Loftus, Andrew J.; Flather, Curtis H. 2012. Fish and other aquatic resource trends in 

the United States: A technical document supporting the Forest Service 2010 RPA 

Assessment. Gen. Tech. Rep. RMRS-GTR-283. Fort Collins, CO: U.S. Department of 

Agriculture, Forest Service, Rocky Mountain Research Station. 81 p.

Abstract: The Forest and Rangeland Renewable Resources Planning Act (RPA) of 1974 requires 

periodic assessments of the status and trends in the Nation’s renewable natural resources including 

fish and other aquatic species and their habitats. Data from a number of sources are used to 

document trends in habitat quality, populations, resource use, and patterns of imperilment among 

aquatic fauna. Freshwater habitat quality varied widely across the United States. Nationwide, 

more than half of monitored lakes were ranked in good condition, but the percentage ranged from 

a high of 91 percent in the upper Midwest to a low of 1 percent in the Northern Plains. Habitat 

conditions in monitored small streams indicated that 42 percent were found to be in poor condition. 

The Southern Appalachians, Southern Plains, and Northern Plains have 50 percent or more of 

their stream lengths in poor condition. The condition of small stream habitats was best in the 

Western mountains. Data availability continues to limit comprehensive evaluations of freshwater 

fish populations. Of the 253 marine fish stocks assessed in 2009, 38 percent were deemed to be 

overfished or subject to overfishing. Pacific salmon have declined throughout much of their range 

although stocks native to Alaska have fared better than those in the Pacific Northwest. Species 

associated with aquatic habitats have higher proportions of species considered to be at-risk of 

extinction than other species groups. At-risk aquatic species are concentrated in watersheds 

occurring in the southern Appalachians and the southeastern coastal plain. The number of anglers 

has declined since the early 1990s. Relationships between land use, water quality, and aquatic 

species conditions are explored in a series of case studies. The report provides implications of 

aquatic resource trends for management and planning.

Authors

Andrew J. Loftus is a natural resource consultant at 3116 Munz Drive, Suite A, Annapolis, MD; 

Curtis H. Flather is a research ecologist at the Rocky Mountain Research Station in Fort Collins, CO.

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Acknowledgments

This work was supported by the Forest Service Research and Development’s RPA research 

program as part of the Forest Service’s national assessment reporting requirements mandated 

by the Forest and Rangeland Renewable Resources Planning Act. The document benefited 

from constructive reviews received from Dr. Craig Paukert (USGS Missouri Cooperative Fish 

and Wildlife Research Unit, University of Missouri), Dr. Nancy Leonard (Northwest Power and 

Conservation Council), and Dr. Linda Langner (USDA Forest Service). We also wish to thank 

Michael S. Knowles (U.S. Forest Service, Rocky Mountain Research Station) for data analysis 

and graphics support, Lane Eskew for editing the final document, Richard Aiken (U.S. Fish and 

Wildlife Service) for unpublished data on angler participation status and trends, Dr. Nancy Nate 

(University of Wisconsin-Stevens Point) and Andrea Ostroff (U.S. Geological Survey) for contributions to the case studies, Dr. Tom Sminkey and Dr. Alan Lowther (National Marine Fisheries 

Service) for assistance with marine fisheries statistics, Jeff Smith (Morrisinformatics LLC) for 

graphics support, and Jason McNees (NatureServe) for his assistance with at-risk species associated with aquatic habitats.
Contents

Introduction...................................................................................................1

Trends in Fish Habitat and Populations.....................................................3

Freshwater Resources in the United States..................................................3

Lake and Stream Conditions.................................................................3

Great Lakes ..........................................................................................6

Water Quality Impairments .................................................................10

Fish Contaminant Advisories ..............................................................12

Fish Populations .................................................................................12

Marine and Estuarine Fish Stocks...............................................................13

Species of Conservation Concern...............................................................16

Nationwide Status...............................................................................18

Imperiled Species Trends by RPA Region ..........................................20

Marine Species ...................................................................................23

Trends in Harvest .......................................................................................23

Trends in Participation...............................................................................25

Recreational Fisheries.................................................................................25

National Participation..........................................................................25

RPA Regional Statistics ......................................................................26

Economics of Recreational Fishing.....................................................27

Recreational Fishing on Forest Service Lands ...................................29

Marine Recreational Fishing ...............................................................29

Commercial Fisheries..................................................................................31

North Central

Great

Plains

Intermountain

Pacific

Northwest

Northeast

NORTH

SOUTH

Southeast

Pacific

Southwest

South Central

ROCKY MOUNTAIN

PACIFIC COAST
Management Implications..........................................................................33

Data Availability ........................................................................................... 33

Program Planning........................................................................................ 34

Case Study 1: Impacts of Urbanization on Fisheries and 

Aquatic Ecosystems.......................................................................37

Case Study 2: Exploring Trends in Largemouth Bass Relative 

Abundance With MARIS.................................................................41

Case Study 3: Status of Northwest Pacific Salmon ................................47

Case Study 4: Atlantic Coast Striped Bass..............................................51

Case Study 5: Synopsis of Climate Change Effects on 

Aquatic Systems.............................................................................55

Case Study 6: National Fish Habitat Assessment...................................61

References ..................................................................................................68

Appendix A. Glossary of terms used in the text......................................75

Appendix B: Scientific names of species mentioned in the text...........78

Appendix C: Source Data for Figure 3.....................................................80

Appendix D: Source Data for Figure 4......................................................81

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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Introduction _________________________________________

Aquatic ecosystems provide a variety of ecological services and economic benefits to society 

(see Appendix A for a glossary of terms). These range from products as fundamental as safe 

drinking water to healthy and abundant fish populations that provide food for consumers and 

sustain leisure opportunities for recreational anglers.

The ecological condition of these resources is driven by many factors. Aquatic systems are the 

recipients of the byproducts from activities in the surrounding landscape and are also affected 

by inputs that can originate from well outside the local ecosystem. Nonpoint pollution delivery is affected by land cover, forest and rangeland management, and agricultural activities 

within watersheds (Allan and others 1997) and freshwater ecosystems are particularly affected 

by the introduction of exotic species originating from intercontinental exchanges (Rahel 

2002). Furthermore, aquatic systems are often collection points for elements from atmospheric deposition. As such, the biotic communities in these systems are heavily influenced 

by forces external to their immediate surroundings (Kennen and others 2005). At the same 

time, aquatic systems can also serve as delivery mechanisms, transporting the accumulation 

of atmospheric deposition, nutrients, and runoff from the surrounding watershed thousands of 

miles away to feed other aquatic systems as well as depositing the sediments that they carry 

on flooded landscapes far away from their original source. Thus, input from the farthest inland 

reaches of the continental United States can influence the health of aquatic biota in the estuarine and marine ecosystems of America’s coastland.

These external influences that may originate in distant landscapes present challenges to managers of aquatic systems around the United States (Fausch and others 2002). The dynamic 

linkage between landscapes and aquatic conditions is nothing new, but the speed at which 

changes can occur before management can react has generally increased with the evolution of 

industrial society. For this reason, periodic evaluations of the current aquatic resource condition (status) and an analysis of how resource conditions have changed over time (trends) are 

a necessary prerequisite for science-based management and policy decisions. This report provides an overview of the information that is available on the status and trends of fisheries and 

aquatic resources, identifies information gaps that impede the assessment of status and trends, 

and highlights some of the large scale landscape processes that are threatening aquatic ecosystems today.

This report is motivated by the Forest and Rangeland Renewable Resources Planning Act of 

1974 (RPA) as amended by the National Forest Management Act of 1976. The RPA directs the 

Forest Service to prepare periodic national assessments of the current and expected renewable 

natural resource situation on all of the nation’s forest and range lands. Fish and other living 

aquatic resources, and the habitats on which they depend, are an important aspect of these 

resource assessments, particularly as managers move to a more holistic ecosystem approach 

and strive to sustain the goods and services that the public derives from aquatic systems.

We review trends in several attributes of aquatic resources including aquatic habitat, fish 

populations, harvests, and participants in recreational and commercial fisheries. We report 

national summaries of emerging trends and, to the extent that the data permit, regional 

aquatic resource trends for each of the four RPA Assessment Regions (Figure 1). In some 
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

instances, data on aquatic resources have been reported for regions that could not be aggregated to conform to the RPA regions defined in Figure 1. For this reason, we also present 

aquatic resource trends for other geographic regions when they are well-established in aquatic 

resource monitoring (for example, EPA ecoregions).

The RPA directs that an assessment of resources and utilization occurring on all lands of all 

ownership be conducted, not just on lands for which the USDA Forest Service has primary 

resource stewardship responsibility. Therefore, case studies and population assessments are 

provided here for a variety of lands, including near-shore marine species. Previous RPA 

assessments have noted that aquatic systems face serious threats from changing landscape 

practices (Loftus and Flather 2000). While this is still true in 2010, scientists and managers 

have more information available today for assessing these threats and formulating possible 

actions to directly address or mitigate them. However, this report is not a detailed accounting of the status of every aquatic resource in the United States and as such differs from some 

other resource assessment documents prepared for the RPA. As we discuss later, the information needed to make such analyses and determinations is incomplete and difficult to access. 

This report does focus on the general condition of aquatic habitats, species (see Appendix B 

for scientific names of species mentioned in this report), and usage trends as reflected by the 

results of existing surveys and data collection efforts. Supplementing this are case studies that 

predominately focus on landscape or environmental agents impacting aquatic species status 

and trends. Intertwined throughout the document, and highlighted in special sections, are the 

socioeconomic benefits attributable to maintaining healthy aquatic ecosystems.

North

South

Pacific Coast Rocky Mountain

Figure 1—Forest Service RPA Assessment regions.
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Trends in Fish Habitat and Populations __________________

Freshwater Resources in the United States

There are over 3.5 million miles of freshwater rivers and streams and 39.9 million acres of 

lakes and reservoirs (excluding Great Lakes) in the United States (USEPA 2006, 2009a). 

These aquatic systems play a vital role in the economic, social, and ecological framework of 

the country. Freshwater lakes and reservoirs provide 70 percent of the drinking water of the 

United States, hydropower for industry, irrigation for agriculture, and transportation corridors 

for shipping among other anthropogenic uses.1 Ecologically, freshwater resources provide 

vital habitat that supports freshwater and estuarine fish populations, aquatic species of conservation concern, and other aquatic flora and fauna that constitute healthy aquatic ecosystems 

which in turn support commercial and recreational fishing activities.

Lake and Stream Conditions

In 2004-2005, the U.S. EPA conducted an assessment of chemical, physical, and biological 

attributes of 1,392 “wadeable,” perennial stream locations in the United States to determine 

the biological condition of those waters (USEPA 2006). These streams constitute approximately 90 percent of the stream and river miles in the coterminous United States. In 2007, 

the EPA completed the National Lakes Assessment (NLA) evaluating the condition of natural 

and human-made freshwater lakes, ponds, and reservoirs greater than 10 acres in size in the 

coterminous United States, excluding the Great Lakes (USEPA 2009). A total of 1,028 lakes 

were sampled during summer 2007, representing the condition of about 50,000 lakes nationwide (excluding the Great Lakes and Great Salt Lake). Taken together, these two assessments 

constitute the most comprehensive scientifically based evaluation of the freshwater resources 

of these 48 states.

The biological condition of lake and stream habitats was measured by the percentage of taxa 

observed compared to those that are expected based on reference conditions in least-disturbed 

aquatic systems (USEPA 2006, 2009a) – also called the Observed/Expected (O/E) ratio of 

taxa loss. Measurements of stream conditions were supplemented with a second measure, the 

Macroinvertebrate Index of Biotic Condition (MIBC). The MIBC is based on the Index of 

Biotic Integrity developed for fish in Midwestern streams that was modified for other regions, 

taxonomic groups, and ecosystems. The MIBC incorporates measures of taxonomic richness, 

composition, and diversity as well as feeding groups, pollution tolerance, and life history 

traits.

Lake ratings were based on an O/E index of phytoplankton and zooplankton taxa loss. The 

wadeable streams survey rated condition based on O/E ratios and MIBC of benthic macroinvertebrates. The results of these assessments are broken down into three regions and nine 

ecoregions (Figure 2) with the rating scales summarized in Table 1. Overall, 22 percent of the 

lakes and 42 percent of wadeable streams were rated in “poor condition” while 56 percent and 

28 percent respectively were rated as being in “good” condition (Table 2).

1 US Environmental Protection Agency http://water.epa.gov/type/lakes/, October 24, 2011.
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

Figure 2—Ecoregions surveyed by the EPA Wadeable Streams Assessment.

Table 1—Condition ratings used to assess habitat quality of lakes and 

streams across the coterminous United States. Stream habitat condition is measured by macroinvertebrate taxa loss determined by the ratio 

of observed number of species (O) to the number of species expected at 

least-disturbed reference sites (E).

Waterbody type

Rating Lakes (> 10 ac) Streams (wadeable)

Good <20 percent taxa loss Stream condition as good as or better than 

(O/E>0.80) 75% of reference sites

Fair 20-40 percent taxa loss Stream condition worse than 75% but 

better than 5% of reference condition 

Poor >40 percent taxa loss Stream condition worse than 95% of 

(O/E<0.60) reference sites
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

The Upper Midwest had by far the greatest number of lakes rated as “good” biological condition (91 percent). The Northern Plains region, where Federal lands account for nearly 26 

percent of the total area, had the greatest number of lakes rated as “poor” biological condition 

with 90 percent of the lakes in that category (Table 3). Lake shorelines in this region exhibit 

very high levels of disturbance due to human activities, with 90 percent of lakes having moderate or high lakeshore human disturbance. This anthropogenic disturbance fosters increased 

sedimentation and runoff and elevated nutrient inputs. Total phosphorus and nitrogen concentrations were poor in 71 percent and 91 percent of lakes respectively in the Northern Plains 

region. Additionally, microcystin (a toxin to humans, plants, and wildlife) was present in 

one third of lakes and at levels of concern in 1 percent of lakes. Analysis of fish tissue contaminants (collected as part of another study) showed mercury concentrations in game fish 

exceeded health-based limits in 49 percent of lakes, and polychlorinated biphenyls (PCBs) 

were found at potential levels of concern in 17 percent of lakes (fish consumption advisories 

are discussed in more detail later in this report). A comparison of these results to comparable 

studies in the 1970s revealed that 75 percent of the 800 lakes sampled in the 1970s showed 

either improvements or no change in phosphorus levels in the 2007 study (USEPA 2009). 

There is some evidence that reservoirs may facilitate the spread of exotic aquatic organisms 

throughout a landscape (Havel and others 2005).

