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The yellow perch, (Perca flavescens), is an important commercial and sport fish in Indiana waters of Lake Michigan. The population is currently managed by temporary restrictions of commercial harvest. A computer simulation model was developed to examine the effects of various constant harvest quotas and alewife densities on yellow perch relative numbers.Model design is based on the SLAM II simulation language incorporating a FORTRAN biological subroutine. The age-structured population model includes measured or predicted biological characteristics of the dynamic pool model. Recruitment is based on a preestablished three-dimensional Ricker stock-recruitment function including alewife (Alosa pseudoharengus) species interaction as a constant or stochastic factor. Sex-specific natural mortality rates were established through life history parameter analysis and the von Bertalanffy growth factors. Density-dependent growth is incorporated into each year of a model run and fluctuates with the simultaneous density of fish. Constant levels of commercial harvest ranging from 0 to 700,000 kg were used in 20-year forecasts. Initial conditions for model runs were 1984 and 1994 trawl CPUE levels when yellow perch were at high and low levels, respectively according to standardized sampling. Response variables were examined as mean catches over each forecast length and included: age 2 fish, spawning stock (z 190 mm), and total catch > age 1.Alewife densities had a tremendous impact on mean catches of the response variables. Highest catches under any forecast period occurred when alewife was considered absent from the system. Catches declined as alewife density was increased as a 20-year constant under each harvest regimen.Catches of spawning size fish were maintained at highest levels for all forecast periods when harvest was set to zero. Catches of young fish were moderate with this harvest regimen if initial catch conditions were high such as in 1984. Catches of young fish were always higher in the absence of a commercial fishery if initial catch conditions were low such as in 1994. Low to moderate harvest quotas could maintain moderate levels of young fish for the forecast length if initial model conditions were high. However, these quota levels for the 1984-2004 forecast length resulted in lower mean catches of spawning size fish as compared to the no commercial fishery regimen. The best case scenario for all response variables when initial catch conditions were low was under a no commercial harvest regimen. / Department of Biology

I determined differences in yellow perch gill-net catch-per-unit-effort (CPUE) at two depths (10 and 15 m) in the Indiana waters of Lake Michigan during June, July, and August from 1989 to 2006. I evaluated the abiotic factors of water temperature, water clarity, wave height, and wind direction to determine whether they influence the differences in yellow perch CPUE. This study suggests that yellow perch in southern Lake Michigan may select habitat based on water temperature during the summer, moving in response to thermocline changes. We also evaluated mortality rates for two distinct periods (1984-1994 and 2000-2007) in order to identify the response of the population to changes in exploitation. Yellow perch during 1984-1994 (high exploitation) and 2000-2007 (low exploitation) displayed an increase in mortality for fish of harvestable size. In addition, during 2000-2007 (low exploitation) we identified that female yellow perch reached exploitable size earlier in life than males. / Department of Biology

A computer simulation model was developed to examine the effects of various levels of alewife densities, harvest, and bycatch rates on yellow perch Perca flavescens relative densities in Indiana waters of Lake Michigan. The model utilized STELLA® Research software to develop the age-structured population model to include measured or predicted biological characteristics of density-dependent growth, recruitment, and mortality.The model was validated by simulating historically documented yellow perch catch per unit effort (CPUE) from 1984 - 1998. A strong linear relationship (R2= 0.70) between the model predicted CPUE values and the actual CPUE values was found. Twenty year model projections were performed using 1998 yellow perch trawl CPUE as starting values. Alewife abundance was established as either constantly high, constantly low, or allowed to fluctuate randomly and forecasts made used the average of 100 runs. Harvest was imposed on the yellow perch population at 20, 40, and 60% rate levels for fish >_ 200 mm coupled with bycatch at20, 40 and 60% rate levels for fish ranging from 165 - 200 mm.Alewife abundance was the major factor determining the relative abundance of the yellow perch population. On average, constantly high alewife abundance with no harvest or bycatch resulted in projected continuing suppression of yellow perch abundance from 1998 levels. The model predicted the population to rebound using constant low and random alewife abundance with no harvest or bycatch to approximately 1,100 fish/h and 700 fish/h, respectively.The model revealed harvest to have a generally negative impact on the yellow perch population. Increasing harvest and bycatch rate levels resulted in the suppression of projected increases in yellow perch relative abundance. Additionally, increasing harvest and bycatch rates resulted in greater predicted declines in yellow perch abundance. / Department of Biology

