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Sessions 4 and 5: Impact of fish community management


43. The scientific community employs a range of methods including modelling, literature reviews and case studies. However, there is also a clear need for increased stakeholder involvement in practical management. Social sciences use quantitative methods in combination with interviews, SWOT-analysis (Strengths, Weaknesses, Opportunities and Threats) and Rapid Rural Appraisals to find out stakeholders’ views on topics, including sturgeon management. Indicator fish species populations were similarly used to quantify the level of the disturbance under the Water Framework Directive (WFD).

44. A French project aimed at involving fisheries management in the application of the WFD divides the national hydrographic network into "contexts", defined as the minimum geographic area/unit able to sustain a complete life cycle of an indicator species population. One case study distinguished five contexts and showed that many aquatic ecosystems are disturbed. The quantitative approach, using indicators, gives the opportunity to propose priorities for action by managers in line with the WFD requirements. This method should be further developed for use in other EU countries.

45. Computer modelling using an eco-hydrological approach in combination with computer analysis of literature data, was used to describe various effects of physically degraded fish habitats in a whole catchment. The results indicate that restoration to a pristine level is not necessary. Rather, the target should be a quality of environment that achieves a compromise between maximum biodiversity and maximum productivity of fish. Impacts on fish habitats are either technological and can be controlled technically, or environmental, such as deforestation, urbanization and canalization. This approach is similar to that adopted by the French on WFD and future cooperation is therefore recommended.

46. Problems are being encountered in Lake Peipsi-Pihkva arising from differences in the species targeted by the fisheries of Estonia and the Russian Federation. Traditional fisheries management may be used to reach the objective of raising the stock, and thereby the actual and potential catch, in a confined lake shared by two nations with shared fish stocks. The choice of technical/physical measures to increase the selectivity and lower the efficiency of the fishing gear, for instance, by larger mesh-sizes, and imposing quotas limiting the total annual catch have successfully raised the catch potential of the stock to cater for higher demand.

47. Similar problems were encountered with the current conservation strategy for sturgeon in the Lower Danube River, which may largely be responsible for the collapse of fisheries and the extinction of the species. The results call for classical remedies including a decrease of fishing effort, catch control, protection of spawning areas, etc. Monitoring and stock assessment measures are needed for better management policies, as is also the enforcement of any regulations.

48. Finnish experience with the conservation of native crayfish (noble crayfish) and the French experiences on the contribution of native and non-native species to fish communities both analysed the impact of non-native species on native species and biodiversity in inland waters. The Finnish example shows the strength of clear and well-defined management rules and practices. It also emphasizes the incentives for local stakeholders not to comply with the rules, as the introduced signal crayfish, that are now restricted, are resistant to crayfish plague and have better growth and reproducing potentials than the native noble crayfish.

49. Classification of species as native and non-native, and mapping the species richness in French reservoirs in a larger scale opens new possibilities of comparing development in fish communities. The underlying ethical objective states that native species per se are of higher value to society than introduced or stocked non-native species. The results of this study therefore add new dimensions to this statement in that it has shown statistically that the introduction of non-native species leads to lower species richness and a reduction in species-biodiversity.

50. In Finland institutional changes have induced changes in fisheries governance closely related to changes in society. The attitude towards the Saimaa ringed seal has changed from that of a competitor to the fishermen and now the seals are partly perceived as part of a diverse fauna in need of conservation. Private ownership of waters is an important factor when regulations are needed on a large scale.

51. Management of fish communities and its impact on the lower trophic levels in shallow ecosystems in Hungary aims at investigating how bio-manipulation in the lakes can lower the nutrient load of the lakes. Different levels of fish stock influence the lower trophic levels differently. Traditional means of reducing external nutrient loads may be aided by a reduction in the biomass of cyprinid fish in shallow waters dominated by these species and thereby decrease phytoplankton biomass. The results build on manipulated pond experiments, food web studies and studies in a smaller lake, as well as studies on the very large Lake Balaton.

52. A conservation project in Lithuania studied socio-economic developments subsequent to the integration of inland fisheries with other aspects of wetland management. The views of the public towards poachers and fish eating birds as a threat to fish stocks are influenced by a number of factors including insider/outsider status, their perceived needs, greed and their aesthetic value. The stakeholders in the Ramsar conservation area, the Regional Park of the Nemunas Delta, rely largely on fishing, agriculture and peat cutting. Their attitudes towards threats to fish indicate that there are human predators in the form of poachers, as well as non-human ones in the form of birds. Individuals are classified as insiders, who are looked upon positively, or outsiders who are considered negatively. This indicates that cultural and social aspects should be recognized and evaluated when conservation policies are established.

53. The review of USA/Europe literature describes the role of constituencies in resolving problems for fishery and biodiversity management, as well as their role in decision making when taking remedial action. The ecocentric approach of biodiversity, consisting of management aiming at restoring a "natural" native fish population, immediately raises problems of definition. Any scientifically based policy statement on biodiversity issues, therefore, needs a more pragmatic stance to be able to gain broad stakeholder support. Ecosystem-based management systems represent a paradigm shift and may best be described as adaptive management, which may be applied to both "altered" or "original" freshwater ecosystem fishery.

54. The democratic process necessary to protect, restore or fund programmes for biodiversity of fish faunas calls for regulations which are accepted and complied with to reduce risk or prevent damage. This goal is most often reached only if the incentive is either positive self interest or a feeling of collective moral and social obligations. Effective fisheries management therefore depends on public support and very often the perception of personal as against collective value trade-offs. For example, the issue of protecting against both intended and unintended introductions of exotic species is a biological, political and economic problem that raises conflicts of value between different stakeholder groups and needs political mitigation to succeed.


55. Traditional fisheries management is still not implemented successfully in many aspects of European inland fisheries. Further, there is a lack of incentive-based regulations in practical fisheries management, even though the scientific knowledge for implementation of more efficient management tools is available.

56. The change in perception of natural, as well as artificial waterbodies, is slowly changing traditional fisheries management into eco-system management. This calls for new management tools to cater for legitimate human demand for recreation, as well as alternative commercial use of waterbodies such as bathing, boating, tourism. At the same time there is an opposing trend towards the intensive management of artificial water bodies as put-and-take fisheries.

57. This session has presented initial work on bio-manipulation in shallow lakes, which may in the future lead to more applicable methods for large-scale implementation.

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