福建省东山岛西埔湾港养斑鰶的繁殖生物学

本文研究了福建省东山岛西埔湾港养斑鰶性腺周期发育、成熟系数周年变化、个体生殖力以及雌雄同体。港养斑鰶能在半封闭式湾内发育成熟而且自然产卵。其卵细胞发育分为6个时相,精巢发育分为6期。卵膜由透明带、外放射带和内放射带组成,内有孔道结构。第4时相中期卵母细胞的内放射带有7～8层纤维状片层。产卵后鞘膜细胞和颗粒细胞分裂增殖变成游走的吞噬细胞。西埔湾港养斑鰶Ⅰ龄鱼初次性成熟,生殖季节从12月下旬至翌年3月下旬,生殖盛期为2月,雌鱼成熟系数高达17.88％。个体绝对生殖力为7575～72621粒,平均 35310粒,系属于分批产卵类型,第1批生殖力大于第2批。

THE REPRODUCTIVE BIOLOGY OF GIZZARD SHAD CLUPANODON PUNCTATUS IN XIPU BAY

The present paper deals with the cyclic gonadal development, thegonadosomatic index, the individual fecundity and the hermaphrodite of Clupa-nodon punctatus in Xipu Bay (a minor and semi--enclosed bay with a seawall) ofDongshan Island, Fujian Province. The ovaries and testis of the fish can developinto ripe stage in Xipu Bay. The oogenesis is composed of six phases: (1) oogonia,(2) oocyte with a single layer of follicle cells, (3) oocyte with lipid droplets andyolk globules, (4) oocyte filled with yolk globules, (5) oocyte with migratory nu-cleus and (6) degenerative oocyte. Based on the six phases of oogenesis, the deve-lopment of ovary is also composed of six maturity stages correspondingly. Thedevelopment of testes may be divided into six maturity stages: (1) spermatogonia,(2) multiplication of spermatogonia, (3) growth of spermatocytes, (4) initialappearance of spermatozoa, (5) maturation of spermatozoa and (6) degeneration ofspermatozoa. The egg membrane consists of zona pellucide, zona radiata externaand zona radiata interna. With the growth of oocyte, the egg membrane increasesin thickness and is traversed perpendicularly by the pore canals containingmicrovilli from both the granulosa and the oocyte. The zona radiata interna inclu-des 7--8 Iayers of fibrous lamellae at phase IV. During maturation or the oocyte,the pore cauals become invisible, but three layers of the egg membrance are stillidentified. After spawning, the process of transformation of thecal cells andgranulosa cells to phagocytes has been observed on the degeneration of oocytes. Themale and female reach first maturity at I age group, spawning season occursfrom late Docember to late March of the next year. The individual absolute fecun-dity ranges from 7575 to 72621 eggs, averaging 35310 eggs. According to thefrequency distribution of ova diameter in the ovary, the ripe ova are released at least two batches during spawning season, the individual fecundity of the firstspawning batch is higher than that of the second. Accidental hermaphrodite existsin the fish, including ovotestes type and testes--ovary type.