Research
Interests
Trent’s research focuses on population- and community-level
interactions involving freshwater fishes in both lotic
and lentic ecosystems. The objective of his research program is to develop
a greater understanding of the role of biotic and abiotic
factors on the population ecology and biology of fishes and community structure
of aquatic ecosystems in order to assist subsequent natural resource
conservation and management efforts. Trent’s current research is focused in three distinct areas: (1)
population ecology and conservation of fishes in the Great
Lakes basin; (2) ecology and biology of fish populations and
communities in large river ecosystems; and (3) impacts of human-induced perturbations
on aquatic community structure and function.
Examples of Trent’s research in these particular areas are outlined below.
Population Ecology and Conservation of
Fishes in the Great Lakes
Basin
Throughout
the Great Lakes, many native fish species are
imperiled due to habitat degradation, overexploitation, and/or the introduction
of exotic organisms. To further
complicate matters, little is known about the population dynamics, stock
structure, and habitat requirements for many of these fishes. As a consequence, restoration of native
species complexes and subsequent management efforts cannot proceed until more
is known regarding basic population-level processes associated with these
species. Since coming to Purdue University,
Trent has initiated a research program focusing
on the population ecology of following three Great Lakes fishes: lake sturgeon,
lake herring, and lake whitefish.
Lake Sturgeon
Characterization
of Early Life History Stages
In the Green Bay
basin, an insufficient understanding of lake sturgeon early life history and
loss of important nursery habitats has been identified as a critical impediment
to successful rehabilitation of this species. Because each life stage has
unique resource requirements, identifying and preserving critical microhabitats
which provide sufficient prey resources and a suitable physico-chemical
environment will be important determinants of successful recruitment.
This study examined linkages among population abundance and structure, distribution,
and movement and usage patterns of larval, juvenile, and subadult
lake sturgeon relative to the availability of physical habitat, chemical
environmental factors, and benthic macroinvertebrate
prey in the lower Peshtigo River
and the immediate, nearshore waters of Green Bay. Sampling results from this project will also
be used to establish a quantitative sampling protocol for standardizing
assessment surveys of early life stages of lake sturgeon in Great
Lakes waters. Age-0
lake sturgeon (mean fork length = 239 mm [range, 223 to 249 mm]; mean weight = 83 g [range, 74 to 90 g] were
captured from September through October 2002 in the lower section of the
Peshtigo River, Wisconsin, using wading
surveys with dip nets, haul seines, backpack electrofishing,
snorkeling, set lines, bottom trawls, gill nets, and fyke
nets. All fish were measured and
weighed, and water quality parameters (i.e. water temperature, dissolved
oxygen, pH, and conductivity), water depth, and river velocity were measured at
each collection location. Radio
transmitters were attached to juvenile lake sturgeon larger than 75 g in
weight, and were tracked at least twice each day. At each capture site, a bottom dredge sample
was also collected. Dominant substrate
types were visually estimated and a sample was preserved for later analysis of macroinvertebrate assemblage. Quantitative analysis of habitat types within
the Peshtigo River was conducted using dredge samples
collected at three points perpendicular to river flow
at 50-m intervals. All juvenile lake
sturgeon were captured over sand substrates, with particle size ranging from
1.99 to 0.12 mm in diameter, in depths less than 1.0-m, velocities greater than
0.66 m/s, and temperatures ranging from 14.5 to 23.8˚C. Eight of thirteen juvenile lake sturgeon were collected over substrate containing macroinvertebrates.
Those with transmitters (N = 4) did not leave their capture site until
water temperatures within the river declined to 12°C, when the fish moved
downstream and into Green Bay within a two- to three-day period. Catch-per-unit-effort
(CPUE) was highest with the day seining (CPUE = 2.02 fish/h), followed by day
wading surveys and night seining (CPUE = 0.86 and 0.80 fish/h,
respectively). No age-0 sturgeon were captured with bottom trawls, set lines, or fyke nets. We
recommend the use of day seining or day wading surveys in rivers similar to the
Peshtigo
River (i.e., shallow and
low turbidity) for capturing age-0 lake sturgeon.
Funding Source: Great
Lakes Fishery Trust
Personnel: Angela Benson (completed
master’s thesis in August 2004)
Publications:
·
Benson, A. C., T. M. Sutton, R. F. Elliott, and
T. G. Meronek. 2006. Biological attributes of age-0
lake sturgeon in the lower Peshtigo
River, Wisconsin. Journal of Applied Ichthyology (in press).
·
Benson, A. C., T. M. Sutton, R. F. Elliott, and
T. G. Meronek.
2005. Movement patterns and habitat preferences of age-0 juvenile lake
sturgeon in the lower Peshtigo River,
Wisconsin. Transactions of the
American Fisheries Society 134:1400-1409.
