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Migration and habitats of diadromous Danube River sturgeons in Romania: 1998-2000

Journal of Applied Ichthyology

By:
, ,
DOI: 10.1046/j.1439-0426.2002.00404.x

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Abstract

Upstream migrant adults of stellate sturgeon, Acipenser stellatus (10 in 1998, 43 in 1999) and Russian sturgeon, A. gueldenstaedtii (three in 1999) were captured at river km (rkm) 58-137, mostly in the spring, and tagged with acoustic tags offering a reward for return. The overharvest was revealed by tag returns (38% in 1998, 28% in 1999) and by harvest within 26 days (and before reaching spawning grounds) of the six stellate sturgeon tracked upstream. A drop-back of > 50% of the tagged sturgeon, some to the Black Sea, shows a high sensitivity to interruption of migration and capture/handling/holding. Harvesting and dropback prevented tracking of sturgeon to spawning sites. Gillnetting and tracking of stellate sturgeon showed that the autumn migration ended in early October (river temperature 16??C) and identified a likely wintering area at river km (rkm) 75-76 (St George Branch). Thus, fishery harvesting after early October captures wintering fish, not migrants. Rare shoreline cliffs in the lower river likely create the only rocky habitat for sturgeon spawning. A survey for potential spawning habitats found five sites with rocky substrate and moderate water velocity, all ???rkm 258. Drift netting caught early life-stages of 17 fish species and one sturgeon, a beluga, Huso huso, larva likely spawned at ???rkm 258. All diadromous Danube sturgeons likely spawn at ???rkm 258.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Migration and habitats of diadromous Danube River sturgeons in Romania: 1998-2000
Series title:
Journal of Applied Ichthyology
DOI:
10.1046/j.1439-0426.2002.00404.x
Volume
18
Issue:
4-6
Year Published:
2002
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
529
Last page:
535
Number of Pages:
7