Inland Fisheries Research Unit

South Canal, OH, United States

Inland Fisheries Research Unit

South Canal, OH, United States

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Roy E.D.,Louisiana State University | Martin J.F.,Ohio State University | Irwin E.G.,Ohio State University | Conroy J.D.,Inland Fisheries Research Unit | Culver D.A.,Ohio State University
Ecological Engineering | Year: 2011

The objective of ecological engineering is to design sustainable ecosystems that integrate human communities and their natural environment for the benefit of both. In this paper, we illustrate how social-ecological modeling can be used as a tool to clarify this objective at a landscape scale for freshwater systems. Coupled social-ecological systems (SESs) are open, dynamic systems subject to both ecological and socioeconomic perturbations. Here we demonstrate the interactive effects of social and technological uncertainties on SES dynamics over time. Additionally, we integrate research on ecosystem stability, social-ecological modeling, and ecological engineering to offer guidance for research at the human-environment interface. Based on a case study of Lake Erie's Sandusky watershed, we use an integrated human-biophysical model to investigate the influence of two parameters on SES dynamics: (1) regional societal preferences that impact watershed management and (2) technological innovation that alters agricultural nutrient efficiency. Our results illustrate ways in which SES dynamics and optimum management strategies depend on societal preferences within the region, indicating a key area of uncertainty for future investigation. As guidance for SES restoration, our model results also illustrate the conditions under which technological change that increases nutrient efficiency on farms can and cannot create a win-win, or increase both human welfare and SES resistance to eutrophication simultaneously. Using these results, we elucidate the value of ecological engineering and offer guidance for assessments of ecological engineering projects using social-ecological modeling. © 2011 Elsevier B.V.


Zweifel R.D.,Inland Fisheries Research Unit | Landis A.M.G.,Ohio State University | Landis A.M.G.,Auburn University | Hale R.S.,045 Morse Road | Stein R.A.,Ohio State University
Transactions of the American Fisheries Society | Year: 2010

We parameterized and evaluated a bioenergetics model for saugeye (walleye Sander vitreus × sauger S. canadensis) by using laboratory experiments in an effort to improve predictions of prey consumption. First, we measured daily prey consumption rate and growth of age-0 and age-1 saugeyes fed two daily rations (ad libitum and 50% of maximum) at five temperatures ranging from 10°C to 28°C. Additional experiments quantified routine respiration rates and waste losses for three ages of saugeye (ages 0, 1, and 2) at five temperatures ranging from 10°C to 28°C. Mean daily rates of prey consumption (g · g -1 · d -1) by saugeyes increased from 10°C to 25°C, declining at 28°C. Respiration rates (g O 2 · g -1 · d -1) increased over the entire range of water temperatures. Waste losses were minor for saugeyes as egestion averaged 3.5% of consumed energy and energy lost via excretion was 4.5% of assimilated energy. We evaluated the accuracy of bioenergetics model predictions of saugeye prey consumption using daily prey consumption and corresponding growth data from our first set of experiments. Model estimates of prey consumption rates (g · g -1 · d -1) closely followed observed trends, providing reasonable estimates of cumulative prey consumption across temperature and fish size. The saugeye model provided improved estimates of consumption compared with a model published for walleyes (Kitchell et al. 1977), especially when water temperatures were in excess of 25°C. The differences we observed in predictive performance between the two models resulted from higher thermal optima for saugeyes compared with walleyes, and waste constants for saugeyes were two to three times lower than those calculated from the walleye model. These differences may largely be responsible for the walleye model's overestimation of consumption. Saugeye thermal optima are warmer than those of either parent species, and saugeye is better suited for warm, productive midwestern U.S. reservoirs. The saugeye model developed herein will improve the ability of managers to more accurately predict the consumptive demand of in situ saugeye populations and better tailor stocking rates to match available prey biomass. © American Fisheries Society 2010.


