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Fish resources and level of their exploitation concerning major commercial fishes.Commercial stock of one of the most valuable fishes - whitefish - is thought to be about 600 ton. Official data state that the catch of whitefishes in 1995 was 191 ton. Experts estimate the actual catch to be 1.5-2.5 times higher than the official figures. Thus, in the last several years 60 to 80% of the commercial stock production have been harvested. The fisheries press on the Ladoga whitefish population is evidenced also by the data from trawl surveys about the shortening of fish life from 13-14 to 9 years, and shrinking share of older age groups in the stock. Mean many-year catches of the Ladoga cisco in Ladoga were 160 ton. In 1974 a thousand ton was caught, where in 1995 it was only 50 ton. The bulk of the commercial stock (88%) in our days is 2-3-year old fish. Maximum vendace yield in the southern part of the lake was recorded in 1983 (1,500 ton, with the mean many-year catch being 1,100 ton). In 1995 vendace catch was only 500 ton. The main smelt fishing sites in the southern part of the lake are the Volkhov and Svir bays. Smelt harvest in 1995 was 1,100 ton, which is 200 ton more than in 1998. The 1995 catch made up 49% of the commercial stock production, which indicated the normal degree of the stock exploitation. After 1986 official pike-perch catches were observed to decline. In the 1980's catches of the species in the southern part of Lake Ladoga fluctuated from 1,100 ton in 1986 to 600 ton in 1988. In the 1990's the minimum catch (182 ton) was recorded in 1994, the maximum (455 ton) - in 1991. However, Statistical data do not give the complete account of the actual pike-perch catches in Lake Ladoga. Experts believe that the real catch is 2-3 times higher than the officially recorded one, and the species is actually being overfished. Bream in Lake Ladoga is a commercial species of secondary importance. Its harvests in the southern part of the lake in 1980-1994 varied from 34 to 345 ton. The catch in 1995 was 49 ton, or 28% of the harvestable part of the population. According to statistical data such harvests indicate low exploitation of the stock. One needs to remember however that large bream are usually sold not through the official trading system. Anyhow, even with the account of illegal fisheries the stock is not over-exploited. The stocks of roach, perch and other under-size fish in the lake are quite considerable, and under-exploited. In 1995 150 ton of roach and 239 ton of perch were harvested. The greatest contribution to the catches in the group "miscellaneous" is made by white bream and ruffe. In 1995 the catch of smaller under-size fish, belonging to this group, was 110 ton. |
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