EIFAC TECHNICAL PAPER
DOCUMENT TECHNIQUE DE LA CECPI
42/Suppl./1

Documents presented at the symposium on stock enhancement in the management of freshwater fish Documents présentés au symposium sur l'amélioration des stocks dans le cadre de l'aménagement des pêcheries d'eau douce CONTENTS/ TABLE DES MATIERES

Volume 1: Stocking/Repeuplement

Held in Budapest, 31 May – 2 June 1982 in conjunction with the Twelfth Session of EIFAC

Tenu à Budapest du 31 mai au 2 juin 1982 à l'occasion de la douzième session de la CECPI

The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.

Les appellations employées dans cette publication et la présentation des données qui y figurent n'Impliquent de la part de l'Organisation des Nations Unies pour l'alimentation et l'agriculture aucune prise de position quant au statut juridique des pays, territoires, villes ou zones, ou de leurs autorités, ni quant au tracé de leurs frontières ou limites.

M-43
ISBN 92-5-002101-1

All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying or otherwise, without the prior permission of the copyright owner. Applications for such permission, with a statement of the purpose and extent of the reproduction, should be addressed to the Director, Publications Division, Food and Agriculture Organization of the United Nations, Via delle Terme di Caracalla, 00100 Rome, Italy.

Tous droits réservés. Aucune partie de cette publication ne peut être reproduite, mise en mémoire dans un système de recherche bibliographique ni transmise sous quelque forme ou par quelque procédé que ce soit: électronique, mécanique, par photocopie ou autre, sans autorisation préalable. Adresser une demande motivée au Directeur de la Division des publications. Organisation des Nations Unies pour l'alimentation et l'agriculture, Via delle Terme di Caracalla, 00100 Rome (Italie), en indiquant les passages ou illustrations en cause.

PREPARATION OF THIS DOCUMENT

This collection of papers represents the Proceedings of the Symposium on Stock Enhancement in the Management of Freshwater Fisheries, held in conjunction with the Twelfth Session of EIFAC (Budapest, Hungary, 31 May – 2 June 1982).

The Proceedings are in two volumes, which are supplementary to the Report of the Symposium issued in 1982 as EIFAC Technical Paper No. 42.

PREPARATION DE CE DOCUMENT

Cette ensemble de documents represente les actes du Symposium sur l'amélioration des stocks dans le cadre de l'aménagement des pêcheries d'eau douce, tenu à Budapest (Hongrie) du 31 mai au 2 juin 1982 à l'occasion de la douzième session de la CECPI.

Les actes sont presentés en deux volumes complémentaires au Rapport du Symposium émis par la CECPI en 1982 sous forme de document technique № 42.

FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS
ORGANISATION DES NATIONS UNIES POUR L'ALIMENTATION ET L'AGRICULTURE
Rome, 1984

Hyperlinks to non-FAO Internet sites do not imply any official endorsement of or responsibility for the opinions, ideas, data or products presented at these locations, or guarantee the validity of the information provided. The sole purpose of links to non-FAO sites is to indicate further information available on related topics.

This electronic document has been scanned using optical character recognition (OCR) software. FAO declines all responsibility for any discrepancies that may exist between the present document and its original printed version.

Les liens hypertextes vers d'autres sites de l'Internet ne signifient nullement que l'Organisation approuve officiellement les opinions, idées, données ou produits qui y sont présentés, qu'elle en assume la responsabilité ou qu'elle garantit la validité des informations qui s'y trouvent. Leur seul objectif est d'indiquer où trouver un complément d'informations sur des thèmes apparentés.

Cette version numérique du document a été scannérisé en utilisant des logiciels de reconnaissance optique de texte (OCR). La FAO décline toute responsabilité pour les éventuelles différences pouvant apparaître dans ce document par rapport à la version imprimée originale.