Metal-contamination of lakes simplifies food webs and reduces the efficiency of energy transfer to top trophic organisms, such as yellow perch (Perca flavescens). Benthic invertebrate community composition and yellow perch diet, growth and activity levels from lakes along a metal-contamination gradient were used to assess the importance of a naturally diverse prey base for maintaining energy transfer to growing fish, and how this is disrupted by metal-contamination. As perch grow larger, they shift their diet to larger prey; otherwise, the activity costs of foraging for many, small prey, instead of a few large prey, become too high and the fish stop growing. Metal contaminated lakes have less diverse zoobenthic communities, particularly the lack of large bodied invertebrate taxa, forcing perch to rely on smaller benthic prey. Perch from metal-contaminated lakes display slow growth and poor condition during benthivory. Estimates of fish activity, using the activity of the glycolytic enzyme Lactate dehydrogenase in perch white muscle tissue as a proxy, suggest that diet shifts to larger prey lower activity costs and may explain how diet shifts maintain growth efficiency as perch grow larger. Perch from metal-contaminated lakes cannot benefit from the energetic advantages of switching to larger prey and thus exhibit poor growth.

No description available.

Individuals within fish populations differ in many traits, such as sex, life-history, habitat residence, diet, and morphology. Such trait differences among individuals (i.e. intra-population variation) may be greater than the differences among populations (i.e. inter-population variation). My dissertation examines intra-population variation, with a focus on trophic relationships and morphology; as well as how variation in these attributes may reflect differences in bioaccumulation of contaminants. The second chapter of my dissertation examines the influence of spatial-temporal variation on the trophic structures of round goby (Neogobius melanstomus) and two age classes of yellow perch (Perca flavescens) within Saginaw Bay, Lake Huron. Using stable isotope ratios (δ13C, δ15N, δ2H, δ18O) and stomach contents as trophic indicators, I examined variation of diets. I found that spatial variation had a greater impact on diet indicators than both annual and seasonal variation. This spatial variation could represent a form of compartmentalization within the community of fish residing in Saginaw Bay, and could provide stability to the community. Chapter three of my dissertation examines intra-population variation in yellow perch morphology through a series of mesocosm experiments. My first mesocosm study determined that yellow perch could be experimentally manipulated to display divergent morphologies using simulated habitats, specifically pelagic and littoral habitats. Following this experiment, I focused on specific environmental drivers (structure, prey resources, and predation risk) as possible influences on yellow perch morphology. Within experimental pools, I exposed yellow perch to one of four treatments (an open pool, a structured pool, pools with chironomid prey resources and pools with a perceived, olfactory, predation risk) in the summer of 2015. Following exposure to these treatments I examined the morphological changes in yellow perch in magnitude and direction. I observed that while each treatment induced some difference in morphology, the open and structured treatments had the greatest magnitude of difference. I repeated the open and structure treatments during the following summer (2016). Again, I found that structure and open morphologies could be induced by my mesocosm treatments, but also observed that shapes differed from the previous year’s structure and open treatments. Finally, my fourth chapter examined how variation in trophic niches and morphology may reflect variation in contaminant concentration of fish in their natural environment. In this chapter, I extended my work with yellow perch to also include black crappie (Pomoxis nigromaculatus) and examined fish from 5 northern Indiana glacial lakes. Using model inference techniques, I found that variation in mercury was closely associated with not only fish total length, but also stable isotopes (δ13C and δ15N) and morphology. Interestingly, morphology-related variables of both species were strong predictors of mercury concentration in fish, following total length. Together, the chapters within my dissertation highlight the importance of considering intra-population variation, in which local factors such as habitat conditions and prey availability can influence individual variation in trophic structuring and morphology. These in turn may reflect other attributes of interest, such as the accumulation of contaminants.