·
Benson, A. C., T. M. Sutton, R. F. Elliott, and
T. G. Meronek.
2005. Evaluation of sampling techniques for age-0 juvenile lake sturgeon
in the lower Peshtigo River, Wisconsin,
and nearshore waters of Green Bay. North American Journal of Fisheries
Management 25:1378-1385.
·
Sutton,
T. M., and A. C. Benson. 2003. Influence of external radio transmitter
size and shape on survival, growth, and tag loss of juvenile lake sturgeon.
Transactions of the American Fisheries Society 132:1257-1263.
Collaborators: Robert
Elliott, Thomas Meronek, and
Gregory Kornely
Assessment
of Remnant Population Status
There is a fundamental and critical lack of knowledge
regarding the size, status, and stock characteristics of most remnant
populations of lake sturgeon currently inhabiting the Lake
Michigan basin. As a result, this lack of understanding has
hindered efforts to rehabilitate lake sturgeon throughout the watershed, a
commitment identified in existing rehabilitation and management plans for this
species. To address this need, a basin-wide study has been
implemented that will involve cooperative research efforts among five natural
resources management agencies (U.S. Fish and Wildlife Service, Wisconsin and
Michigan Departments of Natural Resources, Little Traverse Bay Band of Odawa Indians, Little River Band of Ottawa Indians) and five public universities (Purdue, Michigan State,
Central Michigan, and Michigan Technological Universities, and the University
of Georgia) to comprehensively assess and characterize the most significant
remnant lake sturgeon stocks that persist and spawn in tributaries of Lake
Michigan and Green Bay. Specifically, the Purdue
University component of this study
will examine population abundance and reproductive success of spawning adults,
describe spawner habitat use and availability of
spawning and resident lake sturgeon in the St. Joseph and Kalamazoo Rivers,
tributaries in southeastern Lake Michigan, and sample for early life stages
(i.e., eggs, larvae, and juveniles) in order the characterize spawning,
recruitment success, and nursery habitat availability.
Funding Source: Great Lakes Fishery
Trust, Purdue University Department of Forestry and Natural Resources
Personnel:
Daniel Daugherty, Rebecca Zeiber, and Stephanie Shaw (Project completed in
August 2005)
Publications:
·
Zeiber,
R. A., S. M. Shaw, and T. M. Sutton. 2006. Assessment of remnant lake sturgeon
populations and habitat availability in the lower and upper Kalamazoo River, Michigan.
Great Lakes Fishery Trust, Lansing,
Michigan.
Collaborators:
Robert Elliott, Kim Scribner, Edward Baker, Nancy Auer, Douglas Peterson,
Thomas Meronek, Gregory Kornely, Marty Holtgren,
Tracy Galarowicz, Terrence Lychwick,
Steve Lenart, and Kregg
Smith
Potential
for Habitat Rehabilitation in Lake Michigan
Tributaries
Lake sturgeon Acipenser fulvescens were historically one of the most numerous
fish species in the main basin of Lake
Michigan and Green Bay.
Throughout the Great Lakes, lake
sturgeon abundance declined dramatically during the 1800s, with populations
reduced to remnant levels by the early 1900s.
Factors attributed to these declines include water pollution, physical
habitat alterations, impediments to migration, and commercial overexploitation. Although improvements in water quality and
harvest reductions have allowed for some recovery, limited availability of
staging, spawning, and nursery habitats in historically important tributaries
remains an impediment to rehabilitation.
Many of the rivers that presently support or historically supported lake
sturgeon populations have been altered by the construction of hydropower dams,
changes in land-use practices, and other anthropogenic impacts. As a result, the extent to which these factors
continue to limit habitat availability, and consequently recovery efforts,
remains unknown. Enhancement or
rehabilitation of degraded habitats, including the addition of proper
substrates, creation of backwater areas, maintenance of adequate and natural
stream flows, removal of barriers, and installation of fish-passage structures,
will be necessary to restore lake sturgeon tributaries throughout the Lake Michigan watershed.
Assessment of past and present habitat availability is necessary, and
replacement, enhancement, or renewed accessibility to habitats will be
essential for successful restoration.
Therefore, habitat enhancement or rehabilitation must be a priority for
tributaries of Green Bay
in order to allow for the long-term sustainability and recovery of lake
sturgeon. Specific objectives of this
research include: (1) assessment and quantification of lake sturgeon spawning,
nursery, and adult habitats currently available and potentially available above
existing barriers; (2) examination of spatial (i.e., longitudinal) relationships
of lake sturgeon habitats below and above existing barriers; and (3)
development of a decision tool for prioritizing Green Bay tributaries,
identifying appropriate rehabilitation strategies, and directing future
enhancement or restoration of important habitats or habitat features for lake
sturgeon populations.
Funding Source: Great Lakes Fishery Trust, U.S.
