Reproductive parameters of roach Rutilus rutilus (L.) from the Rybinsk Reservoir reaches differing in anthropogenic loads

Dynamics of indices of metabolism in muscle tissue, liver and gonads of Abramis brama in different periods of the annual cycle

“…Decrease in the main products of metabolism in the muscles of the fish could occur due to the exhaustion of the individuals after winter starvation, as wells as expenditure of energy for the maturation of the gonads and preparation to spawning (Medford & Mackay, 1978;Wallace & Selman, 1981;Jøsrgensen et al, 1997;Grigorakis et al, 2002). By the end of the pre-spawning period, proteins and lipids in the body of fish are expended for trophoplasmatic growth of oocytes and the development of spermatogonia, when they accumulate nutrients, and the gonads, especially the ovaries, increases in size (Shankar & Kulkarni, 2006;Tyheev & Tomitova, 2016;Komova et al, 2017). Fish with low quantity of lipids in the muscles (thin), to which bream belongs, after winter starvation mobilize protein as endogenous energy source, and the exhaustion of the energy resources in the body of hydrobionts leads to general decrease in their condition (Shatunovskii, 1980;Yeannes & Almandos, 2003;Zaboukas et al, 2006).…”

“…In the gonads of bream, in this period, the amount of metabolic products decreased, except lipids, the content of which insignificantly increased in the ovaries (Tables 3, 4). Since the early spring, in the prespawning period, the Cyprinidae begin to feed actively, perhaps, because of this, by the moment of spawning, in the muscular tissue of bream, accumulation of protein was observed (Komova et al, 2017). In addition, the decrease in the expenditure of protein in the muscles of female bream could occur due to use of fat reserves (Shatunovskii, 1980).…”