Table 2—Status of the biological condition of lakes and impoundments greater than 10 

acres and small streams in the United States (USEPA 2006, 2009). Numbers in parenthesis indicate number of lakes or miles of streams in the United States.

Natural lakes Human-made lakes All lakes Wadeable streams

Ranking (29,308) (20,238) (49,546) (671,051 miles)

Good condition 66.5% 40.4% 55.8% 28.2%

Fair condition 16.3% 28.8% 21.4% 24.9%

Poor condition 16.8% 30.4% 22.3% 41.9%

Table 3—Status of the biological condition of lakes > 10 acres 

by region in the United States based on planktonic O/E taxa 

loss (USEPA 2006).

Number of lakes Condition (% of lakes)

Region in each region Good Fair Poor

Nationwide 49,546 56 21 22

Northern Appalachians 5,226 55 30 15

Southern Appalachians 4,690 42 27 31

Coastal Plains 7,009 47 25 27

Upper Midwest 15,562 91 5 4

Temperate Plains 6,327 24 40 35

Southern Plains 3,148 34 36 29

Northern Plains 2,660 1 6 90

Western Mountains 4,122 58 31 11

Xeric West/Southwest 802 35 14 49
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

On a regional basis, the Western streams were in the best biological condition (45 percent 

of stream length in good condition), the Plains and Lowlands region next with 30 percent of 

stream length in good condition, and the Eastern Highlands in the poorest condition with only 

18 percent of stream length in good condition (Table 4).

Table 4—Status of small streams (percent of stream miles in each condition), by region in the coterminous United States (USEPA 2006).

Western Region Plains and Lowlands Eastern Highlands

Condition (152,425 miles) (242,264 miles) (376,362 miles)

Good 45.1 29.0 18.2

Fair 25.8 29.0 20.5

Poor 27.4 40 51.8

On an ecoregional basis, the Southern Plains, Southern Appalachians, and Northern Plains 

regions exhibited the greatest percentage of streams rated in “poor” condition with over 50 

percent of the streams in those regions in this category based on the Macroinvertebrate Index 

of Biotic Condition (Figure 3). In terms of macroinvertebrate taxa loss based on the O/E ratio, 

the Appalachian complex (Northern and Southern Appalachian ecoregions) had the highest 

percentage of stream miles exhibiting greater than 50 percent loss (Figure 4). As with lakes, 

the factors having the greatest impact on streams in all of the regions were elevated nutrients (nitrogen and phosphorus), riparian disturbance (defined as non-existent or a simplified 

network of vegetative cover along the stream bank), and streambed sediments. The risk of 

assigning a stream a condition ranking of “poor” was two times greater for streams that were 

subject to these threats than for streams that were assigned a rank of “good” (USEPA 2006).

Great Lakes

The Great Lakes constitute the largest system of surface freshwater on earth. The five Great 

Lakes and connecting waters contain approximately 20 percent of the earth’s freshwater and 

90 percent of the surface freshwater in the United States. Considering the large geographic 

coverage of the lakes, and their multiple political jurisdictions spanning two national boundaries and eight state boundaries, there is no single assessment of water quality or habitat condition that can characterize the state of the lakes. However, extensive collaboration between 

jurisdictions has resulted in a compilation of assessments that can be applied to this purpose.

Human settlement within the watersheds of the lakes ranges from relatively sparse areas of 

the northern regions of Lake Superior to some of the most densely populated urban centers 

including Chicago, Detroit, Buffalo, Cleveland, and other areas of the southern parts of the 

region. With this range of settlement patterns, each region in the Great Lakes basin faces 

unique sets of challenges to water quality and habitat condition. To varying degrees, all areas 

face major stresses of toxic and nutrient pollution, invasive species, and habitat degradation. 

Pollution sources include sedimentation and agricultural pollutants, industrial discharges, 

runoff and waste water discharges from urban areas, and pollutants from atmospheric 

deposition.
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Figure 3—Stream biological condition as measured by the Macroinvertebrate Index of Biotic Condition in the EPA Wadeable Stream Survey. 

See Appendix C for source data values.
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

Figure 4—Stream habitat condition as measured by macroinvertebrate taxa loss determined by the ratio of observed number of species (O) 

to the number of species expected at least-disturbed reference sites (E) within each ecoregion. Pie charts indicate the proportion of stream 

lengths in various classes of taxa loss. The ” >50%” class indicates that more than half the expected species from least-disturbed reference 

sites were lost (undetected in surveys), and the “ <10%” class indicates that fewer than 10% of the expected species were lost from surveyed 

streams. See Appendix D for source data values.
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Overall, Great Lakes coastal condition is rated as fair to poor in all five of the lakes and connecting waterways (Table 5). In 2008, a compilation of environmental indicator reports was 

assembled for the “State of the Lakes Ecosystem Conference” in Niagara Falls, Ontario. 

These indices produced mixed results for status and trends for the nine indicators measured, 

due largely to the diversity of habitats and stressors across the Great Lakes basin (Table 6) 

(USEPA and Environment Canada 2009). Additionally the effects of climate change were 

identified as a concern and emerging influence although no assessment was presented for the 

“status” or “trends” of that factor.

Further breaking these results down to a lake-by-lake basis reveals both the previously mentioned commonalities of stressors and the particular factors affecting each lake (Table 7).

Table 5—Great Lakes coastal condition based on 

five indices (USEPA 2008).

Index Rating

Water quality (eutrophic condition, water Fair

clarity, dissolved oxygen levels, phosphorus 

concentrations)

Fish tissue contaminants (concentrations Fair

of PCBs, mercury, chlordane, dioxin, 

and toxaphene)

Sediment quality (toxic contamination) Poor

Coastal habitat (amphibian and wetland- Poor

dependent bird abundance and diversity, 

extent of coastal wetlands)

Benthic community Poor

Table 6—Status and trends of environmental indicators for the 

Great Lakes basin (USEPA and Environment Canada 2009).

Indicator Status Trends

Coastal Zones and Aquatic Habitats Mixed Undetermined

Invasive Species Poor Deteriorating

Contamination (toxic chemicals) Mixed Improving

Human Health (drinking water, Mixed Undetermined 

consumption advisories)

Status of Biotic Communities Mixed Undetermined

Resource Utilization (water Mixed Undetermined 

withdrawals, energy consumption, 

urbanization)

Land Use-Land Cover Mixed Undetermined
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

Water Quality Impairments

Sections 305(b) and 303(d) of the Clean Water Act require states to report attainment of the 

water quality goals for their state waterbodies. It is the most comprehensive standardized 

reporting mechanism for evaluating achievement of “designated use” goals for water quality. 

According to the most recent data available,2 934.8 thousand miles of rivers and streams have 

been assessed in the last round of reporting (approximately 26 percent of all such waters in 

the United States). Of those assessed, 464.7 thousand miles (nearly 50 percent) were designated as “good,” 463.7 thousand miles, (nearly 50 percent) as “impaired,” and 6.4 thousand 

miles (1 percent) as “threatened.” For lakes, reservoirs, and ponds, 17.6 million acres were 

assessed, with 5.9 million acres (34 percent) rated as “good,” 11.6 million acres (66 percent) 

“impaired,” and 47.3 thousand acres as “threatened.”

2 http://iaspub.epa.gov/waters10/attains_nation_cy.control, October 30, 2010

Table 7—General condition and highlighted stressors of each of the Great Lakes 

(USEPA and Environment Canada 2009)

Lake Condition Stresses

Superior Ecosystem is in generally good Non-native species, toxic chemicals 

condition and fish consumption advisories, 

shoreline development and hardening, 

habitat loss, land use change, mining, 

and climate change effects.

Michigan Notable return of bird, mammal Major food web disruption, viral

and aquatic species due to habitat hemorrhagic septicemia in fish, 

restoration and dam removal and invasive quagga mussel, detrimental

a continued decline of contaminants algae growth, water levels below

in fish. average.

Erie Yellow perch stocks are recovering; Nutrient management remains the top 

walleye, lake trout, and lake whitefish priority for improving the lake. 

are struggling. PCBs and mercury 

continue to affect fish consumption. 

Zebra mussels, quagga mussels, round 

gobies, and predatory zooplankton, 

are changing the food web.

Ontario The reduction in contaminants Zebra mussels, quagga mussels, and 

continues to improve. predatory zooplankton have become 

established and are impacting food 

web dynamics. Nearshore algal 

blooms, resulting in beach closures, 

drinking water quality concerns, and 

costs to industry.

Huron Degradation is not as severe as in Major changes to the food web, fish

the lower Great Lakes diseases, and nearshore algal fouling.
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

On a national level, the probable sources contributing to these impairments (Table 8) are led 

by agricultural activities (104.3 thousand stream miles and 1.6 million lake acres) and atmospheric deposition (64.1 thousand stream miles, 3.8 million lake acres, and 56.2 thousand mi2

of open water in the Great Lakes). The combined effects of activities associated with urbanization (for example, urban runoff, municipal discharge, industrial activities, construction, 

etc.) are also significant causative factors behind the water quality impairments. Although 

all of these activities impact aquatic ecosystem health, urbanization is known to dramatically 

impact the condition of fish communities and is highlighted in an associated case study in this 

report [see Case Study 1: Impacts of Urbanization on Fisheries and Aquatic Ecosystems].

Table 8—EPA National Summary of probable causes of water quality impairment (USEPA http://iaspub.epa.gov/

waters10/attains_nation_cy.control, October 12, 2010).

Rivers and Lakes, Bays and Coastal Ocean and Great Lakes Great Lakes

streams reservoirs, and estuaries shoreline near coastal Wetlands shoreline open water

Probable source group (mi) ponds (ac) (mi2) (mi) (mi2) (acres) (mi) (mi2)

Agriculture 104,321 1,579,540 2,885 84 1 383,822 4,373

Aquaculture 1,055 4,490 0

Atmospheric deposition 64,119 3,772,737 4,238 70 200,741 285 56,254

Commercial harbor 109,240 481 20 1

 activities

Construction 12,638 305,080 16 3 3 13,971

Groundwater loadings/ 181 98,009 158 3,045

 withdrawals

Habitat alterations (not 33,012 359,247 2,091 8,017

 directly related to 

 hydromodification)

Hydromodification 60,075 1,240,807 2,532 5 115,704

Industrial 9,924 209,500 3,044 37 3 195,980 3

Land application/waste 8,003 80,284 52 1 1,634

 Sites/tanks

Legacy/historical 4,191 755,219 254 8 682 15,128

 Pollutants

Military bases 42 2

Municipal 38,184 644,660 4,499 107 10 458 27 3

 Discharges/sewage

Natural/wildlife 54,403 1,321,007 3,789 100 0 133,558 0

Other 8,560 777,527 2,406 34 65,874 25

Recreation and tourism 1,668 108,069 0 20 4 787

 (non-boating)

Recreational boating 147 126,174 545 1 8

 and marinas

Resource extraction 25,489 509,934 582 12 89,353

Silviculture (forestry) 19,409 247,865 0 2

Spills/dumping 1,698 176,699 26 13 2

Unknown 78,419 2,609,586 3,977 13 283 210,159 134 554

Unspecified nonpoint 44,338 815,722 1,773 106 4 63,901 9 3

 source

Urban-related 32,062 716,410 1,994 47 4 2 2 13,867

 Runoff/stormwater
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

Fish Contaminant Advisories

The number of advisories for fish consumption that are issued by state, tribal, and federal governments cannot be used to indicate trends in the conditions of the waters of the United States. 

The variability in criteria for issuing advisories, monitoring, and other data collection among 

the agencies responsible for issuing advisories creates inconsistencies that do not allow the 

establishment of national trends in fish advisories (USEPA 2009). Additionally, continually 

advancing technologies that allow for the detection of smaller levels of contaminants, greater 

focus on sampling programs over time, and other factors make year-to-year comparisons 

inaccurate.

Despite their lack of utility for assessing trends, advisories can be one piece of a gross snapshot of water quality. By themselves, they should not be used as an absolute indicator of water 

condition. A summary is provided here as simply an indication of the status of fish consumption advisories in the United States in 2008.

All 50 states, the District of Columbia, the territories of American Samoa and Guam, and five 

Native American tribes have issued fish consumption advisories. There are currently 4,249 

advisories in place, an increase of 397 since the previous reporting period in 2006. These 

advisories cover 18 million lake acres and 1.4 million river miles (an increase of 18 percent, 

and 52 percent respectively since 2006) representing 43 percent of the total lake acreage and 

39 percent of the river miles of the United States. However, this increase is not necessarily 

due to additional degradation of the waterways; it is attributed primarily to the issuance of 

several new advisories covering entire states instead of specific water bodies (USEPA 2009).

Advisories have been issued covering 34 different chemical contaminants. Ninety-seven 

percent of all advisories involve only five bioaccumulative chemical contaminants: mercury, 

polychlorinated biphenyls (PCBs), chlordane, dioxins, and dichlorodiphenyltrichloroethane 

(DDT) (Table 9).

Table 9—Number of advisories, lake acres, and river miles under fish consumption advisories for five major contaminants in 

the United States in 2008 (from USEPA 2009).

Number of Lake area under River length under

Chemical advisories advisory (ac) advisory (mi)

Mercury 3,361 16,808,032 1,254,893

PCBs 1,025 6,049,506 130,248

Chlordane 67 842,913 54,029

Dioxins 123 35,400 2,055

DDT 76 876,520 69,198

Fish Populations

To understand the situation of assessing status and trends of fisheries and aquatic resources, 

one must understand the fundamental basis for management of these resources in the United 

States. With only a few exceptions, responsibility for managing freshwater and near-shore 

marine fisheries resides with state and, in some cases, Native American tribal, governments. 

Exceptions exist for federal “trust” species which generally are threatened species, endangered species, interjurisdictional fish, marine mammals, and other species of concern, where 

the federal government’s role varies depending on status of a particular species.
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

With rare exception (for example, certain federal trust species), analysis of the status and 

trends of freshwater fisheries is conducted independently by individual states. Sampling programs, collection methodologies, and data protocols are developed by each state to meet their 

individual needs. Historic management approaches have focused on a waterbody-by-waterbody basis, not a statewide or ecosystem management basis. This system of management, 

which tends to work well for local fisheries management by individual states, does not lend 

itself to conducting large scale (regional or national) analyses of status and trends of freshwater aquatic populations.

In 1998, the U.S. Geological Survey’s Biological Resources Discipline conducted a comprehensive assessment of United States resources on a region-by-region basis. The USGS effort, 

which included fisheries and aquatic resources, engaged an extensive network of professionals from within the USGS ranks, universities, and other agencies. While the resulting report 

documents many case-by-case examples of the trends in specific fish populations, it falls short 

of a comprehensive analysis of the status and trends of aquatic species that is representative of 

an entire nation or region. The report noted that:

“Substantial trend information is only found on birds, some game 

animals, and commercially exploited species. And much of the 

information concerning exploited species comes from the harvest 

activity itself and is not independently measured. Thus, the limited 

information itself sometimes reflects the biases and limitations of the 

practitioners” (Mac and others 1998, vol 1:4).

