Appendix E
SUMMARY REPORT OF THE EIFAC SYMPOSIUM ON INLAND FISHERIES MANAGEMENT AND THE AQUATIC ENVIRONMENTINTRODUCTION
1. A Symposium on Inland Fisheries Management and the Aquatic Environment: the effects of fisheries management on freshwater ecosystems, was organized in conjunction with the Twenty-second Session of the European Inland Fisheries Advisory Commission (EIFAC) in Windermere, United Kingdom, from 12 to 15 June 2002. Mr D. Gerdeaux (France) convened the Symposium, which was chaired by Mr I.G. Cowx (United Kingdom). The Symposium was attended by 114 participants from 27 countries.
2. The Symposium objectives were:
SESSION 1: IMPACT OF STOCKING AND INTRODUCTIONS ON THE ENVIRONMENT
3. Stocking and introductions of non-native species are widespread management techniques that aim at improving the quality and diversity of angling. They are also used to manipulate population structures to influence food webs in order to restore water quality and ecosystem health.
4. Some introductions are made illegally because angling demand is high and commercial benefits override the small penalties incurred.
5. Species-poor fish communities, such as those of European freshwater fish, favour the establishment of non-native populations and are vulnerable to invaders. Direct assessment of the impact of introductions is seldom possible but the local increase in species richness is likely to increase niche overlap, and therefore inter-specific interactive relationships. Interactions could result from competition with indigenous fish or direct predation on native populations.
6. Genetic effects of introductions and stocking are significant and co-introduction of parasites has enabled some diseases to become widespread in Europe.
7. Despite these negative aspects, introductions of some species have been successful where no detrimental effect have been observed while the introduced species now support sustainable fisheries.
8. Fish introductions should not be systematically assumed to be negative but risks are probably higher with exotic species than those made with transplants.
9. There is often insufficient information, on impacts of introductions and stocking programmes particularly, because there is no network for monitoring. Causal relationships are, therefore, difficult to distinguish from indirect correlation with environmental parameters. Managers have a dual role in that they have to maintain, improve and develop fishing at the same time as having to protect the environment. Such a situation can lead to conflicts.
10. Nevertheless, the threat posed by fish introductions is particularly insidious because restoration management tools are not available. Therefore, the precautionary approach should be adopted with regard to the introduction of species, particularly in the case of non-native fishes.
11. Increasing scientific understanding of fish and their habitat will be required to support legislation. More research is needed on behaviour and the mechanism involved in the spread of non-native species. There is also a need for more information on the ecological and dynamic impacts of stocking, the economic evaluation of inland fisheries and the impact of introduced parasites on fish stocks.
12. Stocking programmes represent a major element of fisheries management in much of Europe. The relative merits and cost effectiveness of stocking rivers with different life stages and at different times of the year could be useful in determining if stocking contributes to stock enhancement. When stocking rivers with fed salmon fry, a net gain can be realized when natural survival rates from egg to smolt are in the region of 1 percent or less. At high survival rates in the wild, the advantage of rearing and stocking fish is diminished. For coarse fish, chub, dace and roach, stocking either 1+ or 2+ is unlikely to make a significant difference to catches. In river restoration situations, however, where no population exists, stocking older fish of 2+ years is likely to be more cost effective and lead to faster establishment of self-sustaining population. Knowledge of survival rates is still lacking.
SESSION 2: FISH BIOMANIPULATION AS AN ENVIRONMENTAL MANAGEMENT TOOL
13. Several biomanipulation approaches are used in Europe: (a) the traditional approach to biomanipulation by enhancement of predators and reduction of planktivorous fishes without participation of local stakeholders, and (b) advanced approaches: biomanipulation considering the socio-economic demand of anglers and commercial fishermen, and biomanipulation conducted mainly by means of the fishery.
14. Fish stocks are not always the cause of algal blooms and bottom-up controls may be equally successful under highly eutrophicated conditions.
15. A newer approach to biomanipulation includes the socio-economic interests of recreational and commercial fisheries. This involves stakeholder analysis. The experience and the motivation of the recreational and commercial fishermen can contribute to successful biomanipulation.
16. The classic approach to biomanipulation using small brown trout at low stocking densities as a predator for deep and cool reservoirs does not seem to be effective for biomanipulation in central Europe. The influence of higher stocking densities and higher individual weight of trout on the proportion of fish consumed needs to be further investigated.
