Wild Carp Cyprinus Carpio Research Articles

PH values and activity of digestive enzymes in the gastrointestinal tract of fish in Lake Chany (West Siberia)

Optimum pH of various digestive enzymes and physiological pH values were determined in the gastrointestinal tract of fish species, such as goldfish Carassius auratus gibelio, ide Leuciscus idus, wild carp Cyprinus carpio, perch Perca fluviatilis, and zander Sander lucioperca. Physiological values of pH in the stomach of perch and zander and in different parts of the intestine of all studied fish species range within 3.5–4.5 and 6.5–7.2, respectively. The maximum values of the activity of alkaline protease and nonspecific lipase and esterase are recorded at pH 8–9; the maximum acid protease activity is recorded at pH 2–3. The optimum pH activity of alkaline protease and nonspecific lipase and esterase do not correlate with actual pH value in the digestive tract of fish. Two peaks of α-amylase activity are observed at pH 7 and 9.

Distribution of alien fish species in lakes within the temperate climatic zone of Western Siberia

The composition of the fish community is studied in different lakes of the temperate climatic zone in Western Siberia. The patterns of the region’s occupation by different species in the aspect of geographical zoning are revealed. Only 7 of 19 species live within the limits of the whole region—pike Esox lucius, roach Rutilus rutilus, ide Leuciscus idus, lake minnow Phoxinus percnurus, tench Tinca tinca, crucian carp Carassius carassius, and perch Perca fluviatilis. The most stable species composition of fish is in the forest-swamp zone, where the population is formed by representatives of the aboriginal fauna. In lakes of the forest-steppe and steppe zones, six alien species, namely, sunbleak Leucaspius delineatus, bleak Alburnus alburnus, bream Abramis brama, Chinese goldfish Carassius auratus gibelio, wild carp Cyprinus carpio, and zander Sander lucioperca, have naturalized as a result of introduction. The establishment of Amur sleeper Perccottus glenii and Nikolskyi loach Misgurnus nikolskyi in water bodies of the forest-steppe zone occurs by self-spreading. At present, the share of alien species within the forest-steppe and steppe zones is 47 and 43% of fish species richness, respectively. The spatial distribution of alien species is directed from east to west within the forest-steppe zone. This is evidenced by the composition of self-spreading species whose natural range is the territory of the Far East.