This underscores the findings of previous RPA assessments (Flather and Hoekstra 1989; 

Loftus and Flather 2000), that information is substantially lacking, particularly in the freshwater environment, to conduct a comprehensive status and trends analysis.

However, in recent decades, increasing coordination among agencies in collection methods 

(Bonar and others 2009) and coordinated systems to report information (Loftus and Beard 

2009; Beard and others 1998) are improving the ability to utilize fisheries data that are collected by disparate agencies to develop regional status and trends analyses. Until these 

systems are more developed, a comprehensive status and trends of freshwater fisheries analysis will remain elusive. An example application of one of these systems that was initiated 

in part by the USDA Forest Service, the Multistate Aquatic Resources Information System 

(MARIS), for developing trend information is found in an accompanying case study [see Case 

Study 2: Exploring Trends in Largemouth Bass Relative Abundance with MARIS]

Marine and Estuarine Fish Stocks

States also maintain management authority for most near-shore marine species occurring 

within state waters (generally extending seaward 3 miles from the shoreline). However, a 

series of interstate fisheries commissions collectively covering all United States coastal waters 

has improved coordination among the states for management and stock assessment of fish that 

migrate through multiple state jurisdictions. On the Atlantic coast, while management authority still resides with state governments coordinating management programs through this interstate compact, the federal government maintains a role in helping to enforce the provisions 

of the management plans. This situation is unique to the Atlantic coast and is not in place on 

either the Gulf of Mexico or Pacific coasts.
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

This report highlights a few species that are likely to be impacted by changes in landscape 

usage due to life history strategies that make them dependent on inland freshwater (or estuarine) habitats. The inclusion or exclusion of species is somewhat arbitrary; at its broadest 

interpretation nearly all species could be included. The accompanying case study on northwest Pacific salmon highlights one such fishery that is clearly impacted by landscape changes 

and which the Forest Service plays a key role through management of National Forest system 

lands [see Case Study 3: Status of Northwest Pacific Salmon].

Diadromous species depend on fresh water for either reproduction or, conversely, in their 

adult stages and thus are directly impacted by nearshore habitat conditions. Table 10 lists the 

truly diadromous species on the East coast that are covered under management plans of the 

Atlantic States Marine Fisheries Commission (horseshoe crabs are included due to their direct 

dependence on beaches for reproduction). Of these, only Atlantic striped bass populations are 

considered to be healthy although concern is increasing due to downward trends in key population metrics [see Case Study 4: Atlantic Coast Striped Bass].

Table 10—Status and trends of select Atlantic coast nearshore species 

considered to be diadromous and covered by interstate fishery management 

plans (source: Atlantic States Marine Fisheries Commission, www.asmfc.org)

Species Condition

American eel Unknown; recreational and commercial landings declining.

Atlantic sturgeon Overfished; proposed for listing under Endangered Species Act.

Horseshoe crab Unknown; declines in commercial harvest; increasing trends 

in abundance in the southeast and Delaware Bay regions and 

decreasing abundance in the New York and New England regions.

American shad Most stocks have significantly declined from historic levels 

and do not appear to be recovering.

Striped bass Healthy; not overfished and overfishing is not occurring; some 

disease concerns.

Marine species fall outside of the primary focus of the RPA analysis and are only briefly 

addressed here. The National Marine Fisheries Service (NMFS, also referred to as NOAA 

Fisheries), a division of the National Oceanic and Atmospheric Administration, is the primary 

federal agency responsible for managing fisheries and fish stocks occurring in the United 

States’ Exclusive Economic Zone (or EEZ, which generally extends from 3 miles to 200 

miles offshore). NMFS management occurs through a series of regional management councils 

and, in some cases, international agreement for highly migratory species. Data collection has 

tended to focus on those species of high economic or social importance (NMFS 2009a).

For 2009, NMFS reviewed the status of 522 individual stocks and stock complexes. Data was 

sufficient for 253 of these stocks to make a determination of “overfished and/or overfishing.”3

3 A stock that is subject to overfishing has a fishing mortality (harvest) rate above the level that provides 

for the maximum sustainable yield. A stock that is overfished has a biomass level below a biological 

threshold specified in its fishery management plan.
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Forty-six of these stocks (23 percent) were deemed to be overfished and 41 (15 percent) 

subject to overfishing (NMFS 2010b). This is comparable to 2008, when 46 (23 percent) were 

overfished and 41 (16 percent) of the stocks with sufficient data were subject to overfishing 

(Table 11). Four stocks of fish have been rebuilt.

To measure the sustainability of fisheries, NMFS has developed the Fish Stock Sustainability 

Index (FSSI). This measures the “performance of 230 key stocks that are important to the 

recreational and commercial fisheries. The FSSI increases as overfishing is ended and stocks 

rebuild to the level that provides maximum sustainable yield” (the highest yield that can be 

taken from a fish stock while maintaining a stable population over time) (NMFS 2009b). 

Stocks with biomass exceeding 80 percent of the level that would produce maximum sustainable yield are considered to be in the “sustainable” range.

Table 11—Status of marine fish stocks (NMFS 2008, 2009, 2010b).

Number of Number of stocks Number of stocks Number of stocks subject

Year stocks reviewed with sufficient data overfished (status) to overfishing (trend)

2007 528 255 45 41

2008 531 259 46 41

2009 522 253 46 38

The FSSI is calculated by assigning a score for each of five attributes of individual fish 

stocks:

Maximum Points

1. “Overfished” status is known. 0.5

2. “Overfishing” status is known. 0.5

3. Overfishing is not occurring (for stocks 

with known “overfishing” status). 1.0

4. Stock biomass is above the “overfished” 

level defined for the stock. 1.0

5. Stock biomass is at or above 80 percent 

of the biomass that produces maximum 

sustainable yield (BMSY). This point is in 

addition to the point awarded for being 

above the “overfished” level. 1.0

The maximum score that each stock may receive is 4, which indicates a fish stock in favorable 

condition. The value of the FSSI is the sum of all 230 individual stock scores. The maximum 

total FSSI score is 920, achieved if all 230 stocks were to each receive a score of 4.4 Thus, 

higher indexes indicate generally increasing sustainability of fisheries (even though some 

individual fish stocks may be declining while others are increasing). The FSSI increased from 

357.5 in 2000 to 573 in 2009 (Figure 5). Since 2000, the FSSI has increased 60 percent indicating a generally improving condition.

4 National Marine Fisheries Service http://www.nmfs.noaa.gov/sfa/statusoffisheries/2010/fourth/Q4%20

2010%20FSSI%20Summary%20Changes.pdf
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

Species of Conservation Concern

Trends in species imperilment can be an indicator of aquatic system health. Currently, a total 

of 139 species of fish are formally listed as threatened (66 species) or endangered (73 species) 

under the Endangered Species Act of 1973 (ESA; P.L. 93-205, 87 Stat. 884, as amended; 16 

U.S.C. 1531-1536, 1538-1540). Of these, the NMFS leads the recovery of 22 endangered 

and seven threatened fish species. In addition, 104 endangered and 22 threatened clams, 

snails, and aquatic crustaceans are on the list (USFWS species listing November 1, 2010).5

Geographically, formally listed freshwater fish are concentrated in the southern Appalachians, 

the arid Southwest, and the Pacific Northwest (Figure 6a). The geographic occurrence of all 

aquatic vertebrates and invertebrates show a similar pattern of concentration, but with notable 

numbers of listed species occurring in Peninsular Florida and in tributaries associated with the 

Washbash River in Indiana (Figure 6b).

Perhaps the most comprehensive listing of fishes that are in jeopardy of becoming endangered 

or extinct is provided by Jelks and others (2008) since it builds from a comparative database 

over a period of more than 25 years. Collectively termed “imperiled species,” the conservation status of each taxon was determined by a panel of experts from the Endangered Species 

Committee of the American Fisheries Society. The 2008 analysis built from the results of two 

earlier works of similar nature (Deacon and others 1979 and Williams and others 1989) allowing a comparison of trends in the listing status over that 20 year period.

5 http://www.fws.gov/endangered/species/us-species.html

Year

FSSI

Figure 5—Fish Stock Sustainability Index (FSSI) of 230 key marine fish stocks 

as determined by NMFS (source: http://www.nmfs.noaa.gov/sfa/statusoffisheries/2010/first/q1_2010_fssi_summary_changes.pdf).
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Figure 6—The number of threatened and endangered (a) freshwater fish and (b) aquatic species by 8-digit hydrologic unit for the United States (NatureServe 2010).
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

The conservation status categories as defined by Jelks and others (2008:374-375) were:

“Endangered (E): a taxon that is in imminent danger of extinction throughout all or 

extirpation from a significant portion of its range.

Threatened (T): a taxon that is in imminent danger of becoming endangered 

throughout all or a significant portion of its range.

Vulnerable (V): a taxon that is in imminent danger of becoming threatened throughout all or a significant portion of its range. This status is equivalent to “Special 

Concern” as designated by Deacon and others (1979), Williams and others (1989), 

and many governmental agencies and nongovernmental organizations.

Extinct (X): a taxon of which no living individual has been documented in its natural 

habitat for 50 or more years.”

For the purposes of this report, the data as presented in Jelks and others (2008) were sorted 

by RPA region and an analysis of the number of species in each conservation category was 

conducted. Since the source data were presented on a state-by-state basis, this required removing duplicate species entries that occurred in more than one state in each region. In doing so, 

named subspecies was used as the lowest classification unit. Therefore, some of the unique 

but unnamed strains or “distinct population segments” that may appear as separate taxon in 

Jelks and others (2008) are combined into the larger category of species or subspecies (as 

appropriate) in our regional analysis. Since a species or subspecies may occur in more than 

one RPA region, the results of each RPA region are not additive to provide a national picture. 

Rather, a nationwide summary as reported by Jelks and others (2008) is provided for this 

purpose (Figure 7a and 7b).

In cases where unnamed strains, distinct population segments, or subspecies (for purposes of 

the species analysis) were combined but had a different conservation status, the most conservative classification was used. For example, if three strains, each being classified respectively 

as Vulnerable, Threatened, and Endangered, were combined into a single species, that species 

was assigned as “Endangered” for this analysis. The classification of “Extinct” was only used 

if all taxonomic units that were combined were extinct.

Nationwide Status

The most recent compilation from Jelks and others (2008) includes 700 taxa in total (all taxa 

including strains and unnamed distinct populations). Nearly 40 percent of North American 

freshwater fish species (including the United States, Canada, and northern Mexico) are imperiled (Figure 7). In 2008, 230 were classified as vulnerable, 190 threatened, 280 endangered, 

and 61 presumed extinct. This is a 92 percent and 179 percent increase over the taxa listed 

by Williams and others (1989) and Deacon and others (1979), respectively. However, a more 

comprehensive source list used by Jelks and others may be attributable to at least a portion of 

this increase. Jelks and others (2008:382) reported that “...the pronounced increase primarily results from the addition of taxa that became imperiled since 1989, recent discoveries of 

nominal and undescribed taxa regarded as imperiled, newly added distinct populations, and 

inclusion of extinct taxa.” They also note that only 8 (2 percent) of the taxa listed in 1989 

improved sufficiently to be delisted; 91 percent remained the same or declined.
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

a.

b.

1979 1989 2008

400

350

200

150

100

50

0

300

250

Vulnerable/Special Concern

Threatened

Endangered

Extinct

Figure 7 –Number of fish (a) species considered to be vulnerable, threatened, 

endangered, or extinct and (b) subspecies by each classification (Jelks and others 

2008).

In assembling the list of imperiled taxa, Jelks and others also identified the causative factors 

contributing to the conservation status similar to that used by Deacon (1979) and Williams 

(1989). These factors included: destruction, modification, or reduction of habitat; over-exploitation or intentional eradication either directly or of an organism on which the taxa relied for 

some part of its survival; disease or parasitism; a narrowly restricted range; and other factors, 

including impacts of nonindigenous organisms and hybridization.
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

Habitat degradation was listed as one of the causative factors on most cases (92 percent) followed by restricted range (72 percent). Thirty-eight percent of the listed taxa had both of these 

factors as criteria for listing.

Based on the data presented in Jelks and others (2008), three distinct regions within the 

United States with large numbers of imperiled taxa are the southeastern United States, the 

mid-Pacific coast, and the lower Rio Grande, similar to what was reported in the last RPA 

report (Loftus and Flather 2000). Although the incidence of imperilment spread across many 

taxa, particularly vulnerable were western salmon and trout (where more than 60 percent are 

considered at risk), darters in the southeastern United States, and pupfish and livebearers in 

the southwestern United States.

Based on occurrence data obtained from NatureServe (2010), we mapped at-risk species 

by 8-digit hydrologic units across the coterminous United States. Concentrations of at-risk 

freshwater fish species (full species only) occur throughout the southeastern United States 

(Southern Appalachians and scattered watersheds in the Coastal Plain region); the central 

United States; the arid Southwest; and in a localized set of watersheds associated with the 

Klamath River on the Oregon/California boarder (Figure 8a). If we broaden the taxonomic 

groups to include all vertebrate and invertebrate species that are associated with aquatic habitats, then once again areas of concentration emerge in Peninsular Florida, watersheds associated with the Ohio River system, and watersheds associated with the lower Sacramento and 

San Joaquin River systems (Figure 8b).

Imperiled Species Trends by RPA Region

The four RPA regions are very broad and formed on the basis of state political boundaries. 

Subsequently, each RPA region can encompass many of the smaller geographic ecoregions 

used to characterize the imperilment lists compiled by Jelks and others (2008). However, by 

compiling the data from Jelks and others on the basis of RPA regions, general patterns emerge 

similar to that of the smaller ecoregions.

Two analyses are presented for each RPA region: 1) Counts in each conservation classification by subspecies, and 2) Counts in each conservation classification by species. The extent 

of imperilment (based on number of species or subspecies observed) is substantially greater 

in the southern RPA region than the other regions.6 From 1979 to 1989, the number of species 

determined to be “vulnerable” or “endangered” sharply increased while the number of those 

“threatened” remained relatively steady in this region. The number of “endangered” species 

increased sharply in the Rocky Mountain and Pacific regions. In the northern RPA region, the 

increase in “vulnerable” species noticeably exceeded the relative stability of the other two 

categories (Figures 9a‒h). The analysis of imperilment was essentially the same at both the 

species and subspecies levels in the northern RPA region since few taxa in this region were 

identified below the species level.

