A Spawning Recorded in the Yellowstone River

By Patrick Braaten

Pallid sturgeon code 39 is shown being prepared for release following a post-spawn analysis

Figure 1. Researchers prepare to release pallid sturgeon code 39 following a post-spawn analysis to confirm a successful release of eggs during the spawning event.

She was initially captured in September 1993, but at the time, the sex and reproductive status of the 1325 mm, 15.9 kg pallid sturgeon were not determined. She was implanted with a passive integrated transponder (PIT) tag for future identification and released.  Six years later in April 1999, she was captured again and identified by her unique PIT number.  She measured 1356 mm and weighed 17.7 kg though her sex and reproductive state remained undetermined.  Her history over the course of the next 15 years is unknown as she eluded collection efforts implemented as part of pallid sturgeon propagation and research efforts in the Upper Missouri and Yellowstone rivers.  Her 15-year period of at-large anonymity ended on June 11, 2014, when she was unexpectedly encountered in a trammel net drifted in the lower Yellowstone River.  Reproductive assessment indicated that the unknown pallid sturgeon was indeed a female, in reproductive condition, and likely to spawn soon.  Measuring 1405 mm (approximately 4 feet and 7 inches) and weighing 17.5 kg (38.6 pounds), the spawn-ready female was implanted with radio transmitter code 39 and released.  Female code 39 joined the research population of three other female pallid sturgeon (codes 30, 35, 36) that were already identified as reproductively ready to spawn.

With a cast of four spawn-ready females and numerous telemetered male pallid sturgeon, crews from Montana Fish, Wildlife and Parks (MFWP) and the U.S. Geological Survey Columbia Environmental Research Center (CERC) focused efforts to maintain contact with the spawners and identify spawning locations.  Tracking teams were accompanied by habitat crews and crews equipped with a DIDSON acoustic “camera” – in an attempt to visualize spawning behavior (see previous post “Northbound”).

A USGS research vessel observes pallid sturgeon spawning activities

Figure 2. A USGS research vessel uses DIDSON sonar imaging on the Yellowstone River to document pallid sturgeon spawning activities on June 27, 2014.

For the next several days after being implanted with the telemetry transmitter, pallid sturgeon female code 39 exhibited the pre-spawn “roaming” behavior frequently observed in female pallid sturgeon in the Yellowstone River – alternating sequences of upstream and downstream migrations of 15-30 miles.  Code 39 skirted around and occasionally through a large aggregation of male pallid sturgeon located between rivermile 5.1 – 5.5 of the Yellowstone River while exhibiting her up- and downstream roaming behavior.  A quick recapture of code 39 on June 22 upstream from the male aggregation indicated that she was still carrying her eggs following her most recent passage through the male aggregation. The roaming behavior of code 39 changed on the evening of June 26 as her upstream migration slowed when the male aggregation was encountered at rivermile 5.3 – 5.5.  By morning on June 27, code 39 and numerous males were engaged in spawning activity that persisted through late evening.  DIDSON imaging was deployed during the prolonged spawning event to document spawning activities and fish interactions at the spawning patch (see aggregation and spawning location videos below).  Spawning activities were completed by the morning of June 28 as code 39 was solitary downstream from the spawning patch; her recapture indicated a 20% loss of body weight due to egg deposition.  Habitat crews quantified depth, velocity and substrate conditions in the spawning patch (see previous post “Yellowstone River Habitat Update”).

Videos (click to view in new window):

Image Linking to DIDSON Footage

Video 1: ARIS (Adaptive Resolution Imaging Sonar) imagery showing aggregations of pallid sturgeon and other fishes over coarse substrate deposits in the Yellowstone River, North Dakota.

Image Linking to DIDSON Footage

Video 2: ARIS (Adaptive Resolution Imaging Sonar) imagery showing telemetry-tagged pallid sturgeon over spawning substrate in the Yellowstone River, North Dakota. Spawning locations in the Yellowstone River appear to be characterized by sand dunes interspersed with deposits of sorted, coarse gravels.

