Spawning peak occurs during winter in the japanese subtropical population of the pearl oyster, Pinctada fucata fucata (Gould, 1850)

Perspective of genetic improvement in the culture of pearl oysters

“…lations of each species of pearl oysters and these variation has been suggested to be inherited. 32) Although high genetic variation were found within the single population of P. margaritifera, the wild populations separated by several hundred kilometers showed little differences in allozyme variability in French Polynesia.33-35) Similar results were reported in the Japanese36) and western Pacific37) populations of P. margaritifera and in the western Australian P. maxima population,38) suggesting relatively high gene flow among populations in open ocean. This seem true in all species of pearl oysters which distributed along ocean current.…”

Reproduction, Development and Growth

“…This phenomenon has been observed in P. mazatlanica ( Galtsoff, 1950 ;Saucedo and Monteforte, 1997 ;Saucedo et al ., 2002b ;Vite-García and Saucedo, 2008 ;Figs. 5.6a and 5.6b ), P. maxima ( Wada, 1953 ), P. albina ( Tranter, 1958c ), P. margaritifera ( Tranter, 1958d ;Thielley et al ., 1993b ) and P. fucata ( Ojima and Maeki, 1955 ;Tranter, 1959 ;Chellam, 1987 ;Wada et al ., 1995 ). Rhythmical sex reversal occurs repeatedly, either annually or at shorter intervals.…”

“…Species that have been reported to spawn twice a year include Akoya pearl oysters from India, Iran and eastern Australia ( Herdam and Hornell, 1906 ;Hornell, 1922 ;Tranter, 1959 ;Desai et al ., 1979 ;Chellam, 1987 ;Behzadi et al ., 1997 ;Jamili et al ., 1999 ;O'Connor and Lawler, 2004 ) and P. albina from Australia ( Tranter, 1958b, c ). Those that spawn only once a year include Akoya pearl oysters from Japan ( Ojima and Maeki, 1955 ;Wada et al ., 1995 ;Choi and Chang, 2003 ) and Australian P. maxima . For P. albina sugillata also from Australia, O'Connor (2002) observed at least three spawning peaks during the year.…”

“…Ojima and Maeki (1955) Japan MS-1 HA Continuous breeding throughout the year with a major peak in winter (21°C) and a minor peak in summer (28°C); few cases of bisexuality observed. Wada et al (1995) Korea MS-1 HA Breeding season extends from April through August, with 1 spawning peak in June-July when temperature rises to 21°C. Choi and Chang (2003) Pinctada albina Australia MS-3 HA Description of primary male and female gonad development; color differences of male and female gonads established; full ripeness within 4-5 months.…”

Existence, growth and reproduction of pearl oyster Pinctada margaritifera in Hadhramout coast/Gulf of Aden

“…Such behavior has been observed in almost all of the populations of P. margaritifera in their distribution areas (Crossland, 1957;Tranter, 1958;Hwang, 2007;Pouvreau et al, 2000a,b) and in many of species of this genus (Rose et al, 1990;Wada et al, 1995;Arjarasirikoon et al, 2004;Garcia-Dominguez et al, 1996;Gervis and Sims, 1992). P. margaritifera also can exhibit two periods of maximum spawning, which also can be deduced from the present study (Tranter, 1958;Coeroli et al, 1982;present study).…”