trapO: Trout Data at the Te Whaiau Trap on Lake Otamangakau

trapOR Documentation

Trout Data at the Te Whaiau Trap on Lake Otamangakau


Rainbow and brown trout trapped at the Te Whaiau Trap at Lake Otamangakau in the central North Island of New Zealand. The data were collected by the Department of Conservation.




A data frame with 1226 observations on the following 15 variables.


Date as a class "Date" variable.


numeric vectors, the number of fish trapped daily. B/R is for brown/rainbow trout. F/M is for female/male. TW is for the Te Whaiau trap location (there was another trap just off the Tongariro River).

MinAT, MaxAT

numeric vectors, daily minimum and maximum ambient temperatures in Celsius.


numeric vector, daily rainfall that has been scaled between 0 (none) and 100 (flooding situation).


numeric vector, water level of the stream that has been scaled between 0 (none) and 100 (flooding situation). In a flooding situation it is possible that some fish going upstream were not caught.

Year, Month, Day

numeric vectors, extracted from Date.


a numeric vector, Julian day of year. The value 1 means 1st of January, and so on up to 365.


a factor vector, the year as a factor.


similar to Date but a fictitional year is used for all the data. This allows all the data to be plotted along one calendar year.


These are the daily numbers of fish trapped at the Te Whaiau trap near Lake Otamangakau, during the winter months when spawning is at its peak. These fish were all going upstream. There are two species of trout, split up by males and females, in the data set. The first is brown trout (Salmo trutta) and the second is rainbow trout (Oncorhynchus mykiss). Information on the movement patterns of brown and rainbow trout in Lake Otamangakau and Lake Te Whaiau can be found in Dedual et al. (2000).

Brown trout are more sedentary compared with rainbow trout, and spawning activities of brown trout occur between May and June whilst peak spawning of rainbow trout occurs between July and August. Furthermore, brown trout have been observed avoiding water above 19 degrees Celsius and optimum temperatures for growth are between 10–15 degrees for brown trout and 16.5–17.2 degrees for rainbow trout.

See also lakeO.


Many thanks to Dr Michel Dedual ( for making this data available. Help from Simeon Pattenwise is also acknowledged.


Dedual, M. and Maxwell, I. D. and Hayes, J. W. and Strickland, R. R. (2000). Distribution and movements of brown (Salmo trutta) and rainbow trout (Oncorhynchus mykiss) in Lake Otamangakau, central North Island, New Zealand. New Zealand Journal of Marine and Freshwater Research, 34: 615–627.



VGAMdata documentation built on Sept. 18, 2023, 9:08 a.m.