Barriers and pots for selective access installed on Rio Caprionero 27 Jan

Barriers and pots for selective access installed on Rio Caprionero

The actions to restore and protect the populations of native S. macrostigma trout in the Volturno and Biferno basins continue with great alacrity. To promote the natural reproduction of native Mediterranean trout, we have just finished installing the barriers and pots for selective access to the main reproduction sites of the Volturno and Biferno. But how are these accesses regulated?

During the reproductive migration the individuals go up the current towards the deposition sites in search of the gravel suitable for the construction of the nest. Fixed nets and pots, installed in strategic positions determined to intercept as many as possible, divert their ascent into demarcated areas, monitored at least a couple of times a day. In each station there is a passage upstream, where the catch net is placed, and one towards the valley, which allows the trout to return to safer waters after spawning. The barriers, designed so as not to allow otters to enter, have a specific protection system that guarantees their safety and that of fish at the same time.
Each caught trout is scanned with a pit tag reader to find out if it has already been sampled or not. Each targed trout is immediately recognized. In the unmarked specimens, however, biological tissue is collected by taking a fragment of adipose fin that will serve for genetic typing, together with marking and temporary housing in a large cage placed in current near the barrier. Rapid genetic analyzes are carried out to characterize unmarked breeding animals, in order to retain the individual as little time as possible.
Each individual will be assigned a class of “genetic integrity” based on the diagnostic markers and morphological characteristics defined during action A3 and only individuals considered native will be released upstream of the barrier to allow them to reach the breeding sites.
A part of the native breeding stock will be used for artificial breeding activities that will serve to support natural production and to expand the area of the Mediterranean trout within the project area.