Utilisation of restored wetlands by fish and invertebrates Philip Gibbs, Tracey McVea and Brett Louden NSW Fisheries Office of Conservation P.O. Box 21, Cronulla, NSW, 2230 Australia (INSERT PICTURE HERE) FRDC Project No. 95/150 August 1999 NSW Fisheries Final Report Series No. 16 ISSN 1440-3544 Utilisation of Restored Wetlands by Fish and Invertebrates Philip Gibbs, Tracey McVea and Brett Louden NSW Fisheries Office of Conservation Locked Bag 9 Pyrmont NSW 2009 Australia Project No. 95/150 August 1999 NSW Fisheries Final Report Series No.16 ISSN 1440-3544 Contents i Table of Contents 1. INTRODUCTION.................................................................................................................................. 1 1.1. BACKGROUND...................................................................................................................................... 1 1.2. NEED ................................................................................................................................................... 1 1.3. OBJECTIVES ......................................................................................................................................... 2 1.4. IMPACTS OF ACID WATER ..................................................................................................................... 3 1.5. EXPERIMENTAL DESIGN AND STATISTICAL ANALYSIS ........................................................................... 5 2. PILOT STUDY....................................................................................................................................... 7 2.1. INTRODUCTION .................................................................................................................................... 7 2.1.1. Background ............................................................................................................................... 7 2.1.2. Objectives .................................................................................................................................. 7 2.2. METHODS ............................................................................................................................................ 7 2.2.1. Determination of sampling method ........................................................................................... 7 2.2.2. Determination of sample number .............................................................................................. 8 2.2.3. Spatial variability ...................................................................................................................... 8 2.3. RESULTS ............................................................................................................................................ 10 2.3.1. Determination of sampling method ......................................................................................... 10 2.3.2. Determination of sample number ............................................................................................12 2.3.3. Spatial variability .................................................................................................................... 14 3. METHODS........................................................................................................................................... 15 3.1. STUDY AREA ...................................................................................................................................... 15 3.2. FIELD SAMPLING AND LABORATORY TECHNIQUES.............................................................................. 18 3.2.1. Fish and invertebrates............................................................................................................. 18 3.2.2. Water Quality .......................................................................................................................... 19 3.3. EXPERIMENTAL DESIGN AND DATA ANALYSIS .................................................................................... 19 3.3.1. Fish and invertebrate community structure (multivariate analysis)........................................ 20 3.3.2. Species richness, abundances and biomass of species (ANOVA)............................................ 21 3.4. POPULATION SIZE STRUCTURE (LENGTH FREQUENCY DATA) .............................................................. 25 4. RESULTS ............................................................................................................................................. 27 4.1. GENERAL TRENDS .............................................................................................................................. 27 4.2. FISH AND INVERTEBRATE COMMUNITY PATTERNS (MULTIVARIATE ANALYSIS) .................................. 29 4.2.1. Spatial patterns........................................................................................................................ 31 4.2.2. Temporal patterns.................................................................................................................... 38 4.3. SPECIES RICHNESS, BIOMASS AND SPECIES ABUNDANCES................................................................... 40 4.3.1. Macleay River.......................................................................................................................... 40 4.3.2. Hunter River ............................................................................................................................ 54 4.3.3. Botany Bay .............................................................................................................................. 69 4.3.4. External Reference Estuaries .................................................................................................. 77 4.4. LENGTH FREQUENCY.......................................................................................................................... 84 4.5. WATER QUALITY................................................................................................................................88 4.5.1. Physico-chemical variables..................................................................................................... 88 4.5.2. Macleay River rainfall and data logger information............................................................... 90 5. DISCUSSION ....................................................................................................................................... 95 6. CONCLUSION .................................................................................................................................. 103 7. RECOMMENDATIONS AND IMPLICATIONS .......................................................................... 105 7.1. BENEFITS ......................................................................................................................................... 105 7.2. INTELLECTUAL PROPERTY ............................................................................................................... 106 7.3. FURTHER DEVELOPMENT................................................................................................................. 106 7.4. STAFF............................................................................................................................................... 106 FRDC Project 95/150 Utilisation of Wetlands, (Gibbs, McVea, Louden) ii Contents 8. REFERENCES ...................................................................................................................................109 9. APPENDICES.....................................................................................................................................117 FRDC Project 95/150 Utilisation of Wetlands, (Gibbs, McVea, Louden) Contents iii List of Figures Figure 2.3.1. Small net and large net comparisons for the average number and standard error of (i) number of commercial, non-commercial and total taxa and (ii) number of commercial, non-commercial and total individuals. Figure 2.3.2. Species area curve for pilot study seine net samples. Figure 2.3.3. Non-metric multidimensional ordination plots using community abundance data for the sites sampled on the Macleay and Nambucca Rivers during the pilot study. Figure 3.1a. Map of the study area showing the three wetland estuaries (Botany Bay, Hunter River and Macleay River) and the three external reference estuaries (Wallamba River, Manning River and Nambucca River). Figure 3.1b. Schematic diagram of the sampling design. Figure 4.1. Average (+SE) number of commercial taxa, non-commercial taxa and total taxa collected from impacted wetlands and each of the external reference estuaries during the study period. Figure 4.2. Two dimensional plots of the results from non-metric multidimensional analyses using community abundance data for (i) December 1996 showing the Botany Bay near reference outlier samples and (ii) March 1997 to show the Macleay River site one outlier sample. Figure 4.2.1a. Two dimensional plots of the non-metric multidimensional analyses using community abundance data for each of the sampling periods. Figure 4.2.1b. Two dimensional non-metric multidimensional plot using community abundance data to show the spatial trends in the community. Figure 4.2.2. Two dimensional plot of the non-metric multidimensional analysis using community abundance data to show the temporal trends in the community. Figure 4.3.1a. Mean (+SE) number of taxa collected from the Macleay River and external