Guinand B.,Michigan State University | Guinand B.,Montpellier University | Page K.S.,Michigan State University | Page K.S.,Inland Fisheries Research Unit | And 2 more authors.
Environmental Biology of Fishes | Year: 2012

Humans have played a significant role in reducing levels of genetic diversity and differentiation of many teleost fishes, leading to homogenization across biological entities. We compare patterns of historical and contemporary genetic structure for three sympatric Great Lake's lake trout (Salvelinus namaycush) morphs (lean, siscowet, and humper) that differ in patterns of habitat occupancy, susceptibility to overfishing and predation by invasive sea lamprey (Petromyzon marinus). Differential susceptibilities to overfishing and predation were expected to result in different impacts to levels of genetic diversity loss for each morphotype. Genetic data was collected for samples at three points in time: 1948 (pre-collapse), 1959 (collapse) and 1990s (current), corresponding to periods of intensive fishing, mortality due to lamprey and recovery, respectively. The lean morph preferentially targeted by the fishery and recognized as highly preyed upon by sea lamprey was more highly impacted genetically than other morphs, as evidenced by greater loss of genetic diversity first during the period of overfishing, then during the period of high sea lamprey abundance once the fishery collapsed. The siscowet morph also experienced genetic bottlenecks during the period of overfishing (pre-collapse period). Results indicate significant levels of genetic differentiation among morphs historically prior to declines in abundance and also among contemporary populations, suggesting that periods of population decline and resurgence in abundance and distribution did not result in loss of genetic distinctiveness among morphs. © 2012 Springer Science+Business Media B.V.


Page K.S.,Inland Fisheries Research Unit | Zweifel R.D.,Inland Fisheries Research Unit | Carter G.,District | Radabaugh N.,District | And 4 more authors.
North American Journal of Fisheries Management | Year: 2012

Angler surveys are reliant on the ability of anglers to accurately report various aspects of their fishing trips. Misidentification of sport fishes has been postulated as a source of error among angler surveys but has received little attention. We evaluated the overall ability of anglers to identify sport fishes common to Ohio and the potential impacts on catch estimates derived from angler surveys. During angler surveys conducted on lakes and reservoirs (2007, n = 34) and Ohio River tailwaters (2010, n = 3), anglers were presented with artist-rendered images of 18 different sport fishes common to these waters. Anglers (lake and reservoir, n = 2,442; Ohio River, n = 458) were asked to identify sport fish by their common name. On average, anglers correctly identified sport fishes 42% of the time, but accuracy varied widely among species (lake and reservoir, range = 4.4-85.1%; Ohio River, range = 9.4-71.8%), with greater accuracy exhibited for the most common species (e.g., largemouth bass Micropterus salmoides). However, by grouping angler responses into species groups (e.g., black bass Micropterus spp., sunfish Lepomis spp.) angler identification of sport fishes was more reliable (lake and reservoir, mean = 83.4%; Ohio River, mean = 83.8%). Using these estimates of angler accuracy, we simulated the potential error in sport fish catch estimates using data from an angler survey conducted at one Ohio reservoir. These results suggested that misidentification error may result in a substantial error in catch estimates. A survey of North American fisheries management agencies regarding angler surveys and angler sport fish identification revealed that the majority of agencies group similar species for analysis and cited species misidentification by anglers as the primary reason for doing so. © American Fisheries Society 2012.


Filbrun J.E.,Ohio State University | Filbrun J.E.,University of Southern Mississippi | Conroy J.D.,Inland Fisheries Research Unit | Culver D.A.,Ohio State University
Lake and Reservoir Management | Year: 2013

Grand Lake St. Marys, hereafter Grand Lake, is a large shallow reservoir in western Ohio that has become hypereutrophic in recent decades owing to external phosphorus (P) loading. To restore water quality in Grand Lake, managers must decide whether to reduce external P loading from tributaries or continue to reduce internal P loading from sediments using aluminum sulfate additions. To help managers identify the most effective strategies for water quality improvements in Grand Lake, we quantified the reservoir's seasonal P dynamics using tributary and in-reservoir P measurements during 2009-2011. We also tested the short-term effects of reduced external P loading on Grand Lake's water quality using a pond experiment performed at the adjacent St. Marys State Fish Hatchery. The highest P concentrations in Grand Lake (1660, 391, and 311 μg/L in 2009, 2010, and 2011, respectively) occurred in summer when external P loads from tributaries were minimal, suggesting internal P release from sediments was the major source of P to fuel cyanobacterial blooms. Results from our pond experiment showed that decoupling the reservoir from external P loading during summer months does not improve short-term water quality. We conclude that external P loading during winter and spring, coupled with internal P loading from sediments during summer, drive the extremely high P concentrations in summer that support dense cyanobacterial blooms. Long-term improvement in Grand Lake water quality will first require major reductions to the external P loads from tributaries, followed by manipulations to reduce internal P loading from sediments. © 2013 Copyright Taylor and Francis Group, LLC.


