Evidence of Successful Spawning by Endangered Pallid Sturgeon

By Aaron DeLonay, Kimberly Chojnacki and Robert Jacobson

Three free embryos that were collected by Comprehensive Sturgeon Research Project scientists in May 2014 were recently confirmed to be pallid sturgeon.  The three specimens were among several hundred paddlefish and closely-related shovelnose sturgeon collected from the Lower Missouri River immediately upstream of the confluence with the Platte River in Nebraska during 2014 (see previous entries, We’ve Only Just Begun and One Down, Several To Go).  All three pallid sturgeon free embryos were collected from the main channel of the Missouri River on May 30, 2014.  The specimens ranged in length from 9.59 to 10.42 mm, and were estimated to be between 1 to 3 days old based upon the developmental stage of the specimens and ambient river temperatures.

Pallid sturgeon free embryo at 2 days post hatch.  At two days after hatching the free embryos are generally 9 to 11 millimeters (0.35 to 0.45 inch). (Photo by Kimberly Chojnacki, U.S. Geological Survey)

Pallid sturgeon hatch and disperse downstream from the spawning location as free embryos (figures 1 and 2).  Free embryos lack a well-developed mouth, eyes or fins, and rely a large yolk sac to fuel their rapid development as they drift downstream with the current (see previous entry, A Change Will Do You Good).  After 11-17 days these free embryos develop into larvae (figure 3) that settle to the bottom of the river and begin feeding.

Acipenseriformes free embryo (pallid sturgeon, shovelnose sturgeon, or paddlefish) collected from the Missouri River. (Photo by Dave Combs, U.S. Geological Survey)

Pallid sturgeon larvae at 14 days post hatch. On agerage, pallid sturgeon transition to active feeding at approximately 16 to 18 millimeters (about 0.7 inch). (Photo by Kimberly Chojnacki, U.S. Geological Survey)

The pallid sturgeon free embryos collected during 2014 were positively identified using genetic analyses developed by Jennifer Eichelberger and Dr. Edward Heist at Southern Illinois University Carbondale. Recent developments by Dr. Heist have resulted in genetic tests that use inexpensive Single Nucleotide Polymorphisms (SNP) assays to screen hundreds of specimens of sturgeon and paddlefish to identify possible pallid sturgeon embryos and larvae. Positive confirmation of the genetic identity of pallid sturgeon specimens is then determined using microsatellite DNA markers developed at SIU.   Microsatellite markers are also used to determine whether sturgeon free embryos collected in samples may be closely related, or possibly siblings from a single spawning event. Preliminary analyses suggest that the three specimens are not siblings from a single spawning female.

 

These new genetic identifications add to mounting evidence that critically endangered pallid sturgeon spawned successfully in the Lower Missouri River downstream of Gavins Point Dam, South Dakota during 2014. These findings build on previous year’s effort by the USGS, Nebraska Game and Parks Commission, and U.S. Army Corps of Engineers to track the reproductive migration and behavior of pallid sturgeon, and to locate and describe functional spawning habitat in the Lower Missouri River.  While successful spawning by the endangered fish was detected in the Lower Missouri River in 2014, it does not necessarily mean that the species is on its way to recovery.  During this study, USGS scientists and their collaborators have been able to track adults on their migrations to their spawning sites, describe their spawning behavior, and characterize the habitats they use in the Lower Missouri River.  Until 2014, scientists were unable to locate fertilized eggs or newly hatched embryos and larvae of pallid sturgeon, and therefore were unable to assess whether or where spawning by adults was successful.  These new findings indicate that suitable conditions and functional spawning habitats for pallid sturgeon do at times exist in the Lower Missouri River downstream of Gavins Point Dam, however pallid sturgeon populations remain small and successful reproduction and recruitment to the population is still quite limited.

 

Posted in Early life history, Pallid sturgeon | Tagged , , , , , |

Habitat surveys of 2015 pallid sturgeon spawning patches on the Yellowstone River

By Carrie Elliott, Robb Jacobson, and Casey Hickcox

USGS jetboat with a multibeam on the Yellowstone River

Figure 1. USGS research vessel outfitted with a compact multibeam sonar echosounder system with an inertial motion unit and real time kinematic positioning global positioning system (RTK GPS) surveys the Yellowstone River near Fairview, North Dakota.

