Download 1997-98 New

F-53-R, Michigan
Study 484
New Study
1997-98
484. Name of Study: Population dynamics of yellow perch stocks in Michigan waters of Lake
Michigan.
A. Problem: Since 1990, yellow perch population density in Lake Michigan has declined, and the
age structure has shifted toward older fish due to an almost complete lack of recruitment (Great
Lakes Fishery Commission 1996). These trends have been documented in southern Lake
Michigan by various agencies (Indiana Department of Natural Resources, Illinois Natural
History Survey, Illinois Department of Natural Resources, Wisconsin Department of Natural
Resources, University of Wisconsin, University of Michigan, Ball State University, National
Biological Survey) using a variety of assessment gear (graded-mesh gill nets, seines, trawls, fyke
nets, larvae nets). Other evidence for the decline has come from monitoring sport and
commercial fisheries for yellow perch. Although the trends have been described, current data
sets do not seem sufficient to identify the causes of the decline or to suggest possible
management solutions to the problem. Furthermore, it is not clear if yellow perch density has
declined in Michigan waters of Lake Michigan because the Michigan Department of Natural
Resources has not conducted assessment netting since the late 1970s.
Efforts to understand yellow perch population dynamics in Lake Michigan are made difficult by
the size and complexity of the system. In addition, exotic fauna that have invaded or been
introduced into Lake Michigan (alewife, round goby, white perch, zebra mussel, spiny water
flea) have the potential to influence yellow perch (Barnhisel 1991; Schneeberger 1991). Yellow
perch management is further complicated by the number of state, tribal, and federal agencies
that have interests in and jurisdiction over Lake Michigan waters. Sport anglers and commercial
fishers also have conflicting opinions over use and management of the yellow perch
populations.
B.
Objectives: (1) To summarize pertinent existing data from state, federal, commercial, sport,
university, and private sources; (2) to conduct assessment netting to establish baseline data and
determine whether lack of recruitment and declining yellow perch numbers are problems in
Michigan waters; (3) to determine whether factors of fish health might be affecting abundance
or recruitment of yellow perch; (4) to reestablish a program of biological data collection for
sport-caught yellow perch; (5) to investigate discreteness of yellow perch populations in Lake
Michigan; and (6) to develop information and mathematical models from these data that will
allow managers to predict, with some predetermined level of certainty, the outcome of various
yellow perch management strategies.
C. Justification: Yellow perch are an important component of Michigan's sport fishery in Lake
Michigan. Between 1985 and 1994, an estimated 2,330,888 yellow perch have been caught by
anglers annually, more than any of the other species tabulated by the Michigan Department of
Natural Resources creel census (G. Rakoczy, MDNR, personal communication). Although
individual yellow perch are small relative to the other species, annual harvest of yellow perch
ranks third by weight behind chinook salmon and lake trout. Yellow perch are caught from
piers, small boats, and party boats, and as such are available to nearly all segments of the
F-53-R, Study 484 - 2
angling public. Commercial fishing for yellow perch was banned in Michigan waters in 1970,
in part because it was recognized that the value of yellow perch is maximized when harvested by
the sport fishery. Because populations inter-mix across state boundaries in the lake, it should be
the responsibility of all involved agencies to consider each other's interests and coordinate their
management strategies as much as possible.
Apart from their value to humans, yellow perch are an important part of the Lake Michigan
biological community. Yellow perch are an indigenous species that play an important role in
energy cycling and transfer, especially in the littoral zone.
D. Status: In southern Lake Michigan, yellow perch usually recruit to the sport fishery at age 4 for
males and 3 for females when they reach a size of around 7 inches (G. Rakoczy, personal
communication). Anglers catch yellow perch throughout the open-water season and whenever
ice conditions are suitable, especially in drowned river mouths (e.g., Pentwater, White Lake,
Muskegon Lake, Lake Macatawa). Catches are greatest when fish are concentrated prior to,
during, and right after spawning. Spawning usually occurs from late April through early June
with a peak in mid-May (Auer 1982).