Fish and Wildlife Service, Purdue University Department of
Forestry and Natural Resources
Personnel: Daniel Daugherty (current
doctoral student)
Publications:
·
Project not yet completed; project completion
date: December 2006
Collaborators: Robert
Elliott, Mark Holey, Edward Baker, and Michael Donofrio
Effects
of Mortality Sources on Population Viability
Lampricide applications in streams containing swim-up larvae and
small juvenile lake sturgeon Acipenser fulvescens may negatively impact recruitment,
rehabilitation, and sustained viability of this species in the Great Lakes. As a
result, a no observable effect (i.e., no mortality) treatment protocol has been
implemented in streams supporting lake sturgeon. However, the overall effectiveness of lampricide
treatments may be diminished because greater numbers of parasitic-phase sea
lampreys Petromyzon marinus may
be produced from tributaries through inefficient or failed lampricide
treatments. We used a stage-structured, life-history model to
examine the impacts of lampricide applications and
sea lamprey parasitism on the population viability of lake sturgeon in the Laurentian Great Lakes basin. Population abundance, the number of age-1
recruits, and reproductive potential of lake sturgeon exhibited relative
percentage decreases with increasing mortality of age-0 juvenile fish (range, 0
to 100%) as a result of lampricide applications at
four-year treatment intervals. When
larval sea lamprey mortality (range, 100 to 0%) following lampricide
treatments was incrementally decreased, lake sturgeon mortality from increased
sea lamprey parasitism for both the low and high mortality simulation scenarios
resulted in relative percentage decreases in population abundance, the number
of age-1 recruits, and reproductive potential from baseline conditions. Incremental increases in sea lamprey-induced
lake sturgeon mortality (range, 0 to 22%) as estimated from wounding rate data
resulted in relative percentage decreases in population abundance, the number
of age-1 recruits, and reproductive potential from baseline conditions. Based on the results of our model
simulations, it appears that mortality agents, such as sea lamprey parasitism,
that influence subadult and adult lake sturgeon have
a greater impact on the long-term population viability of this species than
mortality factors that affect early life stages (i.e., lampricide
applications). As a result, we do not
recommend that lampricide-application strategies for
the control of larval sea lamprey populations in tributaries containing lake
sturgeon continue to follow the no effect protocol in order to allow for the
long-term rehabilitation and management for this species.
Funding Source: Great
Lakes Fishery Commission
Personnel: Trent Sutton and Rebecca
Zeiber
Publications:
·
Sutton, T. M., B. L. Johnson, T. D. Bills, and
C. S. Kolar. 2004. Effects of sea lamprey induced mortality
sources on lake sturgeon population viability: an ecological modeling approach.
Great Lakes Fishery Commission Technical Report, Ann Arbor, Michigan.
Collaborators: Barry
Johnson, Cynthia Kolar, and Terry
Bills
Host-Size
Selection and Lethality of Sea Lamprey on Lake Sturgeon
The
use of the no observable effect (i.e., no mortality) lampricide
treatment protocol to protect lake sturgeon Acipenser fulvescens populations might also
increase production of sea lampreys Petromyzon marinus and, consequently, parasitism on lake sturgeon.
However, no studies have examined the influence of sea lamprey parasitism on
lake sturgeon survival. Because previous
model simulations indicate that sea lamprey attacks on adult lake sturgeon
adversely affect long-term population viability, understanding is needed of the
relations among wounding rate, wound type, and host survival to ensure that sea
lamprey control strategies optimize lake sturgeon rehabilitation in the Great Lakes. For
this study, we will examine the following objectives: (1) compare the short-
and long-term survival of three size groups of lake sturgeon after a single sea
lamprey attack; (2) determine the rate of wound healing and scar retention of
lake sturgeon hosts following sea lamprey attacks; (3) develop a classification
system for the categorization of sea lamprey marks on lake sturgeon. For this experiment, we will use three size
classes of lake sturgeon (N = 25 fish per size class; 125 lake sturgeon for this study are currently at Purdue University):
(1) small (400 to 599 mm fork length); (2) medium (600 to 799 mm); and (3) large (800 to 999 mm). Each lake sturgeon will be
weighed, individually placed in a holding tank with a single, pre-weighed sea
lamprey, and the time and location of attachment will be recorded for each
pairing. Following detachment, both fish will be re-weighed and the wound type
on each lake sturgeon will be classified according to standard criteria.
Surviving lake sturgeon will be transferred to recovery tanks at the same
temperature as the test tanks to determine delayed mortality during a 14- to
21-d recovery period. Any mortality during this period will be further
classified into fish that died from sea lamprey attack or secondary infection.
Survivors will be held an additional 60+ days at 10oC to determine
the rate of wound healing and scar retention. The number of live and dead lake
sturgeon will be examined by size class, and location and duration of sea
lamprey attachment. Dead lake sturgeon will also be assessed based on the
source and timing of mortality. Sea lamprey data will be examined by weight
gain, and location and duration of attachment.