Code 39 was the last of the four telemetered females to spawn in 2014.  Spawning by female codes 30 and 35 in the lower Yellowstone River was verified earlier, in mid-June.  Crews from MFWP verified spawning by female code 36 also in mid-June; however, in contrast to the other three telemetered females, spawning by code 36 occurred in the upper Yellowstone River system – most likely in the Powder River.  Codes 30, 35 and 36 were the focus of spawning investigations in 2012, and if the 2-year reproductive periodicity is maintained, these three females will again be the focus of spawning events in 2016.  Fitted with a long-term transmitter, reproductive progression in code 39 will also be assessed through the next several years to determine her reproductive periodicity.  However, unlike female codes 30, 35, and 36, female code 39 will likely be used in the pallid sturgeon propagation program upon reaching spawn-readiness in the next 2-3 years as her genetics have not yet been incorporated into the conservation propagation program.

Posted in Recapture, Reproductive Female, Spawning, Telemetry tracking, Upper Missouri and Yellowstone Rivers | Tagged , , |

July River Sweep

By Kimberly Chojnacki and Aaron DeLonay

The researchers of the Comprehensive Sturgeon Research Project (CSRP) have defined a “river sweep” as an attempt to search for telemetered pallid sturgeon in as much of the Lower Missouri River (from the Gavins Point Dam near Yankton, South Dakota to the confluence near St. Louis, Missouri) as possible. CSRP researchers teamed up with collaborators at the Nebraska Game and Parks Commission (NGPC) during late-July to search approximately 560 river miles of the Lower Missouri River (figure 1). Forty telemetered pallid sturgeon were located during this river sweep effort, including two females (PLS10-029 and PLS12-002), and one male (PLS10-032) that were in reproductive condition during the spring of 2014 (see previous post “A Kettle of Fish”). Researchers will now focus on recapturing telemetered fish that need new telemetry transmitters or a reproductive evaluation (especially those fish there were in reproductive condition during the spring spawning season).

A map showing the location of the CSRP River Sweep in mid-July.

Figure 1. Map showing search effort and pallid sturgeon telemetry locations during the river sweep from July 15-23, 2014.

Posted in Recapture, Reproductive Female, River Sweep | Tagged , , |

Mapping the Chutes

By Robert Jacobson and Casey Hickcox

The R/V Slim Funk in ADCP configuration is shown.

Figure 1. The R/V Slim Funk outfitted with an acoustic Doppler current Profiler (ADCP) and an Odom survey-grade single-beam echosounder maps river velocities and bathymetry for two dimensional modeling.

The presence of pallid sturgeon (Scaphirhynchus albus) on the Federal Endangered Species List generally boils down to their inability to reproduce in the wild. Scientists suspect shallow-water habitat lost when the Missouri River was re-engineered in the mid-19th to mid-20th century to be a contributing factor in this loss of natural recruitment. Understanding the dynamics of the hydrology, hydraulics, and habitats in those shallow environments is critical for informed restoration, but working in the shallow depths can be quite challenging.

Graphic of the model produced from mapping the Lisbon and Jameson Chutes

Figure 2. Digital elevation model used for hydrodynamic modeling of habitats at Lisbon-Jameson area of the Lower Missouri River. The topographic data were developed by combining extensive bathymetric mapping data with LiDAR elevations of the floodplain.

High water throughout June and early July offered research boats extended access to shallow water habitat restoration areas on the Lower Missouri River. Over several weeks, CSRP scientists documented water depths and velocities in the Lisbon and Jameson chutes near Arrow Rock, Missouri (approximately 1.9 and 2.8 miles long, respectively)along with approximately 8.5 miles of the adjacent mainstem channel. By establishing transects perpendicular to the mainstem river at 50 meter intervals and in the chutes at 20 meters, researchers used an acoustic Doppler current profiler (ADCP) to measure water velocities while an Odom survey-grade single-beam echosounder recorded river bathymetry at a resolution that will support two-dimensional hydrodynamic models of the river-chute complex (see Figure 2). These models are intended to be used to gain a better understanding of the environments available to sturgeon larvae and juveniles, including the potential for drifting free embryos to be intercepted and retained in the chutes.

Posted in chute, Habitat mapping, Technology | Tagged , , , |

It’s more than just gravel and sand!

