Main Goals and Tasks

The investigations in the group are connected mainly with ecological and morphological peculiarities of fish reproduction and ontogeny (Cypriniformes, Perciformes, Acipenseriformes and others) under natural and changing environmental conditions with special reference to researches of:

1. spawning, gametogenesis and gonad genesis of fishes,
2. mechanisms of lability and stability of fish reproduction including age of maturity, periodicity of reproduction in water bodies with different hydrological regime,
3. reactions of reproductive system resulted by anthropogenic impact,
4. development of digestive system during early stages of fish ontogeny,
5. teratogenesis of sturgeon fishes connected with artificial breeding at hatcheries,
6. ecological and morphological plasticity of fish species inhabiting large natural ranges.

THE MOST IMPORTANT RESULTS

The ecological and morphological peculiarities of some food-fish (Cipriniformes, Perciformes, Acipenseriformes) reproduction and development under natural and changing environmental conditions were discovered. The regularities of spawning, gametogenesis and gonadogenesis of some freshwater and marine fishes were studied as well as mechanisms of changing in rate of maturity and periodicity of fish spawning in water bodies with various hydrologic regimes

The disturbances in development and functioning of reproduction system of sturgeons from Siberian and European part of Russian Federation river basins with various anthropogenic impacts were analyzed. The spectrum of disturbances in gametogenesis and gonadogenesis and connection between levels of this disturbances and water pollution were revealed. The scheme of systematization of all known up today disturbances of development and functioning of sturgeons reproductive system and disturbances of these species reproduction was elaborated. The scheme based on ideas of levels of living matter organization. The proposed scheme makes it easier to demonstrate the whole complex of mechanisms of fish reproductive system reactions, influencing the population reproduction, on anthropogenic impacts. The proposed scheme of systematization of sturgeon's reproduction disturbances promotes the reveal of causal relations among the disturbances of different levels. It was demonstrated that the scheme of systematization of disturbances of development and functioning of reproductive system and disturbances of fish reproduction initially elaborated for sturgeons is also applicable for other species (Cipriniformes, Perciformes).

In fishes with direct type of development it was discovered previously unknown in teleostean fishes way of embryonic food resources utilization – the participation of intestine in yolk digestion. The mechanisms of transport of endogenous food to intestine, so called “embryonic coprofagy” were also discovered.

Resulting long-term researches of teratogenesis in sturgeon youngs under multifactor anthropogenic impact at Volga-Caspian hatcheries 43 types of development anomalies were described. These disturbances strikes up to 100% of larvae, main part of larvae have 2-7 types of disturbances simultaneously. It was demonstrated that these anomalies are not specific, main part of them are not lethal excluding 5 types which some times causes mass mortality of sturgeon youngs.

Investigations of morphological plasticity of fishes inhabiting wide ranges, using the Siberian sturgeon as example, discovered that forming of phenetic diversity of this species is resulted mainly by parallel latitudinal clinal variability of morphometric and meristic characters in large river basins of the Lena, Yenisey and Ob rivers. The clinal variability of these characters may be caused both by modification variability and the Baldwin effect. Using both these data and the data on ecology of separate populations it was discovered that the Siberian sturgeon is the monotypic species forming population continuums within large river basins. These results are new and differ from previous ideas on species structure of the Siberian sturgeon.

Using the Siberian sturgeon as example it was ascertained the complex connection between duration of male's life, ratio of somatic growth and generative metabolism of fishes, relative fecundity of females, age of maturity, duration of intervals between spawns and trophic conditions of water bodies.