The 2025 Sturgeon Taxonomy Debate: Proposed Changes and Expert Disagreement

One kaluga, three competing scientific names: Huso dauricus, Sinosturio dauricus and Acipenser dauricus. The 2025 sturgeon taxonomy debate puts the names of familiar caviar species at the centre of a deeper question: how should genera reflect evolutionary relationships?

Brownstein and Near proposed extensive changes, including moving kaluga into Sinosturio. Kottelat and Freyhof challenged the nomenclature, while a specialist workshop recommended placing both kaluga and beluga in Acipenser. For permits and regulatory labels, the practical answer is straightforward: use the nomenclature required by the relevant authority, rather than lifting a replacement from a research paper.

Why the sturgeon family tree needs another look

The trouble begins with the family tree. Molecular studies place fish traditionally assigned to Huso among lineages assigned to Acipenser, rather than revealing two cleanly separated genera.

A natural evolutionary group contains an ancestor and all its descendants. Scientists call this monophyletic. A paraphyletic group leaves some descendants outside it. The traditional division between Huso and Acipenser therefore raises a question of classification, not merely spelling: should scientists redraw the genera around smaller branches, or recognise a broader genus? Identifying the problem does not settle which remedy has enough evidence behind it.

Sturgeon genetics makes that decision harder. Their histories include polyploidy, meaning additional chromosome sets, and introgression, the movement of genes between species through hybridisation. Both can complicate the interpretation of family trees. The guide to sturgeon genetics explains those mechanisms; here, the focus is what they mean for names.

What the 2025 proposals would change

Brownstein and Near’s proposal redraws much of the familiar map. It restricts Acipenser to A. sturio, A. oxyrinchus and A. desotoi; revives Sinosturio for seven Pacific-associated species, including kaluga; and expands Huso around beluga and ten species previously assigned to Acipenser. Scaphirhynchus and Pseudoscaphirhynchus remain separate.

Chase D. Brownstein and Thomas J. Near published “Toward a Phylogenetic Taxonomy of Sturgeons (Acipenseriformes: Acipenseridae)” in the April 2025 Bulletin of the Peabody Museum of Natural History, volume 66(1), pages 3 to 23. Their work reanalysed publicly available mitochondrial and nuclear sequences and published morphological data. It did not draw on a newly collected sample of every species. The nuclear analysis used 30 markers, with unequal species coverage between analyses.

Maurice Kottelat and Jörg Freyhof challenged the names in a response published on 4 September 2025 in Zootaxa 5689(3), pages 538 to 548. Their central claim concerns priority: Sterletus Rafinesque, 1820 predates Huso, which they attribute to Lovetzky, 1834. On their interpretation, the older available name must take precedence.

They also place Antaceus, Gladostomus, Helop, Lioniscus and Shipa in the synonymy of Sterletus, rather than Acipenser, and identify Kessleria as available from Bogdanov, 1882. Their response principally addresses the correct names under zoological nomenclature, rather than offering an independently sampled molecular reconstruction of the family.

The February 2026 reply: which name takes precedence?

Brownstein and Near defended Huso. In their reply of 17 February 2026, published in Zootaxa 5759(3), pages 341 to 342, they attribute the name to Brandt and Ratzeburg, 1833. They argue that Sterletus is a nomen oblitum, a forgotten name, while Huso is a nomen protectum, a protected name.

A CITES label supplies traceability information; it cannot authenticate the contents of the container.

Their case invokes the International Code of Zoological Nomenclature, including its treatment of Latinised names and reversal of precedence. They also reject placing all sturgeons in one broad Acipenser as an adequate solution. The reply presents their argument; it does not establish settlement by a nomenclatural commission or trade authority.

There are several disagreements here, each worth keeping distinct. Researchers can agree that genera should reflect ancestry while disputing where their boundaries belong, whether the supporting data are strong enough, or which historical name should apply. Agreement on the principle does not settle the classification or the name.