Funding Source: Great Lakes Fishery
Commission
Personnel: Holly Patrick (current
master’s student)
Publications:
·
Project not yet completed; project completion
date: December 2006
Collaborators: William Swink and Anant Bharadwaj
Mortality and
Recruitment Mechanisms of Lake
Sturgeon Early Life
Stages
Identification
of the factors that regulate fish populations has been a major goal of
fisheries research because variable survival among early life stages determines
overall viability of the species.
Because each life stage has unique requirements, identification and
quantification of egg, larval, and juvenile losses is required to understand
the criteria for successful survival and recruitment to subsequent life
stages. However, the extent to which
mortality mechanisms impact lake sturgeon early life stages and limit recovery
efforts remain unknown. For
rehabilitation to be successful, an understanding of the relationship among
mortality and recruitment factors acting on lake sturgeon populations is
necessary. For this study, we will
examine the following objectives: (1) estimate egg density, production of
larvae during the drift period, and the abundance of age-0 juvenile lake
sturgeon prior to river emigration in the lower Peshtigo River; (2) identify
and quantify the mechanisms of mortality during each lake sturgeon life stage;
(3) determine if predation on age-0 life stages is dependent upon lake sturgeon
body size; and (4) assess how mortality sources influence recruitment dynamics,
year-class strength, and population viability of lake sturgeon. Lake
sturgeon egg density will be estimated using substrate mats (May 2006 and
2007). To examine predation on eggs and
yolk-sac larvae, we will use in-situ
exclosures constructed of plastic boxes filled with coarse substrates. To
estimate relative abundance and production of lake sturgeon swim-up larvae, fish
will be collected using drift nets set below the Peshtigo River
spawning area (May and June 2006 and 2007).
Relative and absolute abundance of juveniles will be estimated from fish
collected and marked or tagged following wading capture surveys (June -
November 2006 and 2007). Fish predators will be collected using gill
nets and electrofishing (May - November 2006 and
2007). This research will
directly increase our understanding of the mechanisms directing recruitment
dynamics of lake sturgeon in the Lake Michigan basin and help to identify
mortality sources that may negatively impact ongoing and future recovery
efforts for this species throughout the Great Lakes basin.
Funding Source: Great Lakes Fishery
Trust
Personnel: David Caroffino
(current doctoral student)
Publications:
·
Project not yet completed; project completion
date: May 2009
Collaborators: Robert Elliott,
Edward Baker, and Michael Donofrio
Lake
Herring
Since declining in the 1960s, lake herring Coregonus artedi populations
have remained suppressed throughout Lake Superior,
and only one strong year class (1998) has occurred over the past decade. During
this time, lake herring populations in Lake Superior
have also exhibited high recruitment variability. To improve our understanding of the
mechanisms which influence year-class strength, we conducted a 225-d laboratory
experiment to evaluate the effects of body size, condition, energy stores, and
food ration on overwinter survival of age-0 lake
herring. Small (total-length range, 60
to 85 mm) and large (total-length range, 85 to 110 mm) fish were maintained
under thermal and photoperiod regimes that mimicked those in Lake
Superior from October through May. Fish in each size class were
maintained at two feeding treatments: Artemia ad libitum or no
food. Mortality of
large lake herring (fed, 3.8%; starved, 20.1%) was significantly less than
those of small fish (fed, 11.7%; starved, 32.0%) within feeding treatments.
Body condition and crude lipid content declined over the experiment for all
fish; however, index values were significantly greater for large and small fed
fish than large and small starved individuals. Final crude protein and gross
energy content was also significantly greater in large fed lake herring (17.6% and
1,966 cal/g, respectively) followed by small fed (17.1% and 1,497 cal/g,
respectively), large starved (15.4% and 1,125 cal/g, respectively), and small
starved (13.2% and 799 cal/g, respectively) fish. Individuals that survived the winter period
had significantly greater energy stores than fish that died during the study.
These results suggest that depletion of energy stores contributes to greater
winter mortality of small fish, and may partially explain the recruitment
variability that has been observed for lake herring in Lake
Superior.
Funding Source: Michigan
Sea Grant College
Program, Purdue University Department of Forestry and Natural Resources
Personnel: Kevin Pangle (completed
master’s thesis in July 2003)
Publications:
·
Pangle,
K. L., T. M. Sutton, R. E. Kinnunen, and M. H. Hoff.
2005. Effects of body size, condition, and lipid content on the survival of
juvenile lake herring during rapid cooling events. Journal of Great Lakes
Research 31:360-366.
·
Pangle, K. L., and T. M. Sutton. 2005. Temporal
changes in the relationship between body condition and proximate composition of
juvenile lake herring. Journal of Fish Biology 66:1-13.
·
Pangle, K. L., T. M. Sutton, R. E. Kinnunen, and M. H. Hoff. 2004. Overwinter
survival of age-0 lake herring in relation to body size, physiological
condition, energy stores, and food ration. Transactions of the American
Fisheries Society 133:1224-1234.
·
Pangle, K. L. T. M. Sutton, and P. B. Brown. 2003. Evaluation of practical and natural diets
for juvenile lake herring. North American Journal of Aquaculture 65:91-98.