By Aaron Delonay, Robert Jacobson, and Casey Hickcox

Scientists hypothesize that pallid sturgeon (Scaphirhynchus albus), like other sturgeon species, spawn over hard or coarse substrate such as bedrock, cobble or gravel. The type, size, or composition of coarse substrate that adult pallid sturgeon select when spawning  is currently a focus of research for the Comprehensive Sturgeon Research Project (CSRP). To investigate, researchers refine their knowledge of substrate use by following telemetry-tagged adults to identify spawning locations.  Once spawning locations are identified sediment samples and hydraulic data are collected to characterize the selected habitat. Studies of pallid sturgeon spawning in the Yellowstone River provide research teams the opportunity to characterize spawning substrate in what is believed to be the least altered pallid sturgeon habitat within the species’ range.

USGS hydrologists prepare to deploy a BM-54 bed-material sampler on the Yellowstone River.

Figure 1. Scientists lower a bed-material sampler to the bed of the Yellowstone River to sample sediment.

A sidescan sonar image sample shows highlighted areas of suspected gravel substrate.

Figure 2. Side-scan sonar imagery of the bottom of the Yellowstone River collected at a frequency of 400 kHz and a range of 50 meters. Researchers identify areas of exposed gravel (outlined in red) by looking at the shape, texture and brightness of the deposits on the sandy bottom.

During the last week in June, researchers sampled the substrate of a 500 meter x 150 meter section of the Yellowstone River (between river mile 5.4-5.7) where pallid sturgeon had been documented to spawn days earlier.  Researchers used a heavy torpedo-shaped, bed-material sampler (see Figure 1) and then a 15-cm pipe dredge to systematically sample the river bottom.  Sampling of bed material was supplemented with bathymetric and velocity mapping, and sonar imagery using side-scan sonar (see Figure 2) and DIDSON.   Two other sites (near river mile 5.3 and river mile 6.3-6.5) were also sampled where spawning was documented in 2013. Scientists hope that quantification of spawning conditions in the least-altered reaches of the Yellowstone River will provide a model of functional spawning habitat that can be translated to other, more altered areas of the species’ range.  Researchers from the CSRP working in the Lower Missouri have also documented spawning habitat, but the river there is highly altered.  Scientists in the Lower Missouri River are concerned that the habitats selected by pallid sturgeon there represent only the best available in a highly engineered river, and may not be necessarily suitable for successful reproduction.  Over 130 sediment samples collected from the Yellowstone River will be analyzed using special graduated sieves to document grain-size distributions.  The samples collected will be compared with substrates known to be available in the mainstem Missouri River.

Posted in Habitat mapping, Spawning | Tagged , , , |

Unpredictable Water in the Missouri River

By Aaron Delonay, Robert Jacobson, and Casey Hickcox

As the temperatures in the Missouri River Basin begin to rise each spring, snowmelt and spring storms typically introduce large quantities of water into the system. This water becomes runoff that enters numerous tributaries that collectively join the main channel of the Missouri River to create a pulse of discharge often referred to as the annual “spring rise”. In most years the mainstem reservoir system stores much of the spring rise, but annual spring rises of 100,000 cubic feet per second (cfs) or more can exist on the Lower Missouri River during extreme runoff years and especially downstream of the Platte and Kansas rivers.

Pallid sturgeon, like many fish species, spawn over a range of temperatures in the spring when seasonal rises in rivers occur. Based upon observations of our telemetry tagged sturgeon, most spawning in the Lower Missouri River occurs between 16-22 °C (61-72 °F). For pallid sturgeon, water temperatures appear to be the primary influence on when and for how long spawning activity occurs during the spring. Seasonal flow changes and river discharge may also influence pre-spawning behaviors, particularly spring migration, and may play a role in determining the precise timing of adult aggregations and spawning events.

During much of this year’s reproductive window (the time when sturgeon are expected to spawn), the Lower Missouri River near Boonville, Missouri, maintained a relatively low flow with only one small pulse that added about 30,000 cfs (figure 1). In areas upriver near Sioux City, Iowa, flow was low and even less variable through the reproductive window (figure 1). Only after the expected peak of pallid sturgeon spawning activity had passed did the Missouri River near Booneville see substantial increases in flow as the river rose 13 feet and discharge increased by over 100,000 cfs in less than 4 days. At Sioux City, meanwhile, cooler water temperatures extended the expected spawning period for pallid sturgeon to early June. A spring rise peaking at over 80,000 cfs occurred in late June due to heavy rainfall in the Big Sioux River, however this pulse was probably too late to influence sturgeon migration and spawning.

