Monday, April 14, 2014

Extreme Length: Beluga Sturgeon

Scientific name: Huso huso
A higher clade it's part of: Acipenseriformes (sturgeons & paddlefish)
Conservation status: Critically endangered
Current range: Mostly Caspian and Black Sea basins, some in Adriatic Sea.

  The beluga sturgeon is a contender for the largest freshwater fish alive today. It swims up rivers to spawn (which is when Sarmatians could have encountered them if they did). It does have the ability to live in brackish water, so that keeps it from holding that record in everyone's eyes. Regardless, it's the second longest extant bony fish after the Giant Oarfish, and might be the longest macropredatory fish.
  Unlike the Great Bustard from last week's post, these fish don't stop growing--a trait called "indeterminate growth". Species with indeterminate growth won't grow at the same rate throughout their lives, but their growth curves never quite reach an asymptote. That makes it hard to say what an average size is--especially when you factor in how heavily hunted they are. The average size sturgeon today is much smaller than the average size would have been during the Sarmatians' time. So to make things simpler, I'm just going to talk about record sizes today.
  The record for largest beluga sturgeon was a female in the Volga River estuary. She was 24 ft (7.2 m) long--that's slightly longer than the longest verified Great White Shark (23 ft), and rivals the possible, but, it seems, unconfirmed, size of the Greenland  Shark. Its confirmed record is 21 ft, but it looks like the Florida Natural History Museum site says it could reach 24 ft. I can't find a trail leading back to the source of that information, unfortunately.

  The sad story of the Beluga Sturgeon is that it's prized as having some of the best caviar and being the source of the best isinglass (a substance made from fish air bladders and used to clarify wine and beer, among other less common uses). In spite of its critically endangered status, it continues to be hunted. Even if only caviar were collected, caviar isn't collected after eggs are laid--its collected by slicing the gravid female open, thus killing her before she can lay her eggs. Sturgeons take a very long time to mature (15-25 years for this species). If the population isn't allowed to replenish itself, it will go extinct.
  Mediterranean populations are protected under the Bern Convention. The United States banned import of Beluga Sturgeon caviar from the Caspian Sea in 2005. But, unfortunately, that's not enough. It turns out you can't trust the labels on caviar jars and cans. Take a gander at the study referenced below (if I could link to a free pdf, I would). With the caveat that the study took place before the US ban, it still shows that just because it's labelled as one thing doesn't mean it actually contains it.
  The researchers collected caviar from the US and Europe from 1995-1997. Sometimes they were labelled with a species, sometimes ambiguously (e.g., river sturgeon, which is meaningless), and sometimes not at all. Nothing they sampled in Europe was mislabelled (it can from Iranian sources). The US caviar came from countries in the former Soviet Union and, depending on the year, 17-32% of sources were mislabeled. Some caviar labelled as American Sturgeon was actually Beluga Sturgeon (some of it wasn't even sturgeon--it was paddlefish). And a dishonest dealer just went right back to his old tricks after serving time for fraud.

  So...don't partake in caviar that might be from the former Soviet Union. Or better yet, not at all. Because all sturgeon species are in trouble.

Birstein, VJ, Doukakis, P and DeSalle, R, 1999, Molecular phylogeny of Acipenserinae and black caviar species identification, Journal of Applied Icthyology, v. 15, p. 12-16.


  1. Interesting! I was just wondering the other day if Sarmatians fished, and if so, what they fished for...

    And considering that the average size of the Beluga Sturgeon is smaller I wonder if these guys gave rise to any sea monster stories back in the day?

    1. I'm not sure if they fished, but it wouldn't surprise me if some living alongside stationary cultures by the seas did. I think it's more likely they could have seen them from the shores of rivers running through the steppes (like the Don or Dneiper) when they spawned.
      Yes. Loch Ness and other lake monster sightings often turn out to be sturgeon. Oar fish, the longest bony fish, are supposedly the origin of many sea serpent stories.