Collaborators: Ronald Kinnunen and Michael
Hoff
Lake Whitefish
Lake whitefish Coregonus clupeaformis
historically supported an important commercial fishery in the Great Lakes. In Lake Michigan, this species formed the basis of the
commercial fishery since the 1970s, with peak harvest occurring in the early
1990s. However, annual yield, length- and weight-at-age, and body condition of lake whitefish have all declined dramatically since this
time. These declines have been largely attributed to the invasion of zebra
mussel Dreissena polymorpha,
which appears to have contributed to the lake-wide decrease and disappearance
of the benthic amphipod Diporeia, the primary
prey of whitefish. Egg lipid and caloric content, size-at-hatching, and
subsequent growth and survival are known to be positively related for lake whitefish. Therefore, declines in Diporeia,
a prey source with a higher energy content and essential omega-3 fatty-acid
(FA) concentrations than many other prey types, may adversely impact
recruitment because females are likely to produce smaller eggs with lower
quality. Consequently, lake whitefish will hatch at
smaller sizes, predisposed to essential fatty-acid deficiency, which may
translate to lower first-year survival due to limited feeding opportunities and
greater predation mortality. Because fall body size is strongly coupled to
summer growth, smaller age-0 fish typically accumulate less energy reserves
prior to the end of the growing season, more rapidly exhaust these stores over
the winter, and are more likely to suffer mortality during this period. This
research will contribute to our understanding of trophic
food-web impacts on recruitment dynamics of lake whitefish
in Lake Michigan and provide critical information necessary for improving
fishery yield forecasts. The
primary objective of this project is to determine the role and relationship of
body size, condition, and proximate composition (i.e., lipid, protein, carbohydrate, caloric, water, and
ash content; fatty-acid composition) on the first-year growth and
survival of juvenile whitefish through the first winter of life. An additional
objective of this study will be to determine the proximate composition of
juvenile whitefish prey. Given the
nature and magnitude of the alterations in trophic
food-web structure that have taken place in Lake Michigan following the
invasion of zebra mussels and the decline in Diporeia, it is imperative that
we develop a better understanding of how these changes are affecting the
dynamics and health of fish populations, particularly those with significant
economic and ecological importance as whitefish. This research will directly
contribute to our understanding of the mechanisms directing recruitment
dynamics of whitefish in Lake Michigan and
help to identify indices of fish health that federal, state, and tribal natural
resource management agencies can use to monitor first-year growth, survival,
and natural mortality of juvenile whitefish.
Funding Source: Great Lakes Fishery Trust,
Purdue Research Foundation
Personnel: Andrew Muir (current doctoral
student)
Publications:
·
Project not yet completed; project completion
date: October 2007
Collaborators:
Ronald Kinnunen, Mark Ebener,
Michael Arts, Marten Koops, John Fitzsimons, Thomas Johnston, Randall
Claramunt, Timothy Johnson, and Robert Montgomerie
Brook
Trout
The successful restoration of native brook
trout Salvelinus fontinalis
populations in Lake Superior depends on an understanding of the phenotypic and
genetic differences among geographically isolated stocks and the successful
rearing of locally adapted populations in the hatchery environment. We propose to quantify developmental,
morphological, and physiological characteristics among brook trout strains
exhibiting variable migratory and non-migratory life history types, using both
traditional and enhanced rearing environments.
We hypothesize that significant differences exist among brook trout
populations with variable life history strategies, and that strains will
perform differently between traditional and enhanced rearing environments. To test our hypotheses, we will: 1) compare developmental, physiological, and
morphological characteristics among brook trout stocks from Lake Superior in
two different rearing environments, and 2) evaluate differences in these
characteristics within stocks reared in either a traditional or enhanced
rearing environment. Brook trout
strains (having both migratory and non-migratory ancestries) currently or
historically used in Lake Superior drainage stocking and rehabilitation efforts
will be used for this study. Fish from
each of five brook trout populations (Siskiwit, Tobin Harbor,
Jumbo River,
Nipigon, Iron River)
will be used for this laboratory experiment.
Treatments will exist of five tanks with traditional rearing (no
substrate or cover, broadcast feeding) and five tanks with enhanced rearing
(providing substrate, cover, and underwater feeding), each strain experiencing
both treatment types. After six months
of growth, individuals will be PIT-tagged, weighed, standard length measured,
and a photo taken for body morphology and coloration (silver index)
measurements. These same data and photos
will be taken every six months through age 2, and individual growth rates
calculated for each interval. We will
examine differences among strains and among families within strains for time to
hatch, and including tests for rearing environment, and rearing environment by
strain effects for morphology, coloration (silver index), and growth. In addition, we will also examine the effect
of rearing environment on social dominance, survival, growth, and condition in
the presence and absence of mutual competition from conspecifics
reared in the alternative rearing environment (i.e., enriched versus
traditional rearing environment for each strain). These attributes for each
strain of fish reared in the enriched environment will also be examined in the
presence of fish from each of the other strains separately (i.e., Nipigon versus Siskiwit, Nipigon versus Jumbo, Nipigon
versus Iron Riever, etc.) to determine differential
suitability among stocks for rehabilitation stocking efforts in Great Lakes
tributaries.
