STUDY ON THE EVOLUTION OF SOME MORPHOLOGICAL CHARACTERISTICS OF ONCORHYNCHUS MYKISS SPECIES IN DIFFERENT DEVELOPMENT STAGES, FARMED IN NEAMŢ COUNTY

I.B. Pagu, C.E. Nistor, B.V. Avarvarei, B. Păsărin

Abstract
The current study tracked the evolution of some morphological characters of rainbow trout individuals, at an age of second, third and respectively four summers, gathered from a fishery in Neamţ County. Trout breed Oncorhynchus mykiss, was the object of the present study being analysed a number of 60 individuals, 20 individuals for each of the third categories of age. Effectuation of corporal measurements and weighting for each age is done to appreciate the maintenance state of them and also their adaptability at the conditions assured by the environment. Based on the obtained and processed data were calculated the most representative indexes and maintenance coefficients. The obtained values were between 3.31-3.55 for profile index; 1.83-1.98 for Fulton coefficient; 1.33-1.44 for Kiselev index; 42.93-48.14 for thickness index; 20.82-21.53 for fleshy index which bring out the ratio of the head from the standard body length and 20.06-21.70 for fleshy index which bring out the ratio of caudal peduncle from the standard length. Having in view the obtained results we can conclude that the analysed fishes had a good state of maintenance.

Key words: morphological characters, rainbow trout, body indices