Larval-rearing and growout of the red porgy (Pagrus pagrus) in the Riopesca hatchery (Greece)

Juveniles of red porgy (Pagrus pagrus 1758 L.) were experimentallyproduced in RIOPESCA hatchery during Spring 1992–95. Wild broodstock,weighing from 500 to 1000 g, was caught and brought to the hatchery insummer 1991. They were placed in a 30 m³ rectangular outdoorbroodstock tank with a sea-water flow of 5 m³ per hour.Salinity ranged from 3.9 to 4.1%, temperature from 13 to25°C , the stocking density was 4 kg m^–3,and the sex ratio was 1:1. The females spawned spontaneously in captivity producing approximately 200 000 eggs per kg of body weight. The percent offertilization was between 85–95%. Hatching was completed 85 hours later at 18 °C with a hatching percent of80–90%. The larvae were introduced into a 15 m³tank using green water (Nannochloropsis gaditana & Isochrysis galbana)and fed rotifers (Brachionus rotundiformis), Artemia salina nauplii andmetanauplii, and artificial food. After the end of the weaning period (day80 posthatch) the juveniles reached a weight of 1.4 g with a mean percentof survival of 10%. The fry were transferred to a cage site in which the growout proceeded without particular difficulties. The onlyproblem during growout was the skin coloration, that was darker than thatof wild porgies. Red porgies growth in our installations is satisfactory,with fry reaching 360 ± 12 g within 19 months, with a foodconversion rate of 1.8:1 , and a 6% mortality.