6 For purposes of this analysis, species counts from Alaska and Hawaii are not included in the Pacific 

RPA region since data from those states were not available from Jelks and others (2008).
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Figure 8—The number of at-risk (a) freshwater fish and (b) aquatic species by 8-digit hydrologic unit for the 

United States (NatureServe 2010).
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

a. b. North

c. South d. South

North

c. d.

e. Rocky Mountain f. Rocky Mountain

g. c Pacific Coast h. Pacific Coast

Vulnerable/Special Concern

Threatened

Endangered

Vulnerable/Special Concern

Threatened

Endangered

Vulnerable/Special Concern

Threatened

Endangered

Vulnerable/Special Concern

Threatened

Endangered

Vulnerable/Special Concern

Threatened

Endangered

Vulnerable/Special Concern

Threatened

Endangered

Vulnerable/Special Concern

Threatened

Endangered

Vulnerable/Special Concern

Threatened

Endangered

Figure 9—The number of fish considered to be vulnerable, threatened, or endangered by species (a, c, e, g) 

and subspecies (b, d, f, h) in each RPA region by year (Jelks and others 2008).
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Marine Species

NOAA Fisheries is the lead agency responsible for listing marine and anadromous species under 

the ESA. Currently, 29 marine and anadromous fish, 20 marine mammals (10 whales, 3 dolphins, 

1 porpoise, 5 seals, 2 sea lions), 8 sea turtles, 3 marine invertebrates (coral, abalone), and 1 marine 

plant are covered under the portion of the ESA program that is overseen by NOAA Fisheries.

Trends in Harvest ____________________________________

While the harvest of species is often used as a surrogate for species population status and 

trends, it must be done so very carefully and nonetheless may still lead to erroneous conclusions (Branch and others 2011). In addition to stock status, a number of other factors influence the amount (numbers or biomass) of species harvested, including fishing effort, gear 

efficiencies, economics (value) of landed fish (which influences effort), and weather patterns. 

However, the RPA directs that measures of utilization be included in resource assessments. 

In addition to the socioeconomic implications, harvest can impact taxonomic and functional 

diversity of aquatic communities, abundance of species, and genetic diversity of individual 

populations (Mac and others 1998). Thus, socioeconomics measures are an important aspect 

of assessing the biological status of aquatic communities.

The total harvest (edible and industrial) of commercial species by fishermen at United States 

ports in 2008 was 8.3 billion pounds (3.8 million metric tons) valued at $4.4 billion. This 

was a decrease of 983.4 million pounds (11 percent), continuing a trend of the past three 

years (Figure 10a), but it was an increase of $191.6 million in ex-vessel value (up 5 percent) 

compared with the previous year. Finfish (free swimming fish with fins, as opposed to crabs, 

oysters, etc.) accounted for 87 percent of these landings (Table 12) but only 51 percent of the 

value. For the past twenty years, landings of Pacific salmon species (Chinook, Coho, Pink, 

Sockeye, and Chum), which include Pacific Northwest stocks as well as Alaskan stocks, have 

fluctuated between 600 million and nearly 1 billion pounds annually.

Trends in commercial harvest landed in United States Great Lakes ports continued their 

decline (Figure 10b).There is now evidence that non-native fishes like Asian carps can have 

ecosystem-scale effects on the condition of native fish species (Irons and others 2007). Given 

that more than 180 non-native species have already been detected in the Great Lakes (including sea lamprey, zebra mussel, round goby, spiny waterflea, and Eurasian watermilfoil), there 

are mounting concerns that colonization of the Great Lakes by Asian carp species will further 

erode the integrity of the native fish communities and diminish populations of species that 

are important to recreational and commercial fisheries (International Joint Commission 2011, 

Rasmussen and others in press).

Outside of the Great Lakes, the harvest of aquatic organisms from freshwater systems of the 

United States is unknown. Limited commercial fishing occurs in the Great Lakes, Mississippi/

Missouri River System, and in some other areas for specific species (for example, snapping 

turtles in many states). Most freshwater fish are harvested by recreational anglers (see Thayer 

and Loftus 2012 for specific example). Although effort estimates are available for recreational 

angling, including anglers targeting specific fish species (discussed later), national or regional 

harvest estimates are not available. Effort alone is not a reliable indicator of harvest; nationwide, 67 percent of anglers report releasing some fish, 20 percent report releasing all fish that 

they caught, and 84 percent report releasing fish that they legally could have kept (USDI and 

USDC 2007).
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

a.

b.

Pacific Salmon Species Only (million pounds)

All Species U.S. Great Lakes Landings

(million pounds)

All Species (million pounds)

Figure 10 (a) Commercial landings (pounds) of all marine species and Pacific salmon species in United 

States ports (source: NOAA Fisheries http://www.st.nmfs.noaa.gov/st1/commercial/index.html October 

27, 2011) and (b) all species from U.S. Great Lakes. (source: 1950-1961 NOAA Fisheries; 1971-2009 

U.S. Geological Survey Great Lakes Science Center http://www.st.nmfs.noaa.gov/st1/commercial/landings/gl_query.html October 28, 2011; 1962-1970 unavailable).
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Trends in Participation ________________________________

Recreational Fisheries

The primary source of national level recreational fishing information is a survey conducted 

every five years by the U.S. Fish and Wildlife Service and U.S. Census Bureau. Initiated in 

1955, this “National Survey of Fishing, Hunting, and Wildlife Associated Recreation” (herein 

referred to as the National Survey) has undergone several changes in methodology that limit 

the comparability of surveys conducted prior to 1991 and those after.

National Participation

Fishing remains the most popular form of outdoor recreation that is dependent upon wildlife 

and fish. The most recent survey (2006) revealed that 30 million individuals in the United 

States, or 13 percent of United States population age 16 years and older, participated in recreational fishing within the United States. This was a 12 percent decline from the previous 

survey in 2001 and a 16 percent decline from 1991 (Figure 11), the earliest year in the comparable time series (USDI and USDC 2007). Anglers spent 517 million days on the water in 

2006, a 7 percent decline from 2001, but relatively unchanged since 1991. Within this time 

series, angler days peaked in 1996 at 626 million days. Despite the substantial declines in 

recent decades, the number of anglers closely approximates the number in 1980 and is twice 

as many as in 1955 based on a standardized index of participation (Richard Aiken, U.S. Fish 

and Wildlife Service, personal communication). Excluding Great Lakes anglers, 72 percent 

of the days spent fishing in freshwater were on lakes, reservoirs, and ponds and 32 percent on 

freshwater rivers and streams.7 The favored species sought by these anglers were smallmouth/

largemouth bass, panfish, and catfish/bullheads (Table 13) (USDI and USDC 2007).

7 Note: Percentages sum to more than 100 due to multiple responses.

Table 12—Domestic species landings in 2008 ranked by biomass and value (NMFS 2009a).

Pounds Dollars

Rank Species Lbs (x1000) Rank Species US$ (x1000)

1 Pollock 2,298 1 Crabs 562,267

2 Menhaden 1,341 2 Shrimp 441,818

3 Flatfish 663 3 Salmon 394,594

4 Salmon 658 4 Scallops 371,641

5 Hakes 550 5 Lobster 336,902

6 Cod 513 6 Pollock 334,477

7 Crabs 325 7 Cod 304,895

8 Herring (sea) 259 8 Halibut 217,735

9 Shrimp 257 9 Clams 186,718

10 Sardines 193 10 Flatfish 184,209
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

Year

Figure 11—Number of anglers and days spent fishing in the United States 1991-2006 (USDI and 

USDC 2007).

Table 13—Top freshwater (excluding Great Lakes) 

species sought by anglers in the United States 

(USDI and USDC 2007).

Days of fishing

Species (thousands)

Black bass (smallmouth, largemouth, etc.) 161,005

Panfish 101,569

Catfish and bullheads 98,190

Crappie 90,732

Trout 75,485

White bass, striped bass, hybrids 65,211

RPA Regional Statistics

Regional trends for recreational fishing participation generally follow the national level 

trends. The steepest declines in number of anglers occurred in the Pacific RPA region, with 

2001-2006 declines of 24 percent and 1991-2006 declines of 28 percent.8 The Southern region 

experienced the smallest loss of number of anglers, declining 7 percent in 2001-2006 and 8 

percent in 1991-2006 (Figure 12).

8 Although summing the number of anglers in each state to obtain regional estimates likely over-counts 

the number of anglers, it can provide an estimate of angling where the activity took place.
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

In terms of angler days, the pattern of generally declining trends continued, although not as 

precipitously as the number of anglers. Two regions experienced an overall increase over the 

longer time span 1991-2006 (Rocky Mountain up 9 percent and South up 1 percent). The 

Pacific Coast and North regions declined 25 percent and 5 percent, respectively. During the 

2001-2006 period, all regions declined in number of angling days, ranging from a 5 percent 

drop in the North to a 26 percent loss in the Pacific Coast (Figure 12).

Economics of Recreational Fishing

The activity of recreational fishing generates significant economic impact both regionally and 

nationally. Expenditure estimates collected by the National Survey provide the basis for economic impact analysis of recreational fishing. Using these data, economists have developed 

economic impact estimates (economic impact, sales, taxes, and jobs) using the IMPLAN economic assessment model from MIG, Inc. (Stillwater, Minnesota).

a. North b. South

c. Rocky Mountain d. Pacific Coast

Figure 12—Number of anglers and days spent fishing in the North (a), South (b), Rocky Mountain (c), and Pacific Coast (d) RPA 

regions from 1991-2006 (USDI and USDC 2007).
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

Nationally, the 30 million anglers age 16 years and older spent $45.3 billion on equipment and 

trip-related expenses pursuing their sport in the United States during 2006 (Table 14). This 

translated into an economic impact of more than $124 billion to the national economy associated with more than 1 million jobs. Fishing activity in Florida, Texas, Minnesota, California, 

and Michigan generated the most, each with more than $2 billion in economic impact attributable to recreational fishing (Table 15) (Southwick Associates 2008).

Regionally, the economic impact of recreational fishing ranged from $7.3 billion in the Rocky 

Mountain region to $29.3 billion in the South. The South also had the largest number of jobs 

attributed to the economic activities tied to recreational fishing, with nearly 300,000 (Table 16).

Table 15—Top 10 states ranked by total expenditures for 

recreational fishing, 2006 (Southwick Associates 2008).

Expenditures Number of anglers

State RPA Region (billion) (million)

Florida South $4.412 2.767

Texas South $3.367 2.527

Minnesota North $2.832 1.427

California Pacific $2.677 1.730

Michigan North $2.099 1.394

Pennsylvania North $1.795 0.994

Wisconsin North $1.755 1.394

South Carolina South $1.493 0.810

North Carolina South $1.204 1.263

Missouri North $1.180 1.076

Table 14—Economic contributions of recreational 

fishing activity in the United States, anglers 16 years 

and older, 2006 (Southwick Associates 2008).

Number of anglers 29.952 million

Expenditures/retail sales $45.336 billion

Total multiplier effect (economic output) $124.959 billion

Salaries, wages and business earnings $38.360 billion

Jobs 1.036 million

Federal, state and local taxes $16.359 billion

Table 16—Economic impact of recreational fishing activity by RPA region (based on data from Southwick Associates 

2008).

Salaries, wages, and Federal tax State and local

Sales Total multiplier effect business earnings Retail jobs revenues tax revenues

Region (billion) (billion) (billion) (thousand) (billion) (billion)

North $17.372 $28.693 $8.806 278.9 $2.106 $1.892

Pacific Coast $4.991 $8.438 $2.725 77.1 $0.629 $0.569

Rocky Mountain $4.569 $7.355 $2.184 73.1 $0.491 $0.451

South $17.342 $29.318 $8.660 292.4 $1.981 $1.717

United States1 $45.336 $124.959 $38.360 1,035.6 $9.012 $7.347

1 Sum does not add to total due to some respondents not being able to assign purchases to a single state
29

Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Recreational Fishing on Forest Service Lands

A 2007 report documents the economic activity associated with recreational fishing on 

Forest Service lands for the primary purpose of recreational fishing (American Sportfishing 

Association 2007). The report quantifies both the state and national economic effects of trips 

to U.S. Forest Service-managed lands. The estimated visits as reported by the U.S. Forest 

Service National Visitor Use Monitoring Survey (2000 to 2003 cycle) were matched with 

the expenditure profiles found in Stynes and White (2006). Expenditures were calculated at 

two geographic scales: (a) a 50-mile radius within the boundary of each Forest Service unit; 

and (b) statewide for the state in which the unit was located. Due to a change in data sources 

and methodologies, the results in this report should not be compared to previous U.S. Forest 

Service (USFS) economic reports produced by the American Sportfishing Association. Due to 

its targeted methodology, the USFS data is more accurate for USFS participation.

Anglers annually spent $592 million within 50 miles of USFS units (Table 17). These expenditures supported 14,500 jobs and stimulated $66 million in federal income tax receipts. 

Wildlife viewers added another $168 million in retail sales annually to the regions surrounding Forest Service units, which in turn supported another 4,700 jobs and nearly $15 million in 

federal income taxes (American Sportfishing Association 2007).

Marine Recreational Fishing

Although the National Survey provides a comprehensive picture of recreational fishing 

throughout the United States and breaks down the fishing sectors between freshwater and 

saltwater angling, a more accurate assessment of marine recreational fishing is likely provided 

through periodic targeted surveys conducted by the NMFS. The results of the NMFS surveys 

discussed below, and those of the National Survey discussed previously, cannot be compared 

due to substantial differences in methodology and target audience.

Since 1979, the National Marine Fisheries Service has conducted the Marine Recreational 

Fisheries Statistics Survey (MRFSS). The principal objective of this survey is to provide estimates 

of catch and effort of marine recreational anglers over larger geographic areas (for example, coastwide). However, the demand for statistically valid harvest information within increasingly smaller 

geographic areas (for example, state level) for specific species has resulted in this survey being 

used for purposes not originally intended and has also resulted in increases in targeted sampling to 

obtain sufficient sample sizes for such purposes. Changes in geographic coverage since 1981 make 

nationwide reporting tenuous, principally due to the absence of Pacific and Gulf coast states from 

the MRFSS sample in some years. However, since 1996 geographic coverage has been relatively 

stable (although Texas is still not covered by the survey).