17. The proposed step-by-step guideline for lake restoration by biomanipulation is a valuable attempt at reconciling fisheries and water quality management by integrating all stakeholders interests. It provides advice for the use of biomanipulation as a regular tool in water quality management. It has to be tested in practice, and the technological parameters have to be completed. The power of the approach lies in the integration of traditional fisheries management measures such as stocking of piscivorous fish with ecosystem-based management. The continuity of interventions is paramount for the long-term success of biomanipulation programmes.
18. The inclusion of experienced carp anglers in biomanipulation projects can be recommended in cases where dense carp stocks lead to a resurgence of eutrophication. Catch and release should be avoided in biomanipulation projects.
19. Data on the amount of baiting should be included in further projects. Bait seems to be a substantial P-source in some cases but more experienced anglers increase their catch without increasing the amount of ground-bait used. More experienced anglers may help to reduce the amount of ground-bait used. Further investigations on P-reduced baits are necessary. Furthermore, specific management guidelines for ground- and pre-baiting are needed because ground-baiting is generally common among coarse fish anglers.
20. The long-term inclusion of fishermen seems to be necessary to the success of biomanipulation projects that depend on continuous fishing pressure and should be adopted especially in countries with significant commercial fisheries.
SESSION 3: REHABILITATION OF INLAND FISHERIES
21. In lakes, fish such as salmonids require satisfactory DO concentrations. Deep-water salmonid habitat can be expanded in lakes suffering from depleted summer oxygen levels by artificial mixing and raising hypolimnic DO levels by oxygenation to at least 4-5 mg/l. Rehabilitation of lakes by artificial oxygenation has shown varied results. Oxygen levels can be elevated resulting in recolonization by fish and invertebrates. Experience has shown that continuing input of nutrients to lakes continues the eutrophic condition and the risk of fish killed from toxic algae production persists. Furthermore, sediments continue to be anoxic and mortality of whitefish eggs will continue.
22. Utilizing cutaway bogs in areas where peat extraction has been terminated can create new fishing opportunities. The size and shape of the created lakes is dictated by the intended purpose of the fishery. Research has shown that water quality in newly created lakes in cutaway bogs is excellent and that plant colonization in the newly created lakes was nearly 95 percent within three years. Although self-sustaining populations have not yet been observed, it is estimated that a stocking rate of 200 kg/ha can maintain a healthy population and provide excellent catch and release fishery for tench and carp. These artificial fisheries can have a considerable amenity value.
23. There is a need to have an overview of the entire catchment in establishing programmes for the restoration of salmonid riverine catchments. Base line studies are needed for an understanding of the relative importance of imbalances in individual channels relative to the overall catchment. Baseline studies of salmonid catchments in preparation for river restoration have identified problem areas, allowing the generation of habitat enhancement procedures that will restore a natural balance. Key problem areas include arterial drainage programmes for flood relief, removal of riparian vegetation to extend grazing opportunities and sheep and cattle overgrazing. A combination of use of natural materials, fencing out cattle and riparian plantings have been successful in mimicking natural conditions in all three categories of damaged channels. It is recommended to leave one subcatchment aside as a control to monitor effectiveness of restoration.
24. Rehabilitation and enhancement activities are often unsuccessful due to lack of understanding of the biotic and abiotic factors influencing the fish populations under study. Rehabilitation schemes often fail to address the wider catchment problems and issues affecting fish communities.
25. Reduction of impacts to fish habitat by development and resource extraction can be achieved by a number of activities but cannot be made by government intervention alone. Agency partnerships as well as legislation enforcement and compliance are necessary but greater emphasis must be made on advice to clients, public education and outreach activities to engender stakeholder participation in conserving habitat.
26. Long term flooding of floodplain ponds increased species richness and relative abundance of fishes showing that borrow pits represent valuable spawning and nursery habitat. However, nursery habitat appears to be limited due to untimely recession of the floodwaters, which could negate any positive effects. Improved control of duration of flooding could be a useful tool but requires further study.
27. Often fisheries do not improve as expected following rehabilitation works. Additionally, improvements achieved often do not warrant the expense of the scheme. Restoration works in many cases cannot achieve the desired results because fisheries managers’ expectations are too high. Furthermore, identification of bottlenecks to viable fish populations in the whole catchment is essential for the planning of individual restoration projects and should be undertaken before their initiation. Post project monitoring of rehabilitation works is essential if unsuccessful schemes are not to be duplicated.