During the last two weeks of June, USGS habitat crews surveyed the pallid sturgeon spawning reach of the Lower Yellowstone River near Fairview, North Dakota.  Using a compact multibeam sonar echosounder system with an inertial motion unit and real time kinematic positioning global positioning system (RTK GPS) mounted on a jet boat (figure 1), crews conducted high-resolution surveys and mapped features of the river bed in pallid sturgeon spawning patches (figure 2).  Multibeam sonar has been used in recent years to understand pallid sturgeon spawning habitats on the Lower Missouri but these efforts were the first to do so on the much shallower Yellowstone River.

Multibeam map showing features and sturgeon locations

Figure 2. Multibeam sonar depth map showing sand dunes and locations of reproductive female code 41 and multiple male pallid sturgeons from June 13 to June 15, 2015 during a presumed spawning event near Fairview, North Dakota.

Multibeam sonar maps the river bottom in great detail with a “sweep” or ping of soundings taken at up to 40 times per second. This generates a very dense cloud of points which allows scientists to generate high-resolution maps of the bottom of the river and visualize features such as sand dunes, submerged trees, and scour holes (figure 3). By conducting multiple passes with the sonar throughout the day,  sand dune movement can be mapped to calculate the rate of sand dune migration.  This information can be used to advance understanding of how spawning habitat may change while eggs are incubating in the substrate.

Multibeam representation of sturgeon spawning habitat

Figure 3. Image showing raw multibeam point cloud in the pallid sturgeon spawning habitat patch near river mile 5.9 on the Yellowstone River. The image is approximately 20 meters wide, is looking downstream on a sand bar, and shows sand dunes that are approximately half a meter high from crest to trough.

Posted in Habitat mapping, Methods, Pallid sturgeon, Reproductive Female, Spawning, Telemetry tracking, Upper Missouri and Yellowstone Rivers | Tagged , , |

Characterizing Spawning Habitat Substrate on the Lower Yellowstone River

By Eric Allen, Ed Bulliner, Carrie Elliott, Robert Jacobson

CERC Scientist Operates a Petite Ponar Sediment Sampler

Figure 1: A USGS scientist operates a Petite Ponar substrate sampler to sample bed material in an area identified as a pallid sturgeon spawning location on the Yellowstone River, North Dakota. (Photo by Pat Braaten, USGS)

Many sturgeon species spawn over coarse, hard substrate, and Missouri River scientists have thought that this was probably the case for the endangered pallid sturgeon (Scaphirhynchus albus)Characterizing the size, type, and distribution of spawning substrate is a key to understanding functional spawning habitat requirements for pallid sturgeon. The lack of channel modifications on the Yellowstone River, North Dakota and Montana, provides scientists with the opportunity to observe and characterize spawning habitat in a relatively unaltered system. In late June 2015, a team of biologists and physical scientists from CERC travelled to the Lower Yellowstone River to document and validate pallid sturgeon spawning locations and reproductive behaviors.  Locations of reproductive males and females were determined using radio telemetry, and spawning was documented using an acoustic camera and by recapturing females to confirm that they had dropped their eggs (see previous posts A Spawning Recorded in the Yellowstone River and It’s more than just gravel and sand!).

A Petite Ponar Sediment Sampler and sames are shown

Figure 2: Collecting and storing substrate samples using a Petite Ponar sampler (top right) for later analysis. (Photo by Pat Braaten, USGS)

Following an observed spawning event for female pallid sturgeon code 41 near river mile 5.9 (5.9 miles upstream of the confluence with the Missouri River), scientists used a Petite Ponar grab sampler (figures 1, 2) to retrieve bed substrate samples in and around the identified spawning habitat patches. The spawning area is predominately composed of sand dunes, although there was some spatial variation in substrate material. Samples from dune crests were sand, whereas samples from troughs downstream from dune crests often consisted of gravel, dominated by lignite believed to originate from local bedrock bluff outcrops (figure 3). Additional samples consisting of both sand and coarser material were obtained from an area approximately one river mile upstream from the spawning site in the vicinity of another spawning event.

A sample of sediment from the Yellowstone River is shown

Figure 3: A close-up image of lignite-dominated gravel sampled from a spawning area with Petite Ponar sampler. (Photo by Pat Braaten, USGS)

Georeferenced substrate samples will be used to characterize substrate particle sizes and to verify observations from hydrographic remote-sensing instruments, including sidescan sonars, a multibeam echosounder, and an acoustic camera.  Verifying substrate characteristics observed from remote-sensing instruments allows scientists to better interpret substrate size and distributions in imagery recorded by the instruments without the need for manual sampling. Such tools allow for rapid substrate classification over a larger area, and will further aid in identification of pallid sturgeon spawning habitats.

