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Incorporating fish monitoring into the Waikato Regional Councils' Regional Ecological Monitoring of Streams (REMS) - preliminary results for wadeable streams 2009-2015

TR 2016/29

Report: TR 2016/29

Author: Bruno David, Callum Bourke, Mark Hamer, Stephen Scothern, Michael Pingram, Michael Lake

About this report

In this report we review preliminary data from the Waikato Regional Council’s State of the Environment (SOE) wadeable rivers fishing programme.  Standardized fisheries sampling commenced in 2009 at a number of least impaired reference sites and by 2011/2012 routine fisheries sampling was added to the Councils existing Regional Ecological Monitoring of Streams (REMS) programme. We illustrate the utility of the randomized probabilistic network for reporting on extent estimates of fish metrics by using the FishIBI as an example across the Waikato wadeable river network. As a further component of this report we examine some species specific patterns that appear to be emerging across the region for frequently encountered species like long and shortfin eels and redfin bullies. In brief over this six year period of assessment longfin elvers (<100mm) were rarely captured throughout the network compared to shortfin elvers and there is a tendency for shortfin elvers to be detected at sites that are predominantly or exclusively dominated by larger size classes (>100mm) of longfin eels.  Redfin bullies on the other hand appeared to be on average smaller but exhibit greater recruitment potential in streams draining to the east compared to sites draining to the west of the region.  In the future it is envisaged that refined fish metrics could be combined with other physical, chemical and ecological components (including invertebrates) to better describe the ‘health’ of individual wadeable river reaches. 

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Incorporating fish monitoring into the Waikato Regional Councils' Regional Ecological Monitoring of Streams (REMS) - preliminary results for wadeable streams 2009-2015 [PDF, 1.5 MB]

Contents

  Acknowledgement i
  Executive summary v
1 Introduction 1
2 Methods 2
2.1 Fishing methods 2
  Protocol 2
  Fishing method selection 2
2.2 Network development and site selection 3
  Minimally impaired reference sites for fish 3
  Random sites - fish 5
  Parameters measured at random and reference sites 6
  Seasonal timing of surveys 6
  Data analysis structure 7
3 Results 8
  Physical and methodological parameters 8
3.1 Site specific assessments 12
  Paprahia stream 12
  Manganui river and tributary reference sites 14
  A closer look at redfin bullies 15
 3.2 Random sites 2011/2012 v 2014/2015  18 
 3.3 Extent estimates  21 
 3.4 Reference sites 2011/2012 v 2014/2015 18  22
 3.5 Random vs Reference fish  23 
   A closer look at eels 23 
 4 Discussion  29 
 4.1 Protocol consistency assessment  30 
   Reference sites 30 
 4.2 Potentially useful metrics  35 
   Random v Reference 35 
   QIBI 35 
   Extent estimates 35 
   Future metric development 36 
 4.3 Other aspects for consideration  37 
   EFM vs Netting 37 
 4.4 Conclusion  37