Trout Health Study by North Canterbury Fish & Game

16 November 2007

Trout populations in New Zealand are facing threats from water abstraction, water degradation and the potential effects of climate change. Other pressures such as the adverse effects of invasive organisms such as Didymo, need to be monitored as well. Also, over harvest may be occurring in some waters. There is a need to have information to substantiate any claims that fish stocks and or fish health are declining.

Fish & Game have designed a national monitoring programme for quantitatively assessing the age and size distribution and growth rate of trout populations in New Zealand over time. Monitoring of these parameters, in addition to trout abundance is fundamental to sound fisheries management. Changes detected in these parameters will underpin management action for fishery recovery – (e.g. changes to harvest regulations and targeted environmental advocacy). This project is intended to be on going so that a long term dataset can be compiled.

Four rivers will be monitored in the North Canterbury Region:
- Hurunui River
- Waimakariri River

- Rakaia River

- Selwyn River

The age of the fish will be assessed from the fish otoliths (small bones located in fish head) and growth analysed based on the weight and length of the fish.

We need your help to collect data for this project. We would appreciate if you kill some of the fish caught in any the four rivers monitored and record precise measurements of fish length and weight, date and the location where fish was caught. Please send or drop off the fish head to our F&G office at 3 Horatio Street, Christchurch. Please use the form at the Fish & Game website to record the fish details.

Davor Bejakovich
Senior Fish & Game Officer

Please provide the trout head (cut it off behind the gills – but the gills don’t need to be provided) and the length of the fish from nose to the middle of the fork of the tail.

Record the date of capture and the place – nearest access point.

Place fish head and this piece of paper with details on in a plastic bag.

Angler Name ______________________________________________

Phone Number _____________________________________________

Trout length (cm) _______________Trout Weight (kg)________________

Date of capture ____________________________________________

Locality _____________________________________________

Any questions - please contact Davor Bejakovich, Fish and Game North Canterbury, 021 221 8332 or 03 366 9191