Assessment of biological and productive parameters of female hybrids between the Volga sterlet (Acipenser ruthenus) and Amur kaluga (Huso dauricus). Part 2. Hybrids between kaluga females and sterlet males. Comparative characteristics of reciprocal h

The second part (for the first part of the article, see No. 6, 2024) of the work describes the production indicators of fertile female hybrids between Kaluga females and sterlet males, and also provides a comparison with the previously described indicators of hybrids between sterlet females and Kaluga males. The study of the production parameters of reciprocal hybrids in the process of long-term formation of breeding stocks is of both scientific and practical interest. The purpose of the work is to evaluate the fish-breeding, biological and production characteristics of female hybrids, and the effectiveness of their use as promising objects for obtaining food caviar. The maturation periods, inter-spawning intervals, the weight of the eggs obtained and the weight of the eggs, fertility and oosomatic indices of 67 females of 5 age-related generations of reciprocal hybrids from the warmwater farm of the Primorsky Territory weighing from 17 to 35 kg, participating in 87 spawning campaigns from the age of 9 to 14–18 years, were studied. One of the generations is represented by real albinos of lemon-yellow color with red eyes and light caviar. The conducted studies have shown that the number of fertile females in different generations varies from 10 to 30%, but from 25% of females it was not possible to obtain eggs even once. Females begin to mature at the age of 9–12 years, the duration of maturation of all females of the same generation reaches 8–10 years. Most females skip 2–4 years between spawning or mature once. Caviar resorption in winter occurs in 17–42% of female hybrids. On average, during one spawning, females produce from 1,5 to 1,7 kg of eggs with an average weight of 23 mg of eggs. The production performance of hybrids is significantly lower compared to hybrids between beluga and sterlet (besters). Due to their biological characteristics and low productivity, reciprocal hybrids between Kaluga and sterlet are of greater scientific interest for genetic research than as producers of caviar. The cultivation of hybrids in order to obtain industrial volumes of caviar for food purposes is recognized as costly, ineffective and inexpedient.