Elucidation of habitat and resource use patterns is important for facilitating sustainable management of fisheries. Discrete habitats in large aquatic ecosystems may offer distinct resources and differentially affect performance. Movement of organisms and organic materials links these habitats and potentially leads to spatially complex trophic pathways between basal resources and consumers. Habitat and resource use are commonly explored via two common methods: stable isotopes and morphometric analysis. The first research chapter of this thesis employed both methods to investigate seasonal habitat use of yellow perch <i>Perca flavescens</i>in eastern Lake Michigan and connected waterbodies known as drowned river mouth (DRM) lakes. Landmark-based geometric morphometrics was used to compare shape differences among habitats. Stable isotopes of ambient water, otoliths, and soft tissues were compared to differentiate among habitats. Both methods provided evidence of resident nearshore Lake Michigan fish, resident DRM lake fish occupying the littoral zone, and transient Lake Michigan fish occupying the profundal zone of DRM lakes. The majority of transient Lake Michigan fish moved into the profundal zone of DRM lakes in the fall. These results support previously published genetic data of distinct populations of yellow perch in eastern Lake Michigan and connected waterbodies. The second research chapter of this thesis also employed stable isotopes and morphometric analysis, but to investigate the consistency of resource use of age-0 yellow perch in Saginaw Bay, Lake Huron. These methods served as long-term diet indicators, as compared to short-term stomach contents analysis. Both stable isotopes of soft tissues and morphometric analysis showed spatial consistency in variation among sites. Fish from the two sites closer to the tributary input had higher δ¹⁵N values and more fusiform bodies, while fish from the third site further away from the tributary had lower δ¹⁵N values and were deeper-bodied. This spatial variation supports stomach content analysis of age-0 yellow perch from a previously published study. δ¹³C ratios displayed annual variation, and while inconsistent with stomach content analysis, was consistent with available prey items. The findings from this study suggest that young yellow perch in Saginaw Bay have limited movement and forage in a similar area to where they were collected. Previous studies have found discrepancies among indicators and have cautioned generalization of trophic relationships when only relying on a single metric. Agreement between complementary techniques provided additional support to previously-published genetic results and stomach content data, and thereby helped more fully describe habitat use by yellow perch in these systems.

