The high demand for caviar made from sturgeon eggs has pushed these fish to the brink of extinction. Today, wild-caught caviar is illegal, but that doesn’t seem to stop some suppliers from getting the animals from the Danube and Black Sea anyway, a research team has found. In every fifth caviar sample examined from Bulgaria, Romania, Serbia and Ukraine, eggs from wild sturgeon were found. The researchers appeal to significantly tighten controls and protection efforts on site.
Caviar made from sturgeon eggs is considered a popular and expensive delicacy. It used to be made from wild-caught sturgeon from the Danube and the Black Sea, but at some point high demand caused the population to collapse so much that European sturgeon were at times on the verge of extinction. The trade and consumption of wild sturgeon and their products has been officially banned since 1998. Since then, caviar can only be produced from sturgeons bred specifically for this purpose in aquaculture.
The big caviar test
However, local reports have repeatedly pointed out in the past that the strict protective measures may not be adhered to everywhere. Researchers led by Arne Ludwig from the Leibniz Institute for Zoo and Wildlife Research in Berlin have now investigated this suspicion scientifically. To find out whether sturgeon are actually being poached along the Danube and Black Sea, the team first purchased over 100 caviar and meat samples from countries bordering the remaining wild sturgeon populations: Bulgaria, Romania, Serbia and Ukraine.
Ludwig and his team purchased the samples both online and on site in local markets, shops, restaurants, bars and aquaculture facilities. The researchers then analyzed the DNA contained in the caviar samples as well as the isotope patterns and were able to determine which species of fish each was and where the animals came from. From this they were able to conclude whether the animals had been caught wild or bred.
Poaching and fraud rampant
The result: 21 percent of all caviar samples examined came from wild-caught sturgeon, as Ludwig and her colleagues report. Products made from such illegal wild catches are therefore sold in all tested countries. “The conservation status of sturgeon stocks in the Danube is critical, so every single specimen is important for their survival. “However, the observed intensity of poaching undermines any protection efforts,” criticize the researchers.
However, the results of the analysis are not only questionable for species protection, but in many cases also include customer fraud. Because 61 percent of the samples of sturgeon products were also incorrectly declared. The producers either passed off less popular sturgeon species for “more noble” ones or provided false information about the country of origin and fishing method. In three Romanian samples, the manufacturers even advertised their product as sturgeon soup, even though there was no sturgeon meat in it, but rather catfish and Nile perch. Additionally, some producers labeled their caviar as “wild caught,” even though they actually obtained it from aquaculture fish.
According to Ludwig and his team, the fact that manufacturers are resorting to this scam indicates that demand for wild sturgeon remains high and farmed versions may be viewed as inferior. This puts local fishermen under pressure. Without poaching, many of them would probably not earn sufficient income, as the researchers suspect. This business model is probably made easy for fishermen through lax on-site controls. Ludwig and his team therefore demand: “The control of the caviar and sturgeon trade in the EU and the accession candidates must be urgently improved to ensure that the sturgeon stocks in the Danube have a future.”
Source: Cell Press, Forschungsverbund Berlin eV (FVB); Specialist article: Current Biology, doi: 10.1016/j.cub.2023.09.067