APPENDIX III
SUMMARY OF RESPONSES TO THE QUESTIONNAIRE ON STOCKING FISH IN EUROPE

by

T. Backiel
Convenor, Symposium

In 1981 a simple questionnaire was distributed to the correspondents of EIFAC. Responses came from 13 countries: Austria, Belgium, Czechoslovakia, Cyprus, Germany F.R., Hungary, Ireland (Rep.), The Netherlands, Norway, Poland, Sweden, Switzerland and the U.K. (for England and Wales).

In all of these countries stocking streams, rivers, reservoirs and lakes is a common practice.

The total number of fish species reported as being stocked is 30 and the list for Europe is very likely not complete (see Table).

Out of these fishes, 10 species have been introduced from outside Europe, some fairly recently like Chinese carps, Salvelinus namaycush and Coregonus peled, and stocking with these species has apparently become a common practice in a few countries.

With regard to priorities, brown trout is in the lead (11 countries, all kinds of waters), then come rainbow trout, pike (8 countries), eel and common carp (7 countries).

All types of water bodies are being stocked and most species are used for both running and standing waters. A few species are stocked only into rivers and coregonids are only stocked into lakes (see Table).

The fishes used for stocking come from hatcheries (reported by all countries), from ponds (reported by 9 countries) or from natural stocks. Thus, rearing fish for stocking and also transfers from one water body to another, are reported from England and Wales, Cyprus, Germany F.R., Ireland, Norway, The Netherlands, Poland and Switzerland.

Systematic assessment of stocking is reported from Austria, Czechoslovakia, Ireland, Norway and Switzerland and partially - with respect to some fish and some water bodies - from Germany F.R., Hungary and Poland.

There is a variety of opinion on the efficiency of stocking. Austrian, Hungarian and Swiss questionnaires claim that stocking is efficient. Norway considers stocking of salmon to be successful as do England and Wales with respect to rainbow trout released into reservoirs, Stocking eels into lakes has been proved efficient in Poland and the German experts consider it necessary, hence, some success has probably been observed. Releasing coregonids into lakes has been successful in Poland and is considered necessary in “eutrophicating lakes” in Germany F.R., and so is stocking running water with brown trout wherever spawning grounds have been destroyed. However, the views from Ireland are that releasing salmonids in various stages (from eyed ova to yearlings) has not been so successful as expected.

The effects of stocking rivers and reservoirs with pike are reported from Germany as variable as is stocking with carp for sport fishing. Ireland reports increased success of stocking “cyprinid waters” under careful management. There is no clear evidence on the efficiency of stocking “coarse fish” in England and Wales and on other species but coregonids and eel in Poland. Czechoslovakia claims “moderate efficiency”, Cyprus that stocking is “efficient to moderately efficient”, Belgium and Sweden report all possible degrees of efficiency. The Dutch response is that stocking is either moderately efficient or inefficient.

The 13 responses to the questionnaire on stocking do not cover the whole of Europe and, because of the simple nature of the questionnaire, lack many important details of information. Nevertheless, they have revealed several interesting phenomena and views. Considering how common and widespread is this medium of management, one wonders why there are so few published accounts and critical studies on stocking fish.

This conclusion confirms the view shared among some participants of the Eleventh Session of EIFAC that the subject was worth reviewing at an international level. One should refer to the Report of the EIFAC Workshop on Mass Rearing of Fry and Fingerlings of Freshwater Fishes (EIFAC Technical Paper No. 35) where it was stated that more than 31 species were cultivated in Europe, and most of them were used for stocking. The question about survival, growth, behaviour and recapture of the stocked fish deserves due attention. The responses to the questionnaire, obviously, do not answer this question but reveal that:

1. a fair number of species is stocked, hence, they are considered useful supplements to the original populations and fish communities.

2. reservations as to the efficiency of such a stock enhancement are fairly common among fishery experts

3. it is well established that effects depend on diverse conditions.

SPECIES (AND SUB-SPECIES) OF FISH STOCKED INTO VARIOUS INLAND WATERS AS REPORTED BY COUNTRIES

EIFAC TECHNICAL PAPERS ISSUED