Since 1997, recreational fishing effort (number of anglers and trips taken) peaked in 2007, when 

14.2 million anglers took an estimated 88.6 million marine recreational fishing trips. This was 

an increase of 60 percent and 29 percent respectively over the numbers at the beginning of the 

time series in 1997. Since the 2006 peak, the number of anglers and trips has dipped slightly 

but remains significantly higher than the early year of the time series (Figure 13) (NMFS 2007, 

2010c). In 2009, marine recreational fishing generated nearly $50 billion in sales accounted for 

more than 327 thousand full and part time jobs. In comparison, in 2006 (the first year of this comparable time series of data) marine recreational fishing generated 64 percent more in sales ($82 

billion) and 63 percent more jobs (533.8 thousand) (NMFS 2010c).
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

Table 17—National and state-specific economic effects of fishing on U.S. Forest Service units, annual average from 

2000-2003 (American Sportfishing Association 2007).

State and national level effects of wildlife-based State and national level economic significance of 

recreation occurring in and around national wildlife-based recreation, including trip-related and 

forest communities1 equipment expenditures2

 Retail sales Jobs (full and Federal income tax Retail sales Jobs (full and Federal income tax

State (thousands) part-time) revenues (thousands) (thousands) part-time) revenues (thousands)

Alabama $612.2 14 $31.6 $1,751.9 39 $88.0

Alaska $11,287.1 181 $404.5 $111,024.6 2109 $4,632.1

Arizona $37,735.6 730 $3,060.4 $196,254.8 3735 $15,549.4

Arkansas $7,080.2 168 $367.8 $14,721.2 327 $714.0

California $96,716.8 1718 $9,225.3 $462,056.8 8224 $45,413.4

Colorado $48,057.7 947 $4,387.9 $210,275.5 4067 $18,735.2

Connecticut n/a n/a n/a n/a n/a n/a

Delaware n/a n/a n/a n/a n/a n/a

Florida $12,975.8 252 $1,017.0 $62,336.6 1152 $4,606.1

Georgia $10,699.4 205 $924.1 $22,065.9 413 $1,857.3

Hawaii n/a n/a n/a n/a n/a n/a

Idaho $25,859.3 586 $1,206.3 $99,042.1 1897 $3,904.4

Illinois $1,849.5 34 $191.6 $3,765.4 67 $372.7

Indiana $5,620.9 110 $450.7 $11,266.5 231 $927.7

Iowa n/a n/a n/a n/a n/a n/a

Kansas $329.4 6 $30.1 $901.1 17 $80.3

Kentucky $12,412.1 241 $775.7 $29,635.7 585 $1,871.0

Louisiana $476.1 9 $33.8 $1,288.3 24 $87.9

Maine $27.1 0 $1.3 $77.5 1 $4.1

Maryland n/a n/a n/a n/a n/a n/a

Massachusetts n/a n/a n/a n/a n/a n/a

Michigan $6,993.3 129 $557.6 $18,068.6 330 $1,475.7

Minnesota $50,153.1 994 $4,054.9 $153,085.2 3041 $12,171.1

Mississippi $9,787.1 203 $465.9 $12,114.8 259 $583.8

Missouri $1,027.0 18 $70.5 $3,234.5 58 $223.5

Montana $31,260.4 724 $1,381.3 $115,568.6 2549 $4,839.3

Nebraska $130.9 3 $6.6 $20,405.6 417 $936.1

Nevada $3,340.4 50 $244.7 $24,520.2 305 $1,501.4

New Hampshire $424.9 8 $21.1 $1,214.2 22 $63.8

New Jersey n/a n/a n/a n/a n/a n/a

New Mexico $8,528.4 180 $508.8 $41,734.4 784 $2,554.3

New York $115.6 2 $6.3 $236.9 4 $13.5

North Carolina $16,710.5 342 $1,220.0 $54,603.3 1226 $4,621.1

North Dakota $227.6 5 $10.1 $879.4 17 $35.3

Ohio $2,798.7 57 $221.2 $6,015.7 124 $520.5

Oklahoma $1,441.8 34 $74.8 $2,998.7 67 $147.2

Oregon $39,579.2 718 $2,594.6 $113,037.0 1,963 $7,023.3

Pennsylvania $5,311.2 100 $447.1 $8,201.0 154 $658.2

Rhode Island n/a n/a n/a n/a n/a n/a

South Carolina $4,360.0 90 $327.7 $11,469.4 239 $838.9

South Dakota $5,274.9 118 $235.9 $19,244.0 416 $826.8

Tennessee $14,832.3 276 $1,158.1 $25,628.1 529 $2,210.0

Texas $2,820.6 57 $259.0 $8,940.1 161 $749.9

Utah $43,396.7 1,006 $2,496.8 $184,460.6 4,146 $10,264.2

Vermont $5,662.7 90 $309.1 $11,605.7 185 $660.1

Virginia $19,831.3 368 $1,468.1 $26,843.5 478 $1,927.9

Washington $18,934.6 347 $1,496.7 $69,020.2 1,175 $5,168.3

West Virginia $7,179.4 142 $309.4 $9,332.6 178 $388.8

Wisconsin $7,638.3 161 $381.8 $20,781.2 451 $1,058.7

Wyoming $12,606.1 232 $427.3 $48,128.8 808 $1,501.1

United States $592,106.2 14,463 $66,149.6 $2,237,836.2 57,707 $263,938.1

1 These figures only include expenditures made by people within 50 miles of a USFS unit and generally exclude expenditures for some triprelated and equipment purchased outside the 50 mile radius.

2 These figures include all trip-related and equipment purchases made within the state and assigned to USFS wildlife-based recreation.
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Figure 13—Saltwater recreational anglers and days 

spent fishing 1997-2008 (NMFS 2007, 2010c).

1965

Year

Number of Craft

196719691971197319751977197919811983198519871989199119931995199719992001

140,000

120,000

100,000

80,000

60,000

40,000

20,000

0

Figure 14—Number of commercial fishing craft 

registered in the United States (USDI Bureau 

of Commercial Fisheries [1967-1969]; NMFS 

[1971-75, 1976a, 1976b, 1977, 1978, 1979, 1980a, 

1980b, 1981-83, 1984a, 1984b, 1985-1996]).

Commercial Fisheries

From 1965-2001, NMFS compiled the number of commercial fishing craft (“vessels” greater 

than 5 tons and “boats” less than 5 tons) in the United States. In 2002, such documentation 

was incomplete and in the following year collection of such information was fully ceased 

(Dave VanVorhees, NOAA Fisheries, personal communication). No comparable nationwide 

substitute has been implemented and this information is intended to provide an illustrative 

completion of a data source that has been included in RPA assessments since 1985. In general, 

the number of commercial fishing craft has shown a gradual decline since the early 1990s 

(Figure 14). However, the latter years of the time series may not be comprehensive enough to 

draw definitive conclusion (Dave Van Vorhees, NOAA Fisheries, personal communication) 

and reduction in the number of craft alone may not indicate a reduction in fishing effort or 

harvesting capacity.
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

Figure 15—Per capita consumption of fish and shellfish in the United States (NMFS 

2010d).

Per Capita Consumption

(lbs/person)

U.S. Population

Note: Data goes from decadal

 to annual in 1981

In 2009, per capita consumption of fish and shellfish in the United States was 15.8 pounds 

(edible meat, fresh, frozen, canned, and cured) (NMFS 2010d). This was 0.2 pounds less than 

consumed in 2008 but still within the highest range observed since the time series began in 

1910 (Figure 15).

Beginning in 2006, NMFS has conducted an annual analysis of the economics of marine fisheries. In 2009 the ex-vessel value of edible and industrial landings totaled $3.9 billion (Table 

18), a 5 percent decline from 2006 (the first year of the time series). In 2009, commercial 

fishing in the United States generated more than 1 million full and part time jobs and more 

than $116 billion in sales.

Overall, the entire commercial seafood industry (harvesters, wholesalers, distributors, processors, dealers, and retailers) generated over $103 billion in sales, $44.3 billion income, and 

supported 1.5 million jobs in 2006. The commercial harvesting sector alone generated $9.1 

billion (9 percent of the total) of the total sales (NMFS 2007).

Table 18—U.S. Commercial Fishery Statistics, 2009 (NMFS 2010c).

Total species

Total landings 7.9 billion pounds

Ex-vessel price $3.9 billion

Sales (all sectors) $116 billion

Income (all sectors) $31.6 billion

Top 5 revenue generators

Shrimp $378 million

Sea scallops $376 million

Pacific salmon $370 million

Walleye pollock $308 million

American lobster $303 million
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Management Implications______________________________

Data Availability

Since publication of the first RPA assessment (USDA, Forest Service 1977), the data needed 

to conduct a thorough evaluation of fisheries and aquatic resources has slowly improved. As 

highlighted in this report, comprehensive aquatic habitat and water quality data is now readily 

available; a nationwide assessment of the condition of freshwater streams and lakes has been 

conducted (which establishes an important baseline of information for future assessments); 

socioeconomic data for extractive use is widely available (some specific to Forest Service 

lands); and regional information sharing efforts are underway to facilitate the compilation and 

exchange of fisheries information. Most of these gains have benefited from new electronic 

technologies that not only allow the rapid distribution of data but also improve the ability to 

better coordinate sampling and data collection in the field.

Despite these incremental improvements, data remain sorely lacking for a comprehensive 

assessment of the status and trends of most aquatic biota, including fish that contribute many 

benefits to human society. This has been noted in previous RPA reports (Loftus and Flather 

2000) as well as by other efforts to document status and trends (Mac and others 1998). 

Positive strides have been made to this end – most noticeably where jurisdictions share management authority over a common stock such as on the Atlantic coast, or where stocks have 

become severely depleted such as Pacific Northwest salmon. On a limited basis in freshwater 

systems, states have developed cooperative arrangements for the assessment and management 

of stocks such as Lake Erie yellow perch and walleye. Still, the ability to assess the status 

and trends of a single species or species complex nationwide remains elusive. This inability hinders the evaluation of large scale factors that may be impacting aquatic populations 

across Forest Service regions or across the nation, such as climate change [see Case Study 5: 

Synopsis of Climate Change Effects on Aquatic Systems], invasive species, or pollution. This 

in turn impacts the ability to conduct large scale program planning efforts such as may be 

required by the Forest Service and other agencies.

The 2000 RPA assessment concluded that “data needed to complete a comprehensive assessment 

of the status and trends of freshwater species in the United States are currently not accessible” 

(Loftus and Flather 2000: 38). While this is still largely true, programs are underway to improve 

the situation. The issue lies largely with the accessibility of data, not with the existence of data. 

Each year, states collect data that could be applied to a status and trends effort. State water quality 

monitoring efforts as well as state natural resources agencies collect data on fish populations, 

benthic communities, and water quality. Some of these data have been shown to be applicable 

for trend analysis (Loftus and Flather 2000; Nate and Loftus this publication, see Case Study 2). 

Increasingly, states are standardizing the way in which these data are collected, stored, and reported as compared to the past (Loftus 2006). Additionally, multiple federal agencies, including the 

Forest Service, collect data throughout the United States that could be applied to the assessment of 

status and trends of aquatic species. Some of these federal programs (for example, National WaterQuality Assessment Program, U.S. Fish and Wildlife Service Fisheries Information System) can 

be applied to select analysis of metrics that may indicate status and trends, but not in a comprehensive way. The issue becomes one of providing access to data from many of these sources 

to facilitate comprehensive analysis.
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

With program funds limited and likely to be so for the near future, avenues need to be developed for leveraging existing projects to achieve gains at multiple geographic and programmatic scales. While the MARIS (described in Case Study 2) embodies this approach for data 

sharing, a system for addressing fishery and aquatic resource national priorities by leveraging 

multiple smaller scale projects is described by Hasler and others (2011). Through this system, 

a network of projects is organized under a single national goal and funding supports these 

individual projects through a strategic grant program specifically designed to achieve the goal.

The National Fish Habitat Action Plan (NFHAP) is a cooperative program between state 

and federal agencies, tribal governments, private and NGO partners, and others to address 

problems impacting fish habitat throughout the United States [see Case Study 6: National 

Fish Habitat Assessment]. As part of NFHAP, a national data infrastructure has been adopted 

to exchange data from disparate sources (including state and federal data sources) for multiple purposes. Ultimately, this program may support the development of future national 

fish habitat assessments that incorporate comprehensive fisheries data. If this system is fully 

implemented as planned, it will provide a strong basis for future RPA assessments of fisheries 

and aquatic resources.

Program Planning

Several of the case studies included in this report are directly applicable to Forest Service 

program planning, including the aforementioned NFHAP Data System. As a cooperator in the 

NFHAP initiative, the Forest Service can work to ensure the implementation of this system 

and investigate mechanisms through which data collected as part of Forest Service programs 

can contribute to this system. In this way, those data collected on Forest Service lands will be 

represented and influential in future plans for fisheries habitat restoration and evaluation of 

the long term success of habitat protection and restoration efforts.

The Forest Service manages 193 million acres of forest and grasslands, which contain 128,000 

miles of stream, 2.2 million acres of lakes, ponds, and reservoirs, and over 12,000 miles of coastal 

shoreline (Loftus and Flather 2000). As such, the Forest Service is poised to be a key player in 

addressing large scale changes to fisheries and aquatic ecosystems stemming from such broad-scale 

threats as climate change, invasive species, and water quality degradation.

Several projects are already ongoing within the Forest Service to research and evaluate potential courses of action to take in response to climate change. Rieman and Isaak (2010) have 

suggested many actions, some of which are outlined in the accompanying case study [see 

Case Study 5: Synopsis of Climate Change Effects on Aquatic Systems], that include conserving and expanding critical habitat for species susceptible to the impacts of climate change 

(particularly increasing water temperature, and sedimentation); establishing refuge zones to 

preserve these species; reducing non-climate stresses, particularly those known to impact 

aquatic systems on Forest Service lands; coordinating efforts among program areas and other 

agencies; and reinforcing connectivity of stream systems through actions such as retrofitting 

dysfunctional road culverts and evaluating the utility of removing other artificial barriers to 

fish movements. With such large areas of water and land under Forest Service management, 

actions taken by the agency, particularly if implemented in concert with plans by state and 

other federal agencies, can produce measurable improvements in the future condition of fisheries and aquatic resources.
35

Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Forest Service lands can also be a buffer to the deleterious impacts of urbanization on aquatic 

systems. The effects of urbanization begin with the cutting of roads to allow access to previously undeveloped land and increase with additional fracturing of the landscape. Large 

tracts of undeveloped lands (undeveloped for either agriculture or urban development) in the 

National Forest System provide areas where the influences of development on aquatic systems 

are minimized (but see Radeloff and others 2010). Even National Forest lands that are located 

in more urban settings can play an important role in protecting aquatic health. As documented 

in the accompanying case study [see Case Study 1: Impacts of Urbanization on Fisheries and 

Aquatic Ecosystems], research indicates that maintaining contiguous undeveloped buffers 

along waterways is significantly more effective than a fractured buffer system.
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Case Study 1: Impacts of Urbanization on Fisheries and 

Aquatic Ecosystems __________________________________

By their very nature, aquatic systems are recipients of the products of activities on the surrounding landscape. Wetlands, streams, and lotic waters are recipients of the runoff from the 

watershed and transporters of that runoff to waters at lower geographic elevations. The same 

anthropogenic processes that affect terrestrial species by reducing landscape connectivity, 

habitat availability, and increasing patch diversity can have a quantifiable effect on aquatic 

assemblage structure (Kennen and others 2005). In short, the physical and chemical composition of streams and lakes are largely a product of the watershed.