CONTENTS

TABLE DES MATIERES

INTRODUCTION

REGULATION OF BIOMASS OF SMALL (LESS THAN 41 cm) NORTHERN PIKE (Esox lucius L.) WITH SPECIAL REFERENCE TO THE CONTRIBUTION OF INDIVIDUALS STOCKED AS FINGERLINGS (4–6 cm)

M.P. Grimm

1.   INTRODUCTION

2.   METHODS

2.1   The experimental waters

2.2   Sampling techniques, estimate procedures

2.3   Subdivision of the populations

2.4   Stocking of pike

2.5   Relationship between biomass of adjacent subgroups

3.   RESULTS

3.1   Influence of abundance of aquatic vegetation on biomass of pike less than 54 cm

4.   DISCUSSION

4.1   Relation between biomass of pike and vegetated area

4.2   Mechanisms causing negative correlation between biomasses of adjacent subgroups

4.3   Interdependence of density of small pike (less than 41 cm) and that of larger individuals. Contributions of introduced fish

4.4   Management measures leading to higher densities of pike

5.   ACKNOWLEDGEMENTS

6.   REFERENCES

GROWTH POTENTIAL OF POORLY GROWN BREAM (Abramis brama L.) REVEALED BY TRANSPLANTATION TO ANOTHER ENVIRONMENT

W.G. Cazemier

1.   INTRODUCTION

2.   METHODS

3.   RESULTS

3.1   Physical and chemical aspects

3.2   Characteristics of bottom and soil

3.3   Plankton sampling

3.4   The fish stocks

3.5   Zoobenthos

3.6   The transplantation experiment

4.   DISCUSSION

5.   ACKNOWLEDGEMENTS

6.   REFERENCES

SURVIVAL OF ROACH CAUGHT WITH A SEINE NET

R. G. Riemans

1.   INTRODUCTION

2.   METHODS

2.1   Introduction

2.2   Experiments in drainable ponds

3.   RESULTS

3.1   Survival of roach provided for stocking in sport fishing waters

3.2   The effect of storage of roach on survival

3.3   Effect of benzocaine

4.   DISCUSSION

5.   REFERENCES

THE EFFECTIVENESS OF EEL STOCKING IN POLISH LAKES

M. Leopold and M. Bninska

1.   HISTORY OF STOCKING

2.   THE COMMERCIAL FISHERY

3.   SIGNIFICANCE OF STOCKING TO THE FISHERY

4.   SUITABILITY OF LAKES FOR STOCKING

5.   INFLUENCE ON RECREATIONAL FISHERY

6.   CONCLUSIONS

7.   REFERENCES

STOCK ENHANCEMENT IN THE IRISH EEL (Anguilla anguilla) FISHERY

C. Moriarty

1.   INTRODUCTION

2.   ELVER RECRUITMENT

3.   FYKE-NET SURVEY

3.1   Methods

3.2   Results

3.3   Discussion

4.   STOCKING AND YIELD DATA

5.   CONCLUSIONS

6.   REFERENCES

THE ENHANCEMENT OF EEL STOCKS IN FINLAND: A REVIEW OF INTRODUCTION AND STOCKINGS

M. Pursiainen and J. Toivonen

1.   INTRODUCTION

2.   STOCKING

2.1   Origin of the material

2.2   Amounts stocked

3.   RESULTS OF INTRODUCTIONS AND STOCKINGS

3.1   Individual cases

3.2   Catch statistics

3.3   The profitability of stockings

4.   PRESENT AND FUTURE ACTIVITIES

5.   REFERENCES

THE SWEDISH EEL STOCKING PROGRAMME

H. Wickstrom

1.   INTRODUCTION

2.   MATERIAL AND METHODS

2.1   Size, age and sex ratio

2.2   Trial lakes

2.3   Miscellaneous

3.   RESULTS

4.   DISCUSSION

5.   REFERENCES

THE ROLE OF WHITEFISH (Coregonus lavaretus L.) STOCKINGS IN FISHERIES MANAGEMENT IN FINLAND

K. Salojarvi

1.   INTRODUCTION

2.   ORGANIZATION OF FISHERIES MANAGEMENT

3.   FINANCE OF FISHERIES MANAGEMENT

4.   GOALS AND OBJECTIVES OF THE WHITEFISH STOCKING PROGRAMME

5.   PROSPECTS FOR WHITEFISH STOCKINGS

6.   REFERENCES

A STUDY OF THE GROWTH AND PRODUCTION OF THE NATIVE WHITEFISH (Coregonus muksun (Pallas)) AND THE INTRODUCED WHITEFISH(C. peled (Gmelin)) STOCKED IN TWO SMALL FOREST LAKES IN SOUTHERN FINLAND