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

Through the Looking Glass

By Kimberly Chojnacki and Aaron DeLonay

Pallid sturgeon eggs are approximately three millimeters, or less than one eight of an inch, in diameter. While the eggs of this endangered sturgeon are small, the changes that happen inside are truly a wonder to behold. After fertilization (see previous entry, Spawning of Pallid Sturgeon for Crucial Experiments) scientists use microscopes to monitor the rapid development of sturgeon eggs. Researchers examine the developing embryos to determine the success of fertilization and to estimate the timing of hatch by monitoring developmental milestones. Development is controlled primarily by temperature. At 18 degrees Celsius, the single cell of the egg begins to divide within hours of fertilization (figure 1).

Figure 1.  Pallid sturgeon embryos approximately 8 hours after fertilization. (Photo by Kimberly Chojnacki, U.S. Geological Survey)

The neural plate or primitive streak develops a few days after fertilization (figure 2). The neural plate is the precursor to the central nervous system.

Figure 2.  The neural plate or primitive streak of developing pallid sturgeon embryos can be seen 2 days after fertilization. (Photo by Kimberly Chojnacki, U.S. Geological Survey)

A well-developed embryo can be seen inside the chorion (outermost membrane of the egg) approximately 4 days after fertilization.  At this stage, the tail of the embryo is wrapped around its body, covering part of the head (figure 3).

Figure 3. Well-developed pallid sturgeon embryos can be seen approximately four days after fertilization. (Photo by Kimberly Chojnacki, U.S. Geological Survey)

These well-developed embryos can even be seen wriggling inside the chorion (see video below).  After approximately 4 to 5 days at 18 degrees Celsius the chorion starts to weaken and the embryos begin to hatch.

Posted in Early life history, Pallid sturgeon | Tagged , , |

Spawning of Pallid Sturgeon for Crucial Experiments

By Kimberly Chojnacki, Aaron DeLonay, and Robert Jacobson

Researchers at the USGS Columbia Environmental Research Center (CERC) have been making preparations to spawn pallid sturgeon to provide eggs and larvae for experiments.  During March and April, the captive population of adult, hatchery-origin pallid sturgeon maintained at CERC were weighed and examined for reproductive readiness (figure 1).  Non-invasive ultrasound technology was used to determine if the pallid sturgeon would be ready to produce viable eggs and sperm in the coming weeks (see previous entry, Did she or didn’t she?).  Fish determined to be approaching reproductive condition were moved to indoor holding tanks so that water temperature could be tightly controlled and their condition could be closely monitored.  The reproductive readiness of female sturgeon was tracked using biopsies and microscopic examination of extracted eggs as the potential spawning day drew near.

Biologists at Columbia Environmental Research Center drawdown and seine a pond to collect reproductive pallid sturgeon. The pond has been specially designed to provide turbid, flowing water that pallid sturgeon need to thrive.  Photo by Aaron DeLonay.

As the female readiness to spawn became imminent, four male sturgeon were given a hormone injection to induce the production of sperm.  Within 48 hours biologists were able to collect milt containing viable sperm from the males.  The milt was refrigerated and stored with an extender until the females were ready.  Finally, at 3:00 am on Tuesday, May 5th, researchers administered the first of two hormone injections to four female pallid sturgeon.  The second, resolving dose was administered 12 hours later.  Ovulation occurred 14-18 hours after the resolving dose on the morning of Wednesday, May 6th.  Biologists began the process of extracting the ovulated eggs from the females at 7:00 am.

Eggs were fertilized in the laboratory with milt (sperm) from 4 males.  Extracted eggs were used in experiments to measure egg density and adhesiveness (figure 2).  Fertilized eggs were incubated in flowing water for approximately 4 days.  Hatched free embryos were used in outdoor stream experiments to evaluate initial dispersal behaviors (see previous entry, Studies of Lake Sturgeon Free Embryo Dispersal Begin).

 

Pallid sturgeon eggs become adhesive minutes after fertilization. Scientists are working to understand the factors that influence the adhesiveness of sturgeon eggs. (Photo by Aaron DeLonay, U.S. Geological Survey)

Improved understanding of the reproductive ecology of pallid sturgeon requires integration of controlled experiments with knowledge gained from studies of fish in the river.  The ability to carry out experiments on pallid sturgeon depends on having a captive population of adult fish available, the knowledge on how to spawn them and raise their young, and the facilities to study these fish in conditions that approximate the river conditions.

