Threat assessments and the IUCN Red List
The Sturgeon SG has actively contributed to assessments of the threat status of several sturgeon species for the IUCN Red List. Initial assessments are mostly undertaken by one or two members of the SSG, followed by further consultation of several members for further review.
The SSG also acts as the Sturgeon Red List Authority (RLA): all sturgeon Red List assessments, whether assessed by members of the SSG or by assessors from outside the SSG, are referred to the Sturgeon RLA for evaluation. At least two named evaluators need to agree with the assessment before the submission can be accepted by the IUCN Red List programme for inclusion on the IUCN Red List.
All 27 species in the order were categorized by IUCN in its 1996 Red List of Threatened Animals (see table, 'List of assessments of taxa from order Acipenseriformes'). All species assessed before 2001 are being reassessed according to the revised Red List criteria, version 3.1 (IUCN 2001).
Seven species were reassessed in 2004 using version 3.1 (2001). Five of these remain in the same threatened categories based on declining populations and habitat (IUCN 2004):
- Acipenser brevirostrum (Shortnose Sturgeon) - VU A2ce; B1ab(iii)
- Scaphirhynchus albus (Pallid Sturgeon) - EN A4ce
- Scaphirhynchus platorynchus (Sand Sturgeon; Shovelnose Sturgeon) - VU A3d+4ac
- Scaphirhynchus suttkusi (Alabama Sturgeon) - CR A4 cde
- Polyodon spathula (American Paddlefish) - VU A3de
Two species were downlisted to Least Concern, although subpopulations within their overall ranges remain in the threatened categories (IUCN 2004):
- Acipenser fulvescens (Lake Sturgeon) - LC (downlisted from VU in 1996)
- Acipenser fulvescens (Mississippi & Missouri Basins subpopulation) - VU A2acd
- Acipenser transmontanus (White Sturgeon) - LC (downlisted from LR/nt in 1996)
- Acipenser transmontanus (Upper Fraser River subpopulation) - EN B1ab(ii,iii); D
- Acipenser transmontanus (Fraser Regional subpopulation) - VU A2abc
- Acipenser transmontanus (Kootenai River subpopulation) - EN B1ab(i,v); C1
- Acipenser transmontanus (Upper Columbia River subpopulation) - CR A3b; E
The following North American species and subspecies were submitted for inclusion on the 2005 Red List, thanks to the efforts of a variety of North American sturgeon specialists led by Richard St Pierre (USA):
- Acipenser medirostris (Green Sturgeon) - proposed downgrading from Vulnerable (1996 assessment) to Near Threatened
- Acipenser oxyrinchus desotoi (Gulf Sturgeon) - proposed upgrading from Near Threatened (1996 assessment) to Vulnerable
- Acipenser oxyrichus oxyrinchus (Atlantic Sturgeon) - proposed reassessment of Near Threatened (no change to 1996 status)
- IUCN 2001. IUCN Red List Categories and Criteria: Version 3.1. IUCN Species Survival Commission. IUCN, Gland, Switzerland and Cambridge, UK.
- IUCN 2004. 2004 IUCN Red List of Threatened Species. Downloaded on 07 March 2005