Gonad development and gametogenesis in the Asian sea bass (Lates calcarifer ) grown in an intensive aquaculture system

Abstract

Summary Early gonad development of the Asian sea bass (Lates calcarifer) grown in a freshwater recirculation system was investigated to determine the onset of sexual maturation. Studied individuals aged between 9 and 15 months. Culture conditions were provided initially in circular tanks (4000 L) and linked to a warm‐water recirculation system (27°C, O2 = 7–8 mg L−1) until they reached 20 g wet weight. They were ongrown in raceways (54 m3; final density 80 kg m−3) connected to a recirculating system with a fluidized bed as biofilter. Their gonads were examined each month (5–12 fish) and prepared for histology. Following microscopic observations testis maturity was categorized and correlated to total length (cm) and weight (g). Gonad development started much earlier in the recirculation system than described previously in both, wild and cultured fish. We assume that spermatogenesis in these fish starts earlier than 9 month of age and the fact that mature spermatozoa were present in testes that contained mostly spermatogonia indicates highly asynchronous spermatogenesis.

Small-scale transcriptomics reveals differences among gonadal stages in Asian seabass (Lates calcarifer)

“…In addition, despite the late sexual maturation age of the species, early testis differentiation can be found in Asian seabass that are grown in intensive freshwater recirculation systems at as early as 9 months old [4]. …”

“…Primary females that do not appear to go through the male phase, as well as males that do not undergo sex change, may also exist, and these possibilities have been inferred from the presence of young, small-sized females and old males, respectively [ 1 , 3 ]. In addition, despite the late sexual maturation age of the species, early testis differentiation can be found in Asian seabass that are grown in intensive freshwater recirculation systems at as early as 9 months old [ 4 ].…”

Gonad development and size‐at‐maturity of silver theraponLeiopotherapon plumbeus(Kner 1864; Teleostei:Terapontidae) in tropical volcanic lakes in south Luzon, Philippines

“…A histological examination of the silver therapon gonads revealed distinct development stages similar in most respects with other teleost species (Bernal, Aya, Jesus‐Ayson, & Garcia, ; Brown‐Peterson et al, ; Coward & Bromage, ; Nagahama, ; Szentes et al, ; Wallace & Selman, ; West, ). The persistent abundance of primary and secondary growth stage oocytes in the ovary indicates an asynchronous mode of development, which is typical of iteroparous fish capable of spawning several times during a prolonged breeding season (Nagahama, ; Nuñez & Duponchelle, ; West, ).…”

“…Sexually mature female and male fish in Sampaloc Lake were significantly smaller than their counterparts in Taal Lake, while sexually mature males were significantly smaller than mature females in both lake habitats ( Figure 10). teleost species (Bernal, Aya, Jesus-Ayson, & Garcia, 2015;Brown-Peterson et al, 2011;Coward & Bromage, 1998;Nagahama, 1983;Szentes et al, 2012;Wallace & Selman, 1981;West, 1990). The persistent abundance of primary and secondary growth stage oocytes in the ovary indicates an asynchronous mode of development, which is typical of iteroparous fish capable of spawning several times during a prolonged breeding season (Nagahama, 1983;Nuñez & Duponchelle, 2009;West, 1990).…”

Controlled Breeding, Seed Production and Culture of Brackishwater Fishes

“…Males will ooze milt if the abdomen is gently pressed. The gonadal condition is assessed by ovarian biopsy (Szentes et al 2012). Brood fishes selected for induction of spawning should be active, free from disease, wounds or injuries.…”