A CASE STUDY ON THE USE OF HABITAT ASSESSMENTS AND BIOLOGICAL INDICES FOR THE MANAGEMENT OF RECREATIONAL STREAM FISHERIES By Stephen van Staden MINI DISSERTATION Submitted in partial fulfilment of the requirements for the degree MASTER OF SCIENCE In ENVIRONMENTAL MANAGEMENT In the FACULTY OF SCIENCE At the RAND AFRIKAANS UNIVERSITY SUPERVISOR: PROF. G. J. STEYN C0-SUPERVISOR: DR. J. F. DURAND SEPTEMBER 2003 An angler who has reached old age and reviews the pleasure of life will be glad that he has been an angler, for he will look back upon days radiant with happiness, peaks of enjoyment that are no less bright because they are lit in memory by the light of the setting sun. LORD GREY OF FALLADON Fly Fishing (1899) ABSTRACT The use of biological and habitat assessment indices in aquatic resource management has been thoroughly researched throughout the world. These indices are generally controlled by strict protocols and as such an in depth investigation into the histories of biomonitoring, the indices and the development of the methodologies was undertaken to ensure that they were correctly applied and understood. Many of the indices produced can provide significant information guiding the management of aquatic resources. One problem has been that these indices have not reached their full potential in the private sector and are not extensivly used by the managers of aquatic resources. Many reasons for this exist including cost, technical skill and the cost of equipment. The methods used in this study are relatively simple and require no expensive technical equipment. To employ the indices used only a short amount of time is required at each site. It was shown that all the indices allowed similar conclusions to be drawn but some were deemed to give more useful information than others. It was also noted that significant duplication of work occurred during the application of the indices investigated. For these reasons a selected suite of indices were defined in order to serve as a prototype suite that can be used in the future management of stretches of rivers for recreational angling purposes. Within this suite there is still duplication of the parameters. Some of the indices cover parameters better than others and allow better conclusions to be drawn causing the need for the suite to replicate work. If some of the more comprehensive indices such as the RVI and GI are further developed in a way that they more comprehensively analyse some of the features they touch on, the suite of indices could be further reduced. The fish assemblage integrity index was not included in this investigation. It is highly probable that this index could provide significant information about the fish community structure of the river being considered to for use as a recreational fishing venue. It may therefore be worthwhile including this index, or an alternative such as the SIBI index, in the suite proposed in this investigation. This study was an attempt to provide a guideline to water resource managers and riparian owners as to which indices should be used in order to identify the best location for recreational fishing venues and also to identify issues within a reach that need attention in order to enhance the utility of an area as a recreational fishing resource. OPSOMMING Die gebruik van biologiese en habitat assessering indekse in akwatiese hulpbronbestuur word tans in verskeie lande ondersoek. Indekse word algemeen deur streng metodes gekontroleer, gevolglik was ‘n volledige ondersoek van die geskiedenis en metodes van die indekse onderneem ten einde te verseker dat die tegnieke op die korekte wyse toegepas word. Die indekse wat tans algemeen gebruik word, voorsien deeglike inligting aan bestuurders van akwatiese ekostelsels. Die volle potensiaal van hierdie tipe assessering is tans nog nie bereik nie, aangesien daar ‘n mate van weerstand in die privaat sektor ervaar word. Daar is verskeie redes vir hierdie probleem insluitend kostes, tegniese kundigheid en die koste van toerusting. Metodes wat gebruik is in hierdie studie is relatief eenvoudig en benodig geen duur tegniese toerusting nie. Aanwending van indekse benodig ook net ‘n minimale hoeveelheid tyd by elke assesseringspunt. In hierdie studie is daar bevind dat verskillende indekse dieselfde eindresultaat lewer, maar somiges meer bruikbare inligting bevat. Daar was ook bevind dat sekere aspekte dikwels gedupliseer is met die aanwending van meer as een indeks. Vir bogenoemde redes was ‘n geselekteerde stel indekse geindentifiseer. Die stel indekse sal dien as ‘n prototiepe model vir toekomstige bestuur van riviere wat vir ontspanningshengel be-oog word. Binne-in hierdie model is daar egter steeds beperkte duplisering van spesifieke parameters. Dit laat egter toe dat meer