Geology topics

Edward S. Rutherford

Publications and source records attributed to Edward S. Rutherford.

15 recordsLinked to original sources

USGS2026

Describing the seasonal abundance and growth rates of larval fishes across productivity gradients in Lake Huron in 2017

Several of the Laurentian Great Lakes, including Lake Huron, have undergone oligotrophication in the past decades and prey fish biomass has concomitantly declined. One potential mechanism to explain declines in prey fish is slower growth and lower survival at the larval stage. To determine whether reduced productivity affects the growth of larval fish, we sampled larval fishes and their environment approximately monthly from May through August 2017 at nine nearshore to offshore transects across Lake Huron that included North Channel, Georgian Bay, and the main basin. North Channel transects had the highest chlorophyll a concentrations and zooplankton densities. Rainbow smelt ( Osmerus mordax ), burbot ( Lota lota ), bloater ( Coregonus hoyi ), and shiners ( Notropis spp.) were the most abundant larval fish taxa, peaking in June and July. We aged rainbow smelt and bloater using otoliths, and estimates of growth rate revealed rainbow smelt always grew faster. For both species, we explained variation in total length by comparing 16 candidate linear mixed-effects models, with age, chlorophyll a , zooplankton, water temperature, larval fish density, and interactions with age as predictor variables. For rainbow smelt, the full model was best; zooplankton had the greatest effect, but it was negative and opposite from our hypothesis. For bloater, four candidate models were most parsimonious; water temperature had the greatest effect, and it was positive as predicted from our hypothesis. To more effectively evaluate whether zooplankton can limit larval fish growth and survival, we recommend that future designs conduct more frequently sampling within a year even at the expense of fewer transects.

Lake Huron↗

USGS2024

Climate-influenced phenology of larval fish transport in a large lake

Elucidating physical transport phenologies in large lakes can aid understanding of larval recruitment dynamics. Here, we integrate a series of climate, hydrodynamic, biogeochemical, and Lagrangian particle dispersion models to: (1) simulate hatch and transport of fish larvae throughout an illustrative large lake, (2) evaluate patterns of historic and potential future climate-induced larval transport, and (3) consider consequences for overlap with suitable temperatures and prey. Simulations demonstrate that relative offshore transport increases seasonally, with shifts toward offshore transport occurring earlier during relatively warm historic and future simulations. Intra- and inter-annual trends in transport were robust to assumed pelagic larval duration and precise location and timing of hatching. Larvae retained nearshore generally encountered more favorable temperatures and zooplankton densities compared to larvae transported offshore. Larval exploitation of nearshore resources under climate change may depend on a concomitant shift to earlier spawning and hatch times in advance of earlier offshore transport.

Lake Michigan↗

USGS2024

Understanding and forecasting potential recruitment of Lake Michigan fishes by modeling growth and survival of larval stages with coupled climate, biophysical, and bioenergetics models

Individual adult fish can produce huge numbers of small offspring, but most die in the first weeks of life. Environmental changes that lead to even small changes in early life survival can have a disproportionate impact on the number of fish that survive and ultimately support fisheries. Lake Michigan supports valuable recreational and commercial fisheries that can fluctuate with how well fish survive in early life. Statistical models have revealed linkages between survival and climate characteristics, such as water temperature, but the exact mechanisms remain unclear and how future climate will affect the survival of young fish is highly uncertain. We integrated a series of models to investigate how climate variability may explain historical variation in the survival of young alewife and yellow perch, two fish populations that support key fisheries either directly or indirectly, while also projecting their future survival in the mid-21st century under different scenarios informed by consultation with fishery managers. Our model results revealed how spring and summer water temperatures in Lake Michigan can affect the environment in which young alewife and yellow perch grow and survive. Specifically, in years when lake warming is rapid, young fish are more likely to be transported from their natal, productive, nearshore environments to cooler and less productive offshore environments, unless adults also spawn earlier in these warm years. Furthermore, model predictions of prey abundance for young fish in the mid-21st century indicate less favorable conditions for growth and survival compared to predictions based solely on warming temperatures. With completion of the final products in the coming year, including predicted growth and survival of young fish under different future scenarios, fishery managers will have more information to share with stakeholders regarding how expectations may need to be modified regarding alewife and yellow perch productivity.

