Source: NORTH CAROLINA STATE UNIV submitted to
FISH RESPONSES TO BIOTIC AND ABIOTIC FACTORS AFFECTING BEHAVIOR, GROWTH AND SURVIVAL
Sponsoring Institution
State Agricultural Experiment Station
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0200457
Grant No.
(N/A)
Project No.
NC07257
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Oct 1, 2004
Project End Date
Sep 30, 2010
Grant Year
(N/A)
Project Director
Rice, J. A.
Recipient Organization
NORTH CAROLINA STATE UNIV
(N/A)
RALEIGH,NC 27695
Performing Department
Biology
Non Technical Summary
Excessive nutrient loading leads to low oxygen conditions in many aquatic systems, but the effects of these changes on fish populations are poorly understood. This study combines field and lab studies with computer modeling to evaluate how factors such as oxygen levels, temperature and food availability interact to affect fish distribution, growth and survival.
Animal Health Component
10%
Research Effort Categories
Basic
90%
Applied
10%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1350810107050%
1350812107050%
Knowledge Area
135 - Aquatic and Terrestrial Wildlife;

Subject Of Investigation
0810 - Finfish; 0812 - Fish habitats;

Field Of Science
1070 - Ecology;
Goals / Objectives
This project will enhance our understanding of the ways in which physical factors, biological interactions and behavior interact to affect the distribution, growth, survival and population dynamics of fishes. Main elements of the current research are focused on estuarine and reservoir systems, but the issues being addressed are related and applicable to other systems as well. 1. We will empirically quantify movements of juvenile spot (Leiostomus xanthurus) under high and low dissolved oxygen conditions in the Neuse River estuary, NC, using hydroacoustic telemetry. These data will be evaluated to determine the appropriate spatial and temporal scale and movement simulation approach necessary to adequately model the effect of water quality conditions on these fish. We will then use a spatially-explicit, individual-based fish response model to evaluate the potential effects of various typical and extreme water quality conditions in the Neuse River estuary on spot distribution, growth, and survival. 2. We will characterize the spatial and temporal distribution of temperature and dissolved oxygen, the size and species composition of forage fish, and striped bass growth and condition in a wide range of NC reservoirs. We will analyze these data in a bioenergetics modeling framework to determine the relative contribution of physical habitat constraints and forage availability to striped bass growth rates across this range of systems, and then apply the Ecopath-with-Ecosim ecosystem modeling approach to evaluate how various management alternatives would likely affect the rest of the reservoir fish community.
Project Methods
1. Hydroacoustic telemetry will be used to collect movement information on individual juvenile spot in the Neuse River estuary during different environmental conditions. Local water quality conditions will be synoptically recorded to characterize both available conditions and those experienced by individual fish. Based on analysis of these data we will adjust the time-step and spatial cell size used in our spatially-explicit individual-based fish response model. We will evaluate alternative approaches for simulating movement, including simple rule-based approaches, random-walk methods, optimization approaches, neural network and hybrid methods. "Rules" used to govern movement in response to environmental conditions are based on results of prior lab experiments. We will use the response model to evaluate how various representative water quality scenarios affect spot distribution, growth and survival. 2. Spatial and temporal distributions of temperature and oxygen will be mapped to determine availability of suitable habitat for striped bass in multiple NC reservoirs. Forage fish will be collected from each reservoir during late summer to determine the species composition and size distribution of available prey. Size and age data will be collected from a representative sample of striped bass in each reservoir to characterize the population age structure and to estimate the growth rate of each age class. An established bioenergetics model for striped bass will be used to determine the relative contribution of temperature-dissolved oxygen constraints and forage availability to the striped bass growth and condition observed in each reservoir. Diet composition used in the model will be determined from field diet samples, forage fish samples, and our prior work. Energy content of striped bass and their primary prey species will be estimated from size- and/or season-dependent relationships determined for each species during our current study. Observations from our current telemetry study in Badin Lake will be used to estimate the temperatures selected by striped bass from the range of temperatures and dissolved oxygen concentrations available throughout the year in each reservoir. Given these inputs the model will use size- and temperature-dependent physiological relationships to estimate patterns of prey consumption required to account for observed striped bass growth rates and condition in each reservoir. We will compare results from these simulations among reservoirs to look for relationships between striped bass performance and reservoir characteristics (which will span a wide range of temperature-dissolved oxygen conditions and forage availability). If such relationships are evident we will determine their implications for striped bass stocking or management options and/or identify any critical information that must be obtained to do so. An Ecopath-with-Ecosim ecosystem model will be parameterized for a typical Southeastern reservoir system using data from our previous work and the literature. Model simulations will be used to evaluate likely impacts on the reservoir community of various management scenarios.

