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Adriatic Sturgeon (Acipenser naccarii)

Status | Taxonomy | Species Description | Habitat | Distribution |
Population Trends | Threats | Conservation Efforts | Regulatory Overview |
Key Documents | More Info


ESA Endangered - throughout its range
CITES Appendix II - throughout its range

Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Acipenseriformes
Family: Acipenseridae
Genus: Acipenser
Species: naccarii

Species Description
Weight: up to 55 pounds (25 kg)
Length: 6 feet (2 m)

olive-green and brown back and a white belly; they have 5 major rows of "scutes"

Lifespan: 50 years
Diet: worms
Behavior: they migrate upriver in late-winter or spring to spawn, they use sensory "whiskers" called barbels to detect food hiding on the bottom

Adriatic sturgeon are a long-lived, "anadromous" fish that depend on "estuaries" for their habitat. They are thought to live as long as 50 years, grow to about 6 feet (2 m) long, and weigh up to 55 pounds (25 kg). They have an olive-green and brown back with lighter flanks and a white belly with five major rows of dermal "scutes".

They are "benthic" feeders and typically forage on invertebrates (especially worm-type prey). They have a moderate length snout that is very broad and rounded at the tip. They also have an interrupted lower lip at the center of the mouth and short barbels that do not touch the mouth. The barbels are close to the tip of their snout, which they use to detect food hiding on the bottom.

Adriatic sturgeon live in estuaries and freshwater rivers. After growing to adulthood in estuaries at the mouths of rivers (in water depths of 30-130 feet (10-40 m)), they swim upriver to spawn in freshwater in the late winter and spring. They prefer muddy or sandy bottoms at the mouths of large rivers and never enter purely marine waters in the ocean outside of the estuary.

The only remaining spawning sites in use by Adriatic sturgeon are at the confluences of the Po River and its tributaries in Italy.

Historically, Adriatic sturgeon were known to occur in the Adriatic Sea ranging from lagoons in Venice, Italy, to the coastlines and rivers of Greece. Recent research on ancient specimens suggests the species may have also been present in the Iberian Peninsula until the 1980s.

Population Trends
Adriatic sturgeon are thought to have declined by at least 80% over the past three generations (~50 years). The last known natural spawning in Italy occurred in the 1980s. In the eastern Adriatic Sea, the population is likely "extirpated".

They have been reintroduced in Italy through a stocking program. Only a few fish have been caught recently, and they likely originated from stocked population releases.


  • overfishing led to widespread declines in Adriatic sturgeon abundance
    • commercial and recreational fishing occurred for hundreds of years but is now generally banned

Current threats include:

  • "bycatch" of sturgeon in fisheries targeting other species
  • habitat degradation and loss from various human activities such as dredging, dams, water withdrawals, and other development
  • habitat impediments including locks and dams
  • pollution and poor water quality
  • small population size
  • climate change
  • competition or predation from introduced Wels catfish

Although there are no known diseases threatening Adriatic sturgeon populations, there is concern that diseases could be introduced through aquaculture operations for other sturgeon species.

Conservation Efforts
Adriatic sturgeon are listed in Appendix II of CITES, which regulates international trade.

Adriatic sturgeon are also listed in Appendix II of the Bern Convention on the Conservation of European Wildlife and Natural Habitats, which prohibits "take" and deliberate habitat destruction. All countries that have signed the convention must coordinate efforts to protect at-risk species and promote:

  • national conservation policies
  • measures against pollution
  • educational and informative measures

Over 400,000 fish were restocked in Italy from 1991-2007. However, no reproduction of these released fish has been documented.

Regulatory Overview
In 2012, WildEarth Guardians and Friends of Animals petitioned [pdf] us to list 15 foreign sturgeon species under the ESA. We proposed to list 5 species as endangered under the ESA. (The other 10 species were determined to be under the jurisdiction of the U.S. Fish and Wildlife Service, and USFWS is reviewing their status.)

Key Documents
(All documents are in PDF format.)

Title Federal Register Date
Final Endangered Listing of Five Sturgeon Species 79 FR 31222 06/02/2014

Proposed Endangered Listing of Five Species of Sturgeons under the ESA

78 FR 65249 10/31/2013
Status Review   10/2013
90-day Finding on a Petition To List Five Species of Sturgeon as Threatened or Endangered under the ESA 77 FR 51767 08/27/2012
Petition to List 15 Sturgeon Species as Threatened or Endangered n/a various

More Information

Updated: June 2, 2014

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