Figure showing the discharges vs Temperatures for two Missouri River sites: Boonville, MO & Sioux City, IA

Figure 1. The Missouri River discharge (blue) for Boonville, Missouri (top) and Sioux City, Iowa (bottom) since January 1st shown against the interquartile range for the measured discharge over the past century. The temperature (red) is shown over the same time period with the range over which most pallid sturgeon spawn are expected to spawn (pale hatching shown from 16-22 degrees C) identified.

Pallid sturgeon have evolved in a river with naturally variable flow and temperature, but management of the Missouri River also creates conditions that are outside of the range of natural variability. CSRP research addresses the question of how well sturgeon can adjust to unnatural variability and still maintain a sustainable population. Long-term studies that include the kind of variability experienced with the extreme flows of 2011, the drought of 2012, and the lack of an early spring rise in 2014, help to answer this question.

Posted in Drought, Flooding, Spawning | Tagged , , , |

Yellowstone River Habitat Update

By Carrie Elliott

In the Northern Great Plains mid-late June is marked by spectacular thunderstorms, an occasional mosquito swarm, and pallid sturgeon spawning season on the Yellowstone River.  The week of June 16 the U.S. Geological Survey CSRP habitat crew mapped a 4 kilometer long reach of the Yellowstone River where pallid sturgeon spawning has been documented in multiple years (figures 1 and 2).  Mapping was done with an acoustic Doppler current profiler and RTK GPS to generate maps of velocity, depth, and bed elevation in transects with a 15 meter spacing.  These data along with side-scan sonar and sediment sampling information will allow us to monitor, model, and understand what pallid sturgeon spawning habitat is  under near-natural conditions.   This reach, a just a few miles downstream from the historic Fairview Bridge has had many male and female pallid sturgeon present over the past few weeks this year and contains the locations where spawning was documented in 2012 and 2013. 

Figure 1. USGS Hydrologic technican Eric Allen monitoring ADCP and RTK GPS survey data quality as it comes in on the Yellowstone River near Fariview, MT.

Posted in Habitat mapping, Upper Missouri and Yellowstone Rivers | Tagged |


By Kimberly Chojnacki and Aaron DeLonay

In mid-June, 4 USGS research crews from the Lower Missouri River packed up their equipment and headed north to the Upper Missouri and Yellowstone Rivers in Montana (figure 1).  Two boats and crews were deployed to help track the migration behavior of large, fast moving, adult pallid sturgeon up the Yellowstone River, and to determine when and where they are spawning (figure 2).  Another boat and crew carried advanced sonar equipment to observe and record spawning behavior.  And a hydrology research crew was deployed to characterize habitat at spawning sites.  The crews drove two days from Columbia, Missouri to Sidney, Montana where they joined biologists from Montana Fish, Wildlife and Parks (MFWP) and researcher, Pat Braaten, from the USGS Project Office in Fort Peck, Montana. Pat and his colleagues from MFWP have been tracking adult pallid sturgeon on the upper Missouri River from Lake Sakakawea upstream to Fort Peck Dam, and up the Yellowstone River to Intake Dam (figure 1).

Figure 1. Map of the Upper Missouri River and Yellowstone River study area.

The large rivers used by pallid sturgeon have been modified and altered to meet human needs, including flood control, irrigation, navigation, hydropower, and recreation.  The Upper Missouri and Yellowstone rivers are unique within the range of the pallid sturgeon in that the morphology of their channels has not been significantly altered and the Yellowstone still retains a natural hydrograph and temperature regime unaltered by large dams.  Scientists hope that by observing and comparing the behavior of pallid sturgeon in different parts of its range, they can gain insight into how sturgeon migration, spawning, and recruitment may be altered in response to different threats. 

Figure 2. A USGS Comprehensive Sturgeon Research Project telemetry crew tracks radio telemetered pallid sturgeon in Montana.