Progress 10/01/04 to 09/30/10

Outputs
OUTPUTS: This project addressed issues of population dynamics, predator-prey interactions, energetic costs of habitat constraints, effects of hypoxia on fishes in reservoirs and estuarine systems, factors explaining variation in mercury contamination in fish tissue across NC, and impacts of invasive species in freshwater and marine systems. We used a combination of field work, lab experiments and simulation modeling to answer key ecological questions in each of these areas and applied our findings to real-world problems to provide insights and guidance for managers and policy makers. In addition to generating databases, analyses and models now being used by other researchers and policy makers in academia, state and federal agencies and NGOs, we disseminated our findings through 17 publications in the peer-reviewed literature, 48 presentations at state, regional, national and international conferences, and through presentations to various state and federal agency advisory committees. This project supported the training and education of 1 post-doctoral, 5 MS and 6 PhD students. PARTICIPANTS: Individuals: J.A. Rice, D.D. Aday, W.G. Cope, R.J. Borski, D. Buchwalter (PIs); J.K. Craig (post-doc); J. Thompson, D. Sackett, M. Brey, J. Godbout, J. Morris, L. Glass, Z. Feiner, B. Galster (graduate students), C. Russell, S. Sills, N. Jeffers, H. Dendy, B. Richardson, A. Bunch, T. Brown, J. Leonard, C. Gille, Z. Tait, D. Heithans, R. Spiedel, J. Dalrymple, J. Remmington, T. Averett, R. Rasmussen, A. Stephenson, M. Daugherty, R. Cooper, M. Wood, L. Garner, B. Noffsinger, S. Poland, S. Petre (hourly workers and technicians). Partner Organizations: NC Wildlife Resources Commission, NC Division of Water Quality, NC Division of Air Quality, NC Division of Public Health, NOAA Center for Coastal Fisheries and Habitat Research, University of Delaware, Duke Energy Co., Louisiana State University, Florida State University, University of Maryland, University of Southern Mississippi, Great Lakes WATER Institute, Colorado State University, University of Florida, University of South Carolina, Duke University. Collaborators and Contacts: D. Aday, R. Borski, J. Hightower, Craig Sullivan, NCSU Biology; G. Cope, D. Buchwalter, R.B. Bringolf, S. Mosher, NCSU Env. and Molecular Toxicology; T. Targett, U. of Delaware; K. Rose, Louisiana State U.; J.K. Craig, Florida State U.; R. Fulford, U. of Southern Mississippi; T.J. Miller, University of Maryland, F.P. Binkowski, Great Lakes WATER Institute, K. Bestgen, Colorado State U.; W. Pine, U. of Florida; Mark Hale, Jeff Deberardinis, NC Division of Water Quality; Mina Shehee, NC Division of Public Health; J. Govoni, K Shertzer, D. Cerino, J. Morris, NOAA Center for Coastal Fisheries and Habitat Research; R.L. Noble, H.C. Edwards, private consultants; B. McRae, C. Waters, K. Nelson, L. Dorsey, NC Wildlife Resources Commission; D. Caughlan, K. Baker, H. Barwick, D. Harrell, W. Foris, M. Abney, Duke Energy Co.; M.R. Bangs, J.M. Quattro, University of South Carolina; Eric Money, Duke University. Training or Professional Development: The project provided numerous training opportunities for graduate and undergraduate student employees and volunteers, post-docs and staff, NCWRC biologists, and Duke Energy biologists. TARGET AUDIENCES: Biologists and Staff Scientists in the NC Divisions of Water Quality, Air Quality, Public Health, and Marine Fisheries; NC Wildlife Resources Commission biologists; National Marine Fisheries Service and National Ocean Service scientists; NC sportfishing groups; Lake Norman Advisory Committee; NC Cooperative Extension agents; graduate and undergraduate students. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
In addition to the numerous post-doc and graduate students who were educated as part of this project and are now actively contributing to our society as researchers, educators and policy makers in their current careers, this project has had impacts in multiple areas. Reservoir Food Web Dynamics: Our black bass genetic and morphometric analyses produced a key that biologists can use to reliably differentiate largemouth and spotted bass and their hybrids. Our analyses of diet and habitat overlap between largemouth and invasive spotted bass provide strong evidence of competition between these two species, implicating introduced spotted bass as a factor in the decline of largemouth bass. Our analyses of white perch population dynamics in multiple reservoirs differing in productivity and time since invasion have given managers information on how this species affects invaded food webs, and the implications for sport fisheries. Based on our work elucidating effects of thermal and food availability constraints on striped bass, the NC Wildlife Resources Commission lowered the length limit on striped bass in Lake Norman, now understands causes of striped bass summer kills in this (and other) systems, and is developing a new, state-wide striped bass management plan. Effects of Hypoxia on Growth of Juvenile Estuary-Dependent Fishes: Our field, lab and modeling studies have documented the ability of estuarine fish to detect and avoid hypoxia, how their growth and survival are affected when they are exposed to it, and provided insights regarding hypoxia's cumulative impact on estuarine fishes. Factors Explaining Variation in Fish Tissue Mercury Content Across NC: Our analysis of previously existing data, combined with new field experiments, has allowed us to develop a model that explains 81% of the 30-100-fold variation in fish tissue methylmercury concentrations among species within and among waterbodies across NC. It also explains why fish near point sources (coal-fired power plants) actually have lower mercury concentrations than fish far from point sources, due to the ameliorating effect of locally-deposited selenium. In response to our findings the NC Divisions of Water Quality, Air Quality, and Inland Fisheries have modified their sampling plans to address these data gaps, and our results are being used by the NC Div. of Public Health to develop a more rigorous protocol for establishing fish consumption advisories. Dynamics and Consequences of the Lionfish Invasion on the Atlantic Cast: Results of our field collections, lab experiments and population modeling are a primary source of information that the National Marine Fisheries Service is using to develop its response to the lionfish invasion, predict its impacts, inform the public about the risks, and develop strategies for predicting and responding to other exotic species invasions in the future.

