Wildlife Diversity Fund Project Proposal – FY15 (January 2014)
Title: Life History of the Freckled Crayfish Cambarus maculatus in two Missouri Streams
Location (County): Meramec River Drainage (Washington County)
Project Leader: R. DiStefano (MDC Project Leader), with C. Ames (MDC), J. Westhoff, and A. Rosenberger
(MO Cooperative Fish & Wildlife Research Unit; MCFWRU)
Total Amount Requested: $24,098 (EXP = $24,098, EQP = $0, HL = $0)
Project Need: Endemic to only the Meramec River Basin of Missouri, the Freckled Crayfish, Cambarus
maculatus, has one of the smallest ranges of all crayfish species. Surveys in the 1970s-80s documented this
species of conservation concern in only 12 streams. Much of its known range falls within MDC’s Middle
Meramec River Conservation Opportunity Area. It is listed (MDC) as “Vulnerable” (S3) due to its narrow range
near the quickly-developing St. Louis metropolitan area and its apparent low abundance at most locations. It was
recommended for upgrading to “imperiled” status in one conservation analysis. After its description in
1988, no research on C. maculatus has occurred, so virtually nothing is known about its distribution, life history,
population genetics or habitat requirements.
Narrowly distributed, endemic species have long been the subject of concern among conservationists due
to their perceived high vulnerability to multiple threats linked to human population encroachment, particularly
physical habit degradation, wholesale loss of habitat, and loss of water quality. Further, native crayfishes are
particularly vulnerable to threats from invasive crayfishes. Recent declines and extirpations of native Ozark
crayfish attributed to pollution, habitat degradation and several alien crayfish invasions have elicited concern
among conservationists for the long term status of narrow endemic Ozark crayfishes such as C. maculatus. It was
recently suggested that Cambarus species may be particularly vulnerable. Extinction risk of North American
crayfish species is linked with specific life history traits: low fecundity, small egg size and body size, and
longevity. Habitat specialization is identified as another trait that could influence extinction risk. Data on these
life history traits with investigation of reproductive behavior and ecology for Ozark crayfishes (particularly those
with narrow ranges) are critical in assessing conservation status and decisions about whether or not to “list” and
recover species under the U.S. Endangered Species Act and provide managers with required knowledge for
conservation planning and management. However, such life history data are lacking or non-existent for most
Ozark crayfishes, including C. maculatus.
A recent analysis of U.S. crayfish life history studies and recommendations from the Southeastern U.S.
Crayfish Biologists Working Group indicate that, when possible, crayfish life history studies should encompass at
least two years of study to account for interannual variation in timing of life cycle events due to variable weather,
temperatures, stream flows, etc. A study is currently underway that will provide only one year of life history data
on C. maculatus. The goal of this proposed project is to complete a second year of that study. Specifically, we
will describe these populations’ life cycles by collecting data on timing of reproductive-related events, size/age at
sexual maturity, realized fecundity, egg size, and timing of recruitment of juveniles. We will also collect
supplemental data on traits important to population management such as molting, sex ratios, size structure,
maximum body size, longevity and growth.
Expected Product: We will provide a final report detailing the life history of C. maculatus that will be
used by managers in MDC and other agencies (e.g., U.S. Forest Service, U. S. Fish and Wildlife Service,
MO Department of Transportation, etc.) in conservation planning and management.
Approach: We will conduct monthly life cycle sampling for 12 months at two stream reaches (on two streams)
in the Meramec River drainage. Diel sampling to collect as many C. maculatus as possible by sampling likely
habitats will be conducted using kick-seining and turning large rocks.
Data recorded for captured crayfish will include sex, carapace length (CL), evidence of recent molting,
male reproductive form, and indications of female reproductive activity such as presence of eggs, hatchlings,
active glair glands, mucilaginous sperm plugs indicating mating, and copulation. Realized fecundity of ovigerous
females will be estimated by counting abdominal eggs in the field. A subset of ovigerous females will be
transported alive to the laboratory where a random sample of 10 eggs from each female will be used to estimate
mean diameter, and developmental progression of remaining (attached) eggs will be observed/described. When
females bearing hatchlings are collected in the field, hatchlings will also be counted and measurements taken on a
small random sample.
We will monitor about 90 C. maculatus that were previously captured and marked with individuallycoded PIT-tags at one study site. Tagged crayfish will be periodically recaptured and CL data used to monitor
growth and supplement size structure and longevity analyses. Pit-tag retention will be estimated via experiments
at the University of Missouri Campus.Water temperature will be recorded continuously at both sites using two
remote Tidbit_v2 temperature loggers as an additional means to evaluate life cycle patterns. Temperature data
will be downloaded each month during crayfish sampling events. We will conduct nocturnal and diurnal
sampling with baited traps to determine if C. maculatus appears to be more active during one of these periods.
Descriptive summary statistics and frequency histograms will summarize temporal life cycle patterns, and
those patterns will be superimposed on calculated mean (and ranges) monthly or seasonal water temperature data.
MDC biometricians will be consulted on any analyses involving inferential statistics. CL-frequency histograms
and PIT-tag data will be used to evaluate size structure, growth and longevity. Sex ratios (M:F) will be calculated
for each month or season and tested for significance against the null hypothesis of an equal 1:1 ratio with chisquare (χ2) tests. Percent of crayfish exhibiting indicators of reproductive activity will be calculated for each
month or season, and mean sizes (and ranges) will also be calculated. Relationships between CL and realized
fecundity will be explored using correlation or regression techniques.
If a WDF grant is provided, monies will be transferred as a cooperative grant to the MCFWRU to support
a contract technician that will work with MDC staff in the field and conduct lab work and data
summaries/presentation (tables, figures). MCFWRU will supply some equipment (e.g., PIT tags, tag reader, etc.),
supplies and staff time as “in-kind” contributions (see table).
Budget Table:
Category
Amount
Requested
Contract or
Agreement
$ 24,098
Cooperative
Agreement
Equipment
$0
Expenses
$0
Personnel Service
(Labor)
Non-MDC/Partner In-Kind Support
Value
$ 0A
Entity
MCFWRU
-
$ 12,360B
MCFWRU
-
-
-
$ 24,098
$ 12,360
MCFWRU
Total
A
Employees of the MCFWRU are not permitted to include their time in dollar values as part of “in-kind” services
estimates. However, it should be noted that at least two employees of the MCFWRU (listed as co-investigators
above) will be providing significant time and expertise to this study.
B
MCFWRU will provide PIT-tagging equipment, laboratory facilities/equipment (living streams, etc.).
Effect of Reduced or No Funding on Proposed Project: It is generally accepted that such life history studies
should encompass a minimum of two years to account for normal interannual variation in timing of life cycle
events due to fluctuating temperatures and stream flows. Without the year-round technical assistance requested in
this proposal, MDC will be unable to conduct a 2nd year of sampling and thus completion of a thorough and
representative life history study of Freckled Crayfish. No funding will result in the project not going forward
beyond the first year.