A case study on the use of habitat assessments and biological indices for the management of recreational stream fisheries

M.Sc.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