OPTIMUM STOCKING SIZE OF POST-LARVAE FOR REARING MARINE SHRIMP, Penaeus semisulcatus, IN EARTHEN PONDS DURING WINTER AND SUMMER.

Abdet-Rahim,, M. M.; Nour, A. M.; Omar, Eglal A.; Zaki, M. A.; Srour, T. M.

doi:10.21608/jappmu.2004.239140

OPTIMUM STOCKING SIZE OF POST-LARVAE FOR REARING MARINE SHRIMP, Penaeus semisulcatus, IN EARTHEN PONDS DURING WINTER AND SUMMER.

Document Type : Original Article

Authors

¹ Marine Hatchery, K21, Alexandria, General Authority for Fish Resources Development, Egypt.

² Animal Production Dep., Faculty of Agriculture, EI Shatby, Alexandria Univ., Egypt.

³ Animal and Fish Production Dep., Faculty of Agriculture, Saba Basha, Alexandria Univ., Egypt.

10.21608/jappmu.2004.239140

Abstract

The experiment was carried out in six earthen nurseries constructed
inside greenhouses with a total area of each of them 300 m² and the water
area/earthen nursery was 250 m² with an average depth of 80 cm. Each nursery
was equipped with inlet and outlet pipes. Three stocking sizes, namely 0.8 (PL'.5).
1.3 (PL7.s) and 2.6 (PL,2.13) mglpce of shrimp. Penaeus semisu/catus, post-larvae
(each in two replicates) were tested during two different seasons. winter (24⁰ e) and
summer (30⁰ e) for 35 days. Post-larvae shrimp were fed on crumble feed
containing 52 % protein at four meals /day (20 % of body weight). Water quality,
survival, growth performance and feed conversion ratio (FeR) of the tested shrimp
during both seasons were studied. The results showed that dissolved oxygen
decreased significantly as stocking size and water temperature increased. Un-
ionized ammonia increased significantly (P < 0.05) as stocking size and water
temperature increased. Growth rates of the post-larvae were better during winter at
high stoking sizes than at lower one. Whilst the opposite was observed during
summer, with much better growth rates compared with those of winter for all tested
sizes of shrimp. The respective FeR of shrimp were 2.24, 1.31 and 1.03 during
winter and 2.82, 2.15 and 2.09 during summer, for 0.8. 1.3 and 2.6 mg/pce stocking
sizes, respectively. with significant differences among stocking sizes and between
seasons. Survival rates increased Significantly with increasing the stocking size but
without significant difference between winter and summer. Finally, it could be
concluded that the minimum ideal size of shrimp, P. semisu/catus to be stocked in
earthen nursery or grow-out ponds is at least 1.3 mg/pce.

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