resources in ponds and fertilization etc., play a significant role in this regard.
Description:
Iranian Fisheries Science Research Institute
Description:
Published
Keywords:
Sturgeon culture
;
Productivity
;
Fertilization
;
Live food
;
Survival
;
Nutrients
Repository Name:
AquaDocs
Type:
Report
,
Refereed
Format:
58pp.
Permalink