Assessment netting in Indiana, Illinois, and Wisconsin waters has indicated that the last strong
year class of yellow perch occurred in 1988 in southern Lake Michigan. Plankton-net tows have
shown that relatively stable densities of larval yellow perch were produced from 1988 through
1993, but fell to virtually zero in 1994 for unknown reasons. Catches of young-of-the-year
(YOY) yellow perch have declined in both trawling and seining gear at least since 1990. Lack
of recruitment is believed to be responsible for declining catch trends in assessment gill nets and
trawls, and for a shift toward increasingly larger and older-aged perch in assessment,
commercial, and sport catches during the 1990’s (Great Lakes Fishery Commission 1996). It is
not known if yellow perch are exhibiting similar trends in Michigan waters.
Various historical data for yellow perch in Michigan waters of Lake Michigan are available, but
since 1985, Michigan DNR yellow perch data consist only of estimates of catch, effort and
limited biological data from the creel census. Length measurements and scale samples were
taken as part of the creel census from 1985 through 1992. These data have not been rigorously
examined. No biological data are available for yellow perch in Michigan waters after the 1992
creel census. Between 1985 and 1995, sport catches of yellow perch did not decrease in
Michigan waters, but fluctuated between 1.6 and 3.2 million fish per year. However,
recreational catch in Michigan waters in 1996 (approximately 800,000 fish) was the lowest yet
recorded. Given this sharp decline in catch, it is even more critical that we continue to monitor
the yellow perch population in Lake Michigan through the statewide creel survey.
Based on the current status of yellow perch populations, state agencies have banded together to
impose coordinated regulations. Beginning in 1995, daily sport bag limits for yellow perch were
reduced from no limit to 25 fish in Indiana and Illinois, from 50 to 25 fish in Wisconsin, and
from 100 to 50 fish in Michigan. The higher daily bag limit in Michigan was agreed to because
Michigan banned commercial fisheries for yellow perch in 1970. A 65% reduction from 1994
catches of yellow perch was imposed on commercial fisheries operating in Indiana, Illinois, and
Wisconsin. In addition, a general closure of the yellow perch fishery was put into effect during
the entire month of June in all Lake Michigan waters south of the 45th parallel. In 1997,
recreational yellow perch limits will be five fish in Wisconsin waters of Lake Michigan
(excluding Green Bay), 15 fish in Illinois and Indiana waters, and 35 fish in Michigan waters
F-53-R, Study 484 - 3
south of the 45th parallel. The June closure will remain in effect in Wisconsin and Illinois, and
commercial yellow perch fishing will no longer be permitted outside of Green Bay.
In addition to coordination of regulations, interagency cooperation also resulted in the formation
of a task group to address current yellow perch problems. Michigan DNR representatives are
and will continue to be active members of this task group.
Literature Cited:
Auer, N. A. 1982. Family Percidae, perches. Pages 581-648 in N. A. Auer, editor.
Identification of larval fishes of the Great Lakes basin with emphasis on the Lake Michigan
drainage. Great Lakes Fishery Commission, Special Publication 82-3, Ann Arbor,
Michigan.
Barnhisel, D. R. 1991. Zooplankton spine induces aversion in small fish predators. Oecologia
88:444-450.
Great Lakes Fishery Commission. 1996. Multi-agency yellow perch research initiative.
Yellow Perch Task Group, Lake Michigan Technical Committee.
Schneeberger, P. J. 1991. Seasonal incidence of Bythotrephes cederstroemi in the diet of
yellow perch (ages 0-4) in Little Bay de Noc, Lake Michigan, 1988.
E.
Procedure:
Job 1.
Review literature and summarize existing data.
In an effort to establish historical trends and identify potential factors affecting yellow
perch population fluctuations and recruitment, data will be sought from a variety of
sources including; a) commercial - catch records will be summarized from as far back
as possible to obtain perspective on historical population fluctuations; b) universities contacts will be established with universities other than those participating in the task
group. For example, Michigan State University has a long-running yellow perch data
set associated with their studies at the Ludington Pump Storage facility; c) private Consumers Power Co. has ongoing studies at various power plant locations (including
Ludington, Port Sheldon); and d) sport - angler clubs and charter associations. Of
interest from all these sources is anything relating to yellow perch catch, effort,
mortality, population fluctuations, discreteness, spawning areas, growth, health,
parasites, movement, economics, recruitment, size, age, or diet.
