池中養成紅尾蝦之種蝦速報

Abstract

The problem of finding possible ways and means to culture young shrimp, under controlled conditions, to become spawners for the purpose of mass production of the much needed shrimp "seeds" has attracted worldwide attention. During recent years, the Tungkang Marine Laboratory has been engaged in conducting research on this challenging problem. Some of the results obtained are summarized as follows: 1. On October 24, 1972, 60 young Penaeus penicillatus, with an average body weight of 19.95 g (propagated at the Laboratory on April 24 of the same year) were stocked in 2 outdoor cement ponds of 2.5 x 1.5 x 0.6 m each. Trash fish and shrimps were used as feed. On April 3, 1973 after 162 days of rearing, the average body weight reached 39.98 g. On July 24, 8 female and 16 male specimens were transferred into an indoor cement tank of 7 x 2.5 x 1.5 m. One month later, one of them was found possessing mature ovary. Two weeks later, another prawn had mature ovary too. The latter was dissected for examination and measurement. The dark-green ovary weighed 5.51 g, with a GSI of 8.99. 2. Tissue sections showed the presence of one nucleus, few nucleoli, and also jelly-like substance just inside the membrane of the ovarian eggs. There was a thin layer of follicle cells surrounding the egg membrane. The egg diameters ranged from 0.133 mm to 0.263 mm, averaging 0.18 mm. The state of development of this ovary was in its maturation stage. 3. On another occasion, one cultured P.monodon was found also to have grown to become a spawner. It was transferred to a 0.5 ton plastic tank and spawning occurred. However, there was no cleavage of the eggs, probably due to either (1) the specimen had not mated or (2) the eggs had not reached full maturity. 4. In total, two cultured spawners of P.penicillatus and one cultured spawner of P.monodon have been produced in the Tungkang Marine Laboratory up to now. Studies on the mechanism of maturation and suitable environmental conditions to induce maturation of prawn are to be continued and intensified.

在培育海產蝦類種蝦之預備試驗中，獲得下述結果： 1）將繁殖所得之 P.penicillatus 蝦苗，放養於室外 2.5×1.5×0.6m 水泥池，並投予下雜魚、蝦，經總飼育日期1年又3個月後，移入室內 7×2.5×1.5m 水泥池繼續飼育，結果一個月後發現其中一尾之卵巢成熟，又半個月後，再次發現另一尾卵巢亦達成熟，經予以解剖，測得卵巢重 5.51 g，GSI 達 8.99，卵巢呈深草綠色。 2）此尾之卵巢組織切片，顯示其 ovarian eggs 之卵膜內側已有 jelly-like substances 堆積，並有一明顯之 nucleus 及多數之 nucleoli，卵膜外之 follicle cell layer 已很薄。卵徑範圍為 0.133~0.263 mm，其平均值為 0.18 mm。依卵巢成熟情形區分，此尾之卵巢已達 maturation stage。 3）另外，得自繁殖的一羣 P.monodon 蝦苗，經放養於池中飼育一段時期，亦曾由其中獲得一尾成熟的種蝦，並經收容後產卵，但卵粒未發生細胞分裂，是否由於未交配抑或卵本身未臻成熟所致則不得而知。 4）總之，迄今已魚池中育成2尾 P.penicillatus 及1尾 P.monodon，其卵巢皆達 maturation stage。今後除了對蝦類成熟 mechanism 之追究外，對最適宜於種蝦成熟之飼育環境之研究尤需加緊。