Funding Source: Purdue University
Personnel: Lorena Edenfield
(current master’s student)
Publications:
·
Project not yet completed; project completion
date: August 2008
Collaborators:
Krista Nichols and Dale Bast
Ecology and Biology of Fish Populations and
Communities in Large River Ecosystems
Large
natural floodplain rivers are among the most biologically productive and
diverse aquatic ecosystems. Fish communities are an integral component of these
freshwater ecosystems as they perform vital fundamental services for
maintaining ecosystem function and resilience and also support regionally and
economically important fisheries.
Because temperate freshwater ecosystems in North
America are being depleted of species nearly as rapidly as
tropical forests, it is imperative that we fully understand the fish
populations that occupy these unique environments. Trent
is currently working with state management agencies to meet this particular
need, focusing on the following three fishes: shovelnose sturgeon, flathead catfish,
and blue sucker.
Shovelnose
Sturgeon
Shovelnose sturgeon Scaphirhynchus platorynchus
support a commercial fishery throughout much of the Mississippi
and Missouri River drainages. There is concern that harvest closures for Eurasian
sturgeons may result in increased exploitation of shovelnose sturgeon to meet
global demands for caviar. For this
study, population attributes of shovelnose sturgeon were examined from an
exploited and unexploited reach of the upper Wabash River, Indiana. Fish (N = 4,789) were captured from April
2003 through November 2004 between Wabash and Terre Haute, Indiana, using
direct current electrofishing, experimental gill
nets, and benthic trawls.
Catch-per-unit-effort (CPUE) varied on a temporal basis, with CPUE for
the unexploited reach greater than the exploited reach from April through June
(range, 5 to 58 fish/hr) while the exploited reach was
greater throughout the rest of the year (range, 4 to 12 fish/hr).
Catch rates were highest for both reaches from March through May, and
approached 500 fish/hr during early May. Fork length (FL) of captured fish ranged from
273 to 858 mm, but few fish < 550 mm were captured. Median
FL and wet weight were 683 mm and
1,208 g, respectively (range = 273 to 858 mm and 52 to 3,381 g,
respectively). Shovelnose sturgeon
ranged from ages 2 to 30, with 95% of the fish between ages 9 and 20. Total annual mortality for fish between ages
13 and 18 was 20%. Empirical growth
rates derived from shovelnose sturgeon that were marked and recaptured were
slow, with 74% of fish showing negative or no growth in length while at
large. Relative weight of shovelnose
sturgeon was significantly different among relative stock density (RSD) length
categories, with trophy length fish (median = 87) having higher values than
preferred and memorable length categories (both, median = 82). Population characteristics of shovelnose
sturgeon in the upper Wabash
River were within the
range reported for other river systems.
Although growth and relative weight were low compared to the Mississippi and Missouri
Rivers, shovelnose sturgeon in the
upper Wabash River attained a larger body size,
reached older age classes, experienced lower mortality rates, and higher
relative abundance. Results from this
study will allow for the detection of shifts in abundance, size and age
structure, and gender ratio in response to harvest or natural perturbations
more quickly and the development of appropriate management actions to ensure
the sustainability of this species and its fishery.
Funding
Source: Purdue University College
of Agriculture and Department of Forestry and Natural Resources, Indiana
Department of Natural Resources, American Fisheries Society
Personnel: Anthony Kennedy (completed
master’s degree in December 2005)
Publications:
·
Kennedy,
A. J., T. M. Sutton, T. C. Stefanavage, and B. E.
Fisher. In review. Effects of harvest and length limits on shovelnose sturgeon
in the upper Wabash River, Indiana.
Journal of Applied Ichthyology.
·
Kennedy,
A. J., T. M. Sutton, and B. E. Fisher. In review. Population attributes of
shovelnose sturgeon in the upper Wabash
River, Indiana. North
American Journal of Fisheries Management.
·
Kennedy,
A. J., T. M. Sutton, and B. E. Fisher. 2006. Reproductive biology of female
shovelnose sturgeon in the upper Wabash
River, Indiana.
Journal of Applied Ichthyology (in press).
