Trend of changes in the sexual Fractures in Tench (Tinca tinca) in Anzali Wetland and breeding conditions

In this study, tissue changes of the sex organs in the Tinca tinca fish in Anzali wetland and breeding conditions was compared. 96 fish were collected from the cultivating pool and 36 others from Anzali wetland. In the microscopic study of Tench and ovaries and testicles in different stages of sexual activity, from the samples of the wetland, from 3 fish of ovary, two of them were in stage III- IV and one was in stage III (colder water). Furthermore, in the samples, of 8 samples taken, 7 were in mature stage, and one was in stages III-IV (in warmer conditions). In late April, when the water temperature increased to 19°C, tissue from ovaries of fish contained follicles after foliar application (oocytes with accumulation of yolks and open oocytes). In the largest oocyte, the vacuoles were near the nucleus. The study on 24 fish species of stage 4 and 5 with weight from 50.9 to 228.2 gr and mean 99.86 ± 41.17 grams and a total length of 146 to 233 with a mean of 176.93 ± 22.28 mm and age equivalent to 3 to 6 with a mean of 4.00 ± 0.93 years. The absolute density ranged from 14086 to 153600 with a mean of 36362 ± 28208.77 and a relative density of 170.1 to 644.8, with an average of 367/9±125/02 pounds per gram of fish. The results are as follows: The testis of this fish is lobular and spermatogenesis in fish coincides with sperm shedding or absorption begins in the spawning season and gradually progresses to mid-autumn.By increase of temperature, the reproduction and sexual properties of male and female of Tench was significantly increased. The highest mean diameter of eggs was observed in May and the lowest in August. The peak of sexual maturation in female fish was in March and April. Spawning of fish began in May and continued until late July. Oogenesis and spermatogenesis in breeding environments start earlier than Anzali wetland.