Yellow perch, Perca flavescens (Mitchill), were collected by trawling and gillnetting in Indiana waters of Lake Michigan near Michigan City, Indiana. Sampling was conducted during the months of June, July and August from 1984 through 1986.Growth rates and length-weight relationships were found to be considerably lower than those reported previously. Males declined 38 mm at age I, 55 mm at age II, 56 mm at age III and 35 mm at age IV comparing 1986 to 1976. Females showed similar declines for the same period at 40 mm for age I, 58 mm at age II, 66 mm at age III and 53 mm at age IV. The primary reason for the decrease in growth appears to be due to the current high population density of yellow perch in Indiana waters of Lake Michigan.Maturation of males for 1986 appears to be slower than that of 1984. All male perch were mature by age III in 1984. However, only 68x of the males were mature at the same age in 1986. In 1984, 94% of the females were mature by age IV while 86% were mature at the same age in 1986.Differences in maturation rate may be a reflection of the reduced growth rates. Size at maturity was found to be similar for both sexes in 1984 and 1986. All females were mature by 230-239 mm in 1984 and 220-229 mm in 1986. All male perch were mature at 180-189 mm in 1984 and 220-229 mm in 1986.Total estimated average annual percent mortalities of 79, 58, 66 and 55 were calculated for combined sexes from age composition analyses end trawl catch data for 1976 and 1984-86. Yellow perch production for 100 fish was estimated for June through August using the Allen curve method. Biomass of substock ( <130 mm), stock ( >129 mm) and quality fish (200 mm or larger) were estimated using Proportional Stock Density to investigate population structure. The Allen curve biomass models were modified to more accurately reflect the trawl catch density data as an index of population changes in 1976 compared to 1984-86. Theoretical biomass for the substock component increased 23 fold from 1976 to 1986. Biomass of the stock sized fish was estimated as 15 times greater in 1986 compared to 1976. Quality fish biomass varied from year to year with the average for 1984-86 estimated as 14 times greater than 1976. The most apparent factor now influencing deterioration of growth and resultant quality of the population is decreased mortality/increased survival with increase in biomass. If the low mortality rates observed for 1984-86 remain unchanged, the data indicate continued population density increases will result in even lower growth rates, and a population dominated by a higher percentage of small, non-quality fish.Food habit analyses for 1984 were compared to a diet study of yellow perch in 1972 for the study area. Zooplankton increased from 0.4x in 1972 to 9% of the volume in 1984 for 100-175 mm perch. This trend may reflect an increase in zooplankton populations in response to the population decline of the planktivorous alewife. Young-of-the-year yellow perch made up 85% of the stomach volume for 176-225 mm perch in 1984 while none were found in samples for 1972. This clearly shows yellow perch are resorting to cannibalism resulting from excessive intraspecific competition.Diet analyses by month revealed alewife eggs were moat important during peak abundance in June and July. Yellow perch (YOY) and Pontocoreia affinis became important during August. Analysis by size interval showed zooplankton and insects (primarily Chironomidae) were important to the diet of perch in the 30-59 mm (YOY) size interval. Copepoda were important by percent volume until approximately 60 mm when the zooplankton component switched to Cladocera. Data for 60-119 mm (age I+) fish indicates alewife eggs were important during June but insects became increasingly more important during July and August. Diversity in food items consumed diminished with increase in size as diet of 120-159 mm (age II+) yellow perch consisted largely of fish. Increases in percent volume of rainbow smelt in June and July, and Y0Y perch in August for age II+ and older perch compared to younger/smaller fish may be related to increased capture success. Diet of fish larger than 160 mm (age III+ and older) consisted almost entirely of rainbow smelt and Y0Y yellow perch.Ball State UniversityMuncie, IN 47306

As a result of the legacy of industrial contamination over the last century, areas of sediment deposition in the St. Lawrence River at Cornwall, ON, contain high concentrations of mercury (Hg). The popular sport-fish species, yellow perch (Perca flavescens) and walleye (Sander vitreus) have been found to contain mercury concentrations exceeding Ontario Ministry of Environment consumption guidelines. Interestingly, a paradox exists between two contaminated sites – despite elevated sediment Hg concentrations at Zone 2, fish from Zone 1 contain higher Hg concentrations. Further research has indicated that these patterns of Hg were not attributed to growth rate, condition factor, diet composition, or trophic position of yellow perch. Rather, Hg concentrations in yellow perch may be described by the heterogeneity of prey contamination and fish bioenergetics. As a result of the paradox between total Hg (THg) concentrations in sediments and biota between two contaminated sites, it was necessary to examine the benthic invertebrate community and how it may transfer Hg from sediments to yellow perch. This apparent paradox now extends to all prey items, since prey items from the stomach contents of yellow perch caught in Zone 1 were significantly more contaminated than those of Zone 2. Use of δ15N and δ13C, measures of trophic position and energy source, respectively, indicated that prey selection, but not food chain length, may also be an important factor in explaining the variation in Hg burdens in yellow perch. Small-scale patterns of biomagnification, as shown by a comparison of δ15N and logTHg, indicated that the rates of biomagnification were similar among zones, but the amount of THg present at the base of the food web was twice as high at Zone 1 as at other contaminated sites. Overall, the relative importance of vertical and horizontal food web structure changed spatially and temporally, highly influencing THg concentrations of prey items and yellow perch. / Thesis (Master, Biology) -- Queen's University, 2007-08-02 08:02:40.26