V. Pruuki, M. Pursiainen and K. Westman

1.   INTRODUCTION

2.   LAKES USED IN THE STUDY

3.   MATERIAL AND METHODS

4.   RESULTS

5.   DISCUSSION

5.1   Growth

5.2   Mortality

5.3   Production

6.   REFERENCES

THE FOOD OF THE NATIVE WHITEFISH (Coregonus muksun (Pallas)) AND THE INTRODUCED WHITEFISH (C. peled (Gmelin)) STOCKED IN THE SAME SMALL FOREST LAKES IN SOUTHERN FINLAND

L. Hakkari, P. Selin, K. Westman and M. Mielonen

1.   INTRODUCTION

2.   MATERIAL AND METHODS

3.   RESULTS

3.1   Zooplankton

3.2   The food of whitefish

3.3   The condition and growth rate of whitefish

4.   DISCUSSION

4.1   Whitefish predation and the species composition of zooplankton

4.2   Zooplankton production and its consumption by whitefish

5.   REFERENCES

BROWN TROUT STOCKING IN NORWAY

P. Aass

1.   INTRODUCTION

2.   RETURNS OF STOCKED TROUT

3.   THE IMPORTANCE OF SIZE AND TIME IN STOCKING

4.   THE IMPORTANCE OF STRAIN IN STOCKING

5.   REFERENCES

FACTORS INFLUENCING THE MOVEMENTS, RECAPTURE AND SURVIVAL OF HATCHERY-REARED TROUT RELEASED INTO FLOWING WATERS AND THEIR MANAGEMENT IMPLICATIONS

R.C. Cresswell, G.S. Harris and R. Williams

1.   INTRODUCTION

2.   PERCENTAGE RECAPTURE

3.   POST-STOCKING MOVEMENTS

4.   INVESTIGATIONS INTO FACTORS AFFECTING THE POST-STOCKING MOVEMENTS AND SURVIVAL OF HATCHERY-REARED TROUT

4.1   Prior acclimation to flowing water

4.2   Resident wild population

4.3   Method of stocking

4.4   Time of stocking

4.5   Fish distributions

4.6   Anglers' returns

4.7   Survival of stocked fish

5.   IMPLICATIONS FOR FUTURE MANAGEMENT POLICIES REGARDING RESTOCKING WITH HATCHERY-REARED TROUT

6.   ACKNOWLEDGEMENTS

7.   REFERENCES

RESULTS OF STOCKING WITH BROWN TROUT (Salmo trutta m. lacustris) IN FINNISH LAKES AND RIVERS

J. Toivonen, H. Auvinen, E. Ikonen, T. Alapassi and U. Kokko

1.   INTRODUCTION

2.   MATERIAL AND METHODS

3.   RESULTS

4.   DISCUSSION

5.   REFERENCES

BROWN TROUT (Salmo trutta m. lacustris (L.)) STOCKINGS AS A COMPENSATION METHOD IN A POLLUTED AREA IN CENTRAL FINLAND

M. Sipponen and L. Hakkari

1.   INTRODUCTION

2.   STUDY AREA

3.   MATERIALS AND METHODS

3.1   Cage tests

3.2   Tagging and stocking

4.   RESULTS

4.1   Cage tests

4.2   Marking results

5.   DISCUSSION

6.   REFERENCES

LIBERATION OF TROUT (Salmo trutta L.) IN DANISH STREAMS

G. Rasmussen

1.   INTRODUCTION

1.1   Trout stocking

1.2   The extent of Danish trout stocking activities

2.   ADMINISTRATION OF STOCKING SCHEMES

3.   FUTURE STOCKING ACTIVITIES

4.   EXAMPLE OF A STOCKING SCHEME

5.   REFERENCES

THE IMPORTANCE OF GENOTYPE, SIZE ON STOCKING AND STOCKING DATE TO THE SURVIVAL OF BROWN TROUT (Salmo trutta L.) RELEASED IN IRISH LAKES

