Paul W. Seelbach

Modeling Steelhead Population Energetics in Lakes Michigan and Ontario

Abstract We developed a bioenergetics model for steelhead Oncorhynchus mykiss that simulates growth and consumption by separate life history forms in Lakes Michigan and Ontario. We estimated abundances of hatchery and wild smolts during 1975–1990 for both lakes based on stocking rates, survival schedules, and discrimination of the proportion of the lake population that was naturally recruited. Recruitment of wild steelhead varied as a function of presmolt winter severity in both lakes. Wild smolts accounted for 6–44% (during 1982–1989) and 18–33% (during 1978–1985) of total annual smolt production in Lakes Michigan and Ontario, respectively. We developed an age-structured population model with separate accounting for run timing (summer, fall, and spring) using the proportions of life history stages observed at weirs and estimated adult survival rates. We summarized data on growth, diet, water temperature, and energy contents of predator and prey to model lakewide prey consumption in both lakes during 1975...

Classifying Regional Variation in Thermal Regime Based on Stream Fish Community Patterns

Abstract Although the importance of water temperature to the ecology of stream fishes is well documented, relatively little information is available on the extent of regional variation in thermal regime and its influence on stream fish distribution and abundance patterns. In streams draining the heterogeneous glacial landscape of Michigans Lower Peninsula, regional variation in summer mean temperature and temperature fluctuation is among the highest reported in the literature. We developed a habitat classification to simplify the description of thermal regimes and to describe the relationships between available thermal regimes and distribution patterns of stream fishes. Changes in community composition, species richness, and standing stocks of key fish species occurred across gradients in mean temperature and temperature fluctuation. These changes were used to identify three mean temperature categories (cold, <19°C; cool, 19–<22°C; and warm, ≥22°C) and three temperature fluctuation categories (stable, <5...

Distributions of stream fishes and their relationship to stream size and hydrology in Michigan's lower peninsula

Abstract We examined the distribution and abundance patterns of 69 fish species that commonly occur in the rivers of Michigans lower peninsula to develop a simple, empirically based model for describing fish assemblages. We used cluster analysis to group fishes that shared similar abundance patterns at 226 stream sites. The 17 clusters we identified explained about 39% of the variation in species abundances among the stream sites, providing a reasonable, albeit simplified, picture of general associations of fishes in lower Michigan streams. Known ecological differences among species and further analyses suggested that a measure of cluster abundance should not be used to predict the abundances of its constituent species. We selected catchment area (CA) and low-flow yield (LFY; 90% exceedence flow divided by catchment area) as axes for plotting fish distributions and rivers because these variables link catchment-scale features of the landscape to multiple, site-scale characteristics of stream habitat (e.g....

Defining and Characterizing Coolwater Streams and Their Fish Assemblages in Michigan and Wisconsin, USA

Abstract Coolwater streams, which are intermediate in character between coldwater “trout” streams and more diverse warmwater streams, occur widely in temperate regions but are poorly understood. We used modeled water temperature data and fish assemblage samples from 371 stream sites in Michigan and Wisconsin to define, describe, and map coolwater streams and their fish assemblages. We defined coolwater streams as ones having summer water temperatures suitable for both coldwater and warmwater species and used the observed distributions of the 99 fish species at our sites to identify coolwater thermal boundaries. Coolwater streams had June-through-August mean water temperatures of 17.0–20.5°C, July mean temperatures of 17.5–21.0°C, and maximum daily mean temperatures of 20.7–24.6°C. We delineated two subclasses of coolwater streams: “cold transition” (having July mean water temperatures of 17.5–19.5°C) and “warm transition” (having July mean temperatures of 19.5–21.0°C). Fish assemblages in coolwater stream...

A Multimetric Assessment of Stream Condition in the Northern Lakes and Forests Ecoregion Using Spatially Explicit Statistical Modeling and Regional Normalization

Abstract We sampled fish communities, water temperature, water chemistry, physical habitat, and catchment characteristics for 94 stream sites selected randomly throughout the Northern Lakes and Forests ecoregion and used those data to explicitly model reference conditions and assess ecological stream condition at each site via a regional normalization framework. The streams we sampled were first order through fourth order, and the catchments ranged from 0.9 to 458 km2. We developed multiple linear regression (MLR) models that predicted fish community metrics, water chemistry characteristics, and local physical habitat from catchment characteristics; we used these models to compare existing conditions with the conditions that would be expected based on the regression models. Our results indicated that the fish communities were relatively unimpaired because the catchment variables associated with human-induced land use change were important in only 1 of the 10 fish metric models. Agricultural land use was a...

