Table Of ContentFisheries Management
Fisheries Management: A Manual for Still-Water Coarse Fisheries Ash Girdler, Ian Wellby and Robin Welcomme
© 2010 Blackwell Publishing Ltd. ISBN: 978-1-405-13332-6
Fisheries Management
A Manual for Still-Water Coarse Fisheries
Ash Girdler CBiol, FIBiol, MIFM, FIFM, CEnv
Ian Wellby FIFM, CEnv
Robin Welcomme PhD, HonFSE, FIFM, CEnv
A John Wiley & Sons, Ltd., Publication
This edition fi rst published 2010
© 2010 by Blackwell Publishing Ltd
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Library of Congress Cataloging-in-Publication Data
Girdler, Ashley.
Fisheries management : a manual for still-water coarse fi sheries / Ashley Girdler,
Ian Wellby, Robin Welcomme. – 1st ed.
p. cm.
Includes index.
ISBN 978-1-4051-3332-6 (hardback : alk. paper) 1. Fishery management.
I. Wellby, Ian. II. Welcomme, R. L. III. Title.
SH328.G69 2010
639.3'12–dc22
2009038733
A catalogue record for this book is available from the British Library.
Set in 10 on 12.5 pt Sabon by Toppan Best-set Premedia Limited
Printed in Singapore
1 2010
Contents
Acknowledgements vii
Part I Ecology of Still-Water Fisheries 1
1 Introduction 3
2 Ecology of Lakes 5
3 Bacteria 25
4 Plants 28
5 Invertebrates 35
6 Fish 43
7 Disease-Causing Organisms 79
Chris Williams and Ian Wellby
8 Mammals and Birds 97
Part II Management of Still-Water Fisheries 103
9 Developing and Preparing a Fishery 105
10 The Construction of a Still-Water Fishery 122
11 Fish Stock Assessment 154
12 Stock Manipulation 170
13 Invertebrate Survey 196
14 Control of Water Quality 198
15 Control of Aquatic Plants 208
16 Control of Erosion 224
17 Control of Predators and Nuisance Species 236
18 Managing the Impact of Climate Change on Still-Water Fisheries 256
19 Control of Fish Disease 259
20 Biosecurity 270
21 Control of Fishing Activities 274
22 Fish Nutrition 285
23 Improving Conditions or Fishery Enhancement 306
24 General Administration 344
Part III Legal and Social Framework 357
25 General Legislation 359
26 Environmental Legislation 364
v
vi Contents
27 Direct Fisheries-Related Legislation 368
28 Agencies and Organisations 373
Appendix A: Example of Risk Assessment 380
Appendix B: Example Model of a Disciplinary Procedure 383
Appendix C: Example of a Fisheries Survey 386
Glossary 393
Further Reading 395
Index 398
Acknowledgements
We express our gratitude to Dr Chris Williams for his work on the fi sh health chapter and
other help he has offered. We also thank Nigel Hewlett for his advice during the preparation
of this book. Many thanks too to Jenny Wellby for the help and support she has offered
and her contribution in editing the various drafts. We also thank the staff of the A.G.A.
Group, who have contributed to this book by taking the time to extend their efforts during
the working day to provide the expansion of our image library, which has ensured that the
text is populated with up- to - date graphics and images.
vii
Part I
Ecology of Still- Water Fisheries
Before looking at the management of a still - water fi shery, it is important to understand how
lake and pond ecosystems function in the absence of human interference. Still- waters are
fascinating and complex aquatic environments that are very different from the terrestrial
environment in which we live. It is important to acknowledge and understand these differ-
ences so that we fully understand the possible consequences of any management
decisions.
Although we describe our still- waters as freshwater lakes, suggesting that the water is in
some way pure water, in reality it is never pure. Even rain is not pure water as it contains
signifi cant amounts of dissolved gases and other chemicals. Water has the ability to dissolve
a vast number of natural and synthetic elements and compounds. It is often referred to as
the ‘ universal solvent’ . As water falls from the sky and runs through or across the land as
surface run - off, it picks up a myriad of chemicals as dissolved substances. It may also collect
further materials, including chemicals that are insoluble but are suspended in the water. This
veritable soup supports a whole range of algae and invertebrates, which support the fi sh
that are of greatest interest to the manager.
Animals that live in water are very different to animals that live on land. Although this
is obvious, the difference is rarely fully appreciated. To understand how to manage a fi shery
we must understand the sorts of conditions the fi sh live in: their environmental
conditions.
Part I of this book looks at still- waters from the basic principles of how they work, con-
sidering some of the conditions prevalent in still- waters and how these fl uctuate over time
and space, and describes the various animals that live in them.
Fisheries Management: A Manual for Still-Water Coarse Fisheries Ash Girdler, Ian Wellby and Robin Welcomme
© 2010 Blackwell Publishing Ltd. ISBN: 978-1-405-13332-6
1
Introduction
Ecologically, still- waters are described as standing ‘ open ’ water, a term that covers wetlands
including fens, marshes and temporary fl ashes as well as inland water bodies such as lakes,
ponds, meres and reservoirs. It is estimated that there are 3344 km 2 of still - waters in the
UK, of which 95% are less than 1 hectare (1 hectare (ha) is equal to 10 000 m 2 ) in area,
which means that there are at least 400 000 lakes, ponds and dams in the UK. It is also
estimated that the number of still - waters has decreased by 35– 75% over the past 100 years,
although numbers are considered to have increased in recent years.