M.F. O'Grady

1.   INTRODUCTION

2.   MATERIALS AND METHODS

2.1   The study areas

2.2   Trout genotypes

2.3   The collection of quantitative data on trout stocks

2.4   Recognition of specific trout stocks

3.   RESULTS

3.1   The influence of genotype

3.2   The importance of size on stocking

3.3   The influence of stocking date

4.   DISCUSSION

5.   ACKNOWLEDGEMENTS

6.   REFERENCES

REPEUPLEMENTS DE Salmo fario DANS LES MILIEUX AQUATIQUES DU SUD OUEST DE LA FRANCE; APPROCHE ECOLOGIQUE

P. Reyes Marchant et J. Moreau

1.   INTRODUCTION

2.   LES REPEUPLEMENTS

3.   MAINTIEN DANS LE MILIEU, SEDENTARITE ET DEVALAISON

4.   COMPETITION AVEC LES INDIVIDUS SAUVAGES

5.   BIOLOGIE DES TRUITES INTRODUITES

5.1   Comparaison avec les sujets “sauvages”

6.   INFLUENCE DES REPEUPLEMENTS SUR LE MILIEU

7.   CONCLUSION

8.   REFERENCES

PHYSIOLOGICAL EFFECTS OF STOCKING STRESS ON SALMON

A. Soivio and E. Virtanen

1.   INTRODUCTION

2.   MATERIAL AND METHODS

2.1   Experimental fish

2.2   Transportation

2.3   Sampling and analyses

3.   RESULTS AND DISCUSSIONS

3.1   The physiological condition and smoltification of the salmons on fish farms

3.2   Changes during the transport and subsequent recovery at the stocking site

4.   CONCLUSIONS

5.   REFERENCES

FACTORS AFFECTING THE SURVIVAL AND DISTRIBUTION OF SALMON (Salmo salar L.) STOCKED IN UPLAND TROUT (Salmo trutta L.) STREAMS IN NORTHERN IRELAND

G.J.A. Kennedy

1.   INTRODUCTION

2.   SITE

3.   METHODS AND MATERIALS

4.   RESULTS AND DISCUSSION

4.1   Comparative survival from salmon stocking with eyed ova, green eggs and swim-up fry

4.2   Comparative survival from salmon stocking with eyed ova in two streams of differing gradient

4.3   Influence of resident fish on the survival of stocked salmon

4.4   Influence of stocked salmon on resident trout

4.5   The distribution of trout and stocked salmon in relation to depth and gradient

4.6   Influence of resident fish on the distribution of stocked salmon

4.7   Dispersal of stocked salmon fry

5.   CONCLUSIONS

6.   ACKNOWLEDGEMENTS

7.   REFERENCES

SALMON SMOLT STOCK ENHANCEMENT IN THE RIVER TUMMEL, SCOTLAND

H.J. Egglishaw

1.   INTRODUCTION

2.   THE UPPER RIVER TUMMEL

3.   MATERIALS AND METHODS

3.1   Fry planting

3.2   Fish population and growth estimates

4.   RESULTS

4.1   Survival of the salmon

4.2   Growth of the 0+ age class

4.3   Growth of the 1+ age class

5.   REFERENCES

A REVIEW OF FISH STOCKING IN FINLAND

K. Westman, U. Eskelinen, P. Tuunainen and E. Ikonen

1.   INTRODUCTION

1.1   Inland waters and their state

1.2   Management of fish stocks

2.   FISH STOCKING IN FINLAND

2.1   General

2.2   Stocking of cultivated juveniles

3.   CULTIVATION OF JUVENILES FOR STOCKING

3.1   Production methods

3.2   Fish farms

3.3   Cultivation facilities

3.4   Distribution of juvenile production

4.   RESULTS OF STOCKING

4.1   Coregonids

4.2   Stocking results of salmon, sea trout and brown trout in the seventies in Finland on the basis of taggings

4.3   Other salmonids

4.4   Pike, perciform and cyprinids

4.5   Summary of the results obtained with stocking

5.   REFERENCES

STOCKING OF FISH IN SWEDEN FROM THE PERSPECTIVE OF TAGGING

O. Enderlein

1.   INTRODUCTION

2.   CHANGES OVER THE PAST THIRTY YEARS

2.1   Numbers tagged

2.2   Species tagged

2.3   Methods

2.4   Purpose

2.5   Results

2.6   Recoveries

2.7   Survival rate estimates

3.   DISCUSSION

4.   REFERENCES