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 12.2°C and 18.5°C. 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 12.2-14.5°C and decreased
rapidly with increasing water temperature from 14.5°C to 18.5°C.
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 12.7±1.2 mm. Initial swim bladder inflation
occurred between day 5 and day 7 after hatching.
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