BIOLOGICAL CONTROL OF BLUE-GREEN ALGAL LEVELS IN RESERVOIRS: THE UTILITY OF SILVER CARP
Report No FR0365

W Parr

Mar 1993

SUMMARY

I BENEFITS

This report gives an objective view of the difficulties and problems encountered when attempting to set up an experiment to investigate the use of silver carp to control blue-green algae in UK reservoirs. Although this appeared to be the most promising biomanipulative approach it has been concluded that at present, it is impractical.

II OBJECTIVES

To investigate the advantages and disadvantages of a silver carp stocking programme in UK reservoirs as a method of controlling blue-green algae.

To recommend whether or not an experiment to assess the suitability of introducing silver carp to UK reservoirs as a means of blue-green algal control should be undertaken.

III REASONS

The information on biological methods of controlling blue-green algae has recently been reviewed (Parr 1992). It was found that although the introduction of silver carp to UK reservoirs appeared to offer a greater chance of success than the other methods, much of the information was contradictory. It was therefore concluded that if the use of silver carp was to be pursued in the UK further work would have to be undertaken before any recommendations could be made on large-scale stocking programmes- An experimental design for a suitable small scale study was proposed, but was found to be difficult to implement. This report reconsiders this information in the light of experience gained in attempting to set up this study.

IV CONCLUSIONS

The use of silver carp may prove to be a suitable method of algal control in UK waters in future, but for the present, even if all the information required for a large-scale programme was available, it would probably not offer any financial advantages.

Definitive information required to undertake a large-scale silver carp stocking programme is lacking and the price of obtaining it is likely to be high in terms of sponsored or in-house research, as any experimental work needs to be continued for several years and requires suitable control sites.

V RECOMMENDATIONS

The silver carp stocking study recommended by Parr (1992) should still be considered as part of a future research programme, but current practical difficulties mean that it is not appropriate to commence work at present.

VI RESUME OF CONTENTS

The practical and theoretical advantages and disadvantages of introducing silver carp to UK reservoirs are considered, together with doubts which have been raised due to apparently conflicting information reported in the literature. Areas of controversy are highlighted, and information which is currently lacking, but still required to establish a UK stocking programme, is identified.

Copies of the Report are available from FWR, price 15 less 20% to FWR Members.