Historical Changes in Large River Fish Assemblages of the Americas

<em>Abstract.</em>—The Ohio River Valley Water Sanitation Commission (ORSANCO), along with cooperating state and federal agencies, sampled fish assemblages from the lockchambers of Ohio River navigational dams from 1957 to 2001. To date, 377 lockchamber rotenone events have been conducted, resulting in the collection of nearly three million fishes, representing 116 taxa, including 7 hybrids, in 19 families. We observed significant temporal trends in Ohio River fish riverwide at the assemblage, guild, and species levels. Modified index of well-being (MIWB) scores and changes in guild structure indicated significantly (<em>p </em>< 0.05) improving fish assemblages throughout the Ohio River. Quantile regression of the abundance of individual species by year revealed significant declines (<em>p </em>< 0.05) in populations of several pollution-tolerant species (e.g., <em>Ameiurus </em>spp., goldfish <em>Carassius auratus</em>) with time, while some intolerant species (e.g., smallmouth redhorse <em>Moxostoma breviceps, </em>smallmouth bass <em>Micropterus dolomieu, </em>and mooneye <em>Hiodon tergisus</em>) have increased in recent years. In all, 40 of the 116 taxa collected in the lockchamber surveys changed significantly over time. Sixteen species did not change. Sixty species could not be analyzed either because of incomplete data or insufficient abundance. Fish assemblage metrics that would be expected to decrease with improving conditions in the Ohio River (percent tolerant individuals, percent nonindigenous individuals, and percent detritivore individuals) also declined (<em>p </em>< 0.05). These changes coincide with marked improvement of the water quality in the Ohio River over the last 50 years, particularly in the aftermath of the Clean Water Act (1972). Some species and metric responses may also be due to the replacement of the 50 wicket dams by the construction of 18 high-lift dams.

<em>Abstract.</em>—The present ichthyofauna (1965–2001) of the Wabash River system is compared to that of three periods: presettlement through 1820, 1875–1900, and 1940– 1950. This second largest Ohio River tributary flows freely for 350 mi. However, its environment and watershed have been altered greatly from presettlement times; twothirds has been converted to agriculture, eliminating all prairies and most forests and wetlands. Canals, large and small dams, channelization, and effluents have extinguished 12 fish species, diminished some, and favored others. Thirteen of approximately 175 species are recent, including 3 aliens. Better municipal and industrial waste treatment has improved water quality, but excessive agricultural runoff remains detrimental to many fishes. Degraded habitats exacerbate these problems. Many sensitive species are today either absent or severely reduced in distribution and abundance compared to 50 years ago. Smallmouth bass <em>Micropterus dolomieu </em>has been replaced by largemouth bass <em>M. salmoides </em>or spotted bass <em>M. punctulatus, </em>and few visual piscivores occur except near reservoirs.


2019 ◽  
Vol 26 (6) ◽  
pp. 590-599 ◽  
Author(s):  
Megan K. Schall ◽  
Timothy Wertz ◽  
Geoffrey D. Smith ◽  
Vicki S. Blazer ◽  
Tyler Wagner

<em>Abstract.</em>—This book’s objective is to document historical changes in the fish assemblages of large American rivers, and to determine patterns in and rationale for those changes. In this chapter, we review pertinent literature on large rivers and fish assemblages worldwide and briefly introduce the chapters. We expect that the information contained in this book will aid river management in general, and stimulate similar historical fish assemblage studies elsewhere. There will never be a better time to learn and understand what has been changed and to reverse or slow undesirable changes.


