Today, I’m continuing to muse and to marvel about sturgeon. I want to use a dead sturgeon to address the question I posed in my last column: “How is it possible for veterinarians to have a working knowledge of so many animals—an estimated 60,000 species of animals within the 5 groups with backbones?”
While I’d like to say the reason is because veterinarians are a lot smarter than most people, I’d be lying to you. The answer as to how and why this is possible is because of the “source code” for animals, the molecule DNA (deoxyribonucleic acid).
Anyone who has hunted, fished, or farmed and then opened and dressed their catch has noted that all animals have a basic design. There are two compartments, a front one for breathing and a back one for digestion. Lungs and a heart are the main organs within the front compartment (called the “thoracic—medspeak for chest—cavity”). The small and large intestines, a liver, spleen, the kidneys, can be found in the back compartment (called the “abdominal—Latin for ‘to hide’—cavity).
Since I was awarded my DVM from The Ohio State University in 1980, the details available to us about the design of animals, down to the molecular level, has grown so exponentially that entire new libraries would be required to house the new books and journal publications. Thankfully, we now have computers to store all this new information. As a Neenah boy in Ohio in 1980, I would have wagered with the cockiness that “certainly, there will be no sturgeon in the Lake Winnebago System by the year 2011.”
Last Wednesday, we noticed a dead sturgeon in the river while running on the bike path along the southern bank of the Wolf just west of the Shawano Street Bridge. Though the fish we discovered might be described as “gross”, Jim, Newton, Gracie, and I were drawn to it like moths to a light. At first, I didn’t realize the sturgeon was on its back—I thought it was on its side, mistaking its large oval mouth for what I thought was a hollow eye socket. If it was bloated, the bloating was minimal. It was 3-4 ft long and was lighter, more yellow in color, than the usual sturgeon greenish-grey. Unfortunately, it was too far out in the river. Jim managed to poke it with a long stick. However, a lot more time and effort would have been required for us to bring it in for a closer inspection. Fortunately, it was too far out for the dogs to get to it. Jim wondered whether a boat might have hit it. We didn’t see any lesions.
Due to the dead sturgeon’s size and, in light of the usual ratio of males to females during spawning season, my guess is that our dead fish was a male—males are smaller than females and a lot more males venture out of the lakes—Winnebago, Butte des Morts, Poygan and Winneconne—to spawn than females. Perhaps this fish simply died of old age? I learned that male lake sturgeon may live some 55 years whereas females can reach the age of 150.
The liver of this sturgeon did what a liver does in all animals. Microscopically and biochemically the primary cells of this one fish’s liver (the hepatocytes, “hepato”—medspeak for liver, “cytes”—medspeak for cell) resemble and function like the liver cells of all animals. It is this commonality of anatomical structure and biochemical function of each and every organ that make it possible to know so much about so many animals—teach a student what a liver is and does in one animal and the student now has a basis for understanding what a liver is and does in all animals.
While the death of this sturgeon is a loss and the reason it died is a mystery, there is a chance that this fish succeeded in spawning hundreds of thousands of new baby sturgeon. Nature is exuberant in just how many seeds and eggs it sows and incubates. I can but marvel at how, regardless of whether it is a mammal, an amphibian, a reptile, a bird, or a lake sturgeon, we now know the molecule DNA provides its life instruction manual. A lack of appreciation for how wondrous design combines with a capacity for the birth of a staggering number of offspring proved wrong a young veterinarian’s pessimistic predictions about sturgeon in the Lake Winnebago System.
Published in the Waupaca County Post East newspaper, 5/26/11.