·
Collaborators: Brant
Fisher, Thomas Stefanavage, Leslie Frankland, and Robert Maher
Flathead
Catfish
Flathead catfish have historically gathered little
interest from recreational and commercial anglers in the northern United States,
resulting in a lack of information regarding the population characteristics,
movement patterns, habitat use, and home range of these stocks. The purpose of this study was to examine
these characteristics of flathead catfish in the lower St. Joseph River, Michigan, to direct future management
efforts and increase our knowledge of flathead catfish in the northern United States. To examine the biological attributes and stock
dynamics of flathead catfish in this system, fish were collected from June
through September 2002 and 2003 using stationary electrofishing. Fish density was estimated at 191
individuals/rkm (range, 92 to 309 fish/rkm) and annual survival ranged from 67 to 76%. Growth was greatest for fish less than two
years of age and decreased among older age classes. The size and age structure of flathead
catfish was dominated by fish less than 400-mm TL and four years of age,
although individuals greater than 1,100-mm total length and up to age 17 were
present in the population. Seasonal
movement patterns, habitat use, and home range of flathead catfish were
determined using ultrasonic telemetry from June 2002 through August 2003. Habitat use of flathead catfish was dominated
by large woody debris and rip-rap at water depths less than 3 m during all
seasons except winter, when fish utilized main-channel pool habitats associated
with coarse substrates at a mean water depth of 4 m. Flow rates at fish locations were not
significantly different among seasons.
The seasonal movement distances and home range of flathead catfish were
greatest during spring and fall months when fish transitioned between summer
and winter habitats. These results
suggested that the population characteristics of flathead catfish in this
system are similar to those of other stocks throughout their geographic range,
and that the rate of exploitation in this system is low. Further, seasonal differences exist in the
movement patterns, habitat-use, and home range of flathead catfish, and that
the availability of structure and main-channel pool habitats are
important considerations in the management of this species.
Funding
Source: Purdue University Department of Forestry and Natural Resources, Great Lakes Fishery Trust, and Michigan Department of
Natural Resources
Personnel: Daniel Daugherty (completed
master’s degree in December 2003)
Publications:
·
Daugherty, D. J., and T. M. Sutton. 2005. Effectiveness
of a chase boat for electrofishing flathead catfish
in the lower St. Joseph River,
Michigan. North American Journal
of Fisheries Management 25:1528-1532.
·
Daugherty,
D. J., and T. M. Sutton. 2005. Diel movement patterns
and habitat use of flathead catfish in the lower St. Joseph River, Michigan.
Journal of Freshwater Ecology 20:1-8.
·
Daugherty, D. J.,
and T. M. Sutton. 2005. Seasonal movement patterns and habitat use of flathead
catfish in the lower St. Joseph River,
Michigan. North American Journal
of Fisheries Management 25:256-269.
·
Daugherty, D. J.,
and T. M. Sutton. 2005. Population abundance and stock characteristics of
flathead catfish in the lower St.
Joseph River, Michigan.
Transactions of the American Fisheries Society 25:1191-1201.
Collaborators: Jay Wesley and James Dexter
Blue
Sucker
The blue sucker Cycleptus elongates is an important species in
freshwater ecosystems because it provides an important prey base for top
predators. Although
no longer listed as a species of special concern in Indiana
(delisted in 2004), blue suckers are considered
threatened or endangered across most of their native range of the Mississippi and Rio
Grande River basins.
The objectives of this study were to describe the age and growth
characteristics of blue sucker in the upper Wabash River, Indiana. Blue suckers (N =
209) were collected using boat electrofishing from
June 2003 to April 2005. Physical structures, which included dorsal and
pectoral rays, scales, otoliths, and opercles, were removed for age estimation. The mean total length of sampled fish was 610
mm (range, 454 to 739 mm) and 2,075 g wet weight (range, 779 to 4,298 g).
The mean age of the population sampled was 5.5 years (range, 3 to 10
years). Log-transformed wet weight (W)
and total length (TL) data were used in an ordinary least-squares regression to
develop a relationship of log10W = 3.3726 × log10TL
- 6.0912. Mean relative condition was
100.6 (range, 66.2 to 141.0), and no length-dependent trends in this index were
detected. Length-at-age and precision
between age estimates among structure’s analysis is ongoing. The results of this study suggest that the
blue sucker population in the upper Wabash
River is comprised of
individuals with good relative condition with a broad size and age structure
range.
Funding Source: Purdue University
College of Agriculture
Personnel: Thomas Bacula
Publications:
·
Project not yet completed; projected completion
date: December 2005
Collaborators: Brant
Fisher, Leslie Frankland, and Daniel Daugherty
Impacts of Human-Induced Perturbations on
Aquatic Community Structure and Function
While
the ecology and management of riparian zones has been well studied in the
American southwest and Pacific Coast of North America, the same cannot be said
of the eastern corn-belt region or boreal mixed-wood forests. Although unharvested
forest strips are often left along permanent streams to protect riparian
habitat, the width of these reserves is typically inadequate to mitigate the
effects of surrounding land-use practices.
Because riparian zones provide important habitat features for aquatic
organisms, understanding how human encroachment of riparian areas influences
the structure and function of aquatic communities is an important
undertaking. Further, developing an
understanding of how the intentional introductions of non-native fishes can
disrupt energy flow, trophic dynamics, and biotic
interactions is also critical for understanding aquatic community structure and
function. Trent has initiated research on the effects
of land-use practices and riparian zone structure in small warm-water streams
in the upper Wabash
River drainage of Indiana and coolwater streams in the boreal forests along the Canadian Shield of northern Ontario.