Posted in Early life history, Pallid sturgeon, Sturgeon culture and propagation | Tagged , |

New shallow water surveying technology deployment at CERC

By Carrie Elliott, Robb Jacobson, Eric Allen, and Casey Hickcox

A USGS scientist uses a remotely controlled "z-boat" to survey the experimental ponds at the Columbia Environmental Research Center.

A USGS scientist uses a remotely controlled “z-boat” to survey the experimental ponds at the Columbia Environmental Research Center.

This spring, experiments to observe shovelnose sturgeon spawning behavior have been ongoing in ponds at the Columbia Environmental Research Center. To characterize the depths and velocities in the experimental ponds, we have deployed a new instrument for the first time. The “z-boat” is 1.80 m long, 0.90 m wide, remotely controlled vessel that houses a survey-grade single-beam echosounder, a precise real-time kinematic global positioning system antenna, and an acoustic Doppler current profiler.  It is controlled by an operator on shore and all the data are transmitted to laptop computers on shore that allow the data and boat navigation information to be viewed in real-time. We are using the z-boat to quantify the conditions in the ponds during the spawning behavior experiments and characterize water flow patterns created by circulators in the ponds over sand and gravel substrates (see figure 1). The z-boat will also be used to survey shallow water habitats on the Missouri River, Yellowstone River, and tributary environments that we cannot access with our larger hydroacoustic survey vessels.

Mapped water depth (left) and velocity (right) data of Pond 15 collected using the z-boat.

Figure 1. Mapped water depth (left) and velocity (right) data of Pond 15 collected using the z-boat.

Posted in Habitat mapping, Technology | Tagged , , |

Studies of Lake Sturgeon Free Embryo Dispersal Begin

By Aaron DeLonay and Kimberly Chojnacki

How much river does a fish need?  For pallid sturgeon on the Missouri River there is a concern that there is not enough river for downstream-dispersing larvae.  Field-based and laboratory work at the Columbia Environmental Research Center are focusing on critical unknowns in the dispersal process, using comparative studies with other sturgeon species to provide key insights.  Our first experiment this year is with lake sturgeon.

Figure 1. One of six experimental stream segments used to study the dispersal of free embryo sturgeon at the Columbia Environmental Research Center. The stream segment is 5 meters long and 0.5 meters wide, and is filled with cobble-sized rock to a depth of 12 centimeters. Streams are covered during studies.

Eggs collected from the lake sturgeon female spawned in the laboratory on April 15th (see previous entry, “Stream studies back in action”) hatched in the early morning hours on Monday, April 20th.  A team of researchers counted out a total of 4800 newly hatched (day-0) lake sturgeon free embryos; 800 free embryos for each of the six experimental stream segments (three with gravel, and three with cobble substrate, see figure 1).  The stream segments were then “seeded” by releasing the free embryos into the substrates of the experimental streams and slowly increasing the water flow over the substrate to 15 centimeters per second.  The streams were monitored around-the-clock to see if free embryos stayed in the stream substrate or dispersed downstream.  Nets at the end of each segment were checked at six-hour intervals for free embryos that dispersed.  Free embryos collected in the nets were counted and preserved for later laboratory measurements of size and development.  On Friday, April 24th, after a 96-hour (4-day) monitoring period the substrate of each segment was removed and any free embryos remaining were collected in the nets downstream.  On Tuesday, April 28th, the experiment was repeated with 8-day old lake sturgeon free embryos (figure 2). Researchers will monitor the streams and record free embryo dispersal over the next 4 days.  The same studies will be repeated with pallid sturgeon and shovelnose sturgeon through May and into June. 

Figure 2. Researchers count out 800 eight-day old, free embryo lake sturgeon for studies of downstream dispersal in experimental streams.  (Photo by Aaron DeLonay)

The development and dispersal strategy of each sturgeon species is adapted to the conditions where it lives.  Comparing the dispersal strategies of newly hatched and 8-day old free embryos of the three sturgeon species (lake sturgeon, pallid sturgeon, and shovelnose sturgeon) in experimental stream systems provides researchers with an estimate of the time each species spends dispersing downstream.  Importantly, the experiments are designed to indicate the extent to which the species delay dispersal by residing for some period of time in the substrate just after hatch.  When and how long free embryos disperse, in part, determines the length of free-flowing river required for the completion of the free embryo life stage and where habitats that support the transition to the exogenously feeding larval stages should be located.