Publications

  • Morris, J.A. Jr, Shertzer, K.W., and Rice, J.A. 2011. A stage-based matrix population model of invasive lionfish with implications for control. Aquatic Invasions. 13:7-12. (Published online June 2010).
  • Sackett, D.K, Aday, D.D., Rice, J.A., Cope, W.G., and Buckwalter, D. 2010. Does proximity to coal-fired power plants influence fish tissue mercury? Ecotoxicology. 19:1601-1611.
  • Thompson, J.S., Rice, J.A., and Waters, D.S. 2010. Striped bass habitat selection in reservoirs without suitable summer habitat offer insight into consequences for growth. Transactions of the American Fisheries Society. 139:1450-1464.


Progress 10/01/08 to 09/30/09

Outputs
OUTPUTS: Reservoir Food Web Dynamics: We continued a 5-year study to evaluate effects of introduced species on a reservoir food web and their implications for management. Sampling was conducted in Lake Norman, NC, to track competitive and predator-prey interactions and habitat relationships. Genetic and morphometric analyses were used to identify juvenile and adult largemouth bass, spotted bass and their hybrids. Diet and habitat use were compared to determine the potential for competition between largemouth bass and introduced spotted bass. Sampling was conducted to evaluate the magnitude of predation upon, and competition with, newly stocked fingerling striped bass. Sampling was initiated in several additional reservoirs to evaluate the population characteristics of invasive white perch. Results were presented at a regional conference, shared with NCWRC biologists, and presented to the Lake Norman Advisory Committee. Effects of Hypoxia on Growth of Juvenile Estuary-Dependent Fishes: We used lab experiments to test three biological indicators of recent growth (RNA/DNA ratios in muscle tissue, plasma levels of insulin-like growth factor-I, and Hepatosomatic Index) for juvenile spot. We also monitored water quality conditions and sampled juvenile spot for growth indicator analyses throughout the summer in the Neuse River estuary and in marsh creeks that experience relatively high and low frequencies of hypoxic conditions. Results are being shared with other hypoxia researchers, and were presented at a national conference and at the NCSU Molecular Biotechnology Training Program Research Symposium. Factors Explaining Variation in Fish Tissue Mercury Content Across NC: To evaluate the effect of proximity to point sources on mercury concentrations in fish tissues we analyzed data on relevant water quality variables, as well as Hg and Se concentrations in sediments, benthos and fish from two trophic levels from 14 selected lakes across NC. We used our results to test and improve a statistical model we previously developed to identify the factors explaining Hg contamination in NC fish. Additional sampling was conducted on a subset of these reservoirs to evaluate the effect of fish size on mercury contamination. Results were presented at a national meeting, and we are also sharing our findings with the NC Divisions of Water Quality, Air Quality, and Inland Fisheries, and assisting them in revising their sampling plans accordingly. We have shared our findings with the NC Division of Public Health and are assisting them in developing a revised protocol for issuing fish consumption advisories. Dynamics and Consequences of the Lionfish Invasion on the Atlantic Coast: Results from histological analyses to determine the timing, frequency and magnitude of egg production were combined with data on growth and survival in various life stages to parameterize a stage-based matrix model of lionfish population dynamics, which has been used to evaluate the potential extent and impact of the lionfish invasion. Results are being disseminated extensively through NOAA websites and popular articles, and were presented at an international scientific meeting. PARTICIPANTS: Individuals: J.A. Rice, D.D. Aday, W.G. Cope, R.J. Borski, D. Buchwalter (PIs); J.K. Craig (post-doc); D. Sackett, M. Brey, J. Godbout, J. Morris, L. Glass, Z. Feiner, B. Galster (graduate students), C. Russell, S. Sills, N. Jeffers, H. Dendy, B. Richardson, A. Bunch, T. Brown, J. Leonard, C. Gille, Z. Tait, D. Heithans, R. Spiedel, J. Dalrymple, J. Remmington, T. Averett, R. Rasmussen, A. Stephenson, M. Daugherty, R. Cooper, M. Wood (hourly workers and technicians). Partner Organizations: NC Wildlife Resources Commission, NC Division of Water Quality, NC Division of Air Quality, NOAA Center for Coastal Fisheries and Habitat Research, University of Delaware, Duke Energy Co., Louisiana State University, Florida State University, University of Maryland, University