Waipoua River 20130219.pdf - Northland Regional Council

The SH bridge site is dominated by pollution sensitive taxa, with at least half of the taxapresent being EPT taxa in all nine years (Table 8). The invertebrate indices are consistentwith the water quality data, that is, showing that Waipoua River is the most pristine of theriver sites routinely monitored in Northland, with typically the highest number of invertebratetaxa, %EPT taxa, MCI and/or SQMCI.Table 8: Freshwater invertebrate data for Waipoua River at SH bridgeYear No. of taxa MCI SQMCI %EPTMar-04 13 121.5 6.70 53.8Mar-05 20 135.0 7.39 55.0Mar-06 20 136.0 8.11 65.0Mar-07 21 129.5 7.20 66.7Jan-08 29 135.5 8.21 72.4Apr-09 26 118.8 6.79 53.8Jan-10 36 121.7 7.86 55.6Mar-11 34 128.5 7.91 58.8Feb-12 32 129.1 7.89 62.5Average 25.7 128.4 7.6 60.4The data for Waipoua River suggests there has been very little ecological change in theinvertebrate communities between 2004 and 2012 (Pohe 2012).3.2.6 Fish communityAlthough a recent survey (O’Brien 2012) only recorded four native fish species at the SH12bridge (banded kokopu, koaro, short jaw kokopu and long fin eel), historical surveys in thelower reaches of the river recorded a diverse fish community of 11 different native species(see section 2.2.2.2). As mentioned in section 2.2.2.2, all of the 11 native fish speciesrecorded in the catchment spend part of their life at sea and must be able to move both upand downstream to complete their life cycles. A ford on Waipoua River Road in the lowercatchment is currently causing a severe barrier to fish passage and has been for manyyears, preventing/limiting fish migration to the optimal habitat in the headwaters (O’Brien2012).Two of the species present in the catchment are regionally rare and one is sparse (koaro,banded kokopu and lamprey respectively, Miller & Holland 2008) and another is in decline(shortjaw kokopu, Allibone et al 2009). O’Brien (2012) suggests that if fish passage wasrestored, the conservation value of the site at the SH bridge would be greatly enhanced.3.2.7 Periphyton communityPeriphyton is an important indicator of environmental quality, as the main primary producerin stream ecosystems, but also because of its ability to respond quickly to changes in waterquality and form excessive growths under ideal conditions, affecting instream values, suchas biodiversity and recreational use.The Waipoua River consistently has low periphyton biomass with chlorophyll α being wellbelow Biggs’ (2000) guideline for ‘clean water’ invertebrates of 50 mg/m 2 (Gray 2012,Dwersteg 2007). The Council’s periphyton monitoring has shown that the periphytoncommunities of streams in native forested catchments are typically dominated by diatomsand desmids, which is the case for Waipoua River in most years. However, in 2007 and28