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summaries - sixth MARBENA e-conference
- Session 1: Biodiversity Action Plan for Fish - fishstock biodiversity
- Session 2: Biodiversity Action Plan for Fish – non-target species biodiversity
- Session 3: Biodiversity Action Plan for Fish - Aquaculture
- Session 4: Biodiversity Action Plan for Natural resources
- Session 5: Biodiversity Action Plan for Economic development
Summary of discussions on Session 1: Biodiversity Action Plan for Fish - fishstock biodiversity
By Einar Eg Nielsen and Uwe Piatkowski
The session was introduced by Einar Eg Nielsen, who outlined current knowledge on biodiversity in fish-stocks and threats to fish-stock biodiversity such as over-fishing and global warming. The level of knowledge is sufficient to know that we should take action to preserve biodiversity in exploited fish stocks. The future challenge will be to formulate appropriate management actions for the preservation of genetic diversity. This will require consensus on what it is we are trying to preserve (e.g. alleles, traits, population structure) and some means of assessing genetic "status". The introduction was ended by a series of questions regarding fish stock biodiversity, which opened the floor for discussion.
The introduction was followed by a discussion on the role of modeling in fish ecology and management of fish-stock biodiversity. This discussion was spawned by a contribution suggesting that modelling of fish stock abundance is too complex to give any good predictions, since the fish are a part of a large and multifaceted ecosystem. Other contributions focused on the quality of data fed to the fisheries models. There were concerns regarding the reliability of official catch statistics and data from scientific surveys on diminishing populations. There was a general consensus that this would lead to uncertain and in some instances wrong predictions from the models. A phenomenon termed “rubbish in – rubbish out”. It was also suggested to abandon the current way of modelling by picking up on the methods applied in metrology and bioinformatics, so-called inferential models. These models do not rely on pure mathematics, but more pattern recognition and case based reasoning by employing neural networks and artificial intelligence.
Finally, it was discussed whether there was a need for a paradigm shift abandoning modelling of fish stock abundance as a tool for managing fish-stock biodiversity. One possibility would be to use protected zones/marine reserves instead. These areas could at the same time serve as general reference points for marine biodiversity. The application of marine reserves as a tool for managing marine biodiversity, however, needs a much more co-ordinated global fishing effort to be effective.
Summary of discussions on Session 2: Biodiversity Action Plan for Fish – non-target species biodiversity
by Michel Kaiser, Melanie C.V. Austen and Henn Ojaveer
A priority identified during the forum was the need to search for methods that might enable the determination of any broader effects of fishing on ecosystem functioning. An examination of ecosystem function moves away from a species by species approach to the examination of the effects of fishing and implies that groups of species or taxa perform similar roles or functions within the ecosystem. The majority of species compose a minor proportion of the total abundance or biomass of most assemblages. As a consequence the loss or replacement of a proportion of the less common species may result in no net change in ecosystem functioning. There was some disagreement with this proposition and it was felt by some that our understanding of the links between loss of biodiversity and loss of ecosystem functioning were insufficiently robust at present based on limited and simplistic mesocosm manipulations of species richness. As a result, the true ecological importance of non-target species was unknown and hence it is not possible to imply ecological redundancy based on our current knowledge. In such circumstances, the use of the precautionary principle was advocated in terms of management measures. However, if assemblages are resilient to the loss of a certain proportion of species, the critical question remains ‘the loss of how many species results in an alteration of ecosystem function?’ and does this have wider consequences for human society? While most contributors appreciated the need or desirability to study the ecological role of individual species, the practicality of such an undertaking, and current funding constraints, dictate that monitoring of the effectiveness of BAP needs a two pronged approach: detailed but targeted studies to understand smaller-scale ecological issues in conjunction with a wide-scale uniform effort in the assessment of more fundamental community characteristics. The discussion also focussed on the BAP research priorities in terms of the level at which they are aimed. Some thought that these should have a stronger emphasis on research to understand the ecological importance of different organisms and biodiversity in general and their relationship to ecosystem maintenance and the sustainability of the ecosystem itself (including the fisheries). Research priorities that focus on ‘biodiversity indicators of ecosystem health’ would address this requirement. The current research priorities of the BAP for Fisheries seem biased towards the ‘topdown’ (predatory fish removal) effects rather than considering the implications of fishing at all trophic levels (from marine mammals down to the benthos). The outcome of this ‘fisheries’ approach to the non-target species BAP means that the research priorities are focussed on the implementation or development of technical or mechanical measures to reduce adverse effects. This is of concern particularly given the lack of fundamental knowledge with regard to non-target species in marine ecosystems. Moreover, there are discrepancies in the level of knowledge for different European seas, with wide variation in the complexity of different systems (e.g. The Baltic c.f. The Mediterranean).