of Southern Mississippi,Great Lakes WATER Institute, Colorado State University, University of Florida, University of South Carolina, Duke University. Collaborators and Contacts: D. Aday, R. Borski, J. Hightower, Craig Sullivan, NCSU Biology; G. Cope, D. Buchwalter, R.B. Bringolf, S. Mosher, NCSU Env. and Molecular Toxicology; T. Targett, U. of Delaware; K. Rose, Louisiana State U.; J.K. Craig, Florida State U.; R. Fulford, U. of Southern Mississippi; T.J. Miller, University of Maryland, F.P. Binkowski, Great Lakes WATER Institute, K. Bestgen, Colorado State U.; W. Pine, U. of Florida; Mark Hale, Jeff Deberardinis, NC Division of Water Quality; J. Govoni, K Shertzer, NOAA Center for Coastal Fisheries and Habitat Research;; R.L. Noble, H.C. Edwards, private consultants; B. McRae, C. Waters, K. Nelson, L. Dorsey, NC Wildlife Resources Commission; D. Caughlan, K. Baker, H. Barwick, D. Harrell, Duke Energy Co.; M.R. Bangs, J.M. Quattro, University of South Carolina; Eric Money, Duke University. Training or Professional Development: The project provides training opportunities for graduate and undergraduate student employees and volunteers, post-docs and staff, and NCWRC biologists. TARGET AUDIENCES: Biologists and Staff Scientists in the NC Divisions of Water Quality, Air Quality, Public Health, and Marine Fisheries; NC Wildlife Resources Commission biologists; National Marine Fisheries Service and National Ocean Service scientists; NC sportfishing groups; Lake Norman Advisory Committee; NC Cooperative Extension agents; graduate and undergraduate students. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Reservoir Food Web Dynamics: This study is directly addressing all the priority research questions identified by the Lake Norman Advisory Committee, a group of stakeholders and fisheries scientists who provide input to the NC Wildlife Resources Commission biologists responsible for fisheries management in the lake. Our black bass genetic and morphometric analyses produced a key that biologists can use to reliably differentiate largemouth and spotted bass and their hybrids. Our analyses of diet and habitat overlap between largemouth and spotted bass provide strong evidence of competition between these two species, implicating introduced spotted bass as a factor in the decline of largemouth bass. Our analyses of white perch population dynamics in multiple reservoirs differing in productivity and time since invasion will help managers predict and manage the impacts of this invasive species. Effects of Hypoxia on Growth of Juvenile Estuary-Dependent Fishes: Understanding how changes in water quality affect survival, growth and production of living resources is a priority need of managers and policy makers, but establishing such linkages has been elusive. Our field observations documented that the spatial and temporal distribution of hypoxia is extremely dynamic, as is fish avoidance behavior, confirming the necessity of finding a short-term growth indicator that reflects the influence of recent conditions actually experienced by the fish. Our ongoing lab experiments will determine the extent to which either of these indicators, RNA/DNA or IGF-I, will provide this sought-after linkage. Factors Explaining Variation in Fish Tissue Mercury Content Across NC: Our analysis of mercury concentrations in fish near and far from point sources revealed that Selenium levels were higher in fish and the environment near point sources than in systems far from point sources, while mercury concentrations were actually lower near point sources than farther away. These findings support growing evidence that Selenium can ameliorate the methylation and/or accumulation of methylmercury. Incorporation of this additional information into our initial statistical model of factors governing mercury concentration in fish tissue across North Carolina further strengthened this model, which explains 81% of the variation in fish tissue mercury concentrations in the NC database. In response to our findings the NC Divisions of Water Quality, Air Quality, and Inland Fisheries have their sampling plans to address these data gaps, and our ongoing field analysis will further clarify what predictive variables are most useful. Dynamics and Consequences of the Lionfish Invasion on the Atlantic Cast: Our results are a primary source of information that the National Marine Fisheries Service is using to develop its response to the lionfish invasion, predict its impacts, inform the public about the risks, and develop strategies for predicting and responding to other exotic species invasions in the future.