Conroy J.D.,Ohio State University | Conroy J.D.,Inland Fisheries Research Unit | Boegman L.,Queen's University | Zhang H.,University of Michigan | And 2 more authors.
Aquatic Sciences | Year: 2011

Calculated hypolimnetic oxygen depletion (HOD) rates depend not only on environmental factors but also logistical ones. In particular, lack of understanding of the effects of weather in addition to how sampling effort determines calculated HOD rates complicates ecological understanding and environmental management of lake ecosystems. To better determine the roles of weather and sampling effort, we combined (1) weekly measurements of temperature and dissolved oxygen (DO) concentrations from seven stations in the Sandusky subbasin of Lake Erie's central basin during 2005, (2) contemporaneous measures of storm activity and tributary discharge, and (3) a two-dimensional coupled hydrodynamic, chemical, and biological model of Lake Erie to investigate (1) how increased storm activity and tributary discharge affected short- (daily) and long-term (seasonal) dynamics of hypolimnetic hypoxia, and (2) how spatial (number of sites sampled) and temporal (sampling frequency) sampling effort affected calculated HOD rates. Our model closely replicated field-observed DO dynamics. When comparing baseline modeled dynamics to those in a second simulation with twice the number of days with high winds, however, we found that with more storm activity (1) periods of entrainment became more frequent, (2) the hypolimnion was warmer, (3) thermal stratification occurred 1 month later, whereas autumnal turnover occurred at least 1 week earlier shortening the duration of stratification by 1-2 months, and (4) HOD rates increased 12%. Further, spatial and temporal sampling intensity also affected calculated HOD rates. Consequently, adequately quantifying actual HOD rates requires sufficient sampling effort and the particular role of weather should be assessed with rigorous field and simulation studies, especially if HOD rates are used to indicate management success. © 2010 Springer Basel AG.


Sindt A.R.,Iowa State University | Sindt A.R.,Inland Fisheries Research Unit | Pierce C.L.,U.S. Geological Survey | Quist M.C.,U.S. Geological Survey
North American Journal of Fisheries Management | Year: 2012

Effective conservation of fish species of greatest conservation need (SGCN) requires an understanding of species– habitat relationships and distributional trends. Thus, modeling the distribution of fish species across large spatial scales may be a valuable tool for conservation planning. Our goals were to evaluate the status of 10 fish SGCN in wadeable Iowa streams and to test the effectiveness of IowaAquatic Gap Analysis Project (IAGAP) species distribution models. We sampled fish assemblages from 86 wadeable stream segments in the Mississippi River drainage of Iowa during 2009 and 2010 to provide contemporary, independent fish species presence–absence data. The frequencies of occurrence in stream segments where species were historically documented varied from 0.0% for redfin shiner Lythrurus umbratilis to 100.0% for American brook lamprey Lampetra appendix, with a mean of 53.0%, suggesting that the status of Iowa fish SGCN is highly variable. Cohen’s kappa values and other model performance measures were calculated by comparing field-collected presence–absence data with IAGAP model–predicted presences and absences for 12 fish SGCN. Kappa values varied from 0.00 to 0.50, with a mean of 0.15. The models only predicted the occurrences of banded darter Etheostoma zonale, southern redbelly dace Phoxinus erythrogaster, and longnose dace Rhinichthys cataractae more accurately than would be expected by chance. Overall, the accuracy of the twelve models was low, with a mean correct classification rate of 58.3%. Poor model performance probably reflects the difficulties associated with modeling the distribution of rare species and the inability of the large-scale habitat variables used in IAGAP models to explain the variation in fish species occurrences. Our results highlight the importance of quantifying the confidence in species distribution model predictions with an independent data set and the need for long-term monitoring to better understand the distributional trends and habitat associations of fish SGCN. © American Fisheries Society 2012.


