Sustainable biodiversity of Lake Peipsi through improved monitoring methods

One of the key components of Lake Peipsi's biodiversity is definitely the species richness of its fish population. The most important management decisions of the fish stocks in the lake are based on experimental trawling regularly carried out since 1994 by the Estonian Marine Institute. The methodology has been developed in cooperation with the colleagues from Russian Federation to monitor the main commercial species of the lake, which are predominatly demersal (i.e. bottom-dwelling). However, in recent decades, due to the high fluctuations of some pelagic species (especially vendace, a highly valued food fish) there have been concerns that the current monitoring methodology is not sufficient and optimal to maintain a good level of pelagic populations and thus also general biodiversity in the lake. Several possible improvements in the monitoring program have been proposed (e.g. monitoring using pelagic trawls, sonars, monitoring during night-time), but due to limited funding and no clear agreement with the Russian colleagues, the improvements have been postponed. The objective of the current project is to test these improvements without the participation of Russian colleagues in order to come up with an improved biodiversity assessment methodology, that could be transferred to the whole lake in the future. More accurate and diverse monitoring of the fish resources of this lake system would result in higher quality of the management decisions and in conclusion reduce the unnecessary fluctuations in the populations, which could otherwise lead to the loss of biodiversity. A well-managed and diverse structure of the biological resources in lake Peipsi is highly important to the fisheries and tourism sector around the lake, as well as contributes to the food security of the communities. The main activities under the proposed short-timed project will be the introduction of the monitoring program of pelagic communities using scientific pelagic trawl. Such a monitoring program needs extensive experiments and tests before it can be implemented as a routine part in the future fish stock assessment. For that objective we will import the methodology from Swedish and Finnish big lakes (size comparable to Lake Peipsi) with preliminary know-how and will adapt the solutions to the shallow and more diverse lake Peipsi conditions.

A higher level of quality monitoring in lake Peipsi will lead to more accurate and stable management decisions which avoid threats to ecosystem components. Successful implementation of the new and improved fish monitoring program will lead to increased capacity to preserve the stocks and guarantee long-term stability in environmental protection as well as in the fisheries sector. Improved stock assessment methods could be implemented also on the Russian side of the lake, after the stabilization of the political situation at the EU-Russia level.