Publications

  • Breitburg, D. L., Craig, J.K., Fulford, R.S., Rose, K.A., Boynton, W.R., Brady, D., Ciotti, B.J., Diaz, R.J., Friedland, K.D., Hagy III, J.D., Hart, D.R., Hines, A.H., Houde, E.D., Kolesar, S.E., Nixon, S.W., Rice, J.A., Secor, D.H., and Targett, T.E. 2009. Nutrient Enrichment and Fisheries Exploitation: Interactive Effects on Estuarine Living Resources and Their Management. Hydrobiologia. 629:31-47.
  • Godbout, J.D., Aday, D.D., Rice, J.A., Bangs, M.R., and Quattro, J.M.. 2009. Morphological models for identifying largemouth, spotted and hybrid largemouth-spotted bass. North American Journal of Fisheries Management. 29:1425-1437.
  • Sackett, D.K, Aday, D.D., Rice, J.A., and Cope, W.G. 2009. A statewide assessment of mercury dynamics in North Carolina waterbodies and fish. Transactions of the American Fisheries Society. 138:1328-1341.


Progress 10/01/07 to 09/30/08

Outputs
OUTPUTS: Reservoir Food Web Dynamics: We continued a 5-year study in collaboration with the NC Wildlife Resources Commission to evaluate effects of several introduced species on a reservoir food web and their implications for fisheries management. Comprehensive, spatially stratified sampling of the Lake Norman, NC, food web was conducted throughout 2008 to track competitive and predator-prey interactions as well as habitat relationships. Genetic and morphometric analyses of black bass were conducted to establish methods for identifying largemouth bass, spotted bass and their hybrids. Initial results were presented at a national conference and have been shared with NCWRC biologists. Effects of Hypoxia on Growth of Juvenile Estuary-Dependent Fishes: We conducted lab experiments to begin testing two biological indicators of recent short-term growth, RNA/DNA ratios in muscle tissue and plasma levels of insulin-like growth factor-I, for juvenile spot. We also monitored water quality conditions and sampled juvenile spot for RNA/DNA and IGF-I analysis throughout the summer at sites in the Neuse River estuary and in multiple marsh creeks that experience relatively high and low frequencies of hypoxic conditions. Results are being shared with other hypoxia researchers as they develop. Factors Explaining Variation in Fish Tissue Mercury Content Across NC: Using all available data on the biotic and abiotic variables known or suspected to affect rates of mercury methylation and accumulation in fish that coincide with fish tissue mercury data collections in NC, we developed a statistical model to identify the important factors explaining mercury contamination in NC fish. To test and improve this model, in 2008 we intensively sampled 14 lakes across NC spanning a wide range of conditions and distance from Hg point sources, collecting synoptic data on all relevant water quality variables, as well as Hg concentration in sediments, benthos and fish from two trophic levels, and stable isotope data (as an indicator of trophic position). Analysis of these samples is underway. Model results were presented at state and national meetings, and we are also sharing our findings with the NC Divisions of Water Quality, Air Quality, and Inland Fisheries, and assisting them in revising their sampling plans accordingly. Dynamics and Consequences of the Lionfish Invasion on the Atlantic Coast: Experiments have been conducted to evaluate the vulnerability of juvenile lionfish to potential predators, and the effectiveness of lionfish as predators on native reef fishes. Histological analyses have been conducted to determine the timing and magnitude of egg production and the ontogeny of venom gland development in lionfish spines. Development of a population dynamics model has been initiated to evaluate the potential extent and impact of the lionfish invasion. Results are being disseminated extensively through NOAA websites, popular articles, and presentations at scientific meetings. PARTICIPANTS: Individuals: J.A. Rice, D.D. Aday, W.G. Cope, R.J. Borski, D. Buchwalter (PIs); J.K. Craig (post-doc); D. Sackett, M. Brey, J. Godbout, J. Morris, L. Glass, Z. Feiner (graduate students), C. Russell, S. Sills, N. Jeffers, H. Dendy, B. Richardson, A. Bunch, T. Brown, J. Leonard, C. Gille, Z. Tait, D. Heithans, R. Spiedel, J. Dalrymple, J. Remmington, T. Averett, R. Rasmussen, A. Stephenson (hourly workers and technicians). Partner Organizations: NC Wildlife Resources Commission, NC Division of Water Quality, NC Division of Air Quality, NOAA Center for Coastal Fisheries and Habitat Research, University of Delaware, Duke Energy Co. Collaborators and Contacts: D. Aday, R. Borski, J. Hightower, NCSU Biology; G. Cope, D. Buchwalter, R.B. Bringolf, S. Mosher, NCSU Env. and Molecular Toxicology; T. Targett, U. of Delaware; K. Rose, Louisiana State U.; J.K. Craig, Florida State U.; R. Fulford, U. of Southern Mississippi; T.J. Miller, University of Maryland, F.P. Binkowski, Great Lakes WATER Institute, K. Bestgen, Colorado State U.; W. Pine, U. of Florida; Mark Hale, Jeff Deberardinis, NC Division of Water Quality; J. Govoni, K Shertzer, NOAA Center for Coastal Fisheries and Habitat Research;; R.L. Noble, H.C. Edwards, private consultants; B. McRae, C. Waters, K. Nelson, L. Dorsey, NC Wildlife Resources Commission; D. Caughlan, K. Baker, H. Barwick, D. Harrell, Duke Energy Co., M.R. Bangs, J.M. Quattro, University of South Carolina. Training or Professional Development: The project provides training opportunities for graduate and undergraduate student employees and volunteers, post-docs and staff, and NCWRC biologists. TARGET AUDIENCES: Biologists and Staff Scientists in the NC Divisions of Water Quality, Air Quality, Public Health, and Marine Fisheries; NC Wildlife Resources Commission biologists; National Marine Fisheries Service and National Ocean Service scientists; NC sportfishing groups; NC Cooperative Extension agents; graduate and undergraduate students. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Reservoir Food Web Dynamics: This study is directly addressing all the priority research questions identified by the Lake Norman Advisory Committee, a group of stakeholders and fisheries scientists who provide input to the NC Wildlife Resources Commission biologists responsible for fisheries management in the lake. Our black bass genetic and morphometric analyses produced a key that biologists can use to reliably differentiate largemouth and spotted bass and their hybrids. Our analyses of diet and habitat overlap between largemouth and spotted bass provide strong evidence of competition between these two species, implicating introduced spotted bass as a factor in the decline of largemouth bass. Effects of Hypoxia on Growth of Juvenile Estuary-Dependent Fishes: Understanding how changes in water quality affect survival, growth and production of living resources is a priority need of managers and policy makers, but establishing such linkages has been elusive. Our field observations documented that the spatial and temporal distribution of hypoxia is extremely dynamic, as is fish avoidance behavior, confirming the necessity of finding a short-term growth indicator that reflects the influence of recent conditions actually experienced by the fish. Our ongoing lab experiments will determine the extent to which either of these indicators, RNA/DNA or IGF-I, will provide this sought-after linkage. Factors Explaining Variation in Fish Tissue Mercury Content Across NC: Our initial model analysis of available data found that 81% of the variation in fish tissue mercury concentrations in the NC database could be explained by species, fish trophic status, ecoregion and pH. However, few data were available for many of the abiotic factors thought to be important to mercury methylation and bioaccumulation. In response to our findings the NC Divisions of Water Quality, Air Quality, and Inland Fisheries are already revising their sampling plans to address these data gaps, and our ongoing field analysis will further clarify what predictive variables are most useful. Dynamics and Consequences of the Lionfish Invasion on the Atlantic Cast: Our results are a primary source of information that the National Marine Fisheries Service is using to develop its response to the lionfish invasion, predict its impacts, inform the public about the risks, and develop strategies for predicting and responding to other exotic species invasions in the future.

