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STUDY PERFORMANCE REPORT
State: Michigan
Project No.:
Study No.: 230695
Title: Northern Lake Huron coolwater fish
community assessment
Period Covered:
F-81-R-14
October 1, 2012 to September 30, 2013
Study Objective: To collect relative abundance, growth rate, and other biological data with which to
assess responses of the Les Cheneaux Islands region and the St. Marys River coolwater fish
communities to exploitation, management initiatives, and changing environmental and biological
conditions.
Summary: Yellow perch abundance in the Les Cheneaux Islands as indicated by the annual
gillnetting survey declined for the second year in a row but was still commensurate with the
improved overall abundance observed since recovery of that population in the mid-2000s.
Yellow perch metrics remained consistent with improved abundance including average age and
growth rates. Recruitment of yellow perch as indicated by gillnet catch rate of age-2 yellow
perch remained unchanged and overall strong. Northern pike were observed at record abundance
in 2012. Their growth rates, however, did not have any indication of stunting relative to the state
average growth rate. Yellow perch figured prominently in northern pike diet and this new
dynamic bears continued monitoring. The St. Marys River was surveyed in 2013 using
nonfederal funds. Evaluation of survey design was performed on both survey components and
reported on in the study renewal.
Findings: Jobs 1 through 7 were scheduled for 2012–13, and progress is reported below.
Job 1. Title: Survey design and coordination.–There were no changes to, or deviations from, the
study design in 2012-13.
Job 2. Title: Conduct surveys and process samples.–A total of six gill-net lifts spanning three
stations in the Les Cheneaux Islands were conducted in 2012. The 2013 survey will be conducted
during the first week of October and will be reported on in next year’s reporting cycle. Sample
collections and analysis were conducted as planned for the 2012 survey. The St. Marys River
was not slated for sampling in the current reporting cycle, but was surveyed in 2013 with project
partners using nonfederal funds. Under the 2014 study renewal, the St. Marys River is scheduled
for surveying again in 2017.
Job 3. Title: Maintain data – maintain databases.–Databases for the Les Cheneaux survey were
updated with information from the 2012 collections.
Job 4. Title: Analyze data, modeling.–Yellow perch abundance in 2012, as indicated by gill-net
CPUE, declined for the second year in a row but remained strong overall (relative to the past 8
years), since resurgence of this recreationally important species began in 2004 (Figure 1).
Resurgence is principally credited to management of double-crested cormorants in the area
(Fielder 2010, Ridgeway and Fielder 2012). Cormorant nesting numbers remained at
management target levels in 2012 (at or below 500 nests). Disconcerting was the decline of
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F-81-R-14, Study 230695
yellow perch abundance as indicated by gillnet CPUE at the Hessel station, which historically
proved to be the survey’s most indicative station.
Recruitment of yellow perch in the annual Les Cheneaux Islands survey is gauged on the gillnet
CPUE of age-2 fish. That rate was 28 age-2 yellow perch per lift in 2012. That represents the
fifth highest year class strength (for the 2010 year class) since the survey began. The age-2
yellow perch CPUE serves as a measure of year class strength before recruitment to the fishery,
but is still subject to two years of natural mortality (predation primarily) before measurement.
This was noted as an important limitation of this recruitment index by Fielder (2010). Other key
yellow perch metrics include trends in growth rates. Mean length of age-3 yellow perch was 196
mm in 2012, close to the state average rate of 188 mm. This suggests that abundance of yellow
perch in the area is commensurate with the available prey base and adult habitat. Average age of
yellow perch declined slightly in 2012 but was generally consistent with the improved mean age
since yellow perch recovery. Previously, mean age greatly declined at the peak of cormorant
abundance and was regarded as an indication of excessive mortality. Total annual mortality (A)
of yellow perch in 2012 was 55%.
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Yellow perch CPUE
120
100
80
60
40
20
0
1969 1973 1977 1981 1985 1989 1993 1997 2001 2005 2009
Year
Figure 1.–Geometric mean gillnet catch-per-unit-of-effort (CPUE) 1969–2012 in the Les
Cheneaux Islands. Error bound represent two standard errors of the mean.
The geometric mean northern pike gillnet CPUE during the 2012 survey was the highest ever
measured in the 44 year time series (although not statistically different from 5 other survey means
over time). It appears that northern pike have also rebounded in recent years. Growth rate as
indicated by age-3 mean length at capture had been declining consistent with increased abundance
but rose slightly in 2012 and was at the state average rate for that time of year. Yellow perch figured
prominently in the diet of northern pike that were examined for food habits. Given the apparent
abundance of both species, the relationship between northern pike and yellow perch bears
monitoring. Brown bullhead was another species exhibiting near record abundance in 2012. Walleye
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F-81-R-14, Study 230695
have never been abundant in this coolwater fishery. Recent trends suggest a small increase which
may reflect stocking performed by the Chippewa Ottawa Resource Authority in neighboring St.
Martins Bay. Cisco, abundance of which is reduced across Lake Huron, inhabit the waters of the Les
Cheneaux Islands although their presence can vary seasonally. Consequently assessment as part of
this survey series is difficult.
The St. Marys River survey is between reporting cycles and there are no new findings for that portion
of the Northern Lake Huron Coolwater Assessment. That survey was last reported on as Schaeffer et
al. (2011).
Job 5. Title: Write annual performance report.–The performance report has been written.
Job 6. Title: Write other reports.–Presently in review is a new manuscript that examines the survey
design of the St. Marys River. The manuscript will be submitted to a peer-reviewed journal for
publication as Schaeffer et al. (in preparation).
Job 7. Title: Evaluate surveys.–Both the St. Marys River Fish Community and the Les Cheneaux
Islands Fish Community surveys were reviewed in 2013. Both studies have been found to be
informative and to fulfill their objectives. Similar to concerns over SFR study 230466, we
believe the design in the Les Cheneaux Islands probably constitutes a cluster design by virtue of
the paired net sets. This would then necessitate a different formulation in the calculation of
standard errors. The Les Cheneaux Islands and St. Marys River surveys both lack an early
monitoring of reproductive success. The dependence on gillnets necessitates recruitment indices
be based on older age groups than desirable. Power analysis of the St. Marys survey suggests that
over-sampling is taking place and gillnet sets could be reduced. These potential design changes
have been taken under consideration for possible alteration and implementation in future surveys.
The full findings of this job were reported out as part of the renewal of Study 230695.
Literature cited:
Fielder, D. G. 2010. Response of yellow perch in Les Cheneaux Islands, Lake Huron to declining
numbers of double-crested cormorants stemming from control activities. Journal of Great Lakes
Research. 36: 207–214.
Ridgeway, M. S., and D. G. Fielder. 2012. Double-Crested Cormorants in the Laurentian Great
Lakes: Issues and Ecosystems. Pages 733 – 766 in W. W. Taylor, A. Lynch, and N. J. Leonard,
editors. Great Lakes Fisheries Policy and Management, second edition. Michigan State
University Press, East Lansing.
Schaeffer, J. S., D. G. Fielder, N. Godby, A. Bowen, L. O'Connor, J. Parrish, S. Greenwood,
S. Chong, G. Wright. 2011. Long-term trends in the St. Marys River open water fish
community. Journal of Great lakes Research 37:70-79.
Schaeffer, J. S., M. W. Rogers, D. G. Fielder, N. Godby, A. Bowen, L. O’Connor, J. Parrish, S.
Greenwood, S. Chong, and G. Wright. In Preparation. Designing long-term fish community
assessments in connecting channels: lessons from the St. Marys River. 19pp.
Prepared by: David Fielder
Date: September 30, 2013
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