There was some consensus that fishing capacity and fishing effort (amount of time spent fishing) should be matched with the available resources (fish) as this will inevitably reduce the impact of fishing on non-target species. Yet the failure to implement appropriate effort reductions proposed over the last 20 years of CFP has resulted in the current situation of declining stocks and fleet overcapacity. Matching capacity and fishing effort with the available resource will be extremely painful for the fishing industry in the short to medium term. It was considered that the reality of unpalatable economic hardship has resulted in the focus on technical measures in the BAP. Technical measures are often easier to implement than an overall reduction in fishing effort and fulfil the requirement for some (any) remedial action to be effected, even if it means that the real problem is not addressed. The BAP for Fisheries has made positive steps towards a consideration of the wider effects of fishing on the marine environment but adequate monitoring will be needed to determine the success of any resulting initiatives, which will require the clear goals and objectives against which achievements can be measured. The BAP for Fisheries targets for 2010 need to be set in light of the objectives and aims of other conventions or agreements that affect similar species. There is also potential for over-lap among the different BAPs which has the potential for positive synergies (e.g. reducing fishing effort benefits for both commercial fish stocks and non-target species), but also carries the risk of antagonistic actions (e.g. the displacement of a fishery to conserve a commercial stock resulting in negative effects for nontarget species that are affected as a result of the displacement of activities).
There was considerable discussion over the rationale behind the utility of Marine Protected Areas (MPAs) to achieve either traditional fisheries management goals or wider-ecosystem management objectives such as the conservation of non-target species or habitats. The combination of adequately designated and managed closed areas in combination with reduced fishing effort was advocated to achieve a sustainable ecosystem approach to management. The mechanism of deciding which areas should be designated as MPAs was considered problematic. Some argued that MPAs can never be too large (a precautionary approach) but that their designation needs input from a broad range of ecologists and marine scientists, not just fisheries biologists. It was also argued that reduction of time that fishing boats spend at sea would lead to a decrease in the overall area of the sea affected by fishing activities, and that this on its own could achieve many of the aims of the BAP Fisheries for non-target species. Faced with a reluctance to reduce the time spent at sea we may be forced to turn to the use of No Take Zones or MPAs as a last ditch mechanism of reducing the adverse affects of fishing, but this may not be the optimal approach (c.f. fishing effort reduction). All concurred that sensitive habitats could only be fully protected from the adverse effects of fishing activity through the exclusion of fishing gear from appropriate areas of the seabed. Reducing fishing effort is critical as it could address many current fishery related problems through one action. In the current political climate, a combination of different approaches could ensure a long term future for a marine environment with a diverse range of ecosystems, habitats and species, coexisting with human activities such as fishing.
It was considered that it was difficult to encourage fisheries managers to consider the wider ecosystem effects of fishing in their deliberations regarding fish stock management, particularly in the case of the former Eastern Block states. For these states, wider ecosystem effects of fishing are likely to be much further down the list of management priorities. A considerable effort in terms of education was considered to be essential to encourage the fisheries managers within EU new member states to take a more holistic view of the consequences of fisheries exploitation.
Acknowledgements:
The summary of the conference presented herein represents the authors’ views and interpretation of the substance of the forum. These views do not necessarily fully represent the opinions of all the contributors to the forum. In addition to the authors, the following individuals contributed to the forum: F. Blanchard, R. Blyth, F Boero, R. Ferris, E. Koutrakis, P. Lorance, E. Mostarda, E. Pinn, F. Pranovi, C. Von Dorrien.Summary of discussions on Session 3: Biodiversity Action Plan for Fish - Aquaculture
By Ioannis Karakassis
Altogether 3 scientists participated in the discussions concerning Session 3 (F. Boero, S. Orfanidis and C. Zago). Among the issues described in the opening statements, the participants addressed only issues regarding the ecological efficiency of fish farming and the effects on Posidonia meadows. Concerns have been expressed regarding the sustainability of the mariculture particularly when carnivorous species are farmed demanding high input of fish protein. It has also been estimated that the effects on Posidonia meadows impose a rather high ecological cost since sea grass ecosystems offer high value ecosystem services. The potential use of alternative aquaculture practices (sea grass farming) as a means for restoration of disturbed habitats has been discussed and there have also been suggestions that polyculture could be used to minimize the ecological effects of fish framing.
However, the main issues regarding the efficiency of BAP priorities have been little discussed during the electronic conference despite the large scientific audience that has been involved in research on aquaculture-environment interactions during the last years. Perhaps, the lack of adequate response denotes that there is still a lot of research needed before arriving at firm conclusions on the significance of aquaculture effects on biodiversity.
General coordination: Carlo Heip ,Herman Hummel and Pim van Avesaath Web site and conference hosted by VLIZ |