Abstracts
- Poster Presentations
Edward A. Baker (Michigan DNR), Patrick Forsythe (Michigan
State University), James Crossman (Michigan State University),
Kim T. Scribner (Michigan State University) and Kregg
M. Smith (Michigan DNR) - Characteristics of spawning
lake sturgeon in the Black River, 2001-06
Description: Data on lake sturgeon spawner abundance
and demographic characteristics are critical to forecasting
recruitment and for prioritizing populations for management
action. Great Lakes populations are exceedingly difficult
to study because of extremely low abundance and because
the fish spawn in large rivers that are difficult to
sample. The lake sturgeon population in Black Lake,
Michigan is uniquely suited to provide critical background
on adult ecology and demographics because of its large
size, degree of reproductive isolation, and vulnerability
of spawning fish to capture. We have intensively sampled
spawning lake sturgeon over 6 consecutive years (2001-2006)
in the upper Black River. The number of fish sampled
annually has varied from 101 in 2004 to 234 in 2006;
the male to female sex ratio has varied annually from
1.6:1 to 2.9:1. The length range of lake sturgeon has
been similar among years and ranged from 111-192 cm.
Estimates of spawning periodicity ranged from 1-5 years
for males and 2-5 years for females with average periodicity
of 2 and 3 years, respectively. Date of first spawning
has varied from 20 April to 7 May among years, the
end of spawning activity has ranged from 19 to 26 May,
and the duration of the spawning run has ranged from
18 to 36 days. Based on adult capture dates and observed
spawning activity there have been multiple spawning
events within each year and males were observed to
spawn during multiple periods within a single year.
There was no clear pattern in the timing of spawning
for individual fish recaptured among years.
David Bos (Purdue University) - Genetic determination
of lake sturgeon sex
Philip Cochran (Saint Mary’s
University of Minnesota), Robert Elliott (USFWS Green
Bay), Kevin Olson (Saint Mary’s University of
Minnesota) and Terrance Martin (Illinois State Museum)
- Historical distribution of lake sturgeon (Acipenser
fulvescens) in the Lake Michigan Basin [view
poster (2.59 MB pdf)]
Description: As part of an attempt to reconstruct
the original distribution and relative abundance of
lake sturgeon in tributaries to Lake Michigan, we surveyed
old newspapers (mid-1800s to early 1900s) and other
documents for accounts of sturgeon captured by sport
and commercial fishers. We also reviewed the zooarcheological
literature for records of sturgeon remains from prehistoric
sites. We are especially interested in reports of sturgeon
from sites to which they no longer have access because
of the construction of dams that have blocked upstream
spawning migrations. Over 200 records that can be plotted
with some degree of accuracy were obtained. Resulting
maps reveal a somewhat broader distribution than previously
published maps based on museum specimens, but there
were few unequivocal reports of sturgeon from reaches
above dams in cases where they were not already known
to have occurred in those reaches. This may be due
in part to the fact that dams were constructed in many
regions prior to the first printing of newspapers.
Based on what has been published, the zooarcheological
record seems more complete for the Michigan portion
of the basin.
Dawn Dittman (USGS Great
Lakes Science Center) - Assessment of lake sturgeon
habitat in Lake Ontario and St. Lawrence River tributaries
[view
poster (171 KB pdf)]
Description: One of the top priorities in restoration
of native fish communities is the assessment of the
current available habitat quality in the target ecosystem.
In response to the imperiled status of one key native
species, the lake sturgeon (Acipenser fulvescens),
the New York Department of Environmental Conservation
formulated a recovery plan to maintain and establish
lake sturgeon populations in at least eight separate
locations. As part of the implementation of the recovery
plan, pre and post stocking assessments of sturgeon
habitat quality and use have been conducted in two
very different rivers. These rivers were the Genesee
River - a tributary to Lake Ontario (9 km of accessible
habitat - low gradient), and the St. Regis River – a
tributary to the St. Lawrence River (32 km of accessible
habitat – higher gradient). A habitat suitability
index (HSI) for lake sturgeon and an index of biotic
integrity (IBI) were applied to each river. Released
juvenile sturgeon are successfully using both rivers
in habitat that is predominantly consistent with the
HSI and IBI evaluations. Contrasts in sturgeon habitat
use and the HSI and IBI values for these rivers give
insights into the status, process, and next steps in
the recovery plan for lake sturgeon and the native
fish community of Lake Ontario and St. Lawrence River
tributaries.
