At the twelfth session of EIFAC it was concluded that despite a long history of stocking with many species in the inland waters of Europe, little knowledge of the ecological and economic implications of these activities exists. It is, however, apparent that despite some successes much of the current stocking practice is misdirected and ecologically and economically unproductive. (EIFAC/XIII/84/2). Guidelines for Stocking Coregonids deals with three species: the vendace (Coregonus albula), whitefish (C. lavaretus L. s.l.) with its several ecotypes and peled (C. peled). Vendace and whitefish are palaearctic; the peled was introduced from Siberia. These guidelines are addressed mainly to fisheries managers and administrators in order to assist them in the development of efficient and economical stocking policies and practices. This does not exclude the needs for further research into proper stocking densities of coregonids. The terminology used throughout this paper is presented in Appendix 1. Because the guidelines have been written as a practical document, detailed literature references to all the statements and opinions have been deliberately omitted. For those who may wish to read further a list of references has been included as Appendix 4. This is intended to provide a balanced picture geographically with papers from Scandinavia, Poland and Central Europe. A further paper (Todd 1993) primarily concerned with fisheries in the Great Lakes also contains a useful historical overview.
The transfer of whitefish and vendace has been practised for centuries, which considerably extended the distribution area of coregonids in Europe. Hatchery operations began in the mid-1800s and spread rapidly throughout Europe and North America. The rearing of juveniles for stocking purposes was initiated in the late 1800s.
The first guidelines for stocking coregonids appeared most probably in the late 1800s in Sweden and later in many European countries. In principle, the guidelines were very similar. They specified the types of lakes appropriate for coregonid stockings (water quality requirements, lake morphology, etc.) and stocking techniques. The purpose in most cases was to establish naturally reproducing populations. Recommendations on suitable stocking rates appeared in the early 1900s. To date the guidelines have been based on experience of fisheries managers and fishermen and very little on research. Although some of the previous guidelines are still applicable in situations where lakes have remained in their pristine state, in other situations where lakes have been subjected to considerable stress, e.g. Poland, such guidelines are no longer applicable. In addition, numerous reservoirs which have appeared in the 20th century have been stocked with coregonids without any guidelines on the effectiveness of this practice.
Whitefish are known to be stocked in many European countries but no comprehensive statistics are available on the numbers stocked. The total annual production of whitefish juveniles in Finland is about 200 tonnes.
Large-scale vendace stocking is practised in Poland and Finland. In Poland vendace are stocked mostly as yolk-sac larvae. The stocking rate averages about 12 000 yolk-sac larvae/ha (range to 70 000) every second year. In Finland the dominating type of stocking material is young-of-the year (Y-O-Y) juveniles caught from natural lakes and transferred into nearby lakes and reservoirs. The stocking rate in small lakes is 500–1 500 ind./ha and in large lakes < 150 ind./ha.
Peled and whitefish are stocked in most countries as yolk-sac larvae and larvae, but the rearing of juveniles is increasing. In central Europe the stocking rate of peled and whitefish with yolk-sac larvae is much higher (to 50 000 ind./ha; normally < 20 000) than in Scandinavia (only a few thousand at maximum). The variation using summer juveniles is in Poland for whitefish < 3 500 and for peled < 6 500. The average stocking rate is in northern Finland 10–20 juveniles/ha, but varies widely between lakes, the highest being > 200.
A general planning and decision scheme pertaining to stocking programmes is presented in Figure 1. Stocking is a management option and therefore it should be consistent with the accepted management policy. Stocking should contribute positively to the catch, should be profitable and/or socially beneficial. Genetic effects and uncertainties involved in the impact assessments should be evaluated and considered before the proposed stocking can be accepted and implemented. The following sections of this handbook amplify particular review boxes of the scheme related to coregonid stocking to give the basic knowledge needed to answer the questions in decision boxes at each level, (Fig. 1).