Ecosphere ◽  
2018 ◽  
Vol 9 (7) ◽  
pp. e02351 ◽  
Author(s):  
Kristen L. Bouska

2019 ◽  
Vol 10 (2) ◽  
pp. 602-618
Author(s):  
Mark J. Fincel ◽  
Nicholas B. Kludt ◽  
Hilary A. Meyer ◽  
Michael Weber ◽  
Christopher M. Longhenry

Abstract Sauger Sander canadensis, Walleye Sander vitreus, and Smallmouth Bass Micropterus dolomieu, are important sportfish in the four main stem Missouri River reservoirs in South Dakota: Lakes Oahe, Sharpe, Francis Case, and Lewis and Clark. However, native Sauger populations, once assumed to be stable, may be in decline. To identify temporal trends and potential interspecific mechanisms affecting Sauger populations, we examined their long-term abundance trends in standard gillnet surveys and angler catch and harvest trends in long-term creel surveys. We also used a robust design occupancy model to examine changes in within-lake distribution of this species. There are concerns regarding the effects of Walleye and Smallmouth Bass on Sauger, so we also described the population trends of these potential competitors. Standard gillnet surveys indicated declining abundance of both Sauger and Walleye in Lakes Oahe and Sharpe. Sauger abundance has trended down in Lewis and Clark, but upward in Francis Case. Conversely, Walleye abundance trends declined in Francis Case and increased in Lewis and Clark. Occupancy (ψ̂) of Sauger declined in all four reservoirs, indicating a contracting distribution throughout the reservoirs. Walleye occupancy remained ∼1.0. Smallmouth Bass occupancy increased in the three reservoirs with sufficient data for analysis, excluding Lewis and Clark Lake. Smallmouth Bass exhibited steady increases in angler catch and harvest, as well as abundance in long-term gillnet surveys, suggesting expanding and increasing populations. Habitat alteration is hypothesized to be a major driver of the Sauger occupancy and abundance declines. However, Walleye and Smallmouth Bass interactions could also be contributing to observed declines of native Sauger.


2001 ◽  
Vol 58 (2) ◽  
pp. 342-351 ◽  
Author(s):  
Pamela SD MacRae ◽  
Donald A Jackson

Fish assemblages in small lakes ([Formula: see text]50 ha) in central Ontario were characterized to determine the impact of smallmouth bass (Micropterus dolomieu) predation and habitat complexity on the structure of littoral zone fish assemblages. Data were collected employing minnow traps and visual assessment. Although species richness did not differ between lakes with and without smallmouth bass, species composition and relative abundance did differ. We identified two distinct fish assemblage types: one characterized by small-bodied species, mainly cyprinids, and a second by large-bodied centrarchid species, e.g., smallmouth bass. Smallmouth bass appear to reduce abundance, alter habitat use, and extirpate many small-bodied species such as brook stickleback (Culaea inconstans), fathead minnow (Pimephales promelas), pearl dace (Margariscus margarita), and Phoxinus spp.


<em>Abstract.</em>—Fish assemblages in Atlantic coastal rivers have undergone extensive ecological change in the last two and a half centuries due to human influence, including extirpation of many migratory fish species, such as river herring <em> Alosa </em>spp. and introduction of nonnative piscivores, notably Smallmouth Bass <em> Micropterus dolomieu</em>. Recently, dam removals and fish passage improvements in the Penobscot River, Maine, have allowed river herring to return to reaches of the river that have been inaccessible since the late 19th century. Alosine populations have increased and this trend is anticipated to continue. This may increase forage in the system which could potentially increase growth for Smallmouth Bass, the dominant piscivore. We examined the diet and growth of Smallmouth Bass collected from areas of the Penobscot River watershed with and without access to river herring as prey. We collected 765 Smallmouth Bass throughout 2015, examined the stomach contents of 573 individuals, and found notable differences in diet among three river reaches with common seasonal trends. Juvenile river herring composed an average of 19% (SE = ±6%) of stomach contents by mass from Smallmouth Bass collected in the freshwater tidal area but were rarely observed in the diets upstream. We used estimates from von Bertalanffy growth models to examine differences in growth among reaches and found that asymptotic length was the longest (425 mm TL) in the Tidal reach where access to river herring was unrestricted. We then used these data to predict changes to growth associated with increased access to juvenile river herring prey with bioenergetics models. Results indicated that substituting juvenile river herring for less energy-dense prey (e.g., invertebrates) may lead to increases in seasonal growth throughout the watershed as river herring populations continue to rebound in response to dam removal. Our results provide insight into the diet and growth of Smallmouth Bass in a large New England river, and provide a foundation for future work investigating unfolding changes to these characteristics following recent dam removals.


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