Dawn Dittman (USGS Great
Lakes Science Center) – New York Lake Sturgeon
Projects [view
poster (231 KB pdf)]
Barbara Evans (Lake Superior
State University) - Retinal development and light response
in larval lake sturgeon [view
poster (2.95 MB pdf)]
Description: Little is known about the role of vision
during the early development of lake sturgeon. Fertilized
lake sturgeon eggs from Black Lake MI were maintained
in the laboratory at 13 degrees C and a 15:9 hour light
dark cycle. At daily intervals after hatching, larvae
were tested for their phototactic response and also
sampled for histological examination. The light source
was a series of narrow bandwidth light emitting diodes
(UV, visible, IR). At hatching, the larvae elicited
negative phototaxis; however, the retina was undifferentiated.
The pineal organ does appear to be differentiated at
time of hatching and likely facilitates the observed
response to light. At 5 days post hatch (dph), cone
photoreceptors were beginning to differentiate in the
central retina, and the larvae appeared less photonegative,
instead they froze when the light source was turned
on. By 10 dph, both large rods and small cones with
oil droplets were present, and the retina showed clear
lamination. Coordinated eye movements were observed
at 15 dph, but the fish did not respond to moving grating
patterns. The retina develops relatively slowly, but
once complete has both rods and cones with low numbers
of ganglion cells. Histological and behavioral results
indicate that the larval lake sturgeon eye is sensitive
to low light, but also has low visual acuity. Under
natural rearing temperatures, vision is not likely
functional prior to 1 week of age, but the light environment
is clearly important.
Jeannette Krieger-Kanefsky (Ohio State University)
and Paul A. Fuerst (Ohio State University) - Investigation
of 18S rRNA gene variant expression in lake sturgeon
tissues
Description: Previous studies of the nuclear 18S ribosomal
RNA (rRNA) gene of sturgeons discovered intraindividual
variation in every species of sturgeon examined (23
species of Acipenser, Huso, Scaphirhynchus or Pseudoscaphirhynchus).
This finding (the first in a vertebrate) was highly
unusual. We have previously reported that at least
17 sequence variants of 18S rDNA are found in the genome
of the lake sturgeon. A process termed concerted evolution
ordinarily homogenizes the many copies of the rRNA
genes occurring within an individual. Why do sturgeon
possess large numbers of 18S rRNA gene sequence variants
when very few other species show this characteristic?
Possibly, different sequence variants are active in
different tissues of the sturgeon. We examined the
expression of rRNAs in the liver and found that a single
sequence variant is primarily (if not solely) expressed.
To test whether tissue specific expression of variant
forms occurs, we amplified and sequenced 18S rDNA sequences
from a lake sturgeon, and then reverse-transcribed
the 18S rRNA from eight different tissues and sequenced
the expressed transcripts to determine if there are
differences among variants for the tissues in which
they are expressed. The same single sequence variant
was found to be expressed among all tissue types.
Heidi Keuler (University of Wisconsin La Crosse)
- Growth and condition of lake sturgeon (Acipenser
fulvescens)
in Legend Lake and the Wolf River – Lake Winnebago
System of northeastern Wisconsin
Description: Age, growth, and body condition of feral
lake sturgeon (Acipenser fulvescens) have been studied
in numerous waterbodies; however, comparison of growth
and body condition of feral sturgeon to stocked fish
is lacking. The objective of this study was to determine
if there was a significant difference between a feral
population of sturgeon in the Lake Winnebago system,
and a stocked population in Legend Lake on the Menominee
Reservation. Length and weight of sturgeon were measured
and approximately 250 pectoral fin rays were collected
from sturgeon in both populations. Fin rays were sectioned
with a low-speed saw, aged, and length-at-age was back-calculated
from annuli. Sturgeon from Legend Lake showed greater
growth than the sturgeon from the Lake Winnebago system
in years one (F = 19.12, P = 0.0002), four (F = 7.92,
P = 0.0090), six (F = 6.62, P = 0.0167), and eleven
(F = 14.53, P = 0.0029). However, the younger lake
sturgeon from Legend Lake had slightly poorer growth
and condition than sturgeon from Lake Winnebago, while
older sturgeon from Legend Lake had superior growth
and condition. This may reflect a diet shift or stocking
too many fish of certain year classes. Stocking fewer
fish in the future may decrease competition and increase
growth and condition of lake sturgeon.