Posted in Upper Missouri and Yellowstone Rivers | Tagged , |

A Change Will Do You Good

By Aaron DeLonay, Amy George, and Kimberly Chojnacki

Rows of hatching jars lined the shelves in the laboratory at USGS this spring and summer.  In each jar, pallid sturgeon and shovelnose sturgeon gently tumbled in the 18 °C water as USGS scientists closely monitored and documented fish development.  The eggs came from a captive population of pallid sturgeon adults held at the Center for research purposes and from shovelnose sturgeon adults captured from the Lower Missouri River.  Four pallid sturgeon and ten shovelnose sturgeon females were induced to spawn using hormone injections in the laboratory.  The eggs were fertilized by multiple males of the corresponding species and each family lot was placed in separate jars to develop and hatch.  Scientists monitored each group of eggs for fertilization, development, and survival to hatch.  After hatch, three to six sturgeon were removed and preserved in formalin at 2-4 hour intervals around the clock to document the rapid growth and developmental changes that occur during this early life stage.  Free embryos hatch without a well-developed mouth, eyes or fins, and must rely a large yolk sac to fuel their rapid development (figure 1).  At 18° C, the development from newly hatched free embryo to exogenously feeding larvae takes about 14 days for both species.  Although their abilities are limited, sturgeon are capable of changing their depth and orienting to water flow even before the initiation of feeding.  Once the larvae began feeding, behavioral and developmental changes are not as rapid and samples were taken every 12 hours.  At this stage, they have fins, eyes, a mouth bordered by four fleshy barbels, and resemble sturgeon in miniature.  Scientists at USGS closely examined the timing and trajectory of developmental changes to better estimate where  sturgeon free embryos collected by our crews in the Missouri River may have been spawned, how early life stages of sturgeon disperse along the river, and where habitats needed for early feeding may be located.  Differences in developmental timing, behavior, and requirements between species may provide insight into why one species, the shovelnose sturgeon, is reproducing and recruiting, while the pallid sturgeon is not.

Figure 1. Pallid sturgeon free embryos preserved at 3 days post hatch. Free embryos at this stage have only a rudimentary mouth, their pectoral fins are only beginning to develop, and they rely on a large yolk sac for food.

Posted in Early life history |

An Incredible Journey

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.  

Figure 1. Map of telemetry locations for male pallid sturgeon PLS10-014 since spring 2010.

Posted in Telemetry tracking | Tagged , , |

Pallids in the Platte

By Kimberly Chojnacki, Justin Haas (Nebraska Game and Parks Commission), and Aaron DeLonay

Comprehensive Sturgeon Research Project (CSRP) scientists have documented that some tributaries may have significant value to the endangered pallid sturgeon (see previous posts “Where Are You When I’m Not Looking”, and “A Fork in the Road”).   The spring of 2014 is providing additional insights for collaborating Nebraska Game and Parks Commission and U.S. Geological Survey research crews.  From late April through May, four telemetered pallid sturgeon were found in the Platte River, two males and two females.  The two male pallid sturgeon were located between 1 and 5 miles upstream in the Platte River during late May (Figure 1). 

Female PLS10-29 was recaptured during the fall of 2013 and determined to be likely to spawn during the spring of 2014.  She stayed in the Missouri River through mid-April before moving into the Platte River.  During late April and early May PLS10-029 was located one to two miles up the Platte River and has since gone missing (Figure 1).  Scientists believed that female pallid sturgeon PLS11-015 should also have been ready to spawn this spring, but she swam upstream into the Platte River before she could be captured and assessed.  Since entering the tributary mouth she has been located on three occasions in the Platte River; the last time more than 30 miles upstream, near its confluence with the Elk Horn River, during late May (Figure 1).  Both of the female pallid sturgeon that were found in the Platte River this spring are believed to have previously spawned there during 2011 (PLS11-015) and 2012 (PLS10-029).  The Platte River is very difficult for fish tracking using acoustic telemetry tags because it is very shallow with braided sandbar complexes, so it is not uncommon to lose track of the tagged fish.  Luckily, scientists have another way to determine whether they have spawned in the Platte River.  CSRP scientists will attempt to recapture both of the females as soon as they emerge from the Platte River to determine if they have released their eggs and to recover the data storage tag that records temperature and depth data to find out (see previous post “Where Are You When I’m Not Looking”).    In 2011, the temperature and depth data provided indirect, but strong, evidence that the fish had spawning in the Platte River.  From these long-term tracking datasets, scientists have learned that female pallid sturgeon in the Lower Missouri River can spawn every 2 to 3 years, and that females attempting to spawn in the Platte River will return to the Platte River on subsequent spawning migrations. 

Figure 1. Map of telemetry locations for pallid sturgeon PLS08-039, PLS10-014, PLS10-029, PLS11-005 during April and May 2014.

Posted in Telemetry tracking | Tagged |