Sovic M.G.,Ohio State University | Denlinger J.C.,Inland Fisheries Research Unit | Fuerst P.A.,Ohio State University
North American Journal of Fisheries Management | Year: 2012

Hybridization and introgression continue to gain recognition as important issues in the management and conservation of native fishes. It is often necessary to identify hybrids in natural populations and to distinguish among individuals of various hybrid categories. Molecular methods are important for these purposes, and it is valuable if researchers have a range of molecular methods to apply, since each method has unique advantages and disadvantages. The determination of the best class of marker for a particular study depends on various factors, including the goals of the study, the resolution required, and the genomic and marker information already available for the taxa of interest. We modified a protocol to generate fluorescent randomly amplified polymorphic DNA (FRAPD) markers for hybridization studies. To our knowledge, this type of marker has not previously been used for hybrid identification. To demonstrate the utility of the modified methods, FRAPD markers were used to evaluate potential reproduction by saugeye (female walleye Sander vitreus × male sauger Sander canadensis) in a central Ohio reservoir. Our approach successfully generated a battery of diagnostic genetic markers that were used to test the hypothesis that young-of-year saugeye were later-generation offspring of saugeye cohorts previously stocked into the reservoir. Alternatively, the fish may have been immigrant first-generation saugeye from other sources. Data obtained from the FRAPD markers provided strong support favoring the alternative hypothesis. These methods provide a very useful tool for distinguishing between pure parentals and various classes of hybrid individuals, both in Sander spp. and in other taxa, offering a powerful and easily developed alternative to othermolecularmethods of generating informative genetic markers for hybridization studies. © American Fisheries Society 2012.


Kane D.D.,Defiance College | Conroy J.D.,Ohio State University | Conroy J.D.,Inland Fisheries Research Unit | Peter Richards R.,Heidelberg University | And 2 more authors.
Journal of Great Lakes Research | Year: 2014

Both abiotic and biotic explanations have been proposed to explain recent recurrent nuisance/harmful algal blooms in the western basin and central basin of Lake Erie. We used two long-term (>. 10. years) datasets to test (1) whether Lake Erie total phytoplankton biomass and cyanobacterial biomass changed over time and (2) whether phytoplankton abundance was influenced by soluble reactive phosphorus or nitrate loading from agriculturally-dominated tributaries (Maumee and Sandusky rivers). We found that whereas total phytoplankton biomass decreased in Lake Erie's western basin from 1970 to 1987, it increased starting in the mid-1990s. Total phytoplankton and cyanobacterial seasonal (May-October) arithmetic mean wet-weight biomasses each significantly increased with increased water-year total soluble reactive phosphorus load from the Maumee River and the sum of soluble reactive phosphorus load from the Maumee and Sandusky rivers, but not for the Sandusky River alone during 1996-2006. During this same time period, neither total phytoplankton nor cyanobacterial biomass was correlated with nitrate load. Consequently, recently increased tributary soluble reactive phosphorus loads from the Maumee River likely contributed greatly to increased western basin and (central basin) cyanobacterial biomass and more frequent occurrence of harmful algal blooms. Managers thus must incorporate the form of and source location from which nutrients are delivered to lakes into their management plans, rather than solely considering total (both in terms of form and amount) nutrient load to the whole lake. Further, future studies need to address the relative contributions of not only external loads, but also sources of internal loading. © 2014 International Association for Great Lakes Research.


Bridgeman T.B.,University of Toledo | Chaffin J.D.,University of Toledo | Kane D.D.,Defiance College | Conroy J.D.,Ohio State University | And 3 more authors.
Journal of Great Lakes Research | Year: 2012

The Maumee River is an important source of phosphorus (P) loading to western Lake Erie and potentially a source of Microcystis seed colonies contributing to the development of harmful algal blooms in the lake. Herein, we quantified P forms and size fractions, and phytoplankton community composition in the river-lake coupled ecosystem before (June), during (August), and after (September) a large Microcystis bloom in 2009. Additionally, we determined the distribution and density of a newly emergent cyanobacterium, Lyngbya wollei, near Maumee Bay to estimate potential P sequestration. In June, dissolved organic phosphorus (DOP) was the most abundant P form whereas particulate P (partP) was most abundant in August and September. Green algae dominated in June (44% and 60% of total chlorophyll in river and lake, respectively) with substantial Microcystis (17%) present only in the river. Conversely, in August, Microcystis declined in the river (3%) but dominated (32%) the lake. Lake phytoplankton sequestered <6% of water column P even during peak Microcystis blooms; in all lake samples <112μm non-algal particles dominated partP. Lyngbya density averaged 19.4gdrywt/m 2, with average Lyngbya P content of 15% (to 75% maximum) of water column P. The presence of Microcystis in the river before appearing in the lake indicates that the river is a potential source of Microcystis seed colonies for later lake blooms, that DOP is an important component of early summer total P, and that L. wollei blooms have the potential to increase P retention in nearshore areas. © 2011 Elsevier B.V.

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