1. In accordance with the decision of the Seventeenth Session of EIFAC, Lugano, Switzerland, the Third Session of the Working Party on Stocking was organized by D. Gerdeaux, and held in Thonon; France, from 15 to 19 November 1993. The meeting was attended by 11 participants; 9 were from the following EIFAC countries: Gerdeaux and Champigneulle (France), Salojarvi (Finland), Hartmann (Germany), Bninska (Poland), Enderlein (Sweden), Banks, Cowx and Lorenzen (U.K.). Reshetnikov (Russian Federation) and Petr (FAO, Italy) also attended, the last as Technical Secretary of this Working Party (see Annex 1).
2. The major objectives of the meeting (for the Agenda see Annex 2) were to:
3. The final draft of the Guidelines for Coregonid Stocking had been circulated before the meeting. This draft was a concise and updated version of the previous draft, and included comments and suggestions from discussions held during the Second Session (1991, Beroun, Czechoslovakia) and the ad hoc meeting (1992, Lugano, Switzerland) of the Working Party. The Guidelines were discussed in detail and amended. The discussion showed the difficulty of producing general guidelines on a group of species with geographical distribution in subarctic and temperate water bodies, of different levels of trophy and pollution and with different dominance of coregonid species. Banks offered to produce the final edited version and submit it to the EIFAC Secretariat by mid-January 1994, so that it could be published and distributed prior to the 18th Session of EIFAC in May, 1994. The Contents of the document is presented as Annex 3 to this Report. The full document is to appear as an EIFAC Technical Paper.
4. A draft document on Stocking Strategies, presented by Cowx, was prepared in response to suggestion of the ad hoc meeting in Lugano, 1992. This draft (see Annex 4) provides general principles of stocking and describes a strategic approach to stocking aimed at maximizing the potential benefits. The recommendations address the need for clear identification of objectives, strategies for stocking approach, necessity for post-stocking evaluation of the stocking efficiency, and a cost/benefit analysis. This document should be considered as being complementary to the guidelines on individual groups or species of fish in preparation, e.g. salmonids. Further guidelines for the conservation of genetic resources and population genetic structure of a fishery that is to be rebuilt or augmented through hatchery produced stocking material could be used. These guidelines have been derived from Dr. D. Bartley at an FAO Expert Consultation on Utilization and Conservation of Aquatic Genetic Resources, Grottaferrata, Italy, 1992, and a Workshop to produce a User Manual to facilitate Implementation of the ICES/EIFAC Codes of Practice and Manual of Procedures for Consideration of Introductions and Transfers of Marine and Freshwater Organisms held in Manila, Philippines, 11–13 November 1993, and are available from Dr. D. Bartley, FAO, Fisheries Department, Rome, Italy.
5. In response to the recommendation of the 17th Session of the EIFAC, Lugano, 1992 to consider the application of new theoretical models on stocking, Lorenzen gave a presentation on population dynamics modelling and adaptive management for Asian culture-based reservoir fisheries without natural recruitment (Annex 5). The model incorporates explicit sub-models for density-dependent growth and size-dependent mortality. All parameters used in the model could be estimated from stocking and catch data, provided that there is some variation in the biomass density and the size of seed fish. This presentation should be considered to be the first step towards formulating and testing theoretical models on stocking. The Working Party recommended compilation of existing quantitative methodologies for the assessment of stocking practices and requested Lorenzen to prepare the first annotated bibliography to be presented for further consideration at the 18th Session of EIFAC in Rome, May 1994. As much of the information is expected to be in the grey literature, the next step proposed was to request, at the 18th Session of EIFAC, additional information through national correspondents. Salojarvi informed the meeting that stocking models are going to be tested on coregonid data for different Finnish lakes. This work is to be executed in collaboration with Beverton and his group in Cardiff, Wales. After some discussion the meeting supported the proposal to await the results of the bilateral collaboration between Cardiff and Finland, and based on these to decide how to proceed in the second phase.
6. Reshetnikov presented a simulation model for optimizing the production of stocking material of coregonids in ponds.
7. The preliminary results of the questionnaire on current stocking practices, based on replies received from 15 countries, were presented by Banks. The data are heterogeneous and cannot fulfil the quantitative objectives as the informants in many cases have not provided information on individual life stages stocked in different water bodies. Some countries (Netherlands, Austria, Switzerland) will be contacted again by Banks. It was also agreed that Hartmann will supply information on Lake Constance. Overview of the results is presented as Annex 6. This overview has guided the current session of the Working Party in its decision on the priority needs for future guidelines. More detailed analysis will be completed for the 18th Session of EIFAC, distributed as an information paper at the Session and presented there for discussion.
8. The Working Party agreed on the following first steps for the preparation of guidelines on stocking of salmonids. The existing guidelines, e.g. those already available for Finland and France, to be translated into English. Salojarvi from Finland and Gerdeaux from France agreed to arrange for the translations. The members of the Working Party will in the meantime approach experts in salmonids to review the suitability of the existing guidelines and their potential use in the preparation of guidelines for Europe. The Chairman of the Working Party will coordinate the information flow between the members of the Working Party and reviewers, arrange for delivery of the documents, so that the assessment of the existing guidelines is available for discussion at ad hoc meeting of the Working Party at the 18th EIFAC Session. The Working Party agreed that the future salmonid guidelines should deal with the following species: Salmo trutta, Oncorhynchus mykiss, Salvelinus alpinus, and S. fontinalis. The ad hoc meeting in Rome should also discuss the first responses to the coregonid guidelines, and use the information to develop strategies for the preparation of guidelines on salmonids.
9. The possibility of organizing a mini-symposium on the contribution of stocked fish to the total yield was discussed. Cowx informed the meeting that he was prepared to organize a Symposium on stocking and introductions in April 1996 in Hull, U.K. This could be used as venue for the next session of the Working Party and a Workshop as proposed for the mini-symposium. The Chairman of the Working Party was requested to correspond with Cowx about arrangements and to let the EIFAC Secretariat know about the outcome in the near future. For meaningful discussions the Working Party should be expanded to incorporate other European experts and the Secretariat should look into the feasibility of this.
10. It was agreed that the proposed Workshop will focus on natural lakes. For this purpose the following preparatory activities have been proposed to take place during the intersessional period:
the specialists from Finland, France, Germany, Poland, Sweden, Switzerland and Russian Federation will provide lists of available morphometric, physico-chemical and fishery parameters to Lorenzen, U.K. (January 1994);
Lorenzen will instruct the experts which data are required to construct models and provide them with standard format for retrieval (April 1994);
Experts will submit required information (November 1994).
In the meantime Thonon Laboratory, the Marine Resources Assessment Group and FAO will look into the possibility of obtaining funds for the preparation of draft models, subject to availability of funds or a suitable expert willing to prepare the models free of charge. The Chairman of the Working Party would coordinate future activities. Ideally a draft model should be made available for the Hull Meeting in April 1996.
