First Findings of Sunbleak Leucaspius delineatus (Cyprinidae) in the Lake Baikal Basin

Since the early 1960s, the sunbleak Leucaspius delineatus (Heckel, 1843), along with carp acclimatized from European Russia, regularly entered the siberian carp ponds, first in the Ob’ basin, and then in the Yenisei and Angara basins. In the last decade, we have discovered the sunbleak in two water bodies of the Baikal basin: in May 2013 - in the water intake and discharge canals of the Gusinoozersk regional power plant situated on the large lake Gusinoe in the Selenga River basin (Republic of Buryatia), and in November 2016, the sunbleak was registered in the diet of pike inhabiting the reservoirs of the Talaya-Pokhabikha lake-bog complex in the immediate vicinity of the Baikal coastline at the southern end of the lake in Irkutsk Region. The age series in the samples of the sunbleak in the water intake canal of the power plant was represented by five age groups from 1+ (SL 34.2 mm and 0.59 g of weight) to 5+ (SL 73.9 mm and 6.73 g, respectively) with a predominance of individuals aged 1+ and 2+. In the discharge canal only group 1+ (SL 35.5 mm and 0.69 g) was noted. The sex ratio in catches at the age of 1+ was 1:1.2 with a predominance of males; by the age of 3+, the proportion of males increased significantly (1:8.6). Sexual maturity of the sunbleak from Lake Gusinoe occurs at the age of 3+. Spawning is portioned, the first portion is layed down not earlier than the second half of July. The total fecundity of the seven studied females at the age of 3–5 + varies from 632 to 1539 eggs, averaging 1312 eggs. The sunbleaks from Lake Gusinoe are predominantly benthophagous. In the first half of May 2013, near the water intake canal, the main food components were the nymphs of the Corixidae water bugs and larvae of Phryganea caddis flies, planktonic crustaceans and imago of aerial insects were also consumed. In July 2014, in the discharge channel, the main food item was the chironomid larvae. In the lake Sludyanskoye, three specimens were identified from the stomachs of the pike living there. All fish were partially digested, and therefore it was not possible to analyse it.