 

Posted in Early life history, Stream studies | Tagged , , , , |

What a Difference a Day Makes

By: Kimberly Chojnacki and Aaron DeLonay

Scientists at the USGS, Columbia Environmental Research Center have initiated research that closely examines the differences in early life stages of three sturgeon species; lake sturgeon, pallid sturgeon, and shovelnose sturgeon.  On Wednesday, April 15th the first of the three species was induced to spawn in the laboratory.  Milt from three male lake sturgeon was used to fertilize eggs from one female lake sturgeon (see previous entry, “Stream studies back in action”).  The embryos from that spawning event began to hatch during the early morning on Monday, April 20th.  Sturgeon embryos hatch without well-developed eyes, mouth, or fins and rely on a large yolk sac to fuel rapid early development (figure 1).  Researchers began collecting newly hatched free embryos soon after hatch to examine the rapid growth and developmental changes that occur during this early life stage.  Each day, 20 free embryos are photographed, measured, and examined for changes in developmental characteristics.

Figure1. Newly hatched lake sturgeon free embryos. Sturgeon embryos hatch without well-developed eyes, mouth, or fins and rely on a large yolk sac to fuel rapid early development. (Photo by: Kimberly Chojnacki)

Some of the similarities and differences between lake sturgeon and pallid sturgeon (spawned in the laboratory during 2014, see previous entry, “A Change Will Do You Good”) are apparent, even at this early stage.  By the time the sturgeon free embryos are three days-old, the eyes are pigmented and they are developing fins and mouth parts, including barbels (figure 2).  Lake sturgeon free embryos are already much darker in color than pallid sturgeon, with a dark stripe beginning at the rostrum (or snout).  Pallid sturgeon are pale in comparison, with a dark tail.

Figure 2. Lake sturgeon free embryos 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. (Photo by: Kimberly Chojnacki)

All sturgeon are not the same.  Each species is uniquely adapted to survive in the environment in which it lives.  Characterizing and comparing the growth, development, and behavior during the earliest life stages of these fascinating species helps researchers to understand what each needs to thrive.  Comparisons among species may help to explain why one species may be doing well, while another is declining or rare.  The work to understand sturgeon early life stages will continue with pallid sturgeon and shovelnose sturgeon through the spring and summer of 2015.

Posted in Early life history | Tagged , , , , , |

Stream studies back in action

By Aaron DeLonay, Robert Jacobson, Kim Chojnacki, and Casey Hickcox

USGS Biologist prepares to artificially spawn a female lake sturgeon in the laboratory at the Columbia Environmental Research Center.

Final preparations are underway to initiate lake sturgeon laboratory and artificial stream studies at the Columbia Environmental Research Center (CERC).  One 46.5 lb. female and three males have been selected for the study.  The female and males were induced for artificial spawning by the injection of hormone. Milt from the males was collected throughout the second week of April and has been cryo-preserved for future studies. Eggs were collected from the female early on the morning of Wednesday, April 15.  Following egg collection, CERC scientists conducted a specific gravity study using a small number of eggs to improve understanding of the fate of eggs on spawning grounds. The fertilized eggs are being incubated in a recently completed laboratory incubation system located at CERC.  Embryos will be used to seed an artificial stream, and released into two substrates within the stream: one substrate composed of gravel and one composed of cobble.  The objective of the stream studies is to compare behavior of lake sturgeon free embryos, which are known to hide in interstices, with pallid and shovelnose sturgeon.  The artificial streams will be monitored for 96 hours (4-days).  The stream will then be cleared and re-seeded with day-8 embryos, followed by a 96-hour monitoring period. These studies will be repeated later in the spring with pallid sturgeon and shovelnose sturgeon.

Posted in Early life history, Spawning, Sturgeon culture and propagation | Tagged , |

Spreading the word on pallid sturgeon research

By Robert Jacobson, Kim Chojnacki, and Casey Hickcox

Columbia Environmental Research Center (CERC) scientists took to the road in March to share some of the center’s work over the last year with the Missouri River Natural Resource Conference (MRNRC) in Nebraska City, Nebraska. In total, CERC scientists authored or contributed to five posters and 12 presentations over the three-day conference. The conference was attended by individuals from over 50 organizations involved with various aspects of Missouri River science and management.  The annual MRNRC offers an opportunity for scientists to share their work with scientists, managers, and the public throughout the entire Missouri River basin.  Here is a list of this year’s presentations and posters by CERC scientists and collaborators:

