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Bayesian modelling suggests that the sterlet (Acipenser ruthenus, Linnaeus 1758) population is ageing in the middle Danube River

Bayesian modelling suggests that the sterlet (Acipenser ruthenus, Linnaeus 1758) population is... In the past, sturgeons played an important role in commercial and recreational fisheries in the Danube River and its tributaries. Human impacts in the Danube River Basin coupled with exploitation of sturgeon stocks led to all species being either locally extinct, critically endangered or of unknown status. Sterlet (Acipenser ruthenus, Linnaeus 1758) is the last known sturgeon species occurring in the upper and middle Danube; however, the population of this species is considered unbalanced and decreasing since the beginning of the twenty‐first century. The decline of sturgeon stocks has been noted before owing to their economic importance. With commercial fisheries being forbidden in the Slovak section of the Danube River, there is generally no information available about the status of what is considered a local population. Databases containing recreational catch of sterlet (2003–2018) and historical records of commercial harvest (1961–1990) were used to describe the trend in the weight and number of sterlet caught over the following years. Modelling indicated that the number of fish caught each year appears to be lower, while the average weight of each individual is increasing. This might suggest that the population is ageing. Although older individuals can contribute a great deal more to spawning because they produce a greater number of eggs, several problems are apparent. The number of spawners might be decreasing as a result of bycatch or fishing, their ability to spawn might be obstructed, or annual recruitment may fail owing to unpredictable events. Although restocking programmes are in place to help maintain the sterlet population in the Danube River, their efficiency seems to be drastically low. In fact, restocking could be of little value unless studies on the availability of key habitats are conducted and their protection and restoration are ensured. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Aquatic Conservation: Marine and Freshwater Ecosystems Wiley

Bayesian modelling suggests that the sterlet (Acipenser ruthenus, Linnaeus 1758) population is ageing in the middle Danube River

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References (46)

Publisher
Wiley
Copyright
© 2021 John Wiley & Sons, Ltd.
ISSN
1052-7613
eISSN
1099-0755
DOI
10.1002/aqc.3515
Publisher site
See Article on Publisher Site

Abstract

In the past, sturgeons played an important role in commercial and recreational fisheries in the Danube River and its tributaries. Human impacts in the Danube River Basin coupled with exploitation of sturgeon stocks led to all species being either locally extinct, critically endangered or of unknown status. Sterlet (Acipenser ruthenus, Linnaeus 1758) is the last known sturgeon species occurring in the upper and middle Danube; however, the population of this species is considered unbalanced and decreasing since the beginning of the twenty‐first century. The decline of sturgeon stocks has been noted before owing to their economic importance. With commercial fisheries being forbidden in the Slovak section of the Danube River, there is generally no information available about the status of what is considered a local population. Databases containing recreational catch of sterlet (2003–2018) and historical records of commercial harvest (1961–1990) were used to describe the trend in the weight and number of sterlet caught over the following years. Modelling indicated that the number of fish caught each year appears to be lower, while the average weight of each individual is increasing. This might suggest that the population is ageing. Although older individuals can contribute a great deal more to spawning because they produce a greater number of eggs, several problems are apparent. The number of spawners might be decreasing as a result of bycatch or fishing, their ability to spawn might be obstructed, or annual recruitment may fail owing to unpredictable events. Although restocking programmes are in place to help maintain the sterlet population in the Danube River, their efficiency seems to be drastically low. In fact, restocking could be of little value unless studies on the availability of key habitats are conducted and their protection and restoration are ensured.

Journal

Aquatic Conservation: Marine and Freshwater Ecosystems – Wiley

Published: Mar 1, 2021

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