While agricultural activities are still responsible for degradation of the greatest expanse of 

impaired waters in the United States, urbanization and associated infrastructure (for example, 

municipal sewage) remains one of the leading causes of water quality impairment to lakes and 

streams in the United States (Table 8). The impacts of urbanization, or the human settlement 

into areas of higher population density, on aquatic systems are well documented and were 

recently shown to be an important factor affecting the risk of wetland conversion throughout 

the South (Gutzwiller and Flather 2011). Transforming a landscape from an undeveloped state 

to one dominated by the infrastructure associated with urban areas brings detrimental consequences to aquatic systems and the fauna inhabiting those systems. Land use changes that 

increase impervious surfaces (roads, rooftops, parking infrastructures, etc.) that characterize 

urban landscapes foster hydrologic changes impacting stream flow, sedimentation, and other 

physical and chemical attributes which in turn impact the makeup of the aquatic biota.

One of the defining features of urban landscapes is the construction of roads that connect 

areas and, in some cases, drive development into as yet undeveloped landscapes. Twenty 

percent of the United States’ land area is directly impacted by road presence, and 50 percent is 

within 1,253 ft (382 m) of a road (Riitters and Wickham 2003 as cited in Wheeler and others 

2005). The impact of roads on aquatic systems can be broken into three discrete phases: road 

construction, road presence, and urbanization (Angermeier and others 2004). The mere act of 

constructing roads causes physical destruction to the surrounding floodplain and watershed 

(Wheeler and others 2005) including removal of riparian vegetation, substantial movement 

of soils, and heavy equipment impacts on wetlands and other hydraulic attributes of the 

watershed. The greatest threat of highway construction to streams is fine sediment pollution (Wheeler and others 2005). Even with sediment control techniques, streams impacted 

by highway construction carried 5-12 times more fine sediments than streams not impacted 

(Weber and Reed 1976). Fine sediment pollution has been shown to impact macroinvertebrates and periphyton (algae and microbes attached to subsurface structures) levels and clog 

the gills of fish (Wheeler and others 2005) as well as alter the reproductive success of fish 

(Burkhead and Jelks 2001).

Roads continue to impact aquatic systems after all construction is completed and equipment 

has moved onto the next project. Bridge abutments and culverts may destabilize stream channels by altering stream flows, causing downstream incision of stream channels and upstream 

sedimentation, and serving as conduits for transporting sediment, oil, grease, and heavy 

metals directly to waterways. Commonly, culverts can act as impediments to fish passage to 
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

upstream or downstream habitats. Currently, the Chesapeake Bay watershed has over 5,000 

miles of fish spawning habitat that remain blocked by dams, culverts, and other blockages 

even though 1,838 miles have been restored between 1988-2005 (www.chesapeakebay.net, 

October 12, 2010).

Effects of Urbanization

Activities associated with urbanization are one of the leading causes of water quality impairment to lakes and streams in the United States (Table 8). Studies have demonstrated that 

increasing coverage of the landscape by impervious surface causes a degradation of watershed 

health that begins when impervious surfaces coverage exceeds 10 percent of the watershed 

(Arnold and Gibbons 1996, Wheeler and others 2005). The greatest changes occur in the 

initial stages of urbanization as compared to prolonged urbanization. Fitzpatrick and others 

(2005) found that base flows in streams were consistently low in watersheds with an urbanization measure of greater than 33 percent, or approximately 10 percent impervious surface. 

However, Cuffney and others (2010) concluded that invertebrate assemblages began to 

degrade quickly following disturbance of the background land cover and continued on a linear 

downward trend after that.

Mechanisms Resulting From Urbanization

The mechanisms that cause these impacts to the aquatic systems with greater urbanization 

are varied, and include changes to flow regimes and hydrography, introduction of contaminants, increases in water temperature, and increases in sedimentation. Paving 20 percent of a 

watershed can increase the peak discharge of the mean annual flood by an order of magnitude 

(Hollis 1975 as cited in Wheeler and others 2005). These increased flows can induce a variety 

of impacts, including increased erosion of stream banks that add fine sediments to the stream 

system and incision of the stream channel. Urbanization also clears riparian vegetation and 

reduces woody debris in aquatic systems, which is an important source of nutrient input to the 

stream and cover for fish and macroinvertebrates (Flebbe and Dolloff 1995). While increased 

peak flows are a consequence of urbanization, reduced base flows into the stream also result 

with increasing impervious surface in the watershed. Rather than a gradual filtering of precipitation through the soils and into aquatic systems through the base flow, impervious surfaces 

direct runoff immediately into waterways. Increasing impervious surface also results in higher 

stream water temperatures (Nelson and others 2009).

Effects on Aquatic Biota

The quantitative impact of increased urbanization has been extensively documented. Urban 

streams have been shown to exhibit reduced aquatic taxa richness (Garie and McIntosh 1986) 

and lower Index of Biotic Integrity (IBI) scores (Steedman 1988 as cited in Wheeler and 

others 2005). In one study, fish IBIs were low in watersheds with greater than 25 percent 

urban land cover; no high IBI scores were seen in watersheds with greater than 40 percent 

urbanization (Fitzpatrick and others 2005). One causative factor in this may have been the 

reduction in fish passage in urban streams. In terms of species composition, the warmer and 

greater instability of the physical/chemical environments in disturbed systems tends to favor 
39

Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

more tolerant taxa. Aquatic systems in landscapes that have been fragmented and disturbed 

by urbanization promoted highly tolerant species but have deleterious impacts on sensitive 

species (Kennan and others 2005).

Although the research literature strongly points to a decline in aquatic habitat conditions 

with increasing urbanization, the degree to which the environment is impacted depends on a 

number of factors, including land use in the watershed prior to urbanization. Although fish 

IBIs and stream hydrology are impacted by urbanization, the extent to which streams are 

impacted depends on watershed characteristics such as clayey deposits, watershed slope, 

glacial landforms, and stormwater management practices (Fitzpatrick 2005). In a study of 

the effects of urbanization in nine metropolitan areas, areas that show lower effects from 

urbanization for invertebrates were those where urbanization progressed by the conversion 

of agricultural lands (row crop, pasture, and grazing lands) to urban landscapes (Cuffney and 

others 2010). The macroinvertebrate communities in those areas had already been impacted 

by agricultural activities (the top cause of water quality impairment according to the EPA) 

before urbanization progressed. Cuffney and others (2010: 191) concluded that “these results 

indicate that the efforts to mitigate effects of urbanization in areas with high levels of antecedent agriculture must take into account the negative effects of the agriculture when determining 

the levels of recovery that can be achieved.” The success of popular mitigation techniques 

such as restoration of riparian buffers may also depend greatly on the surrounding landscape. 

Riparian buffers may be less able to moderate negative effects of urbanization than they do 

in forest or agricultural watersheds, since hydrologic alterations attributed to storm sewer and 

culvert installation in urban landscapes may allow water to bypass these buffers (Fitzpatrick 

2005). Even in partially forested watersheds, landscape practices that promote continuous 

forest cover along waterways are preferable to those that result in the same extent of coverage 

but in a patchwork or fragmented distribution (Kennan and others 2005).
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Case Study 2: Exploring Trends in Largemouth Bass Relative 

Abundance With MARIS _______________________________

Nancy Nate9 and Andrew Loftus

The Multistate Aquatic Resources Information System (MARIS) is a distributed information 

system designed to exchange fisheries survey information among multiple state fisheries management agencies. The design and implementation of MARIS, as well as an evaluation of its 

utility in assessing status and trends, was reviewed in the 2000 RPA Assessment (Loftus and 

Flather 2000). The USDA Forest Service has been a participant in MARIS since its inception 

in the mid 1990s (Beard and others 1998) and was instrumental in funding the initial foundation of this program.

In the time since the 2000 RPA Assessment, MARIS has expanded in geographic coverage 

and content. Data from Michigan, Wisconsin, Minnesota, Pennsylvania, New York, New 

Jersey, Iowa, Illinois, Wyoming, Maryland and Georgia, and limited data from Indiana and 

Ohio, are available in the MARIS system. Several southeastern states are evaluating their 

ability to contribute in 2011. At the time of the 2000 RPA Assessment, only data collected in 

lake and reservoir surveys were available through MARIS; now data from stream and river 

systems are also available. Catch-per-unit-effort data have been supplemented with population 

estimate data. These changes have resulted in a system that is capable of accepting data from 

the entire breadth of most state sampling programs.

In 2008, an assessment was conducted of the data available in MARIS at that time. This 

included an analysis of an assembled database from Michigan, Wisconsin, Minnesota, 

Pennsylvania, New York, New Jersey, and Iowa. This seven-state database contains 7,751 

lake, 9,473 stream, and 489 impoundment surveys, encompassing 14,321 unique waterbodies 

(lakes and streams) sampled between 1944 and 2008 (Figure CS2-1).

The primary quantitative variable for lakes in MARIS is catch-per-unit-effort (CPUE), an 

index of fish relative abundance. Catch per unit effort data have been used to monitor stock 

abundance over time (for example, Hansen and others 1995), evaluate spatial distribution 

patterns within stocks (for example, Ward and others 2000), compare stocks across waterbodies (Nate and others 2003), and describe fish assemblages (for example, Spangler and 

Collins 1992). The number of sampled waterbodies with historical CPUE estimates varies 

greatly among the states currently participating in MARIS (Figure CS2-2), with Wisconsin, 

Pennsylvania, Minnesota, and New York all contributing more than 2000 estimates.

9 Dr. Nancy Nate is a research associate at the University of Wisconsin-Stevens Point.
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

Figure CS2-1—Distribution of surveys in lakes (black squares), streams (grey circles), and impoundments (light grey triangles) by state 

included in the MARIS Assessment Project Database. 

State

Number of Water Bodies

2001-2004

1949-2005

1900-2008

1950-2008

1976-2007

1975-2007

1944-2008

1987-1996

Figure CS2-2—The number of lakes, streams, and impoundments by state included in the MARIS Assessment Project Database, with the time span for CPUE data included.
43

Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Sampling methods were not necessarily standardized within states through time and were 

not coordinated among states represented in the MARIS dataset. However, many factors that 

influence catchability (how likely a particular fish species is to be captured in a specific gear) 

may be accounted for from variables currently stored in MARIS. Querying for specific criteria 

would allow post hoc standardization. For example, analyses of status and trends within single 

waterbodies or among many waterbodies across jurisdictional boundaries may be possible by 

querying for specific gear types deployed during specific season, for species that are known to 

be indexed well from the gear and season combination selected. The degree to which 1) actual 

sampling methods diverge from “standard”, or 2) important aspects of standardization are not 

accounted for during analysis will affect the accuracy of the catch per unit effort index of relative abundance, and ultimately the conclusions about status and trends. However, in a dataset 

as large in scope as MARIS, any divergence from “standard” is likely to be random and not 

systematically occurring within or among states over time. Systematic patterns would lead 

to bias and inappropriate conclusions in a trend analysis. If broad general trends in species’ 

relative abundance are revealed despite inevitable variations in methods or gear (that is, lack 

of true standardization), these patterns are likely to be robust and worthy of further investigation. Finally, the intended use of the data should dictate the rigor with which records are 

screened for inclusion in any analysis. The accuracy required for setting harvest policy on specific 

waters differs from accuracy required to explore regional changes in species abundance or 

distribution.

Example: Regional Trend in Largemouth Bass Abundance

Largemouth bass (Micropterus salmoides) are a species likely to be monitored by fisheries management agencies given its rank as one of the most commonly sought species by 

recreational anglers (see Table 13). Moreover, largemouth bass were the most prevalent 

species observed in lake and impoundment surveys in the MARIS assessment database—

being present in 4,679 lakes and surveyed by 6 of the 7 states included in the assessment 

(Figure CS2-3). Of these, 1,577 lakes had three or more years of survey data available for 

analysis of trends on individual waterbodies.

Electro-fishing CPUE during spring when largemouth bass are spawning has been used to 

index largemouth bass density (McInerny and Cross 2000). Of the 4,679 lakes with largemouth bass present, 1,302 lakes had spring electro-fishing catch per hour available for regional analysis of trends in largemouth bass relative abundance (Figure CS2-4). Data from Iowa, 

Michigan, Minnesota, New Jersey, Pennsylvania, and Wisconsin were included in the regional 

analysis. Across the region, average largemouth relative abundance indexed from spring 

electro-fishing catch per hour increased during 1960–2008 (Figure CS2-5). Average catch per 

hour ranged 2–127 largemouth bass. The surface area of the lakes included in the analysis 

ranged 1.2-14,000 acres. The cause for the increasing trend in largemouth bass relative abundance is unknown, but stocking practices, habitat improvement, or improving climatic conditions for largemouth bass are all possible explanations that could be explored further with 

integration of other data types (for example, stocking records, spatially explicit land use data 

surrounding waterbodies, etc.). Increasing efficiency of electro-fishing gear over time could 

also explain an increasing trend through time, but this would have to be occurring systematically among states over time to be a plausible explanation for the pattern in Figure CS2-5.
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Figure CS2-4—Lakes and impoundments with largemouth bass present during May electro-fishing surveys in the MARIS Assessment Database. Grey circles represent lakes with 3 or more years of survey data.

Figure CS2-3—Lakes and impoundments with largemouth bass present in the MARIS Assessment Database. Grey circles represent 

lakes with 3 or more years of survey data. 
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Figure CS2-5—Regional trends in largemouth bass relative abundance for spring electro-fishing surveys in the 

MARIS Assessment Database, 1960–2008. Catch/Hour was 

calculated as the yearly average ± 1 standard error for 2,780 

surveys on 1,302 lakes where largemouth bass were captured 

during May and catch per hour (CPUE_TIME) was provided 

Year by the state.

