Female pallid sturgeon PLS11-019 was implanted in spring 2011 in non-reproductive condition, but with “small white eggs.” Over the course of a year, those small eggs matured into large dark grey or black eggs. In March 2012, she was targeted for recapture by CSRP biologists and determined to be ready to spawn later this spring. Since fall 2011, she has moved approximately 20 miles upstream in preparation for her spring spawning migration.
Female pallid sturgeon PLS11-007 was initially implanted in April 2011 in non-reproductive condition, also with “small white eggs.” She was targeted for reproductive evaluation during fall 2011 (see previous post Head Start). During that second evaluation, biologists determined that she would spawn, or at least attempt to, in spring 2012. From mid-September to mid-November 2011, she has steadily moved approximately 100 miles upstream.
Female pallid sturgeon PLS09-011 was originally implanted with telemetry devices in fall 2009 as a non-reproductive female. She was targeted for recapture two years later, in fall 2011, and biologists were able to determine that she would likely attempt to spawn in spring 2012. Her reproductive readiness was confirmed by biologists again in March 2012. Since her initial recapture date, PLS09-011 has moved approximately 28 miles upstream.
Female pallid sturgeon take a long time to mature (12-14 years) in the Missouri River and they do not spawn every year. Biologists hope to follow these females for several years to observe them as the mature, become reproductive, migrate, and spawn. These long-term observations of individual sturgeon are very important for understanding the reproductive cycle of these long-lived fish. These particular females of interest are large (10+ pounds) and capable of swimming 10 miles or more per day. Keeping up with them may prove to be a challenge for the CSRP biologists.