Lake Michigan↗

USGS2023

Gap analysis: A proposed methodology to describe and map historical and contemporary populations and habitats

This is a methodology paper that describes an approach for modeling and mapping historical and contemporary spawning areas for coregonine fishes in the Laurentian Great Lakes. Coregonines are a family of native whitefishes and ciscoes that are now greatly reduced or extirpated, but once served important roles for both the food web and society. This method can illustrate where habitats once existed and where they are today - critical information for restoration and conservation actions.

Great Lakes↗

USGS2022

Predicting larval alewife transport in Lake Michigan using hydrodynamic and Lagrangian particle dispersion models

Several species of fish in large lakes and marine environments have a pelagic larval stage, and are subject to variable transport that can ultimately regulate survival and recruitment success. Alewife, Alosa pseudoharengus , are subject to transport by complex coastal currents during their pelagic larval stage (~ 30 d). We assessed backward-trajectory simulations, consisting of a Lagrangian particle dispersion model linked to the Finite Volume Community Ocean Model, to estimate likely hatch locations of aged larval alewife collected from locations on both the eastern and western sides of Lake Michigan during July 2015. We used four deployments of three satellite-tracked drifter buoys in coastal waters to assess model skill in estimating the origin of a drifter from its final location. We found that the trajectories of drifters varied greatly, depending on wind events and associated coastal transport processes, including upwelling/downwelling and coastal jet currents. In 2 of 12 cases, the backward trajectory simulations failed to predict the drifter origin, associated with transport of 170 km in a narrow coastal jet current. In the remaining 10 cases, the known drifter origin was within 3.5 km of the spatial patch of predicted possible origins for a scenario of horizontal diffusivity (188 m 2 s −1 ) consistent with the offshore model grid resolution. Modeled backward trajectories estimated that alewife originated from the same side of the lake where they were collected, within ~ 100 km of the collection site. Our paper demonstrates the utility of hydrodynamic models to estimate a region of origin for aged larval fish.

Lake Michigan↗

USGS2021

Consequences of changing water clarity on the fish and fisheries of the Laurentian Great Lakes

Human-driven environmental change underlies recent changes in water clarity in many of the world’s great lakes, yet our understanding of the consequences of these changes on the fish and fisheries they support remains incomplete. Herein, we offer a framework to organize current knowledge, guide future research, and help fisheries managers understand how water clarity can affect their valued populations. Emphasizing Laurentian Great Lakes findings where possible, we describe how changing water clarity can directly affect fish populations and communities by altering exposure to ultraviolet radiation, foraging success, predation risk, reproductive behavior, or territoriality. We also discuss how changing water clarity can affect fisheries harvest and assessment through effects on fisher behavior and sampling efficiency (i.e., catchability). Finally, we discuss whether changing water clarity can affect understudied aspects of fishery performance, including economic and community benefits. We conclude by identifying generalized predictions and discuss their implications for priority research questions for the Laurentian Great Lakes. Even though the motivation for this work was regional, the breadth of the review and generality of the framework are readily transferable to other freshwater and marine habitats.