Catch/Hour

200

150

100

50

0

1960 1970 1980 1990 2000 2010

Year

Discussion

The process of assembling datasets by applying post-hoc standardization criteria is more 

likely to result in large datasets if the frequency of gear types, seasons, and metrics in the 

MARIS assessment database are considered. For example, electro-fishing is the most common 

gear type used in stream sampling, whereas electro-fishing, trap netting, and gill netting are 

all common gear types used in lakes and impoundments. Standardizing analyses of stream 

data by selecting only electro-fishing surveys will result in the largest possible dataset. As 

more screening criteria are applied, fewer surveys will meet all criteria and resulting datasets will decrease in size. Stream surveys most often occur during the month of July. May, 

September, and October are common sampling months for lakes. Not all species will be targeted during the most common sampling months, but summaries by month provide a starting 

point for querying MARIS data. Finally, CPUE metrics supplied by each state varied. Timebased catch per unit effort was the most common CPUE metric for stream surveys, whereas 

space (or distance) based CPUE was the most common metric for lakes. Various metrics 

of relative abundance can be combined to broaden analyses, but analyzing surveys where 

common metrics were supplied is more straightforward.

At present, MARIS data, which is available to anyone, can be used to examine patterns in fish 

distribution, species presence, trends in species relative abundance on individual waterbodies, and trends in species relative abundance by state or region across many waterbodies. The 

potential exists to explore shifts in fish communities over time or classify waterbodies based 

on morphometric characteristics that influence presence of species, or relative abundance of 

fishes. The robustness of these analyses depends in part on the completeness of each state’s 

collection of these data and subsequent contribution to MARIS. The opportunities for using 

MARIS will increase as more historic data are included, more states become involved, more 

metrics are included, and with enhancements to the current structure.
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Case Study 3: Status of Northwest Pacific Salmon _________

Current Situation

Salmon in the Pacific Northwest have been intensively studied since at least the latter half of 

the 20th century. The decline of many of these stocks has been documented in numerous publications, including in the last RPA assessment (see Loftus and Flather 2000).

Five indigenous species of salmon and one species of anadromous trout have been a 

dominant focus of concern in waters of the Pacific Northwest: chinook (or king) salmon 

(Oncorhynchus tshawytscha), coho (or silver) salmon (Oncorhynchus kisutch), sockeye 

salmon (Oncorhynchus nerka), pink (or humpback) salmon (Oncorhynchus gorbuscha), chum 

(or dog) salmon (Oncorhynchus keta), and steelhead trout (Oncorhynchus mykiss). No individual species is in danger of extinction as a whole; rather, distinct populations (also referred 

to as evolutionarily significant units, or ESU) are considered as threatened in some manner. 

Additional species such as sea run cutthroat trout are also experiencing population declines.

Factors contributing to the decline of Pacific salmon are generally related to anthropogenic 

induced changes to spawning and rearing habitat (Buck and Upton 2010, Loftus and Flather 

2000). Excessive siltation caused by landscape changes (for example, grazing and agricultural 

activities that remove vegetation; urbanization; and impervious surfaces in the watershed); 

water removals for irrigation, consumption, and industrial uses; obstructions (for example, 

hydroelectric facilities, road culverts) preventing salmon from reaching spawning habitats; 

and direct physical changes to their spawning and rearing habitats are among the factors 

presenting challenges to successful reproduction of Pacific salmon (Buck and Upton 2010). 

Even when dams are breached or fish passage constructed to allow migrating salmon access 

to upstream spawning habitats, the changes to the aquatic systems behind the dams from the 

natural lentic system in which salmon evolved to a lotic system common to hydroelectric 

facilities may impact the survival of young salmon migrating back downstream. Attempts to 

mitigate for salmon losses and restore populations through stocking of hatchery-produced fish 

have had mixed success; while such stockings may enhance the number of salmon available 

for harvest, improper stocking techniques have resulted in the loss of genetic diversity and 

mixing of populations. Hatchery-produced fish generally have a lower survival than native 

fish, and mixed hatchery/wild stocks present a problem for harvest managers. Eighty percent 

of the salmon caught commercially in the Pacific northwest and northern California come 

from hatcheries, but allowing harvest of hatchery fish may also increase harvest of sensitive 

wild fish in the same system (Buck and Upton 2010).

In general, Pacific salmon have declined throughout much of their range although stocks 

native to Alaska tributaries are much more robust than those in the Pacific Northwest 

(Piccolo and others 2009, Loftus and Flather 2000). A comprehensive evaluation of 

all salmon, steelhead, and sea-run cutthroat trout was conducted 20 years ago by the 

American Fisheries Society. At that time, 214 stocks of salmon, steelhead, and sea-run 

cutthroat trout in the Northwest and California were at risk of extinction or of special 

concern and 106 were already extinct (Nehlsen and others 1991). Today, much of the 

focus in the Pacific Northwest is on stocks that are considered threatened, endangered, 

or of special concern as legally defined under the Endangered Species Act (ESA). Of the 

52 distinct populations of salmon and steelhead in the Pacific Northwest, 28 (17 salmon 

and 11 steelhead) are currently listed under ESA (Buck and Upton 2010) (Table CS3-1). 
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Table CS3-1—Status, trends, and Biological Review Team (BRT) opinions of Pacific Northwest Salmon and 

Steelhead Populations. Base Modified from Buck and Upton 2010.

 Federal

Population 10 Year BRT Register

Species (ESU) Status a Trendb opinion c citation

Coho salmon Central Endangered Declining Danger of 70 FR 37160

(Oncorhynchus California Coast extinction (June 28, 2005)

kisutch) Southern Oregon/ Threatened Unknown Likely to 70 FR 37160

Northern California become (June 28, 2005)

 endangered

Lower Columbia Threatened Stable or Danger of 70 FR 37160

River increasing extinction (June 28, 2005)

Oregon Coast Threatened Stable or Likely to 73 FR 7816

increasing become (Feb. 11, 2008) 

 endangered

Puget Sound/ Species of 69 FR 19975

Strait of Georgia Concern (Apr. 15, 2004)

Southwest Undetermined

Washington

Chinook salmon Sacramento Endangered Stable or Danger of 70 FR 37160

(Oncorhynchus River increasing extinction (June 28, 2005)

tshawytscha) (winter-run) 

Upper Columbia Endangered Stable or Danger of 70 FR 37160

River (spring-run) increasing extinction (June 28, 2005)

Snake River Threatened Stable or Likely to 70 FR 37160

(fall-run) increasing become (June 28, 2005)

 endangered

Snake River Threatened Stable or Likely to 70 FR 37160

(spring-/ increasing become (June 28, 2005)

summer-run) endangered

Central Valley Threatened Stable or Likely to 70 FR 37160

(spring-run) increasing become (June 28, 2005)

 endangered

California Threatened Unknown Likely to 70 FR 37160

coastal become (June 28, 2005)

 endangered

Puget Sound Threatened Stable or Likely to 70 FR 37160

increasing become (June 28, 2005)

 endangered

Lower Columbia Threatened Stable or Likely to 70 FR 37160

River increasing become (June 28, 2005)

 endangered

Upper Threatened Stable or Likely to 70 FR 37160

Willamette River increasing become (June 28, 2005)

 endangered

Central Valley (fall- Species of 69 FR 19975

and late fall-run) Concern (Apr. 15, 2004)

(continued)
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Chum salmon Hood Canal Threatened Stable or Likely to 70 FR 37160

(Oncorhynchus (summer-run) increasing become (June 28, 2005)

keta) endangered

Columbia River Threatened Stable or Likely to 70 FR 37160

increasing become (June 28, 2005)

 endangered

Sockeye salmon Snake River Endangered Unknown Danger of 70 FR 37160

(Oncorhynchus extinction (June 28, 2005)

nerka) 

Ozette Lake Threatened Stable or Likely to 70 FR 37160

increasing become (June 28, 2005)

 endangered

Steelhead trout Southern Endangered Unknown Danger of 71 FR 834

(Oncorhynchus California Extinction (Jan. 5, 2006)

mykiss) 

Upper Columbia Threatened Stable or Danger of 74 FR 42605

River increasing Extinction (Aug. 24, 2009)

Central Threatened Unknown Likely to 71 FR 834

California Coast become (Jan. 5, 2006)

 endangered

South Central Threatened Unknown Likely to 71 FR 834

California Coast become (Jan. 5, 2006)

 endangered

Snake River Threatened Stable or Likely to 71 FR 834

Basin increasing become (Jan. 5, 2006)

 endangered

Lower Columbia Threatened Stable or Likely to 71 FR 834

River increasing become (Jan. 5, 2006)

 endangered

California Threatened Unknown Danger of 71 FR 834

Central Valley Extinction (Jan. 5, 2006)

Upper Threatened Stable or Likely to 71 FR 834

Willamette River increasing become (Jan. 5, 2006)

 endangered

Middle Threatened Stable or Likely to 71 FR 834

Columbia River increasing become (Jan. 5, 2006)

 endangered

Northern Threatened Unknown Likely to 71 FR 834

California become (Jan. 5, 2006)

 endangered

Puget Sound Threatened Declining 72 FR 26722

 (May 11, 2007)

Oregon Coast Species of 69 FR 19975

Concern (Apr. 15, 2004)

a Base data: NMFS, “Snapshot of ESU Status” (http://www.nwr.noaa.gov/ESA-Salmon-Listings/upload/snapshot-7-09.pdf).

b NMFS 2010a

c Good and others (2005)

Table CS3-1—(Continued).

 Federal

Population 10 Year BRT Register

Species (ESU) Status a Trendb opinion c citation
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All but two of these (Puget Sound steelhead and Central California Coast coho) where 10 

or more years of abundance data are available are considered “stable or increasing” (NMFS 

2010a). An ESU is considered “increasing” when 75 percent or more of its populations exhibit 

a statistically significant upward trend in abundance. When 75 percent or more of the populations exhibit a statistically significant downward trend in abundance, it is considered as 

“declining.” Otherwise it is classified as “stable” (NMFS 2010a).

However, trends in abundance alone may not indicate an ESU’s true potential for recovery. 

Risk factors such as low levels of abundance, lack of access to historical spawning habitats, 

extirpation of subpopulations, and the lack of spatial connectivity among extant component 

populations are significant factors in determining recovery status (NMFS 2010a). The “viable 

salmonid population” concept developed by NOAA Fisheries attempts to capture some of 

these parameters (NMFS 2000). Likewise, Good and others (2005) developed a criterion 

based on self-sustainability to classify the risk level of an ESU along a gradient of: a) not 

likely to become endangered, b) likely to become endangered in the foreseeable future, and 

c) in danger of extinction. “Biological Review Teams” (BRTs) of experts used this criterion to 

classify the populations listed as “threatened” or “endangered” under the ESA at that time. As 

table CS3-1 summarizes, 8 populations were classified in the most severe category (“danger 

of extinction”) and 19 were classified as “likely to become endangered in the foreseeable 

future.” None were classified as “not likely to become endangered” although the BRTs were 

closely divided on the risk to two stocks (Middle Columbia River Steelhead and Southern 

Oregon/Northern California Coho) (Good and others 2005).

The Future

The future for Pacific salmon is uncertain. Although fisheries managers and researchers have 

vastly more knowledge than their counterparts of even 20 years ago, the forces impacting 

Pacific salmon are formidable. Changes to the way that society generates and utilizes electricity, produces agricultural-based food stocks, and delivers drinking water to urban consumers may necessitate wholesale changes to lifestyles. The impact of climate change [see 

Case Study 5: Synopsis of Climate Change Effects on Aquatic Systems] on Pacific salmon 

reproduction, growth, and survival, not only in their natal streams but in the open ocean, is 

not clearly understood (Schindler and others 2008) and poses uncertain risk to the recovery 

of already stressed populations. However, scientific understanding of the threats to Pacific 

salmon is continuing to increase and current legal protections afforded through such laws as 

the Endangered Species Act provide some opportunity for recovery of these stocks.
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Case Study 4: Atlantic Coast Striped Bass________________

Background

Striped bass (Morone saxatilis) have historically been one of the most important species for 

both the recreational and commercial fisheries along the Atlantic coast. Commercial landings of striped bass dropped dramatically in the 1970s signaling a path toward stock collapse 

(see Loftus and Flather 2000), declining to a low point in the early 1980s. These populations 

rebounded only after dramatic fishery management efforts that significantly reduced fishing 

mortality on 1982 and subsequent year classes. Once considered ”overfished,” striped bass 

populations were declared fully restored in 1995 and have since been managed for a sustainable harvest (Loftus and Flather 2000). The success of striped bass restoration, largely 

attributable to passage of the Atlantic Striped Bass Conservation Act (P.L. 98-613), created 

the foundation for passage of a similar law to aid the management of other interjurisdictional 

Atlantic coastal species such as weakfish (Cynoscion regalis), summer flounder (Paralichthys 

dentatus), and others .

Historical Situation

Commercial landings of coastal Atlantic striped bass fluctuated around 4,000 metric tons (mt) 

in the 1960s and early 1970s before starting a precipitous downward trend in the mid 1970s 

(Figure CS4-1). To address this continuing decline, in 1979 Congress created the Emergency 

Striped Bass Study program to assist states in researching the causes behind the decline and 

to implement measures to arrest and reverse the decline. In 1981, the first interstate fishery 

management plan for striped bass was developed by the Atlantic States Marine Fisheries 

Commission (ASMFC) and applied to states from Maine to North Carolina. Implementation 

of the provisions of this plan was voluntary, with no enforcement mechanism or penalties for 

states that did not enact the recommended management measures. As a result, implementation was spotty most often due to political pressures within individual states, which prevented 

enactment of necessary restrictions on harvest.

Year

Commercial

Recreational

Figure CS4-1—Atlantic coast striped bass landings (source: ASMFC 2009).
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

Action

In 1984, the Atlantic Striped Bass Conservation Act (P.L. 98-613) was passed by Congress 

and signed into law by President Reagan which mandated the implementation of striped 

bass regulations contained within the fishery management plan developed by the ASMFC. 

Amendment 3 to the Striped Bass Management Plan was approved in 1985. The primary 

strategy contained within this amendment was to protect the 1982 year class until 95 percent 

of the females reached spawning age. Maryland, which had jurisdiction over the primary 

spawning grounds for striped bass in the Chesapeake Bay, completely closed its commercial 

and recreational fisheries, and other states enacted increasing size limits in their fisheries to 

achieve this objective. Eventually, Delaware and Virginia, other prime spawning areas, closed 

their fisheries in the Delaware and Chesapeake Bays respectively. Additionally, the Hudson 

River fishery, another prime spawning area, was closed due to PCB contamination issues.

Figure CS4-2—Population of Atlantic coast striped bass (source: ASMFC 

2009).

Response

A numerical trigger based on spawning success was established to signal that recovery objectives were being met and to allow relaxation of fishing restrictions. This trigger was reached 

in 1989. Consequently, in 1990, Amendment 4 to the interstate fishery management plan for 

striped bass was enacted that allowed states to reopen their fisheries at an interim fishing mortality rate that was set at 1⁄2 the estimated fishing mortality rate needed to achieve maximum 

sustainable yield. In 1995, coastal striped bass were declared restored by the ASMFC, and 

Amendment 5 was adopted to increase the target fishing mortality to 0.33, a cautionary level 

that was midway between the interim target (0.25) and a revised fishing mortality rate at 

maximum sustainable yield of 0.40 (ASMFC 2010).

