Long-term assessment of a vendace (Coregonus albula L.) stock in Lake Paravani, South Georgia
A total sample of 1854 vendace (Coregonus albula L. ) specimens was collected on a seasonal basis from Lake Paravani during 1999–2005. Nets of different types (seines, trap nets and gillnets) with various mesh sizes and length were used for sampling. Samples were collected from 3 horizontal strata. In the samples collected, most vendace were age 1+ and 2+ although a few individuals lived to age 4. Vendace is the dominant species comprising 70% of the annual catch. Catches from this study were compared with historical data. It was found that the annual abundance of vendace decreased dramatically from 1994 to present, from 50 tonnes to 17 tonnes or less annually. The average size of vendace in catches has also decreased in recent years. We believe intensive poaching, in addition to commercial fishing, climate changes and global warming, are the leading factors that have caused the decrease in overall number of individuals and the smaller sizes of adult vendace in the current population.