by Daniele Pieracci
The reproduction of salmonids of the genus Salmo in Italy is carried out canonically in the winter months. However, there may be delays in the reproductive period between the various populations depending on the latitude, altitude and hydrological characteristics since these aspects can cause the scrub to anticipate in the late autumn months or postpone it to the beginning of spring. Within the same population, then, not all individuals reproduce in a synchronized manner, but there will always be fish that will anticipate and others that will take a few weeks, sometimes months, later.
With an average incubation time of 400 degrees day (eg: 40 days at a temperature of 10 °C) and a slow resorption of the yolk sac, the fry will remain hidden under the substrate for months. Only in late spring or in the first weeks of summer, with the increase in temperatures and the awakening of underwater life, the young trout of just a couple of centimeters will begin to emerge, to carry out a first exploration of the surrounding environment, then disperse. along the watercourse and subsequently begin their “countercurrent” life.
It will be difficult to observe them in these early stages of their life, at least until the end of the summer when, once they have reached 6 cm, they can be easily sampled with the electro-fishing.