Experimental works on factory reproduction of tench (Tinca tinca L.) in the Saratov region

Abstract

Currently, the practice of artificial reproduction of tench in fish farms is extremely limited. This is based on the lack of effective methods of its factory reproduction. The purpose of our research was to develop biotechnical elements that optimize artificial reproduction of tench in the conditions of the Saratov region. The objects of research were producers of tench caught in the Volgograd reservoir by water nets. In total of 25 specimens were caught and pre-planted in trays tench producers, including 15 specimens females weighing from 750 to 1555 g and 10 specimens males — from 673 to 1055 g. Two schemes were used to stimulate puberty in female tench with the acetonated pituitary gland of the carp. The first group of females was injected with pituitary solution twice: a preliminary dose of 0.6 mg/kg; allowing — 6 mg/kg of body weight with an interval between injections of 12 hours. The second group of females was injected once with a pituitary dose of 15 mg/kg. The best indicators in the production of ovulated oocytes were shown by females who were injected twice, and in this group an additional second portion of a small amount of eggs was obtained. Male tench were injected once with a pituitary dose of 3 mg/kg. According to the time of injection, the males were divided into two groups: the first group was injected with the pituitary gland simultaneously with the pre — injection of the females; the second — at a resolution. The best results in terms of ejaculate volume were obtained in the first group (0.5–0.6 ml). From the second group of males, the volume of seminal fluid was 0.3–0.4 ml. Methods for the desticking of fertilized eggs using the proteolytic enzyme alkalase and tannin are investigated. The proteolytic enzyme showed a well-defined decongestant activity, but during the incubation of eggs, the shells of shell eggs burst and at the time of hatching single instances of larvae were observed. More stable results on hatching of larvae were obtained with the use of tannin, as a degumming substance.