SESSIONS 4 AND 5: IMPACT OF FISH COMMUNITY MANAGEMENT
28. 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 stakeholder’s 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).
29. Computer modelling using an eco-hydrological approach in combination with computer analysis of literature data, can be used to describe various effects of physical 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.
30. 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.
31. 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.
32. Finnish experience with the conservation of native 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 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 reproduction potential than the native noble crayfish.
33. Classification of species as native and non-native, and mapping the species richness in French reservoirs on a larger scale opens new possibilities for 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. This study has shown statistically that the introduction of non-native species leads to lower species richness and a reduction in species-biodiversity.
34. 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 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.
35. In Hungary 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.
36. 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 aestethic value. Attitudes of stakeholders in the Ramsar conservation area, the Regional Park of the Nemunas Delta, indicate that 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.
37. The review of US and European 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.
38. The democratic process necessary to protect, restore or fund research 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.
39. 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 are available.
40. The change in perception of natural, as well as artificial waterbodies, is slowly changing traditional fisheries management into ecosystem-based 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 and tourism. At the same time there is an opposing trend towards the intensive management of artificial water bodies as put-and-take fisheries.
SESSION 6: ROLE OF FISH CONSERVATION IN ENVIRONMENTAL MANAGEMENT
41. Fresh waters have suffered the most intense intervention of all ecosystems over the past 100 years. Many fish species are now extinct, rare or endangered and many species are now protected by active management of the environment, as well as more traditional conservation methods of management, including regulation of exploitation, nature reserves, captive breeding programmes. Implementation of the management plan for the conservation of Anaecypris hispanica in Portugal might have benefits both to fisheries and to ecosystems.
42. The survival of rare sturgeons and conservation of their genetic diversity is of great economic and biological significance. Because the possibilities for management and protection of wild populations are limited, it is important to develop and implement measures for the conservation of a wide diversity of world sturgeon populations under artificial conditions. One of the most urgently needed measures for conservation of sturgeon biodiversity is the establishment and maintenance of collections of live sturgeon as gene banks. Conservation of complicated population systems requires an assessment of total genetic variability, including intraspecies variability. The adequate conservation of genetic resources according to the population structure of different species must be ensured. Research in the Sea of Azov on seasonal regime dynamics, food sources in brackish lagoons and rearing ponds of sturgeon hatcheries, index of survival and rates of growth of various age-graded Russian sturgeon (Acipenser gueldenstaedti) and stellate sturgeon (A. stellatus) juveniles, produced by natural and artificial reproduction in different conditions, resulted in a proposal for a new scheme to release juveniles to natural water bodies.
43. Long-term ecological and physiological monitoring of sturgeon populations showed the positive role of artificial propagation, and suggests a simplified strategy aimed only at increasing the number of released juveniles. The imperfections of traditional biotechnologies considerably transform species, as well as the population structure of sturgeons.
44. Different release locations of sturgeon juveniles of various sizes and ages in various conditions would help maintain populations and minimize the selective consequences of artificial propagation. Migration of juvenile sturgeon to the sea in natural conditions at different ages has a deep adaptive significance and confirms the biological importance of intrapopulation differentiation. The conservation of a variety of Russian sturgeon, stellate sturgeon and giant sturgeon (Huso huso) released at different dates, permits a gradual and more rational use of food resources of brackish lagoons and marine coastal areas, compared with traditional large-scale and simultaneous standard release of juveniles into rivers.
45. Research work carried out in Minsmere reedbed reserve (United Kingdom) have identified the potential application of fish population management as a key component to the suite of tools available to enhance the conservation status of bitterns and probably that of other fish-eating birds.
CONCLUSIONS AND RECOMMENDATIONS
46. The Symposium considered biological, environmental, social and economic impacts of fisheries management of lakes and rivers. Fisheries management has produced clear benefits to the ecosystem and to stakeholders over and above benefits to the fishery itself. However, such activities as stocking and introduction can produce negative impacts, but this is not always the case.
47. The Symposium highlighted that traditional fisheries management is not always implemented successfully in European inland fisheries. At the same time, the trend away from traditional management of fisheries resources towards integrated management of the ecosystem emphasizes the need to develop new participatory approaches.
48. Many of the issues and approaches highlighted have fundamental implications to the EU Water Framework Directive because of the need to improve the status of fresh waters in the future. The implications of global environmental change should be recognized and given due consideration in future management approaches.