What the specialist workshop recommended

The workshop’s answer was conservative, but it still meant changing familiar names. It recommended dissolving Huso into Acipenser, producing Acipenser huso for beluga and Acipenser dauricus for kaluga.

The joint SSG and World Sturgeon Conservation Society discussion took place in Yichang, China, on 22 October 2025. WSCS published its summary on 13 November 2025, before NASPS carried the outcome on 2 December. Anyone tracing the statement should start with that earlier publication.

Participants rejected both the extensive Brownstein and Near revision and the Kottelat and Freyhof nomenclatural response. Their concerns included missing data, weak support for several branches, insufficiently defined morphological diagnostics, polyploidy and gene flow between species. They also warned that extensive renaming could complicate conservation instruments.

Rather than preserving the traditional genera intact, the workshop proposed the broader Acipenser arrangement. It also recommended recognising A. oxyrinchus and A. desotoi as distinct taxa.

The outcome is a specialist workshop recommendation, separate from a CITES amendment. Its conservation context complements the species assessments discussed in sturgeon on the Red List.

Names readers may encounter

The table compares published scientific treatments. “Proposed” identifies the named author’s treatment; regulatory acceptance must be checked separately before changing a label.

The first column gives the species names used across caviar.uk. As of 2026, Eschmeyer’s Catalog of Fishes treats beluga as Acipenser huso, and WoRMS follows the workshop.

What CITES adoption would require

A scientific paper can change the debate without changing a permit. CITES uses standard nomenclature adopted by its Conference of the Parties, and its glossary says those adopted names should appear on permits and certificates. Publication alone does not amend that documentary standard.

The post-CoP20 resolutions index lists Resolution Conf. 12.11 (Rev. CoP20) for standard nomenclature and retains Resolution Conf. 12.7 (Rev. CoP17) for sturgeons and paddlefish. The revised number on the general nomenclature resolution does not establish adoption of these particular sturgeon proposals.

No sturgeon-specific CoP20 nomenclature change has been confirmed here. Check the current standard reference before relying on a revised name.

Permits, labels and national law

Start with the rules for the jurisdiction handling the document. A scientific catalogue and a permit authority serve different purposes, and an updated entry in one does not automatically change the other.

For the EU, Regulation (EC) No 338/97 supplies the wildlife-trade annexes; Commission Regulation (EU) 2026/1383 amended them after CoP20. Read that update alongside the implementing nomenclature provisions when establishing the wording for a permit.

For the UK, check the operative position separately for Great Britain and Northern Ireland. Confirm the name with APHA, which issues UK CITES permits for both.

For the US, 50 CFR 23.23 requires scientific names on CITES documents to follow the standard nomenclature in the Appendices or references adopted by the CoP. Follow that documentary requirement, rather than whichever scientific database changed most recently.

Keep the caviar codes separate from proposed genus changes. The codes in use are HUS for Huso huso and DAU for Huso dauricus. Confirm them against the current annex to Resolution Conf. 12.7 before relying on them, and do not invent replacement three-letter codes from a proposed name.

A CITES label supplies traceability information; it cannot authenticate the contents of the container. Scientific identification and consumer food naming are separate matters. The broader framework is explained in CITES and caviar.

How caviar.uk handles competing names

Our editorial policy keeps CITES names in titles, fact boxes and legal discussions, with alternative combinations listed alongside their source and date. Each alternative should be identified as belonging to a paper, a workshop recommendation or an adopting catalogue, rather than presented as a universally accepted synonym.

For professional records, use separate fields for the regulatory name, the research name and the reference supporting each. When comparing older papers with newer databases, match the underlying species before combining results.

That simple discipline preserves a readable history. It also keeps a change of name from quietly changing the identity attached to a permit, tissue sample or conservation record.

Where to go next

• Sturgeon Biology: background for reading the scientific literature.
• The CITES Caviar Code Explained: how the label’s species field fits the wider traceability system.