Saturday, November 16, 2013

Three sturgeons

Watching a show last night about one of my favourite animal groups, the sturgeon, giant prehistoric migrant fish of the northern hemisphere it occured to me I should show you some pet pictures.....

I recently went home and took my underwater housing to try and get some nice shots of my parent's pet sturgeon. We have three species:

This is an albino sterlet. Sterlets are among the smallest sturgeon reaching only 3 - 4 feet or so in length. It's vulnerable in the wild but widespread due to successful aquaculture projects breeding them for both food and ornamental purposes.
albino

This is Acipenser gueldenstaedtii, the diamond or danube sturgeon. They can get up to 8 feet in length and are a pretty serious beastie. Found in the caspian sea and the various former soviet states like the stans, georgia and iran. Note the rounded nose to the extent you can see it in the shoddy photos.

diamond2

The third species we keep is the Siberian sturgeon (Acipenser baerii) another large species wikipedia descrbes as present in all of the major Siberian river basins that drain northward into the Kara, Laptev and East Siberian seas, including the Ob, Yenisei (which drains Lake Baikal via the Angara River) the Lena and Kolyma rivers. It is also found in Kazakhstan and China in the Irtysh River, a major tributary of the Ob. This is probably the species first and most commonly bred by aquaculture and caviar farms. This is a dark species without the big scutes of the diamond so I resorted to setting the camera to video and using some squished up wet bread to lure them to the camera. You can see a close pass here.... and a full on "gimme the bread" attack here (that's the albino sterlet you can see cruising around at the bottom first up): Whilst having these guys cruising our pond gives me tremendous pleasure, the knowledge that we're able to enjoy them as a result of successful breeding programs providing wonderful foodstuffs whilst easing pressure on wild populations makes it all the better. I dream of a day when wild sturgeon are returned to the great rivers of western europe as a result of successful breeding (it's happening already: http://www.bfn.de/habitatmare/en/spezielle-projekte-wiederansiedlung-stoer.php but the relict population of European sturgeon seems to be restricted to the Gironde) and these dinosaurs once again dominate huge untamed(ish) european river systems - imagine these beasties running through a system of ecologically non-damaging hydropower lagoons and into the upper reaches of the severn or people sportfishing for these giant fish in the thames or seine.

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