Job 2.
Conduct standardized assessment sampling.
Different types of fishing gear will be used in an effort to collect the various life stages
of yellow perch. The S/V Steelhead will deploy overnight gillnet (1 to 3.5-inch stretch
mesh nylon) sets to collect yearling and older yellow perch at four southern Lake
Michigan ports (Grand Haven, Saugatuck, South Haven, St. Joseph) in April. Nets
will be set perpendicular to the 10 and 20 m depth contours. The presence of
competitors and predators will be evaluated as factors with potential for influencing
F-53-R, Study 484 - 4
yellow perch recruitment. Similar data will also be collected in conjunction with
studies at the Ludington Pump Storage facility.
Trawling for YOY yellow perch will be conducted by District 9 and 12 personnel in
July and August using a semi-balloon nylon otter trawl having a 16-ft headrope and a
21-ft footrope. The body and codend of the net will be composed of 0.75-inch and
0.62-inch bar mesh, respectively, while the codend inner liner will be constructed of
0.25-inch stretch mesh. Ten-minute hauls will be made at depths from 1 to 5 meters at
each of the ports sampled in spring assessment netting. Catch-per-unit-of-effort will
be reported for all species collected. Beach seining will be conducted at intervals to
calibrate trawling with other state agency sampling procedures. Seine hauls will be
200-ft long parallel to the shoreline using a 50-ft long by 6-ft high nylon beach seine
with 0.25-inch mesh.
All yellow perch collected (all methods) will be counted, weighed, and measured. A
representative number of scales will be collected in 10 mm intervals to confirm ages.
Fish species that are considered potential competitors with or predators on yellow
perch will also be collected as they may provide important clues relating to
recruitment of yellow perch. Stomach samples of yellow perch and competitor /
predator species will be collected for diet analysis. Addition of species other than
yellow perch will provide an index of inshore fish populations not currently sampled
by other MDNR programs.
Other sampling (zooplankton collection, larval fish netting) will be conducted by
MDNR personnel as deemed necessary and where time permits. Some additional
sampling of yellow perch early life history stages and lower trophic levels
(phytoplankton, zooplankton, benthos) may also be conducted by graduate students or
on a contract basis as funding permits.
Job 3.
Investigate the potential impacts of disease on yellow perch populations.
Early Mortality Syndrome (EMS) has been found to be very detrimental to fry survival
of coho salmon, rainbow trout, and other species. Survival has increased dramatically
when these fry were treated with thiamine. EMS or other facets of fish health may be
influencing recruitment of yellow perch as well. To investigate these possibilities,
Fish Quality Laboratory personnel will collect mature male and female yellow perch
from Lake Michigan. Investigations will include thiamine treatments, tissue analyses,
blood sample work-up, and examination of yellow perch for internal parasites.
Wisconsin DNR is also investigating the possibility that EMS affects yellow perch
recruitment, both in Lake Michigan and in an inland lake that will serve as a reference
for Lake Michigan findings. Our analyses will be coordinated with State of Wisconsin
personnel for continuity of procedure.
Job 4.
Collect and analyze biological data from sport-caught yellow perch.
Data from the recreational creel will be collected at the five sites for which fisheriesindependent assessment data is available. At any given site, data will be collected
from up to 400 angler-caught yellow perch per month. For each fish, length will be
F-53-R, Study 484 - 5
measured to the nearest millimeter. Scale samples will be taken from below the lateral
line under the distal end of the pectoral fin. Permission from anglers will need to be
obtained to make a small ventral cut allowing examination of the fish's gonads to
determine sex and level of maturity. Maturity will be subjectively categorized on a
scale of 0 to 6 where 0 = unknown - gonads undeveloped to the degree that sex cannot
be distinguished, or gonads not examined; 1 = immature - sex can be distinguished but
gonads undeveloped; 2 = mature - gonads partly developed; 3 = mature - gonads well
developed; 4 = ripe/running - fish in spawning condition; 5 = spent - ovaries or testes
empty; and 6 = reabsorbing - fish that retain sex products past spawning season.