Great Lakes↗

USGS2020

The geometry of reaction norms yields insights on classical fitness functions for Great Lakes salmon

Life history theory examines how characteristics of organisms, such as age and size at maturity, may vary through natural selection as evolutionary responses that optimize fitness. Here we ask how predictions of age and size at maturity differ for the three classical fitness functions–intrinsic rate of natural increase r , net reproductive rate R 0 , and reproductive value V x −for semelparous species. We show that different choices of fitness functions can lead to very different predictions of species behavior. In one’s efforts to understand an organism’s behavior and to develop effective conservation and management policies, the choice of fitness function matters. The central ingredient of our approach is the maturation reaction norm (MRN), which describes how optimal age and size at maturation vary with growth rate or mortality rate. We develop a practical geometric construction of MRNs that allows us to include different growth functions (linear growth and nonlinear von Bertalanffy growth in length) and develop two-dimensional MRNs useful for quantifying growth-mortality trade-offs. We relate our approach to Beverton-Holt life history invariants and to the Stearns-Koella categorization of MRNs. We conclude with a detailed discussion of life history parameters for Great Lakes Chinook Salmon and demonstrate that age and size at maturity are consistent with predictions using R 0 (but not r or V x ) as the underlying fitness function.

Great Lakes↗

USGS2019

Densities, diets, and growth rates of larval Alewife and Bloater in a changing Lake Michigan ecosystem.

Variability in abiotic and biotic factors during larval stages has profound impacts on fish recruitment. In Lake Michigan, where the composition of lower trophic levels has undergone considerable changes in the past decade, managers are concerned that fish recruitment could be negatively affected. We hypothesized that spatial variation in Lake Michigan larval fish density and growth can be explained by various environmental predictor variables. In July 2015, we sampled larval fish and zooplankton at 24 sites (distributed among eight transects) around Lake Michigan. We measured larval fish densities and estimated growth rates and diets of the two most abundant species: the Alewife Alosa pseudoharengus and Bloater Coregonus hoyi (prey fish that represented 89% and 4% of the total catch, respectively). Larval Alewife densities at a given site ranged from 0 to 42.57 larvae/100 m 3 , but no explanatory variables explained the variation. Alewife mean growth rate equaled 0.50 mm/d, and fish age and zooplankton density best explained growth variation across sites. Larval Bloater densities ranged from 0 to 1.16 larvae/100 m 3 , and mean growth rate was 0.21 mm/d. Across all sites, 67% of larval Alewife stomachs were empty, whereas only 16% of Bloater stomachs were empty. Larval fish growth rates observed in our study were at least 40% slower than those reported in previous decades for both Alewife and Bloater. Worsening prey environment for pelagic larvae, such as Alewife and Bloater, during the era of abundant dreissenid mussels could reduce the probability of strong year‐classes, which in turn may affect growth and survival of recreationally important salmonine predators.

Illinois, Michigan, Wisconsin↗

USGS2019

Interactive mapping of nonindigenous species in the Laurentian Great Lakes

Nonindigenous species pose significant risks to the health and integrity of ecosystems around the world. Tracking and communicating the spread of these species has been of interest to ecologists and environmental managers for many years, particularly in the bi-national Laurentian Great Lakes of North America. In this paper, we introduce the Great Lakes Aquatic Nonindigenous Species Information System (GLANSIS) Map Explorer. The Map Explorer provides access to records of documented nonindigenous species and their spatial distributions. Users may view the distributions of well-known nonindigenous species (such as zebra mussels) as well as perform custom queries. Additional map layers allow users to compare the distribution of nonindigenous species to environmental conditions. This tool serves to communicate knowledge to diverse stakeholder groups and to enable further in-depth research on nonindigenous species.

Laurentian Great Lakes↗

USGS2018

Are changes in lower trophic levels limiting prey-fish biomass and production in Lake Michigan?

