Reproduce Biology Of Schizopygopsis Malacanthus Baoxingensis

Schizopygopsis malacanthus baoxingensis Fu, Ding et Yesubsp. Nov. mainly inhabits those channels such as mahuang channel,gari channel,bori channel,heping channel and dengchi channel. So it belongs to the distribution area extremely narrow type. From May to October 2005 and May to August 2006, 671 specimens collected were used for studies on the reproductive strategies such as reproduction time, spawning type, the ratio and the fecundity, and gonad development and characters of early life history. The main results are as follows:1.Every year speaking of spawning season the male's is earlier than female's slightly. The spawning aggregation lasts from May to September, reaching the peak at June and August. For the reason of climate the reproductive time could possibly occurred in April. The egg size existed fluctuation, and two peaks appeared obviously. In a stageⅣovary, besides primary oocyte in phase 4, there were oocytes both in phase 2 and in phase 3. So the fish could spawn twice within a reproductive period, and the quantity of mature ovum for the second batch is greatly less than the first batch.2. The body length of mature male was longer than 6.7cm with the body weight of 4.1g, the ovary weight of 0.2g and GSI 5.41% at 5 years old。The body length of mature female was longer than 12.8cm with the body weight of 28.2g, the ovary weight of 2.8g and GSI 12.5% at 10 years old。3.During the period of reproduction the sex ratio of Schizopygopsis malacanthus baoxingensis was 0.76: 1(N=308). The female was more than the male(0.01＜P＜0.025). The sex ratio changed along with the body length. When the body length were smaller than 119mm, the emerged frequency for female was less than the male's(P＜0.005). When the body length were between 120mm and 139mm, the sex ratio was almost 1∶1(P＞0.05), and when the body length were bigger than 139mm, the emerged frequency for female was observably more than the male's(P＜0.05). 4.The absolute fecundity was2311±857 eggs. They went up along with body length,body weight,gonad weight. They had no significant difference between different age group (P＞0.05).5. The exterior configuration for the male and female had no difference out of reproduction seasons. But during reproduction seasons some white nuptial organs were visible in males, and almost no organs could be checked in females.6.The egg diameters were about 3.22～3.60mm. The ripe eggs had yellow colors like a limpid pellet with a lot of yolk, and they were expanded by absorption of water. At the temperature of 8.5 to17.2℃, on average 14.16℃, 282h55min were needed to hatch the all embryos. Newly hatched larvae measured 8.951±0.401mm. At the temperature of 14.3±1.1℃, four days after hatching the jaws could open and shut; nine days after hatching the intestines had run through; eleven days after hatching larvae began to feed; And seventeen days after hatching the yolks had been exhausted; seventy one days after hatching, every fins had developed.