The management of still - waters as ecologically important systems is therefore of high
priority for the UK’ s biodiversity and, as fi sheries are often the primary use of such waters,
there will be a requirement for fi shery management skills that deal with the suitability of
the environment to support fi sh. It is thought that as many as 90% of the nation’ s still - waters
may be in private ownership and thus removed from the direct infl uence of conservation
bodies, regulators and freshwater scientists, further emphasising the role of fi shery managers.
In addition, UK managers often manage fi sheries on continental Europe, mainly for UK
fi shermen.
There has been a growing trend for the recreational fi sheries in England to be based in
such still - waters, in particular those for coarse fi sh. This has created a need for the systematic
management of many ponds, dams, gravel pits and lakes to maintain good populations of
fi sh and good - quality fi sheries. At the same time, the management of such fi sheries is becom-
ing increasingly complex. It is no longer suffi cient to keep a few fi sh in a pond, as increasing
regulation and demands for high- quality fi shing experiences by the public force the manager
Fisheries Management: A Manual for Still-Water Coarse Fisheries Ash Girdler, Ian Wellby and Robin Welcomme 3
© 2010 Blackwell Publishing Ltd. ISBN: 978-1-405-13332-6
4 Fisheries Management
to stricter policies. Underlying this is the fact that still- water pond management is a business
in many instances and must satisfy customers to make a profi t by providing good- quality
fi shing; the manager can only achieve this by providing a suitable environment and good -
quality fi sh.
Fisheries management, in common with most other activities that involve a combination
of problem solving and improvement that result in physical solutions, requires that well -
developed planning is a necessary part of the process. Fishery managers are no different
from us all in as much as we all plan. We all plan to lesser or greater degrees: we plan what
we are going to eat, for example, and where and when we are going to buy the food we
have decided to eat. However, the way we approach fi sheries management planning often
needs to be more prescriptive. Each fi shery will ideally have a written management plan that
will have been developed for it; certainly where the fi shery management involves more than
a solitary individual a plan should be developed and put in place as a priority. It is important
to ensure that the aims and objectives are clear and understood, that the actions required
to achieve them are well considered and planned, and that the tools to measure or monitor
the management actions are in place at the onset of the plan and not developed as an
afterthought.
Of course, the degree of complexity of the plan can vary greatly across a broad spectrum.
A fi shery can vary from a small one acre pond used exclusively for angling as the only single
interest to large water bodies such as the Norfolk Broads that will have many users. Most
of these users will have as an overriding priority their own single interest. They will often
include botanists, conservationists, ornithologists, sailors and walkers, among many more.
This book is, therefore, intended to provide the information that the vast number of
enthusiastic but amateur fi shery managers who are responsible for maintaining and enhanc-
ing our still - water heritage need to increase their effectiveness. It is more a compendium
than a novel and is thus not intended for reading from cover to cover but to address, in a
series of chapters, the various aspects of ecology and management of still - water fi sheries. It
is written in three parts.
The fi rst part describes the basic ecology of still - waters and catalogues the various species
that are signifi cant to the fi shery manager. Here it should be noted that most personnel
associated with still- water fi sheries should have a strong naturalist bent and be aware of the
various living things that inhabit their premises. This part refers mainly to the UK although
the fauna and fl ora are very similar to those of the rest of northern Europe.
The second part deals successively with the details of actual management, providing
information on construction, assessment, and monitoring and control methodologies. The
methods and procedures set out here are drawn from the north temperate region, but similar
approaches would be appropriate to recreational fi sheries worldwide.
The third part touches on the complex area of legislation and the social context of still-
water fi sheries. We have been restricted to considering the legal context of England and
Wales because that of Scotland is in a state of fl ux at the time of writing. The institutional
section is of more general application, however.
Examples have been provided of some of the procedures and methods described. These
are to be found in a series of appendices.
It has been decided not to include references within the text of this book, in order not to
break up the fl ow of words for the user. Instead, a further reading list has been included
for those who wish to explore particular issues in greater depth.
2
Ecology of Lakes
2.1 Water
Water is the basic medium for all fi sheries. It falls on the earth as precipitation (rain- and
snowfall) and moves to the sea through streams and rivers. It can be temporarily stored in
ponds, lakes and reservoirs that form the environment for still- water fi sheries (Fig. 2.1 ).
2.1.1 The s tructure of w ater
The fact that water will dissolve a vast range of substances is one of the many properties
that make it such a vital compound for all life on earth. Its chemical structure is the impor-
tant factor that allows water to act in the way it does.
A water molecule is made up of two hydrogen atoms and one oxygen atom. In the mol-
ecule these ball - like atoms come together in a V - shaped structure (Fig. 2.2 a). This structure
means that the shared electrons of the atoms are unevenly distributed in its outer layer,
which creates slight positive and negative charges on the ends of the molecule.
Because all the molecules in water are charged particles, each hydrogen atom can form a
weak attachment with the oxygen atom of another water molecule. At the same time, the
oxygen can form a weak attachment with two hydrogen atoms of another water molecule
(Fig. 2.2 b). These weak bonds give a molecule of water the potential to link simultaneously
Fisheries Management: A Manual for Still-Water Coarse Fisheries Ash Girdler, Ian Wellby and Robin Welcomme 5
© 2010 Blackwell Publishing Ltd. ISBN: 978-1-405-13332-6
