The wild trout struggle for suvival starts right from the moment that it is fertilized as an egg. The truth of the matter is that like everything else in the natural world, survival for young trout is low, from egg to larva and then from larva to young fry. As the small trout grow young parr, they will have a better chance at seeing maturity and even reproduction.
A brook trout fry will emerge from their gravel spawning beds in the month of January, in spring creeks like Millennium Creek, and as late as mid-May, on the mainstem of creeks like the Bighill Creek. Prior to emergence, the trout larva will develop from an eyed egg into a trout larva with egg sack attached. The small trout will continue to live off of their egg sacks until they are all used up.
Larger, mature trout will lay larger eggs, this will result in young trout that are further developed by the time the egg sacks are used up. These trout will also be larger and more able to compete for available food and habitat. So keeping larger trout in a system is of major importance. Fisheries managers sometimes neglect this well known fact about reproduction of wild trout.
There are all kinds of natural predators that feed on young trout, including insects, such as the dragon fly nymph or various beetle larva, among others. Larger trout will also include young trout in their diet, but this is more so if pickings are slim. Then there are the birds, just about any foraging waterfowl will eat young trout, besides their main diet of vegetation. Of course there are some diving waterfowl and ambush feeders, like Blue Herons, which will also feast on young trout.
Young trout are very curious fish and their curiosity has led to the demise of many a young trout. However, weeks after emergence from spawning beds, the trout start to develop more caution and they also disperse into small micro habitats with plenty of hiding places. Still abundant, predation continues until only a few of the original hatch are left to live into maturity. This is just natures way. If you look at how many willow and tree seeds are dispersed every spring, and only a few will result in germination and then other types of predation and weather conditons will take its toll. This is why both eggs and seeds are so plentiful with fish and plants.
The early winter hatch on Millennium Creek is the most important one on our watershed of the Bighill Creek system. There are no outside influences to prevent a reliable annual spawn and hatch of brook trout on this spring creek. A spring creek with stable flows, good quality water and consistant seasonal water temperatures, is perfect for the brook trout that live in this small stream or those that return to spawn.
If a trout has plenty of food and places to hide when predators visit their habitats, they will possibly survive into maturity. When the juvenile rainbow trout enter the Bow River, after spending their first year of life in the Jumpinpound Creek, they are faced with the tough challenges of living in a river that is far less productive, but has lots of space for the young trout to disperse into.
Sit back and enjoy this video of small brook trout fry, on a small spring creek, where they hatched from eggs.