November 2025
The Waipa fish trap was decommissioned at the end of November, marking the conclusion of the 2025 winter trapping season.
We recorded 163.5 mm of rain at the trap site, with no flood events. The arrival of summer has seen the number of migrating trout reduce significantly. This month we processed 271 Rainbow trout. The biggest Rainbow was a hen that measured 580 mm, 2.15 kgs and 39.8 CF, and had spawned previously.
Once again there were no Brown trout recorded through the trap. These trout begin their spawning migration earlier in the season and also finish earlier, so the result is expected.
The downstream pen of the fish trap was kept busy with spent trout as they return to Lake Taupō after successfully spawning.
Graphs and tables November 2025 (XLXS, 66K)
October 2025
We recorded 370 mm of rain at trap site in October, with two flood events recorded, suggesting some spawning fish may have evaded the trap on their upstream migrations. These fish will be identified in the downstream pen of the trap later, so they can be factored into the final numbers.
The numbers of fish were typical for this year and a reduction on the same time last year. As expected, we also saw an increasing number of spent fish returning through the downstream pen.
The number of Rainbow trout that passed through the trap this month was 339, significantly lower than 510 recorded last October.
The heaviest Rainbow trout was a jack measuring 560 mm and 2.25 kgs. The longest was also a jack, 580 mm. Both fish had spawned previously. As expected at this time of year, the Brown trout spawning runs have nearly finished with only 4 hens recorded. The biggest was 590mm, 2.65 kgs and 46.6 CF.
The downstream pen of the fish trap becomes increasingly busy as we head towards the end of the spawning season. We monitor fin clips on the downstream fish as a method of determining what percentage of trout avoided upstream capture.
Graphs and tables October 2025 (XLXS, 66K)
September 2025
The rain gauge at the trap site recorded 261 mm of rain in September. There was one flood event which saw the trap breached by high flows.
The number of Brown trout has dropped dramatically now, as their spawning season concludes. Only 5 fish were processed, all of which were hens.
Elevated flow rates encouraged greater numbers of rainbow trout to enter the trap compared to last month. The 412 trout processed consisted of 230 hens and 182 jacks.
As is often the case, the heaviest fish was a brown hen that weighed 3.0 kgs. This fish was 610 mm long with a Condition Factor of 47.8. The presence of a fin scar confirmed this fish had spawned last year.
Graphs and tables September 2025 (XLXS, 66K)
August 2025
Heavy rain witnessed in previous months abated through August, with only 31 mm measured at the trap site. This may have had a limiting effect on the number of fish migrating up this headwater spawning stream.
Brown trout are now coming to the end of their spawning season, so numbers are dropping significantly. Only 30 brown trout in total were processed through the trap this month. The majority were hens (27), with only three jacks recorded. This is typical for this time of year.
Rainbow trout numbers were much higher than browns, but a little down on the previous month. Rangers processed 101 hens and 86 jacks.
The heaviest fish was a brown hen that weighed 2.9 kgs. This fish was notable having been processed through the trap for three consecutive years. This is determined by examining the fins for scars from previous clips.
Graphs and tables August 2025 (XLXS, 66K)
July 2025
Another month of heavy rain, with 411 mm recorded at the trap site – the highest figure recorded so far this year, which included two flood events.
Frequent wet weather this winter encouraged high numbers of trout through the fish trap. A rain event in late July brought a pulse of 77 rainbows and 18 browns into the upstream pen. We are also recording good numbers of early run fish passing back through the downstream pen of the trap having already spawned.
Runs of rainbows are expected to peak over the next couple of months as the brown trout run wraps up in August.
A total of 70 brown trout were processed through the upstream pen of the trap (43 hens and 27 jacks). The biggest brown was a 3.4 kg hen, measuring 665 mm long. Fin clip scars confirm this fish had spawned in the Waipa Stream on at least four previous occasions. A large jack weighing 3.3 kgs and 615 mm long was also spawning for at least the fourth time.
Rainbow trout were far more numerous with 267 fish recorded. Numbers were evenly split between the sexes, with 135 hens and 132 jacks. Rainbows don’t recover as readily from spawning, so repeat spawners are less frequent. However, the biggest jack and the biggest hen recorded this month were both spawning for the second time. The hen, 575 mm and 2.1 kgs, the jack, 565 mm and 2.5 kgs.
Anglers will find trout throughout the Tongariro river and will begin to encounter increasing numbers of recovering fish as we head into August and September.
Graphs and tables July 2025 (XLXS, 66K)
June 2025
The heavy rainfall encountered in May continued through June, delivering 291 mm of rain at the trap site on the Waipa Stream, causing the trap to flood on two occasions.
Trout are migrating upstream in good numbers with 193 fish processed through the fish trap in June. Rainbows are now the most numerous species with 113, compared to 80 brown trout. The overall number of trout is higher than last month but down on the very high numbers recorded at the same time last year. June 2024 witnessed a surge in trout following a prolonged period of dry weather.
Brown trout numbers consisted of 34 hens and 46 jacks. The heaviest brown was a hen that weighted 3.58 kg, measured 650 mm and had a Condition Factor of 47.1. This was also the biggest fish recorded overall this month. Numbers of fish aside, the size, weight and Condition Factor figures were generally consistent with last year.
Rainbow trout numbers were split between 67 jacks and 46 hens. The largest was a hen, tipping the scales at 2.6 kg, with 600 mm and a CF of 43.5.
Good flow rates have encouraged a steady stream of trout to enter the Tongariro River and progressively head upstream to the spawning streams. If current weather patterns continue anglers can expect to find trout throughout the river.
Graphs and tables June 2025 (XLXS, 66K)
May 2025
In alignment with previous years, the fish trap on the Waipa Stream was recommissioned in May. This allows consistent data collection across multiple years at this important trout spawning stream.
In May 2025 brown trout averaged 575 mm in length and 2.4 kg in weight. These figures are similar to 2023 and 2024 but down on the exceptional fish encountered in 2022, where browns averaged 607 mm and 3 kg respectively. The number of browns trapped during May this year was relatively low. Fishery Rangers processed only 23 browns, which is higher than the 16 trapped last year but much lower compared to 80 fish in both 2022 and 2023.
The rainbow trout trapped during May this year averaged 501 mm and 1.5 kg which is similar to those trapped during May 2024 (492 mm and 1.55 kg) and May 2023 (471 mm and 1.46kg), but again down on the solid fish trapped during May 2022 (531mm and 1.9 kg). The numbers of rainbows trapped during May this year (71) is up considerably on last year where only 33 rainbows were recorded but consistent with the 77-100 rainbows trapped during May 2022 and May 2023.
May 2025 was the second wettest May out of the last 4 years at 302 mm behind the peak of 2023 (400 mm) and much wetter than May 2022 (213 mm) and May 2024 (118 mm).