Introduction

This is the second in our series of monthly reports where we share details of the trout recorded passing through the Waipa spawning trap.

Highlights

Located on the Waipa Stream, the Waipa spawning trap is positioned within a significant spawning tributary of the Tongariro River, 24 km upstream from Lake Taupo.

Fishery Rangers record the numbers of trout, their sex, length, weight and iteroparity (how many times individual fish have spawned). From this data we also determine a Condition Factor, which reflects how much food has been available to the trout.

This trap has been operational since 1998 and has provided a valuable long-term data set. We view this information in combination with a variety of other studies such as angler surveys, drift dives and lake productivity work, to ensure a broad understanding of fishery's health.

Date:  22 July 2019

Trap data for June

As the winter season progresses so the number of trout reaching the trap increases. A total of 160 trout were documented this month compared to 60 in May. This trend is likely to continue over the coming months.

Compared to June last year there is a significant improvement in the size and condition of the trout – very good news for anglers. Our graphs and tables show improvements across the board for brown and rainbow trout.

Larger average lengths and weights are good to see. Yet for many anglers, the most significant observation will be the improvement in condition factor (CF). This translates to healthy well-fed fish, that not only provide a challenge to land but are good to eat – important to those who choose to harvest trout.

The increased size and condition of trout passing through the trap echoes reports from anglers, retailers and accommodation providers, who are all in buoyant mood and optimistic for the season ahead.

To see all our data and graphs for June, you can download this month's report sheet (XLSX, 45k). Further information is also available on the May 2019 trap report.

Waipa trap data June 2019, compared to June 2018
  June 2019 June 2018
  Brown trout female Brown trout male Rainbow trout female Rainbow trout male Total Total rainfall (mm) Brown trout female Brown trout male Rainbow trout female Rainbow trout male Total Total rainfall (mm)
Count 54 70 10 26 160 140.0 54 88 18 20 180 153.5
Average length (mm) 591 614 532 504     578 597 483 490    
Max length (mm) 660 720 585 560     660 680 535 555    
Average weight (kg) 2.7 2.8 1.8 1.6     2.5 2.5 1.3 1.3    
Max weight (kg) 3.7 4.1 2.3 2.1     3.5 3.9 1.8 2.3    
Condition factor 46 43 43 43     45 42 42 40    
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