Publications

  • Cope, W.G., Bringolf, R.B., Mosher, S., Rice, J.A., Noble, R.L., and Edwards, H.C. 2008. Controlling nitrogen release from farm ponds with a subsurface outflow device: implications for improved water quality in receiving streams. Agricultural Water Management. 95:737-742.


Progress 10/01/06 to 09/30/07

Outputs
OUTPUTS: Reservoir food web dynamics: We initiated the first year of a 5-year comprehensive food web study in collaboration with the NC Wildlife Resources Commission to evaluate these dynamics and their implications for reservoir fisheries management. Comprehensive, spatially stratified sampling of the Lake Norman, NC, food web was conducted throughout 2007 to track seasonal changes in benthic and zooplankton prey, recruitment of larval fishes, and the species composition, size structure and diets of all fish in the Lake. Direct and indirect effects of hypoxia on juvenile estuary-dependent fishes: We completed the second year of intensive field sampling under a wide range of conditions for both juvenile fish and their potential predators at locations in the Neuse River estuary ranging from nearshore areas that are rarely hypoxic to the center of the river which is most often hypoxic. Water quality conditions were monitored continuously using datasonde loggers, and detailed data on the spatial distribution of water quality conditions was collected during sampling trips using a hand-held datasonde. We measured abundance of all organisms collected and examined diets of juvenile spot and all their potential predators to determine spot feeding success as a proxy for short-term growth, and changes in predation risk under different conditions. Results are being shared with other hypoxia researchers as they develop. Factors explaining variation in fish tissue mercury content across NC: We initiated a 1-year study funded by the NC Water Resources Research Institute to examine this issue We are synthesizing and analyzing all available data on the biotic and abiotic variables known or suspected to affect rates of mercury methylation and accumulation in fish that coincide with fish tissue mercury data collections in NC, to identify the important factors and develop predictive models for mercury contamination in fish that can be used by managers and policy makers. The database has been assembled and analyses are underway. We are sharing our findings with the NC Divisions of Water Quality, Air Quality, and Inland Fisheries, and assisting them in revising their sampling plans accordingly. Dynamics and Consequences of the Lionfish invasion on the Atlantic coast: Experiments have been conducted to evaluate the vulnerability of juvenile lionfish to potential predators, and the effectiveness of lionfish as predators on native reef fishes. Histological analyses have been conducted to determine the timing and magnitude of egg production and the ontogeny of venom gland development in lionfish spines. Development of a population dynamics model has been initiated to evaluate the potential extent and impact of the lionfish invasion. Results are being disseminated extensively through NOAA websites, popular articles, and presentations at scientific meetings. PARTICIPANTS: Individuals: J.A. Rice, D.D. Aday, W.G. Cope (PIs); J.K. Craig, J. Fleming-Reynolds (post-doc); D. Sackett (Research Biologist) M. Brey, J. Godbout, J. Morris, L. Glass, J. Thompson, L. Davias (graduate students), C. Russell, S. Sills, Nick Jeffers, Heather Dendy, Bryan Richardson, J. Leonard, C. Gille, Z. Tait, D. Heithans, R. Spiedel, C. Krahforst, J. Dalrymple (hourly workers and technicians). Partner Organizations: NC Wildlife Resources Commission, NC Division of Water Quality, NC Division of Air Quality, NOAA Center for Coastal Fisheries and Habitat Research, University of Delaware, Duke Energy Co. Collaborators and Contacts: D. Aday, R. Borski, J. Hightower, NCSU Zoology; G. Cope, D. Buchwalter, NCSU Env. And Molecular Toxicology; T. Targett, U. of Delaware; K. Rose, Louisiana State U.; J.K. Craig, Florida State U.; R. Fulford, U. of Southern Mississippi; K. Bestgen, Colorado State U.; W. Pine, U. of Florida; Mark Hale, Jeff Deberardinis, NC Division of Water Quality; J. Govoni, K Shertzer, NOAA Center for Coastal Fisheries and Habitat Research; B. McRae, C. Waters, K. Nelson, L. Dorsey, NC Wildlife Resources Commission; D. Caughlan, K. Baker, H. Barwick, D. Harrell, Duke Energy Co. Training or Professional Development: The project provides training opportunities for graduate and undergraduate student employees and volunteers, post-docs and staff. TARGET AUDIENCES: Biologists and Staff Scientists in the NC Divisions of Water Quality, Air Quality, Public Health, and Marine Fisheries; NC Wildlife Resources Commission biologists; National Marine Fisheries Service and National Ocean Service scientists; NC sportfishing groups; NC Cooperative Extension agents; graduate and undergraduate students.

