The Critically Endangered cobice or Adriatic sturgeon Acipenser naccarii, endemic to the Adriatic basin, declined drastically in the latter half of the 20th century, and with no natural reproduction was on the brink of extinction by 1990. Recovery activities, mainly in the Po basin, have been implemented almost annually for 40 years, with the release of hundreds of thousands of individuals, mostly juveniles. All are descendants from a single stock held by a farmer, Giacinto Giovannini, who saved the species from extinction.
The life cycle of the Adriatic sturgeon can exceed 50 years, and the effects of conservation measures are therefore only expected after several decades. In recent years there have been increased sightings of large individuals, many of which have been genetically verified as released individuals, but no evidence of reproduction. Fingerlings of a size that suggest they are not reintroduced individuals have been reported in the River Ticino (a tributary of the River Po) and the River Livenza (which flows into the North Adriatic) but never in the River Po mainstream.
However, on 26 June a young Adriatic sturgeon, c. 4 cm long, was accidentally caught, and photographed and released, by a fisher (MG), in a stretch of the River Po sufficiently far from the River Ticino to indicate that reproduction must have occurred in the mainstream of the Po. The most recent reintroduction there was in 2020 and the size of the individual caught indicated it could not be one of the reintroduced individuals. The length indicates the individual was c. 2 months old, which suggests reproduction earlier than in captivity, where the species reproduces in late May or June.
This finding provides the first evidence that the River Po remains suitable for the reproduction of the Adriatic sturgeon and that the long-term conservation efforts for this species may be successful. The potential success of this reintroduction demonstrates the need for continuous and long-term support for the conservation of individual species.
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