Posters

  1. Survival and Drift Behavior of Pallid Sturgeon Free Embryos in an Artificial Channel By: Kevin Buhl and Travis Schaffer
  2. Identifying Floodplain Conservation Land Management Priorities and Science Needs for the Lower Missouri River By: Kristen Bouska, Garth Lindner, Robert Jacobson, and Craig Paukert
  3. Identifying Sturgeon Spawning Locations through Back-Calculations of Free-Embryo Drift: Complexities in Characterizing Drift Dynamics By: Edward A. Bulliner, Susannah O. Erwin, Kimberly A. Chojnacki, Amy E. George, Jake D. Faulkner, and Aaron J. DeLonay
  4. Hydrodynamic Modeling to Evaluate the Influence of Channel Morphology and Hydrology on Larval Drift of Pallid Sturgeon in the Lower Missouri River By: Susannah Erwin, Robert Jacobson, Christopher Holly, Eric Allen, Caroline Elliott, and Edward Bulliner
  5. Substrate Effects on Hatch and Initiation of Drift of Scaphirhynchus Sturgeon Species in an Artificial Stream By: Jake D.A. Faulkner, Aaron J. DeLonay, James S. Candrl, Kimberly A. Chojnacki, and David K. Combs

Presentations

  1. Gonadosomatic Index and Fecundity of Lower Missouri and Middle Mississippi River Endangered Pallid Sturgeon Estimated Using Minimally Invasive Techniques By: Janice L. Albers, Mark L. Wildhaber, and Aaron J. DeLonay
  2. Trends and Variation in the Reproductive Ecology of Pallid Sturgeon in the Upper Missouri River Basin By: Patrick J. Braaten and David B. Fuller
  3. Empirically Modeling Interior Least Tern Habitat Response to River Hydrographs Using Landsat TM Imagery By: Edward A. Bulliner, Caroline M. Elliott, Robert B. Jacobson, Casey Lott, and Colin Sheppard
  4. Developing Models to Identify Successful Sturgeon Spawning Locations Using Free Embryo Collections, Lower Missouri River By: Kimberly A. Chojnacki, Edward A. Bulliner, Susanna O. Erwin, Amy E. George, David K. Combs, Jake D. A. Faulkner, and Aaron J. DeLonay
  5. Characterization of Patterns of Sturgeon and Paddlefish Spawning and Dispersal in the Lower Missouri River to Guide Restoration Actions By: Aaron J. DeLonay, Kimberly A. Chojnacki, Caroline M. Elliott, Susannah O. Erwin, David K. Combs, Amy E. George, and Edward Heist
  6. Assessment of Pallid Sturgeon Spawning Habitat on the Lower Yellowstone River By: Caroline M. Elliott, Patrick Braaten, Aaron J. DeLonay, Robert B. Jacobson, Eric Allen, David Combs, Casey Hickox, and Chad Vishy
  7. Bedform Dynamics and Sand Transport in the Lower Missouri River in Pallid Sturgeon Spawning Reaches By: Caroline Elliott, Robert Jacobson, Susannah Erwin, Edward Bulliner, Aaron DeLonay, Eric B. Allen, and Christopher Holly
  8. Quantifying and Defining Functional Habitat to Inform Recovery of Pallid Sturgeon in the Missouri River By: Susannah Erwin, Robert Jacobson, Caroline Elliott, Todd Gemeinhardt, Tim Welker, Aaron DeLonay, and Kimberly Chojnacki
  9.  Missouri River Pallid Sturgeon Effects Analysis: Progress and Prospects By: Robert B. Jacobson, Mandy L. Annis, Michael E. Colvin, Daniel A. James, Michael J. Parsley, Michael Randall, Tim L. Welker
  10.  Pallid Sturgeon Reproduction in the Yellowstone River, 2014 By: Mathew Rugg, Patrick Braaten, Kenneth Backes, Caleb Bollman, Christopher Wesolek, Caroline Elliott, David Combs Chad Vishy, Beau Griffith, Aaron DeLonay, and Robert Jacobson
  11.  Relationships Between Land Capability Potential Index (LCPI) Classes and the Distribution of Plant Species and Communities By: Matthew A. Struckhoff
  12.  Population Trends, Bend Use Relative to Available Habitat, and Within-River Bend Habitat Use of Eight Indicator Species of Missouri and Lower Kansas River Benthic Fishes: 15 Years After Baseline Assessment By: Mark L. Wildhaber, Wen-His Yang, Ali Arab, Nicholas S. Green, and Janice L. Albers
 
Posted in Education, Habitat mapping, Technology |