Classification Tree Models for Predicting Distributions of Michigan Stream Fish from Landscape Variables

Traditionally, fish habitat requirements have been described from local-scale environmental variables. However, recent studies have shown that studying landscape-scale processes improves our understanding of what drives species assemblages and distribution patterns across the landscape. Our goal was to learn more about constraints on the distribution of Michigan stream fish by examining landscape-scale habitat variables. We used classification trees and landscape-scale habitat variables to create and validate presence-absence models and relative abundance models for Michigan stream fishes. We developed 93 presence-absence models that on average were 72% correct in making predictions for an independent data set, and we developed 46 relative abundance models that were 76% correct in making predictions for independent data. The models were used to create statewide predictive distribution and abundance maps that have the potential to be used for a variety of conservation and scientific purposes.

A River Valley Segment Classification of Michigan Streams Based on Fish and Physical Attributes

Abstract Water resource managers are frequently interested in river and stream classification systems to generalize stream conditions and establish management policies over large spatial scales. We used fish assemblage data from 745 river valley segments to develop a two-level, river valley segment-scale classification system of rivers and streams throughout Michigan. Regression tree analyses distinguished 10 segment types based on mean July temperature and network catchment area and 26 segment types when channel gradient was also considered. Nonmetric multidimensional scaling analyses suggested that fish assemblages differed among segment types but were only slightly influenced by channel gradient. Species that were indicative of specific segment types generally had habitat requirements that matched segment attributes. A test of classification strength using fish assemblage data from an additional 77 river valley segments indicated that the classification system performed significantly better than random...

A spatially constrained clustering program for river valley segment delineation from GIS digital river networks

River valley segments are adjacent sections of streams and rivers that are relatively homogeneous in hydrology, limnology, channel morphology, riparian dynamics, and biological communities. River valley segments have been advocated as appropriate spatial units for assessing, monitoring, and managing rivers and streams for several reasons; however, methods for delineating these spatial units have been tedious to implement or have lacked objectivity, which arguably has limited their use as river and stream management units by natural resource agencies. We describe a spatially constrained clustering program that we developed for delineating river valley segments from geographic information system digital river network databases that is flexible, easy-to-use, and improves objectivity in the river valley segment delineation process. This program, which we refer to as the valley segment affinity search technique (VAST), includes a variety of options for determining spatial adjacency in stream reaches, as well as several data transformation methods, types of resemblance coefficients, and cluster linkage methods. The usefulness of VAST is demonstrated by using it to delineate river valley segments for river network databases for Michigan and Wisconsin, USA, and by comparing river valley segments delineated by VAST to an expert-opinion delineation previously completed for a Michigan river network database.

Population Biology of Steelhead in a Stable-Flow, Low-Gradient Tributary of Lake Michigan

Abstract I examined the characteristics and dynamics of a population of wild steelhead Oncorhynchus mykiss in the Little Manistee River, an extremely stable-flow, low-gradient (sandy) tributary of Lake Michigan. I monitored autumn pan populations by electrofishing (1981–1983), and I monitored spring emigrant populations at a weir near the river mouth (1982–1984) and both autumn- and spring-returning adults at this weir (1979–1987). Relative to other Great Lakes populations, steelhead in the Little Manistee River had several notable characteristics that are probably linked to abundant groundwater and stable flows: (1) high abundances of age-1 parr, smolts, and adults, (2) constant autumn age-1 parr densities, (3) few emigrant parr, (4) fast growth when in the stream environment, and (5) relatively late age at maturity (after 3 years in the lake). An excessive sand bed load occurs in the low-gradient sections of the river, limiting gravel spawning areas to higher-gradient sections. This limited spawning are...

Identification and Contribution of Wild and Hatchery Steelhead Stocks in Lake Michigan Tributaries

Abstract We developed and validated a simple and accurate assignment rule, based on one quantified scale characteristic, for the identification of wild and hatchery stocks of Great Lakes steelhead Oncorhynchus mykiss (formerly Salmo gairdneri). A ratio between the first winter and spring growth rates, inferred from scale circulus patterns, met the criteria of being both distinct between wild and hatchery adults and consistent among life stages, years, and geographic locations within respective wild and hatchery groups. This rule was applied to samples of unknown-origin adult steelhead collected in seven rivers in the northwestern Lower Peninsula of Michigan during 1983–1984, to estimate the percentage of wild fish in each river and its variance. Adults returning during these periods were representative of pre-1983 hatchery production in Michigan, when yearling parr was the typical life stage stocked. The percentage of wild fish in the adult population was estimated to be 100% for an unstocked trout river,...