Impacts
Reservoir food web dynamics: This study is directly addressing all the priority research questions identified by the Lake Norman Advisory Committee, a group of stakeholders and fisheries scientists who provide input to the NC Wildlife Resources Commission biologists responsible for fisheries management in the lake. Direct and indirect effects of hypoxia on juvenile estuary-dependent fishes: Our ongoing research on the effects of hypoxia (low oxygen) on estuary-dependent fish is addressing the hypothesis that crowding of fish into oxygenated refuges during hypoxia events results in indirect effects on growth and survival via density-dependent mechanisms, and may increase their vulnerability to predation. Preliminary analyses indicate that water quality conditions often change rapidly, on a time scale that we may not be able to adequately track with our current approach. Therefore we have secured additional Sea Grant funding to validate and apply molecular approaches using muscle RNA/DNA ratios and blood levels of Insulin-like Growth Factor I as indicators of short-term growth that will provide an integrated measure of oxygen effects on recent growth of fish from impacted and unimpacted habitats. Factors explaining variation in fish tissue mercury content across NC: Our preliminary results suggest that several abiotic and biotic variables may explain a substantial portion of the 30-100-fold variation in fish tissue methylmercury concentrations among species within and among waterbodies across NC, but also indicate that most of the fish concentration observations lack associated data for more than one or two of the many potentially important factors. In response to our findings the NC Divisions of Water Quality, Air Quality, and Inland Fisheries are already revising their sampling plans to address these data gaps. Dynamics and Consequences of the Lionfish invasion on the Atlantic coast: Our results are a primary source of information that the National Marine Fisheries Service is using to develop its response to the lionfish invasion, predict its impacts, inform the public about the risks, and develop strategies for predicting and responding to other exotic species invasions in the future.

Publications

  • Craig, J.K., Rice, J.A., Crowder, L.B. and Nadeau, D.A. 2007. Density-dependent growth and survival in an estuary-dependent fish: an experimental approach with juvenile spot Leiostomus xanthurus. Marine Ecology Progress Series. 343:251-262.
  • Thompson, J.S., Waters, D.S., Rice, J.A. and Hightower, J.E. 2007. Seasonal Fishing and Natural Mortality of Striped Bass in a Southeastern Reservoir. North American Journal of Fisheries Management. 27:681-694.
  • Pine, W.E., Kwak, T.J. and Rice, J.A. 2007. Modeling management scenarios and the effects of an introduced apex predator on a coastal riverine fish community. Transactions of the American Fisheries Society. 136:105-120.
  • Bestgen, K.R., Beyers, D.W., Rice, J.A. and Haines, G.B. 2006. Factors affecting recruitment of young Colorado pikeminnow: synthesis of predation experiments, field studies and individual-based modeling. Transactions of the American Fisheries Society. 135:1722-1742.


Progress 10/01/05 to 09/30/06

Outputs
This project addresses issues of population dynamics, predator-prey interactions, energetic costs of habitat constraints, and effects of hypoxia on fishes in reservoirs and estuarine systems. We analyzed striped bass thermal experience, growth, diet, and predator and prey energy densities in seven NC reservoirs to determine the relative importance of summer thermal conditions and food availability in determining striped bass growth. Fish growth to age-7 varied from less than 2 kg to nearly 6 kg, and fish spent between 0 and 87 days in very warm (more than 27 degrees C) water during summer stratification. Striped bass from lakes that experienced the most severe summer temperatures also exhibited relatively fast growth. Bioenergetics modeling indicated that food availability usually accounted for more of the difference in growth among reservoirs than did thermal experience, except in comparisons involving Lake Rhodhiss, which has both good thermal habitat and abundant food. In cases when optimum temperatures and prey densities occur in different patches, the distribution of an integrated measure of habitat quality such as growth rate potential (the rate of growth expected at a particular combination of temperature and food availability) may be a better predictor of habitat selection. We tested this hypothesis by evaluating the spatial correlation between the distribution of striped bass implanted with sonic transmitters and the distributions of temperature, pelagic forage fish density (determined using hydroacoustics), and growth rate potential in Badin Lake, NC, in the summer and fall of two consecutive years. Significant correlations between striped bass abundance and growth rate potential were found in both summers and in the fall of the first year. However, growth rate potential was not always the best predictor of striped bass distribution, indicating that it is important, but not the only factor affecting habitat selection. We also conducted field and modeling work to evaluate the impact of hypoxia on juvenile estuarine fishes. Our prior hydroacoustic telemetry work showed that juvenile spot in the Neuse River estuary change their movement patterns depending on the extent of hypoxia in the system; when hypoxia is widespread, the fish tend to move to nearshore, oxygenated areas. In light of our previous experimental work showing density-dependent effects on growth and survival of juvenile spot, we hypothesized that crowding of fish into oxygenated refuges during hypoxia events could result in indirect effects on growth and survival via density-dependent mechanisms. To test this hypothesis we initiated intensive field sampling under a wide range of conditions for both juvenile fish and their potential predators at locations ranging from nearshore areas that are rarely hypoxic to the center of the river which is most often hypoxic. We measured abundance and examined diets to determine feeding success as a proxy for short-term growth. Analysis of our first season's data is underway.

