Due to the efforts of the North Canterbury Acclimatisation Society, Brown Trout ova were introduced into the Avon River in 1867. This first hatchery was located in the Botanic Gardens, not far from the new Christchurch Women’s Hospital.
The release was a great success, hundreds of trout encouraging all types of fishermen to the banks of the Avon as early as 1871. That largest caught on record was 4kgs in weight.
Brown Trout spawn between winter and spring, the ‘hen’ laying her eggs under river gravel, making numerous small pockets with her tail. The eggs are then fertilised by a ‘jack’ and the process starts again. Development takes between four to six weeks, depending on water temperature. The babies are called ‘alevins’ and remain under the gravel until they have used up all their yoke sacks. After that, they venture out to feed on the rivers macro-invertebrates with the adults.
Sadly, the numbers of Christchurch’s Brown Trout have dropped significantly – very much so these past 20 years. The 2011 earthquakes certainly didn’t help with the Avon suddenly surging up 80cms and liquefaction turning the waters a murky grey and brown. The major concern was that these events would alter the natural spawning behaviour and with the June 2011 quakes, what eggs that had been laid were in serious danger by shifting gravel.
As their numbers continue to be closely monitored in all parts of the Avon, they remain a welcoming part of the living artwork that makes Christchurch such a special place to call home.
*Photo taken by Annette Bulovic*