To improve understanding of how recent changes in lower trophic levels in Lake Michigan could be affecting prey-fish biomass and production, the Lake Michigan Committee (LMC) convened a Lower Trophic Level Task Group and provided several charges that are responded to in this report. First, we compiled a comprehensive summary of lower trophiclevel data in Lake Michigan, separating out nearshore versus offshore trends over time. Declining trends were prevalent in offshore time series for phosphorus, chlorophyll a, biomass of total crustacean zooplankton, biomass of herbivorous cladocerans, and density of Diporeia spp. In the nearshore, declining trends were evident only for biomass of cyclopoid copepods and density of Diporeia spp. Second, we hypothesized specific mechanisms by which changes in lower trophic levels could affect prey-fish biomass and production and described the degree of empirical support for each mechanism. The best-supported hypothesis was that declining invertebrate prey (especially Diporeia spp.) was responsible for declining growth of prey fish, especially over the last decade when competition for prey resources should otherwise have been lessened due to declining prey-fish densities. As a result, declining growth potentially limits the prey-fish biomass that could have been attained had growth been maintained at the levels that were achieved in the 1980s and earlier. Third, we prioritized several lower trophic-level indicators that fishery managers could use to better inform decision making. The top-ranked indicator was annual reporting of Alewife (Alosa pseudoharengus) condition. Fourth, we prioritized the key monitoring and research gaps that limit our current understanding of how lower trophic levels influence fish production. The highest-priority monitoring gap was coordinated sampling of the nearshore, which, if accomplished, would complement annual reporting on offshore sampling. The top-ranked knowledge gap was identifying bottlenecks that regulate fish recruitment, given that recent changes in zooplankton distribution and abundance could be suppressing survival of larval fish and, ultimately, the biomass and production of prey fish. We provided three specific recommendations for the LMC to consider as they seek to better incorporate lower trophiclevel changes into their management decision process: (1) implement a coordinated and standardized nearshore monitoring program, (2) encourage funding agencies to use our prioritized lists in their decision processes, and (3) foster the already improved dialogue between those researching lower trophic levels and those researching fisheries.

Miscellaneous Publication↗

USGS2016

Using scenarios to assess possible future impacts of invasive species in the Laurentian Great Lakes

The expected impacts of invasive species are key considerations in selecting policy responses to potential invasions. But predicting the impacts of invasive species is daunting, particularly in large systems threatened by multiple invasive species, such as North America’s Laurentian Great Lakes. We developed and evaluated a scenario-building process that relied on an expert panel to assess possible future impacts of aquatic invasive species on recreational fishing in the Great Lakes. To maximize its usefulness to policy makers, this process was designed to be implemented relatively rapidly and consider a range of species. The expert panel developed plausible, internally-consistent invasion scenarios for 5 aquatic invasive species, along with subjective probabilities of those scenarios. We describe these scenarios and evaluate this approach for assessing future invasive species impacts. The panel held diverse opinions about the likelihood of the scenarios, and only one scenario with impacts on sportfish species was considered likely by most of the experts. These outcomes are consistent with the literature on scenario building, which advocates for developing a range of plausible scenarios in decision making because the uncertainty of future conditions makes the likelihood of any particular scenario low. We believe that this scenario-building approach could contribute to policy decisions about whether and how to address the possible impacts of invasive species. In this case, scenarios could allow policy makers to narrow the range of possible impacts on Great Lakes fisheries they consider and help set a research agenda for further refining invasive species predictions.

Great Lakes, Lake Superior, Lake Huron, Lake Michi↗

USGS2013

Trophic shift, not collapse

Jerald Schnoor’s editorial describes the recent changes in Lake Huron’s aquatic ecosystem as a trophic collapse and attributes this collapse to invasive species dominating energy and nutrient ﬂows in the food web. As state and federal scientists who are closely monitoring Lake Huron’s food web, we believe that the ongoing changes are more accurately characterized as a trophic shift in which benthic pathways have become more prominent. While decreases in abundance have occurred for some species, others are experiencing improved reproduction resulting in the restoration of several important native species.

Environmental Science & Technology↗

USGS2011

Spawning habitat unsuitability: an impediment to cisco rehabilitation in Lake Michigan?

