Download 16.09.16 - Are we releasing the wrong sturgeons in our waters

Press Release 16.09.16
Are we reintroducing the wrong sturgeon species in our
waters?
Using bone fragments found at archaeological sites, researchers from the Royal Belgian Institute of
Natural Sciences have reconstructed the occurrence of sturgeon in the North Sea during the last 7.000
years. It appears that an unexpected sturgeon species was dominant in our region. Is this species the
most suitable candidate for restocking and to save sturgeons from extinction?
Sturgeons are famous for their eggs, the caviar also known as ‘the black gold’. But the fish itself is also special.
There are 20 different kinds of sturgeon, of which some can grow to a stunning 6 meters in length and 400 kilo in
weight. Sturgeons are not only large but also long-lived: about 50 years on average, but century-old sturgeons
are no exception. The scaleless fish with a dark back and white abdomen usually feed on small fish and shrimps.
Most of the species live in the sea for years, before migrating upstream for spawning. Sturgeons have been on
earth for about 200 million years, and are sometimes referred to as ‘living fossils’.
Another dominant species
Researchers always assumed that the European sturgeon Acipenser sturio was the sole sturgeon species living
in the North Sea and Baltic Sea. This species, that once occurred in all European rivers and seas, is now only
found in the Gironde-Garonne-Dordogne basin in France. Archaeological remains, discovered in the
Netherlands, Belgium, Great Britain or France were blindly ascribed to the European sturgeon, until researcher
Els Thieren from our Institute took a closer look at thousands of century-old sturgeon remains.
She found that about 6.500 years ago, not only Acipenser sturio occurred here, but also the Atlantic sturgeon A.
oxyrinchus, a species that was thought to live only off the Atlantic coast of North America. The new study even
demonstrates that the Atlantic sturgeon was the dominant species in the North Sea.
Which species should be reintroduced?
Most sturgeon species are threatened with extinction as a result of overfishing for caviar and habitat loss. The
decline of the North Sea sturgeon population is also noticeable in the archaeological remains: starting from the
Middle Ages, less and less sturgeon remains are found. Since the 1980’s, policymakers and environmental
organizations are trying to reintroduce the sturgeon: A. oxyrinchus in rivers flowing towards the Baltic Sea, and
A. sturio in North Sea rivers. In 2012, dozens of members of A. sturio, coming from Gironde, were released in the
Nieuwe Maas, near Rotterdam and in the Waal near Nijmegen, both in the Netherlands. A similar operation was
performed in the Haringvliet in 2015.
But are we releasing the right species? “Reintroducing A. sturio in our waters is not wrong, technically”, says
archaeozoologist Wim Van Neer (RBINS), who supervised the study. “The species occurred here for thousands
of years, but it was always outnumbered by A. oxyrinchus . Or maybe A. sturio is in fact a good choice, as the
climate is changing and this species thrives in warmer waters. Policymakers may consider releasing both species
and looking which species survives best. In any case, this study shows that we can learn a lot from the past to
protect our environment today”.
The study was published in Journal of Fish Biology.
Contact
Wim Van Neer
Archaeozoologist, Royal Belgian Institute for Natural Sciences
[email protected]
02/627.44.38