Tracy Kolb (Michigan State University), William Taylor
(Michigan State University), Doug Beard (USGS Reston)
and Andrew Loftus (Loftus Consulting Annapolis) - Developing
an Information Infrastructure for North American Sturgeon
In 2004, the Michigan State University Department
of Fisheries and Wildlife began working with the U.S.
Geological Survey’s National Biological Information
Infrastructure (NBII) to develop an information framework
for North American fisheries and aquatic resources.
The objective is to create an information system that
can be overlaid with existing watershed databases to
aid managers and researchers in assessing landscape
effects on aquatic populations.
In order to meet this objective we are creating a
data system to assess fisheries status and trends across
state boundaries using sturgeon as a pilot species.
Sturgeon are an especially appropriate species complex
because of their ubiquitous nature and vulnerability
to habitat disturbances. The guiding principles of
this project include:
• Creating a system that is useful to managers
and researchers for a variety of purposes associated
with status and trends
•
Utilizing the expertise of managers and researchers
in the sturgeon community throughout design and development
•
Creating a system adaptable enough to incorporate information
from multiple existing management programs, as well
as new information as it develops
The result will be a dynamic system that can change
to meet the emerging needs of researchers and managers.
Scott Koproski (USFWS Alpena),
Meghan Kline (Lake Superior State University), Ashley
Moerke (Lake Superior State University) and Roger Greil
(Lake Superior State University) - Lake sturgeon telemetry
study in the St. Marys River, Michigan [view
poster (202 KB pdf)]
Habitat loss and fragmentation have been identified
as major factors contributing to the decline of lake
sturgeon in the Great Lakes. Lake sturgeon currently
utilize the St Marys River system, but little is known
about the locations and timing of use of habitats by
lake sturgeon. The main objective of this study is
to identify critical habitat used by lake sturgeon
in the St. Marys River by tracking fish implanted with
sonic telemetry tags. During the summer of 2006, 75
lake sturgeon were captured using setlines. All of
the lake sturgeon that were captured for the first
time received an external cinch tag along with an internal
PIT tag. All sturgeon were measured and weighed, and
a small section of the left pectoral fin ray was removed
for aging and genetic purposes. Sonic telemetry tags
were implanted in 12 of the lake sturgeon that exceeded
50 inches in length. Tracking began immediately after
the first fish was implanted with a sonic tag. Preliminary
results illustrate that the tagged lake sturgeon remained
mostly throughout the northern channel of Sugar Island
during the summer. However, a couple individuals were
located along East Neebish Island, demonstrating movements
up to five miles within a three day period. Lake sturgeon
tracking will continue through 2007 to identify patterns
of seasonal movement and habitat use.
Travis Moore (Missouri DOC), Greg Snellen (Western
Illinois University), Mark Miller (Western Illinois
University), and Dr. Timothy Spier (Western Illinois
University) - Lake sturgeon capture methods and habitat
use in the lower pooled portion of the Upper Mississippi
River, Missouri
Description: The Missouri Department of Conservation
has stocked nearly 300,000 fingerling lake sturgeon
into the Mississippi and Missouri Rivers since the
mid-1980’s. Two projects (capture techniques,
habitat use) were initiated in 2004 to help answer
questions about this developing population.
Capture Techniques: While there are scattered reports
of large fish being caught in hoopnets by commercial
fishermen, hoopnets are labor intensive and yield smaller
total numbers of fish. Trotlines baited with nightcrawlers
have proven effective at catching various-sized fish
when water temperatures are less than 75 degrees. Gillnets
have also proven to be an effective method if placed
in locations where fish congregate. Larger meshes yield
larger fish. Three-inch bar mesh gillnets captured
a wider size range of lake sturgeon than other meshes.
Habitat Use: Radio and ultrasonic telemetry was used
to track movements of adult and sub-adult lake sturgeon.
