U:\2021\BM210482_IBo_Waihi_North_Project\Documents\WNP_Freshwater_Report_May_2022\FINAL_Freshwater_Report_FOR DELIVERY_June 2022\FINAL DELIVERED 17 JUNE 2022\WAI-985-000-REP-LC-0007_Rev0_Freshwater_20220621_FINAL.docx Over the past four monitoring occasions, four native fish have been identified including shortfin eel, longfin eel ), Crans bully and common bully (as well as unidentified bully and eels). Longfin eel are classified as At Risk (declining). In addition, kōurakōura have been captured as well as the introduced rainbow trout (Oncorhynchus mykiss). There are also five records from the freshwater fish database for the Mataura Stream (these records appear to be separate to the annual monitoring records). Kōaro is was the only other species recorded in addition to those already identified from the annual monitoring. There were 14 records from adjacent catchments (Walmsley Stream, Ratarua Stream and Ohinemuri River reach between the confluence of these two streams), which also identified banded kokopu and the introduced brown trout (Salmo trutta). We consider all the species identified from the annual monitoring, as well as from the freshwater fish database (including adjacent catchments), to be present within the Mataura Stream. Koaro have a conservation status of At Risk (declining). Fish IBI is provided in Table 13. The rating of ‘excellent’ fish IBI rating for the Mataura Stream means that the fish species present were as expected for the attributes of the location (i.e., distance from the coast, altitude). Notwithstanding the existing weir downstream in the Ohinemuri River, there appear to be no barriers preventing climbing fish reaching the Mataura Stream. The fish IBI for the unnamed tributary 2 is ‘fair’ reflecting the more degraded nature of the catchment and the potential for barriers to fish access. Table 13: Summary of Fish IBI scores from Mataura Stream catchment. Assessed site IBI score Rating Mataura Stream 58 Excellent Unnamed tributary 2 20 Fair 7.8 Stream Ecological Valuation The overall SEV score for the unnamed tributary 2 the SEV score was 0.594, indicating impaired function within the sampling reach. No SEVs were undertaken in the Mataura Stream or the Waiharakeke Stream as, other than the warm spring, no loss of the stream will occur as a result of WNP. The tributary 2 reach scored high for connectivity to natural species migrations, natural connectivity to groundwater and natural flow regime, which were all greater than 0.75. Most of the assessment is only based on the assessed reach (90 m) so any wider issues within the tributary, are not accounted for within the assessment. The reach scored particularly poorly for organic matter input and riparian vegetation intact (both less than 0.10), which is due to the lack of riparian vegetation. A summary of the SEV data is provided in Appendix 5. Although prepared for a different purpose, WRC (2020) conveys a range of SEV scores throughout the Waikato region, including rural streams; we note that the SEV score for tributary 2 is placed within the range reported for low intensity agricultural streams. Although a different region, we note that overall SEV score was similar to examples of rural stream scores within the Auckland region (AC 2011). 7.9 Summary of Ecological Values In this section we provide an overview of the components used to determine the ecological values of the assessed aquatic features, summarised in Table 14. The assessed reach of Mataura Stream has good instream habitat quality and quantity consisting of an array of different habitats, including, riffles, runs, pools, undercut banks and overhanging / encroaching vegetation. Sediment cover was minimal with some sediment build up in slower flowing or more
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