The cisco Coregonus artedi was one of the most important native prey fishes in Lake Michigan and in the other four Laurentian Great Lakes. Most of the cisco spawning in Lake Michigan was believed to have occurred in Green Bay. The cisco population in Lake Michigan collapsed during the 1950s, and the collapse was attributed in part to habitat degradation within Green Bay. Winter water quality surveys of lower Green Bay during the 1950s and 1960s indicated that the bottom dissolved oxygen (DO) concentration was less than 2 mg/L throughout much of the lower bay, and most cisco eggs would not successfully hatch at such low DO concentrations. To determine present-day spawning habitat suitability in lower Green Bay, we compared cisco egg survival in lower Green Bay with survival at a reference site (St. Marys River, Michigan–Ontario) during 2009. We also conducted winter water quality surveys in lower Green Bay and the St. Marys River during 2009 and 2010. Cisco egg survival in lower Green Bay averaged 65.3%, which was remarkably similar to and not significantly different from the mean at the St. Marys River site (64.0%). Moreover, the lowest bottom DO concentrations recorded during the winter surveys were 11.2 mg/L in lower Green Bay and 12.7 mg/L in the St. Marys River. These relatively high DO concentrations would not be expected to have any negative effect on cisco egg survival. We conclude that winter water quality conditions in lower Green Bay were suitable for successful hatching of cisco eggs and that water quality during the egg incubation period did not represent an impediment to cisco rehabilitation in Lake Michigan. Our approach to determining spawning habitat suitability for coregonids would be applicable to other aquatic systems.

North American Journal of Fisheries Management↗

USGS2003

Spatially explicit measures of production of young alewives in Lake Michigan: Linkage between essential fish habitat and recruitment

The identification and protection of essential habitats for early life stages of fishes are necessary to sustain fish stocks. Essential fish habitat for early life stages may be defined as areas where fish densities, growth, survival, or production rates are relatively high. To identify critical habitats for young-of-year (YOY) alewives ( Alosa pseud oharengus ) in Lake Michigan, we integrated bioenergetics models with GIS (Geographic Information Systems) to generate spatially explicit estimates of potential population production (an index of habitat quality). These estimates were based upon YOY alewife bioenergetic growth rate potential and their salmonine predators’ consumptive demand. We compared estimates of potential population production to YOY alewife yield (an index of habitat importance). Our analysis suggested that during 1994–1995, YOY alewife habitat quality and yield varied widely throughout Lake Michigan. Spatial patterns of alewife yield were not significantly correlated to habitat quality. Various mechanisms (e.g., predator migrations, lake circulation patterns, alternative strategies) may preclude YOY alewives from concentrating in areas of high habitat quality in Lake Michigan.

Estuaries and Coasts↗

USGS2002

Dynamics of the Lake Michigan food web, 1970-2000

Herein, we document changes in the Lake Michigan food web between 1970 and 2000 and identify the factors responsible for these changes. Control of sea lamprey ( Petromyzon marinus ) and alewife ( Alosa pseudoharengus ) populations in Lake Michigan, beginning in the 1950s and 1960s, had profound effects on the food web. Recoveries of lake whitefish ( Coregonus clupeaformis ) and burbot ( Lota lota ) populations, as well as the buildup of salmonine populations, were attributable, at least in part, to sea lamprey control. Based on our analyses, predation by salmonines was primarily responsible for the reduction in alewife abundance during the 1970s and early 1980s. In turn, the decrease in alewife abundance likely contributed to recoveries of deepwater sculpin ( Myoxocephalus thompsoni ), yellow perch ( Perca flavescens ), and burbot populations during the 1970s and 1980s. Decrease in the abundance of all three dominant benthic macroinvertebrate groups, including Diporeia , oligochaetes, and sphaeriids, during the 1980s in nearshore waters ( 50 m deep) of Lake Michigan, was attributable to a decrease in primary production linked to a decline in phosphorus loadings. Continued decrease in Diporeia abundance during the 1990s was associated with the zebra mussel ( Dreissena polymorpha ) invasion, but specific mechanisms for zebra mussels affecting Diporeia abundance remain unidentified.

Canadian Journal of Fisheries and Aquatic Sciences↗