Olomouc's Dead Arm of the Morava River Comes Back to Life: Scientists Count 15 Fish Species

In the restored Dead Arm of the Morava River in southern Olomouc, scientists have discovered 15 species of fish, and a survey has confirmed that fish are naturally reproducing there. The reconstruction of the water body was completed last year as part of flood-prevention measures, Petr Loyka, head of the environmental department at Olomouc City Hall, told ČTK.

The research was carried out by experts from the Institute of Vertebrate Biology of the Czech Academy of Sciences. The city plans to continue monitoring the development of the ecosystem in the Dead Arm and the surrounding area.

The Dead Arm in the Nové Sady district is a remnant of a historic meander of the Morava River. It once formed part of the main riverbed, with water flowing through it freely. However, as the river was gradually straightened and regulated, the arm was cut off from the main flow, losing its regular water exchange and gradually becoming silted up and overgrown.

After the connection with the river was restored, favorable conditions for aquatic life returned to the water body. The lower section of the arm was reopened and linked to the river, while the upper section allows water to flow in from the Morava whenever its level rises, naturally flushing out the channel. Beyond its ecological role, the restored arm now also helps protect the city from flooding.

According to Loyka, the area is important not only for fish but also for bats, birds and insects. The idea of reconnecting the Dead Arm with the Morava River first emerged back in April 1997, but those plans were derailed by a catastrophic flood that submerged much of Olomouc, including the city's southern district.

Read also: 8 best swimming spots near Prague: lakes, quarries and beaches an hour from the capital

Around Prague, based on reporting by ekolist.cz