By Kimberly Chojnacki and Aaron DeLonay
The scientists of the Comprehensive Sturgeon Research Project (CSRP) have known that pallid sturgeon are quite capable of travelling long distances (see previous post “Long Distance Runner”). Occasionally, we are reminded of the incredible journeys on which these remarkable fish often embark. One such example is the chronicle of male pallid sturgeon PLS10-014. Since spring 2010, PLS10-014 has covered more than 1200 river miles (Figure 1) spanning across four states. This male fish was initially tagged in the Missouri River in Nebraska near river mile 620, about 25 miles upstream of the Platte River confluence in late April 2010. He remained within approximately 25 miles of this location until that summer when he began to move downstream, continuing through the following spring. A year later, in April 2011 he was located at the confluence of the Osage and Missouri Rivers near river mile 130. By August 2011 he was located more than 100 miles further downstream near river mile 10 in the Missouri River (near St. Louis, Missouri). Between March 2012 and September 2013, PLS10-014 changed direction and moved back upstream. Over the next 18 months he was relocated numerous times between river miles 80 and 230. In the late fall of 2013 something changed and PLS10-014 began moving rapidly back upstream to where he was first captured and tagged near river mile 620. Scientists were curious. Was he making an early start back to a spawning location for spring 2014? In early May of 2014 tracking crews located him near river mile 610 and shortly thereafter he was making his way up the Platte River (see previous post “Pallids in the Platte”). Some pallid sturgeon are fairly sedentary and spend long periods in the same locale, while others go off on long journeys, sometimes returning to very nearly the exact location. Why do sturgeon undertake such extensive movements and how do they recognize specific places in the deep, muddy Missouri River? CSRP scientists are using long-term tracking data to try to answer these questions.