Impacts
The results of this project have shown that regardless of temperature, low food consumption will only yield moderate to slow growth of striped bass in reservoir systems. On the other hand, striped bass subjected to very warm temperatures can still maintain good growth, but only if adequate forage exists. With knowledge of availability and abundance of clupeid prey, in addition to information on thermal conditions, managers of striped bass populations in southern reservoirs can adjust stocking rates and harvest regulations on a reservoir-specific basis to optimize the quality of striped bass fisheries.

Publications

  • Fulford, R.S., Rice, J.A. and Binkowski, F.P. 2006. Examination of sampling bias for larval yellow perch in southern Lake Michigan. Journal of Great Lakes Research. 32:434-441.
  • Craig, J.K., Burke, B.J., Crowder, L.B. and Rice, J.A. 2006. Prey growth and size-dependent predation in juvenile estuarine fishes: experimental and modeling analyses. Ecology. 87(9): 2366-2377.
  • Fulford, R.S., Rice, J.A., Miller, T.J. and Binkowski, F.P. 2006. Elucidating patterns of size-dependent predation on larval yellow perch (Perca flavescens) in Lake Michigan: an experimental and modeling approach. Canadian Journal of Fisheries and Aquatic Sciences. 63(1) 11-27.
  • Fulford, R.S., Rice, J.A., Miller, T.J., Binkowski, F.P., Dettmers, J.M. and Belonger B. 2006. Foraging selectivity by larval yellow perch (Perca flavescens): implications for understanding recruitment in small and large lakes. Canadian Journal of Fisheries and Aquatic Sciences. 63(1) 28-42.


Progress 10/01/04 to 09/30/05

Outputs
This project addressed issues of population dynamics, predator-prey interactions, energetic costs of habitat constraints, and effects of hypoxia on fishes. We mapped spatial and temporal distributions of temperature and oxygen in 5 NC reservoirs to determine availability of suitable habitat for striped bass. Striped bass growth rates and energy density were determined from representative annual samples in each lake, as were forage fish composition and energy density. These data were combined in a bioenergetics modeling framework to determine the relative contribution of temperature-dissolved oxygen constraints and forage availability to the striped bass growth and condition observed in each reservoir. Preliminary results suggest that in reservoirs with poor physical habitat forage availability plays a major role in governing striped bass growth, while in reservoirs with good habitat temperature and food affect growth more equally. We used data from the literature and our previous work to parameterize a preliminary Ecopath-with-Ecosim ecosystem model for a typical Southeastern reservoir system and demonstrated the utility of this approach by conducting model simulations evaluating the community impacts of different striped bass stocking rates. We also conducted field and modeling work to evaluate the impact of hypoxia on juvenile estuarine fishes. Hydroacoustic telemetry was used to collect movement information on individual juvenile spot at 2-hr intervals in the Neuse River estuary over a wide range of environmental conditions. Local water quality conditions (DO, temperature, salinity) around each relocation site (0.5-1 km range) were synoptically recorded and periodically mapped on a larger scale to characterize both available conditions and those experienced by individual fish. Movement parameters (e.g., velocity, direction, linear distance, elliptical area) of tracked fish were analyzed to determine the appropriate spatial and temporal scales at which fish responses to water quality conditions should be modeled. This information was incorporated into our spatially-explicit, individual-based fish response model using several different movement modeling approaches. Results to date indicate that the most substantial effects of hypoxia on juvenile spot are likely indirect effects via density-dependence of spot growth and survival in oxygenated refuges, and that the choice of movement model has a major impact on overall model predictions.

Impacts
The results of this project have shown that application of a bioenergetics modeling approach to data on striped bass growth, habitat quality, and forage availability can give fisheries managers a useful tool to customize striped bass stocking or management options for specific reservoirs based on their unique characteristics. It has also advanced our efforts to provide fisheries managers with a way to evaluate both the indirect and direct effects of hypoxia on the distribution, growth and survival of juvenile estuarine fishes.

Publications

  • Shimps, E.L., Rice, J.A. and Osborne J.A. 2005. Hypoxia tolerance in two juvenile estuary-dependent fishes. Journal of Experimental Marine Biology and Ecology. 325(2):146-162.
  • Pine, W.E., Kwak, T.J. Waters, D.S. and Rice J.A. 2005. Diet Selectivity of Introduced Flathead Catfish in Coastal Rivers. Transactions of the American Fisheries Society. 134(4):901-909.