akkurate gevolgtrekkings gemaak kan word. As party van die meer volledige indekse soos die RVI en GI verder ontwikkel word, om gebrekkige funksies beter te omskryf, kan die stel indekse verder verminder word. Die “Fish Assemblage Integrity Index” (FAII) was nie ingesluit in hierdie ondersoek nie. Dit is hoogs waarskynlik dat laasgenoemde indeks meer volledige inligting oor die samestelling van die visgemeenskap sal lewer. Dit mag gevolglik waardevol wees om bogenoemde indeks, of ‘n alternatiewe indeks, soos die SIBI indeks, te inkorporeer in die voorgestelde model. Hierdie studie poog om leiding aan water hulpbronbestuurders en oewer-eienaars wat ontspanningshengeloorde moet bewaar en bestuur te gee. Die voorgestelde model kan gebruik word om ontspanningshengeloorde te analiseer en sodoende probleem areas te identifiseer. TABLE OF CONTENTS Page CHAPTER 1. INTRODUCTION ...............................................................................1 1.1 BIOMONITORING........................................................................................1 1.2 AFFECTED PARTIES IN A RECREATIONAL FISHERY........................10 1.3 BACKGROUND TO THE RECREATIONAL ASPECTS OF RIVER MANAGEMENT..........................................................................................13 1.4 MOTIVATION AND GOALS OF THE STUDY.........................................16 CHAPTER 2. DESCRIPTION OF THE STUDY AREA......................................19 CHAPTER 3. MATERIALS AND METHODS....................................................28 3.1 THE RIPARIAN VEGETATION INDEX (RVI)...............................................28 3.2 THE SOUTH AFRICAN SCORING SYSTEM VERSIONS 4 AND 5.....30 3.3 THE INVERTEBRATE HABITAT ASSESSMENT SYSTEM (IHAS) ..35 3.4 THE HABITAT ASSESSMENT MATRIX (HAM)..................................38 3.5 THE U.S. E.P.A. HABITAT ASSESSMENT INDEX (HAI)....................39 3.6 THE SITE FISH HABITAT INTEGRITY INDEX (SFHI)...........................41 3.7 THE HABITAT COVER RATING (HCR)...................................................42 3.8 THE GEOMORPHOLOGICAL INDEX (GI) ..............................................44 CHAPTER 4 RESULTS AND DISCUSSION FOR THE INDIVIDUAL SITES ............................................................................................................47 4.1 THE PIG FARM.................................................................................................47 4.2 MAKITI LODGE ...............................................................................................55 4.3 RAINBOW TROUT FARM...............................................................................64 4.4 BROOKWOOD ESTATE..................................................................................73 4.5 GLENBURN LODGE........................................................................................83 CHAPTER 5. INTEGRATED ECOLOGICAL ASSESSMENT OF THE BLOUBANKSPRUIT: RESULTS AND DISCUSSION.......................................93 5.1 THE RIPARIAN VEGETATION INDEX .........................................................93 5.2 THE SOUTH AFRICAN SCORING SYSTEM 4 AND 5..................................94 5.3 THE INVERTEBRATE HABITAT ASSESSMENT SYSTEM........................98 5.4 THE HABITAT ASSESSMENT MATRIX .......................................................99 5.5 THE U.S. E.P.A. HABITAT ASSESSMENT INDEX .....................................100 5.6 THE SITE FISH HABITAT INTEGRITY INDEX..........................................102 5.7 THE HABITAT COVER RATING..................................................................103 5.8 THE GEOMORPHOLOGICAL INDEX .........................................................105 5.9 SUMMARY AND RECOMMENDATIONS ..................................................108 CHAPTER 6: THE USE OF A SUITE OF INDICES IN RECREATIONAL FISHERY MANAGEMENT...................................................................................111 CHAPTER 7. CONCLUSION...............................................................................113 CHAPTER 8. REFERENCES...............................................................................115 LIST OF FIGURES Figure 1.1. Important biological, physical and chemical variables influencing aquatic ecosystems (modified from Roux 1999). 8 Figure 2.1. The study region and some of the more important and common features of the region. 20 Figure 2.2 The study region indicating topography and drainage with the study sites indicated in red. 22 Figure 2.3 The Pig farm site in a downstream direction. 23 Figure 2.4 A general view of the Makiti Lodge site. 24 Figure 2.5 A riffle in the Trout farm site. 25 Figure 2.6 A general view of the Brookwood Estate site. 26 Figure 2.7 The Glenburn Lodge site in a downstream direction. 27 Figure 5.1.