Spawning in captivity and early life history of cultured red porgy, Pagrus pagrus


A. Mihelakakis, T. Yoshimatsu, Ch. Tsolkas-2001

Aquaculture, 199(3,4): 333-352

Abstract:

Spawning in captivity of the red porgy, Pagrus pagrus, was studied at ambient temperature and photoperiod during one breeding season. Spawning lasted 114 days from February 12 to June 5, 1997, within a temperature range of 12.2C and 18.5C. The total number of eggs collected during the spawning period was estimated at 77 million of which 14.3% were sinking and 85.7% were buoyant. The percentage of fertilized buoyant eggs was generally high (95-100%). Mean egg diameters ranged from 0.991 to 1.093 mm within a temperature range of 12.2-14.5C and decreased rapidly with increasing water temperature from 14.5C to 18.5C.

Larval development, growth, and morphological changes were described from day 0 to day 34. Larvae were reared intensively in 2 m3 tank under a constant photoperiod (18 h light and 6 h dark), and fed initially on rotifers, followed by Artemia nauplii and weaned onto an artificial diet. A green water technique was applied using Nannochloropsis sp. Larvae completed yolk absorption on day 4 after hatching. Feeding began on day 3. Absorption of the oil globule was completed by day 7. Notochord flexion started on day 20 at about 7.0 mm total length (TL). Transformation from larval to juvenile stage occurred between days 23 and 32 after hatching, at a mean TL of 12.71.2 mm. Initial swim bladder inflation occurred between day 5 and day 7 after hatching.

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