Radio transmitters were useful the first year but it
was difficult to find fish when they used deeper water
habitats. Ultrasonic transmitters have proven more
effective with much higher location rates. Tagged fish
preferred deep water habitats (20+ feet) with moderate
flow. Main channel and channel border habitats, either
diked or undiked, have been the most used habitats.
There are also seasonal movements that appear to be
related to flow rates. Fish moved upstream during high
spring flows and into the dam tailwaters in late summer.
Fish dispersed throughout the lower half of the pool
in winter. While all fish were captured, tagged, and
re-released in Pool 24, some fish have relocated to
other pools.
Holly Patrick (Purdue University)
- Host-size selection and lethality of lake sturgeon
on sea lamprey [full
presentation (556 KB pdf)]
Description: Populations of lake sturgeon Acipenser
fulvescens remain imperiled in the Great Lakes, despite
conservation and restoration efforts. Parasitism by
sea lampreys Petromyzon marinus may contribute to the
failure of sturgeon rehabilitation. The objectives
of this research were to examine the short- and long-term
growth and survival and rate of wound healing and scar
retention of lake sturgeon following a sea lamprey
attack. A series of 80 experimental trials each allowed
one sea lamprey to feed on one lake sturgeon in the
laboratory. Lake sturgeon were from one of four size
groups; 400-600 mm fork length (FL), 600-800 mm FL,
800-1,000 mm FL, and 1,000-1,500 mm FL. Each trial
was terminated upon sea lamprey detachment or lake
sturgeon mortality. Surviving sturgeon were allowed
a two-week short-term recovery period to assess survival,
and a longer-term recovery period to assess growth
and wound healing. Estimated growth rates of lake sturgeon
decreased following sea lamprey attack, pronouncedly
for the smaller fish. Lake sturgeon mortality was greater
for the smaller fish. Sea lamprey marks on lake sturgeon
differed from those seen on teleosts with scales, with
lampreys attaching most frequently on the axils of
the pectoral fins. Results from this study will aid
fisheries managers in making appropriate decisions
for concurrent sea lamprey control and successful rehabilitation
of lake sturgeon populations in the Great Lakes.
Mike Thomas (MDNR Lake St. Clair Research Station)
- Does hook size matter?: Evaluation of two hook sizes
for survey setlines in the St. Clair River
Since 1996, the Michigan Department of Natural Resources
(MDNR) has assessed the status of the lake sturgeon
(Acipenser fulvescens) population in the lower St.
Clair River with setlines. From 1996 through 2004,
setlines were constructed and fished using stainless
steel size 4 Mustad Kirby Sea Hooks. During this time
period, lake sturgeon less than 30 inches total length
(TL) were rarely caught. Over time, cohorts that initially
appeared weak based on setline catches, appeared in
higher numbers in subsequent years. In 2005 and 2006,
we investigated the effect of hook size on the catch
of lake sturgeon by alternating small and large hooks
on each individual setline. The objective of this study
was to determine the effect of hook size on the catch
of lake sturgeon for assessment setlines in the North
Channel of the St. Clair River. Two different sizes
of hooks were fished in an alternating pattern on each
individual setline. Large hooks were baited with round
gobies (Neogobius melanostomus) larger than approximately
2.5 inches TL, while small hooks were baited with round
gobies less than 3 inches TL. Upon retrieval of the
setline, the size of the hook and size of each sturgeon
caught was recorded. For fish captured in 2005, ages
were estimated from pectoral fin ray sections. The
mean TL of lake sturgeon caught on small hooks in 2005
and 2006 was nearly identical, but significantly smaller
than the mean TL of lake sturgeon captured on large
hooks in both years. Over a two year period, small
hooks consistently caught much higher numbers of lake
sturgeon under 35 inches TL or 7 years old, compared
with larger hooks alternated on the same setlines.
Small hooks were much less effective than large hooks
for catching lake sturgeon over 40 inches TL or 10
years old. These results suggest that length frequency
and age composition data collected by setlines fished
with at least two hook sizes are more representative
of the sturgeon population. Assessment setline surveys
using only one hook size would likely provide a biased
sample of lake sturgeon populations, possibly misleading
researchers or managers into ineffective management
actions. Sampling with setlines incorporating both
small and large hooks has improved MDNR efforts to
monitor recruitment and investigate juvenile lake sturgeon
habitat utilization in the St. Clair River.
Back to Contents | Back to
Home