Jacobs G.R.,University of Michigan |
Jacobs G.R.,U.S. Fish and Wildlife Service |
Breck J.E.,University of Michigan |
Breck J.E.,Institute for Fisheries Research |
And 3 more authors.
Journal of Freshwater Ecology | Year: 2012
In temperate environments, seasonal selective sources of mortality (e.g., starvation and predation) may drive season-specific energy allocation patterns of young-of-year fish. However, when quantifying such phenomena, the effect of ration is rarely considered. We conducted two experiments to investigate the effect of ration on seasonal energy allocation patterns of age-0 largemouth bass (Micropterus salmoides) during summer and fall. In a laboratory experiment designed to evaluate short-term effects of ration on energy allocation, recent ration history strongly affected body dimensions and length-adjusted energy content. In outdoor raceways, young largemouth bass grew at different rates under different ration levels. In response, length-adjusted energy content, a size-independent index of condition, differed among raceway ration treatments during late summer. However, during fall, high-and low-growth treatment fish expressed similar length-adjusted energy content. Thus, while low-growth fish appeared to allocate a disproportionately low amount of energy to growth of energy-rich storage tissue during late summer, as winter approached, low-growth fish switched and instead allocated a disproportionately high amount of energy to storage tissue. We conclude that energy availability (via ration level) affects short-term energy allocation patterns and may interactively influence seasonal shifts in energy allocation patterns. © 2012 Taylor & Francis.
Vanderploeg H.A.,National Oceanic and Atmospheric Administration |
Pothoven S.A.,Lake Michigan Field Station |
Krueger D.,Institute for Fisheries Research |
Mason D.M.,National Oceanic and Atmospheric Administration |
And 5 more authors.
Journal of Great Lakes Research | Year: 2015
A plankton survey system, fisheries acoustics, and opening/closing nets were used to define fine-scale diel vertical spatial interactions among non-indigenous alewives and visually preying cercopagids (. Bythotrephes longimanus and Cercopagis pengoi) and indigenous zooplankton in nearshore and offshore Lake Michigan during August 2004. Because of increased water clarity associated with dreissenid mussel expansion and radically different thermal structure between cruises, we were able to observe the effects of thermal structure on diel vertical migration under high light conditions favorable especially to visual predation by cercopagids. Vertical position and overlap between alewives, Bythotrephes, and Daphnia mendotae at a 60-m site were strongly driven by thermal structure. Daphnia showed the strongest diel vertical migration of zooplankton that included migration between the epilimnion at night and the metalimnion-hypolimnion boundary during the day, whereas its major predator, Bythotrephes, was confined at all times to the epilimnion-metalimnion. Some alewives migrated from the hypolimnion to the metalimnion and epilimnion at night. As a result, most spatial overlap of Daphnia, Bythotrephes, and alewives occurred at night. Simple bioenergetics models were used to contrast predatory interactions between alewives and cercopagids at nearshore and offshore sites. Bythotrephes was the preferred prey of alewives, and at the 10-m site, alewives were the major controller of zooplankton because of its elimination of Bythotrephes. In contrast, Bythotrephes offshore likely escaped predation because of low spatial overlap with a low concentration of alewives and was the major predator and shaper of zooplankton community structure. © 2015.
Zorn T.G.,Marquette Fisheries Research Station |
Seelbach P.W.,Institute for Fisheries Research |
Seelbach P.W.,U.S. Geological Survey |
Rutherford E.S.,Institute for Fisheries Research |
And 2 more authors.
Journal of the American Water Resources Association | Year: 2012
In response to concerns over increased use and potential diversion of Michigan's freshwater resources, and the resulting state legislative mandate, an advisory council created an integrated assessment model to determine the potential for water withdrawals to cause an adverse resource impact to fish assemblages in Michigan's streams. As part of this effort, we developed a model to predict how fish assemblages characteristic of different stream types would change in response to decreased stream base flows. We describe model development and use in this case study. The model uses habitat suitability information (i.e., catchment size, base-flow yield, and July mean water temperature) for over 40 fish species to predict assemblage structure in an individual river segment under a range of base-flow reductions. By synthesizing model runs for individual fish species at representative segments for each of Michigan's 11 ecological stream types, we developed curves describing how typical fish assemblages in each type respond to flow reduction. Each stream type-specific, fish response curve was used to identify streamflow reduction levels resulting in adverse resource impacts to characteristic fish populations, the regulatory standard. Used together with a statewide map of stream types, our model provided a spatially comprehensive framework for evaluating impacts of flow withdrawals on biotic communities across a diverse regional landscape. © 2012 American Water Resources Association.
Tsehaye I.,Michigan State University |
Jones M.L.,Michigan State University |
Irwin B.J.,U.S. Geological Survey |
Fielder D.G.,Alpena Fisheries Research Station |
And 2 more authors.
Natural Resource Modeling | Year: 2015
The proliferation of double-crested cormorants (DCCOs; Phalacrocorax auritus) in North America has raised concerns over their potential negative impacts on game, cultured and forage fishes, island and terrestrial resources, and other colonial water birds, leading to increased public demands to reduce their abundance. By combining fish surplus production and bird functional feeding response models, we developed a deterministic predictive model representing bird-fish interactions to inform an adaptive management process for the control of DCCOs in multiple colonies in Michigan. Comparisons of model predictions with observations of changes in DCCO numbers under management measures implemented from 2004 to 2012 suggested that our relatively simple model was able to accurately reconstruct past DCCO population dynamics. These comparisons helped discriminate among alternative parameterizations of demographic processes that were poorly known, especially site fidelity. Using sensitivity analysis, we also identified remaining critical uncertainties (mainly in the spatial distributions of fish vs. DCCO feeding areas) that can be used to prioritize future research and monitoring needs. Model forecasts suggested that continuation of existing control efforts would be sufficient to achieve long-term DCCO control targets in the state and that DCCO control may be necessary to achieve management goals for some DCCO-impacted fisheries in Michigan. Finally, our model can be extended by accounting for parametric or ecological uncertainty and including more complex assumptions on DCCO-fish interactions as part of the adaptive management process. © 2015 Wiley Periodicals, Inc.
Canale R.P.,University of Michigan |
Breck J.E.,Institute for Fisheries Research |
Breck J.E.,University of Michigan
Aquaculture | Year: 2013
This paper demonstrates that conventional bioenergetic models, that are commonly used to simulate fish growth or consumption, violate basic requirements of energy conservation when improperly applied for cases where the energy density of the fish is either a function of fish wet weight or an independent function of time. It appears that many previously published modeling results suffer from this deficiency unless the authors have made perspicuous provisions to avoid implicit imbalances that occur in the equations under these conditions. The incorrect solutions tend to overestimate fish growth and net energy consumption. The magnitude of these errors is a function of how rapidly the fish energy density changes as the fish increases in size. The errors can be as much as 30% for small fish in the range of 1 to 5. g per individual where the energy density changes rapidly. Although this mathematical error does not occur if fish energy density is modeled as a constant, this assumption is probably inadequate for most applications and results in a substantial "biological error." It is recommended that published results for these various cases be critically reviewed and corrected where warranted. The errors can be readily eliminated when the bioenergetic model equations are handled properly as demonstrated in this paper. © 2013 Elsevier B.V.