Tez özetleri Astronomi ve Uzay Bilimleri Anabilim Dalı

The Determınatıon Of The Egg Incubatıon Perıod And Productıvıty Levels Wıthın The 60-Day Posthatch Raınbow Trout (Oncorhynchus Mykiss, Walbaum,1792) In Sapanca Condıtıons.

In our country, the first incubation system in a modern sense has been established at the Sapanca Research and Application Unit, which is a branch of Istanbul University, Fisheries Faculty. Water temperature is an average of 12°C in the rainbow trout incubation system. Water quality, considering its drinkable chemical and physical structure, shows parallelism with the natural conditions in which the rainbow trout live. For this reason, in an environment where the incubation system works properly and gets the contribution from technical personnel, it is necessary that the highest level product is obtained. However, the amount of products obtained from the incubation system of Sapanca Unit showed differences according to years.

The results of our study, which aims to determine the productivity level in the incubation system and the most critical period, in the first 60-day period posthatch rainbow trout, will contribute to the development of the establishment.

Two groups of brood fish are used in our study. The growth periods of the fertilized eggs and larvae taken from these fish showed similarity, because of the fact that water warmth (average temperature, 12,33°C) is the most distinctive factor. It was observed that the fertilized eggs became the eyed eggs on the 14^th -16^th days, the hatching period of the eyed eggs was between on the 30^th and the 32^nd day, and the alevin stage was observed in the period between 43^rd and 46^th day.

In our study, the fertilization rate was 97,54 % ± 0,263, survival rate up to the stage of eyed eggs was 93,12 % ±2.35. This rate in the hatching period was 89,4 % ±1,021, up to the alevin stage of larvae was 87,77 % ±13,89, and in the first 60-day posthatch period was 86,58 %±12,31. These results are from the first group, which consisted of the eggs taken from 4-5 year-old brood fish. In the second group, which consisted of the eggs taken from 2-3 year-old brood fish, the fertilization rate was 95,62 % ±0,918, survival rate up to the stage of eyed eggs was 87,02 % ±2,78, in the hatching period was 75,08 % ±3,68, up to the alevin stage of larvae was 72,41 % ±16,59, and in the period of the first 60 days on which the research ended was 71,08 % ±17,83.

The data we obtained from this research have shown that the productivity level in the hatchery and fry units of Sapanca is high, and also is parallel to international standards. Because of the fact that the water used in Sapanca Unit is dependent on the energy which is very expensive, it is impossible to keep up its productivity and profitable conditions. The applications of developing the productivity level of Sapanca Unit in producing the egg and fry, eventually pulling it to the top level, and growing the produced fish in the sea, which is much more profitable, will give successful results and provide the status of “model plant” in the country