Further, he has begun new research on the impacts of western mosquitofish on native fish and amphibian assemblages in lotic and lentic waters of Indiana.
Agriculture-Dominated
Streams of the Upper
Wabash River
Using the
National Water-Quality Assessment (NAQWA) developed by the U.S. Geological
Survey, we conducted an examination of the physical (i.e., in-stream and
riparian habitat, channel conditions, and hydrology), chemical (i.e., dissolved
gases, ions, and nutrients), and ecological (i.e., fish, benthic macroinvertebrates, and algal communities) components as
part of an integrated assessment to determine the status and trends in water
quality of wadeable lotic
systems within the upper Wabash River basin.
By developing an understanding of the major natural and anthropogenic
factors that affect observed water-quality conditions and trends in this
drainage, we will be able to provide private landowners and natural resource
planning agencies with the information necessary to not only effectively manage
aquatic ecosystems, but to develop and implement land-use strategies that are
consistent with sound stewardship practices across terrestrial-aquatic
boundaries. This implementation
framework will be enhanced by the development of an empirical relationship
among habitat availability, water quality, and biological condition at regional
and local scales that will allow for the development and use of an integrated
ecosystem model to forecast changes in environmental conditions given
alternative approaches for maintenance or rehabilitation efforts within the
upper Wabash
River basin. Specific study objectives of this project
include: (1) development of relationships among fish community structure,
benthic macroinvertebrate community structure, algal
community structure, physical habitat complexity, and water chemistry under
varying environmental gradients; (2) examination of local natural and human
land-use patterns and practices on the relationship between biological,
physical, and chemical components of the aquatic ecosystem; (3) determination
of the influence of regional and segment characteristics and dynamics of the
basin on the relationship between biological, physical, and chemical components
of the aquatic ecosystem; and (4) development of a framework for bioassessment that integrates metric data collected on
biological, physical, and chemical components in upper Wabash River tributaries.
Funding Source: Purdue University
Department of Forestry and Natural Resources
Personnel: Emmanuel Frimpong
(completed doctoral degree in August 2005) and Peter Hrodey (completed master’s
degree in December 2005)
Publications:
·
Frimpong, E. A., T. M. Sutton, and T. P. Simon. In review. Ecological
health and integrity: integrating concepts with a model for aquatic ecosystem
management. Environmental Management.
·
Frimpong, E. F., J. G. Lee, and T. M. Sutton. 2006. Cost
effectiveness of vegetative filter strips and instream
half-logs for ecological restoration. Journal of American Water Resources
Association (in press).
·
Frimpong, E. A., T. M. Sutton, B. A. Engel, and T. P.
Simon. In revision. Physical habitat evaluation, spatial scale effects, and
prediction of biotic integrity in agricultural watersheds. Environmental
Management 36:899-917.
·
Frimpong, E. A., T. M. Sutton, K. J. Lim, P. J. Hrodey, B.
Engel, T. P. Simon, J. G. Lee, and D. C. Le Master. 2005. Determination of
optimal riparian forest buffer dimensions for stream biota landscape
association models using multimetric and multivariate
response. Canadian Journal of Fisheries and Aquatic Sciences 62:1-6.
Collaborators: Bernie Engel, John Lee, and
Thomas Simon
Half-Log
Introductions into Agriculture-Dominated Streams
One of the
greatest factors limiting fish productivity in stable, low-gradient, headwater
streams is the amount of in-stream cover provided by course woody debris.
In order to compensate for this lack of structure, managers often add woody
materials into the stream channel to increase cover complexity and overall
productivity. In addition to providing valuable habitat features, the
placement of woody debris within streams can create pools, increase the
retention of sediment and organic materials, stabilize the physical streambed,
and create unique channel morphologies. A design typically used by
managers in small stream systems is half-log habitat enhancement
structures. Half-logs attract juvenile and adult fish by providing
overhead cover where it did not previously exist or may have existed but has
been since removed. These structures can also provide an additional forage site
for fish through the macroinvertebrates and periphyton that colonize them. Half-logs (N = 108) were added to headwater
streams (N = 9) of the upper Wabash River basin, Indiana,
in July 2003. Each stream contained
three paired control and treatment reaches.
Treatment sites had added to them four half-logs each, while control
sites were spaced a minimum of 100 m upstream and left unaltered. Study sites (25 m in length) were sampled
once monthly through October 2003 and April through September 2004 using
backpack electrofishing employing a three-pass
depletion method. After manipulation,
fish abundance was higher at treatment than control sites (mean = 652 and 493
fish, respectively). Similarly, both
catch-per-unit-effort (fish/hr) and biomass (g/m²) were higher at treatment
sites (mean = 194.65 and 177.96; 4.25 and 2.85, respectively). Species richness and the relat