Set in Their Ways

Popular media coverage of Lake Sturgeon characterizes them as an ancient fish, and few adjectives could be more apropos. Yes, they are ancient on geological time spans. The fossil record confirms there have been sturgeon like fish swimming somewhere on the planet for 250 million years. However, the characterization as “ancient” works on multiple levels. In terms of an individual’s life history, sturgeon can live to be ancient. By counting rings on fin spines or ear bones scientists have determined that Sturgeon can live to over 150 years old (Pflieger 1997). A final connection I will offer to sturgeon being old is a little more metaphoric and —“gasp”— anthropomorphic. We are beginning to learn that our tagged Lake Sturgeon, like your parents or grandparents that go to dinner at Denny’s every Tuesday evening at 4:30pm and order nothing but the 55+ grilled cheese and soup, (cut diagonally!!), are often creatures of habit. When it comes to where they go and when, Sturgeon can be downright curmudgeonly, obdurate, and immutable.

Case in point, there are fish like Aldo and Cosmopolis that wander about the lower Missouri Basin and then reliably show up in the Gasconade in the spring. There is Moe, which last summer was the lonely soul who braved the soupy bathwater of the lower Gasconade River by himself, returning this summer to its steamy waters. There is Edward, who is the only fish that really seems to like a particular shallow, wood-strewn reach in the lower Osage. He showed up right on time in the early summer just as he did last year. Julio, Liam, the list goes on. Fancy statistical analysis of site fidelity and homing in our Lake Sturgeon will come once we have collected a couple more years of movement data, but the anecdotal evidence is racking up that some sturgeon may be predictable. When you are guessing, correctly, which tag is about to ping as you round the river bend it probably is not a leap to imagine something more than random is occurring. A recent paper showed similar behavior in Lake Sturgeon in the St. Clair system that connects Lakes Huron and Erie. The population of Sturgeon broke out into four movement patterns that were more or less consistent across years (Kessel et al. 2018).

MU Grad Student Corey Dunn holding Moe. Photo Credit: Brandon Brooke

Just like long-lived people, perhaps long-lived fish when making decisions — such as where are good places to find food, where are good places to rest — defer to experience. However, when our environment is changes faster than the population is turning over, what is a sturgeon to do? When the price of the 55+ grilled cheese and soup special raises 30 cents to adjust for inflation you had better believe we are going to hear some grumbling. This is a big ecological question and one that takes decades to address, but it is one worth thinking about. For the sake of our long-lived species and the long-term health of aquatic ecosystems, there is no time like the present to begin.

 

References:

Kessel, S., D. Hondorp, C. Holbrook, J. Boase, J. Chiotti, M. Thoomas, T. Wills, E. Rosman, R. Drouin, and C. Krueger. 2018. Divergent migration within Lake Sturgeon (Acipenser fulvescens) populations: Multiple distinct patterns exist across an unrestricted migration corridor. Journal of Animal Ecology 87:259-273.

Pflieger, W. L. 1997. The fishes of Missouri, 2nd edition. Missouri Department of Conservation, Jefferson City, Missouri.

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