Similar data will be solicited from party-boat (charter) captains and from anglers
through something like the angler diary program. Twice each month, the charter
captains will be asked to record the lengths of every yellow perch caught during the
entire day. Alternatively, District 9 and 12 personnel will ride these boats at the same
intervals and record the desired data.
Yellow perch length and age data collected between 1985 and 1992 from Michigan's
creel census will be analyzed and compared to similar data from other agencies.
Job 5.
Investigate discreteness of yellow perch populations in Lake Michigan.
Discreteness of yellow perch populations will be determined through tagging, as well
as through comparison of growth rates, condition, and other physiological variables
among populations.
To be effective, tagging must be coordinated lake-wide and all state agencies must
participate. Tagging will be conducted during spring (when maximum stock
separation likely occurs), in conjunction with other agencies through the Lake
Michigan Committee Yellow Perch Task Group study. Yellow perch will be tagged in
Lake Michigan as well as connected drowned river mouths, to determine how fish in
these areas relate to populations in the main basin. Besides providing much needed
information on fish movements, growth, exploitation rates, and mixing of stocks, this
coordinated effort should serve as a model for future cooperative studies on the Great
Lakes.
Job 6.
Develop information and mathematical models related to yellow perch management
strategies.
Successful modeling of Lake Michigan yellow perch populations will require
collection of an expanded biological data set. Minimally, information on length,
weight, age, sex, maturity, egg production, diet, movement, harvest rates, and
predation is needed. This data will be collected in Jobs 1-5 (see above). Modeling
efforts will be aimed at investigating energetic tradeoffs for inshore fish populations,
predictability of yellow perch population fluctuations, and the influence of commercial
and recreational harvest on yellow perch populations.
Job 7.
Evaluate results, write reports, and develop future study plans for Michigan waters of
Lake Michigan south of the 45th parallel.
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Results of research will be presented in summaries to various MDNR and external
committees, annual progress reports, and peer-reviewed journals. Study plans will be
revised as necessary.
F.
Schedule:
Year
Work planned
1997-98
Job 1.
Job 2.
Job 3.
Job 4.
Job 5.
Job 6.
Job 7.
Review literature.
Conduct assessment sampling.
Investigate potential impacts of disease.
Collect and analyze creel data.
Investigate discreteness of perch populations.
Develop models.
Evaluate results, write reports.
1998-99
Job 1.
Job 2.
Job 3.
Job 4.
Job 5.
Job 6.
Job 7.
Review literature.
Conduct assessment sampling.
Investigate potential impacts of disease.
Collect and analyze creel data.
Investigate discreteness of perch populations.
Develop models.
Evaluate results, write reports.
1999-00
Job 1.
Job 2.
Job 3.
Job 4.
Job 5.
Job 6.
Job 7.
Review literature.
Conduct assessment sampling.
Investigate potential impacts of disease.
Collect and analyze creel data.
Investigate discreteness of perch populations.
Develop models.
Evaluate results, write reports.
2000-2001
Job 1.
Job 2.
Job 3.
Job 4.
Job 5.
Job 6.
Job 7.
Review literature.
Conduct assessment sampling.
Investigate potential impacts of disease.
Collect and analyze creel data.
Investigate discreteness of perch populations.
Develop models.
Evaluate results, write reports.
2001-2002
Job 1.
Job 2.
Job 3.
Job 4.
Job 5.
Job 6.
Job 7.
Review literature.
Conduct assessment sampling.
Investigate potential impacts of disease.
Collect and analyze creel data.
Investigate discreteness of perch populations.
Develop models.
Evaluate results, write reports.
Cost
2,704
27,975
16,223
13,519
10,815
6,759
6,759
F-53-R, Study 484 - 7
G. Geographical Location: Charlevoix Great Lakes Fishery Station, Charlevoix, Michigan; District
Offices; Fish Health Lab (Wolf Lake Hatchery); Ludington Pump Storage Facility; field sampling
locations.
H. Personnel: David F. Clapp, Fishery Research Biologist; crew of the S/V Steelhead; Fisheries
Division personnel at District offices and the Fish Health Lab.