By 2008, the allowable commercial harvest levels for striped bass were restored to 100 

percent of the states’ average landings during the 1972-1979 period, except for Delaware, 

which remained at the level allocated in 2002 (ASMFC 2010). In the recreational fisheries, 

all states continued to maintain a two fish bag limit with a minimum size limit of 28 inches, 
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

except for producer areas such as the Chesapeake Bay and Albemarle/Roanoke sound which 

allow fisheries with different size and bag combinations that provide “conservation equivalency” equal to, or more conservative than, the standard coastal fishing mortality level 

(ASMFC 2010). Despite this, recreational landings far exceed the commercial landings, averaging nearly 12,000 mt annually between 2003-2008 while the commercial landings averaged 

slightly more than 3,000 mt in this same time period. The federal Exclusive Economic Zone 

(or EEZ, generally the area from 3 miles to 200 miles offshore) remains closed to the possession or harvest of striped bass.

Future

While this recovery was underway, another problem was developing that held the potential 

to challenge the maintenance of the record number of striped bass. Mycobacteriosis, a bacterial disease causing inflammation, tissue destruction, and formation of scar tissue in vital 

organs (spleen, kidney) of striped bass, sometimes accompanied by external lesions, was first 

diagnosed in the Chesapeake Bay in 1997. Up to 60 percent of striped bass in the Maryland 

portion of the Chesapeake Bay are infected with mycobacteriosis and in the Virginia portion 

mycobacteria were found in the spleens of 76 percent of striped bass collected from 1999-

2001.10 Stress factors contributing to the susceptibility of striped bass to mycobacteriosis may 

include dietary deficiencies resulting from depleted stocks of prey species and high summer 

temperatures or reduced dissolved oxygen (U.S. Geological Survey 2005).

Striped bass may be infected with this disease but have no outward sign. The actual quantitative impact on the striped bass populations is unknown. However, according to the 

ASMFC (2009: 96) “...some studies have suggested that natural mortality of striped bass 

in Chesapeake Bay has increased since 1997 due to disease (mycobacteriosis) and reduced 

forage base” as well as other factors. By 2008 the total abundance of striped bass had declined 

25 percent from the peak in 2004; by 2009 the legal striped bass harvest of 2.96 million fish 

(13,000 mt) had decreased 9 percent by number and 13 percent by weight from 2008. The 

recruitment (age 1 abundance) decreased from the all-time high in 2004 (22.7 million fish) 

to below the 12.5 million fish average for the post-recovery time period. However, the 2008 

recruitment estimate of 13.3 million fish was above that average (ASMFC 2010).

In response, the ASMFC initiated an addendum to the management plan designed to reduce 

fishing mortality by up to 40 percent. One of the priority research needs identified by the 

ASMFC (2010: 15) is to “...continue analysis to determine linkages between the mycobacteriosis outbreak in Chesapeake Bay and sex ratio of Chesapeake spawning stock, Chesapeake 

juvenile production, and recruitment success into coastal fisheries.”

Research into the impact of mycobacteriosis as well as its causative factors is continuing. 

Striped bass populations are near their all-time high of the past quarter century and harvest 

continues to be high. However, if the trend of the latter years of this time period continue, 

striped bass populations and the continued relaxed levels of harvest that they support will 

become increasingly difficult to sustain.

10 Chesapeake Bay Program, 2011. http://www.chesapeakebay.net/mycobacteriosis.

aspx?menuitem=19598.
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Case Study 5: Synopsis of Climate Change Effects on 

Aquatic Systems _____________________________________

Climate change is a global phenomenon, the effects of which are playing out at local levels. 

Extensive research is being conducted within the global scientific community on various 

aspects of climate change, including its implications for aquatic systems. In the United States, 

climate change research is being carried out by multiple federal agencies (including the 

USDA Forest Service) and universities – some aimed directly at its implications to aquatic 

ecosystems. The purpose of this case study is not to provide a comprehensive overview of the 

growing literature that is focused on climate change issues associated with aquatic systems. 

Rather, this case study will briefly highlight some topics being addressed by researchers at the 

global and national scale and will review some of the potential implications of climate change 

on the status and trends of aquatic communities.

Global Climate Change: What Is Happening

Based largely on the 2007 report of the Intergovernmental Panel on Climate Change (IPCC), 

for the 100 year period 1907-2007 global atmospheric temperatures have generally increased 

(Solomon and others 2007). During this period, surface temperatures around the globe have 

increased 0.74 ± 0.18°C with an even greater warming trend over the last 50 years. Eleven of 

the 12 years during the period 1995-2006 ranked among the warmest since surface temperature began to be collected in 1850. For the next two decades, a continued warming of approximately 0.2°C per decade is projected. This warming has been the greatest over land and at 

most high northern latitudes and least over Southern Ocean and parts of the North Atlantic 

Ocean.

Concurrent with rising temperatures, the annual average Arctic sea ice cover has shrunk since 

1978 by an average of 2.7 percent per decade, with larger decreases in summer of 7.4 percent 

per decade. Mountain glaciers and snow cover generally have declined in both hemispheres. 

Snow cover is projected to continue to contract in the future.

From 1961-2003, global ocean temperatures rose by 0.10°C from the surface to 700 m depth. 

The oceans have become more acidic, with a 0.1 unit decrease in surface ocean pH from 

1750–1994 and the rate of decrease in pH over the past 20 years has accelerated to 0.02 units 

per decade.

Precipitation over the last century has increased significantly across eastern parts of North 

America and several other regions of the world. Concurrently, extreme weather events and 

storm intensity have increased. The IPCC considers it very likely that precipitation increases 

in high latitudes and decreases in most subtropical land regions will continue the observed 

recent trends.

Climate Change in the United States

Climate-related changes have already been observed in the United States and its coastal 

waters. Changes that are particularly relevant to aquatic resources include: increases in heavy 

downpours, rising temperature and sea level, rapidly retreating glaciers, thawing permafrost, 

lengthening growing seasons, lengthening ice-free seasons in the ocean and on lakes and 
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rivers, earlier snowmelt, and alterations in river flows (Karl and others 2009). In the United 

States, relative sea levels have been rising along most of the coasts at rates of 1.5–3 mm per 

year (Julius and West 2008). These trends are expected to continue and perhaps accelerate in 

some areas.

Regionally, mean annual air temperatures in the Rocky Mountains during the twentieth 

century increased by approximately 1 °C (Saunders and others 2008, as cited in Reiman and 

Isaak 2010), greater than the global average. Current projections for the western United States 

suggest that mean annual air temperatures will increase by another 1–3 °C by mid-century 

(Karl and others 2009, Reiman and Isaak 2010).

Implications for Aquatic Species Status and Trends

Aquatic communities in the United States will be affected by a combination of direct (for 

example, increases in water temperature) and indirect (for example, landscape changes) 

effects attributable to climate change. Consequently, some species may decrease in abundance 

and range while other species may increase in abundance and range (Isaak and others 2010). 

Already, there have been observed ecological changes including shifts in genetics, geographic 

range, ecosystem processes (for example, rates of organic matter decomposition), and the mix 

of life history strategies among members of the species assemblage (Reiman and Isaak 2010).

Direct Effects

Direct effects are those that result from increases in water temperature that result from 

increases in atmospheric temperature. Although there is less documentation of the effects of 

climate change in aquatic ecosystems than terrestrial (Heino and others 2009), some changes 

have been observed in species distributions (Hari and others 2006) and shifting prevalence 

of certain life history strategies (Reiman and Isaak 2010). Reiman and Isaak (2010) conclude 

that important changes for fishes and their habitats will be driven primarily by air temperature 

and precipitation. Changes to stream thermal regimes are likely to impact species distribution, 

abundance, growth rates, and population persistence in streams more than any other factor 

(Isaak and others 2010). As water temperatures increase, habitats for cold water species, such 

as salmon and trout, are very likely to contract. Already, Atlantic salmon are returning to the 

Penobscot River about two weeks ahead of when they migrated historically. This accelerated spawning schedule causes the young fish to utilize their internal yolk sac too early in 

the spring and are released into the rivers to feed before the water is warm enough to support 

the invertebrates they need for survival (http://www.fws.gov/northeast/climatechange/stories/

salmon.html). Isaak and others (2010) concluded that the impacts of a warming climate have 

begun to alter temperatures and thermal habitat distributions in streams across the Boise River 

basin. The impacts of these changes vary with species; these changes are not expected to alter 

the status of rainbow trout in this basin due to the extent of the habitats that they are able 

to occupy, but 8-16 percent of the habitat suitable for bull trout in this basin could become 

unsuitable each decade due to rising water temperatures, thus making bull trout one of the 

more vulnerable salmonids to climate-induced population declines and range shifts.

Indirect Effects

Indirect effects result from the impacts of climate change on aspects external to the aquatic 

ecosystem. Changing watershed landscapes, such as altered forest and riparian communities, change the amount and character of inputs such as sediment entering aquatic systems. 
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

This, combined with wildfire activity, will change inputs of sediment and large wood, and 

these basic channel constituents will be routed differently by hydrologic regimes that are 

also evolving (Barnett and others 2008; Miller and others 2003, as cited in Reiman and Isaak 

2010). Predicting the expected impacts on aquatic resources from indirect effects is particularly difficult and highly uncertain.

Combined Effects

Nelson and others (2009) investigated combined effects of climate change and urbanization 

discussed in a related case study [see Case Study 1: Impacts of Urbanization on Fisheries 

and Aquatic Ecosystems]. Overall, they found that the effects of existing stressors on aquatic 

systems (for example, urbanization) and climate change will threaten the viability of existing 

fish community structure in the piedmont streams that they analyzed. Although both factors 

produced detrimental effects to the systems, climate change effects were the most dominant, 

due in large part to increases in precipitation and resulting changes in runoff and hydrologic 

features of the streams. Their results suggested that 50–75 percent of the fish species in these 

streams would be highly stressed under all future climate scenarios. Moreover, declines in 

abundance are likely for many species, including species that comprise the important coldwater (trout) and warmwater (bass, sunfish) recreational fisheries. Wenger and others (2011) 

project that a combination of water temperature changes and shifts in hydrologic events will 

result in an average decline in habitat for trout species of 47 percent in the interior western 

United States. Specifically, their modeling analysis projects that cutthroat trout will lose 58 

percent of existing habitat, brook trout and brown trout will lose 77 percent and 48 percent, 

respectively, and rainbow trout, 35 percent based on current conditions and assuming that 

current trends continue.

Most aquatic systems in the United States are already under multiple stresses. Coastal and 

near-shore ecosystems are impacted by urbanization as Americans have migrated to the 

coasts, rising sea level threatens low lying areas, and increasing acidification of ocean waters 

is altering near-shore marine habitats. A distinct decline in horseshoe crab numbers has 

occurred that parallels climate change associated with the end of the last Ice Age (Faurby 

and others 2010) – a trend that is expected to continue in the future given predicted climate 

change. In streams throughout the western United States, growing human populations and 

water supply needs combined with impacts of climate change (for example, warmer atmospheric temperatures, increased precipitation, and greater wildfire incidence) will combine 

to threaten the integrity of existing aquatic systems (Karl and others 2009, Isaak and others 

2010). The extent to which aquatic systems will be affected will depend on unique features 

of each aquatic system and watershed, the magnitude of realized climate change, the degree 

of ecosystem sensitivity, and the availability of adaptation options for effective management 

responses (Julius and West 2008). Some of the ecosystem services currently provided by 

aquatic systems will be threatened by climate change, while others will be enhanced (Karl and 

others 2009).

Conclusion

Climate change will lead to some irreversible impacts on aquatic systems. Some of these 

impacts will be as drastic as extirpation of currently vulnerable species, dramatic range shifts 

for other species, and wholesale shifts in aquatic community structure. Some more tolerant 
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species may sustain their populations or even thrive in these changing conditions (Nelson and 

others 2009). Changes in the climate system will continue into the future regardless of any 

potential emissions mitigation (Julius and West 2008). So, what can resource managers do 

about it? Reiman and Isaak (2010) suggest six main management actions:

• Enhance resistance and resilience, such as reducing non-climate stresses, conserving 

critical habitat re-connecting streams and habitats, and conserving genetic and phenotypic diversity.

• Prioritize limited resources by considering the relative vulnerability of specific populations and likelihood of success of potential actions.

• Facilitate transitions to new conditions.

• Develop local information.

• Coordinate efforts.

Many existing best management practices for “traditional” stressors of concern may be 

applied to mitigate stressors resulting from climate change (Julius and West 2008). These 

authors recommend similar measures as Reiman and Isaak (2010) including protecting key 

ecosystem features, reducing anthropogenic stresses, protecting variant forms of a species 

or ecosystem so that, regardless of the climatic changes that occur, there will be areas that 

survive, maintaining more than one ecosystem or population, and establishing refugia that are 

less affected by climate change to protect vulnerable species.

Table CS5-1—Observed trends and issues for the future resulting from climate change in the United States (Karl and 

others 2009)

Region Observed trends Key issues for the future

Northwest o Annual average temperature rose 1.5°F over • Declining springtime snowpack leads to 

the past century, with some areas experiencing reduced summer streamflows. 

increases up to 4°F. •	 Increase in insect outbreaks, wildfires, and

o The region’s average temperature is projected changing species composition in forests. 

to rise another 3 to 10°F in this century. •	 Salmon and other coldwater species will

o Increases in winter precipitation and decreases experience stresses from rising water 

in summer precipitation are projected. temperatures and declining summer streamflows.

o Impacts related to changes in snowpack, •	 Sea-level rise along coastlines will result 

streamflows, sea level, forests, and other in increased erosion and the loss of land. 

aspects are already underway.

Southwest o Recent warming has been among the most rapid • Water supplies become increasingly scarce.

in the nation. •	 Increasing temperature, drought, wildfire, and

o Declines in spring snowpack and Colorado River invasive species will accelerate transformation

flow. of the landscape.

o Projected continued strong warming. •	 Increased frequency and altered timing of flooding

o Projected summertime temperature increases are will increase risks to people, ecosystems, and

greater than the annual average increases in parts infrastructure.

of the region. •	 Unique tourism and recreation opportunities are

o Water cycle changes are projected, which signal a likely to suffer.

serious water supply challenge. •	 Cities and agriculture face increasing risks from

o The prospect of future droughts becoming more a changing climate.

severe due to warming is a significant concern.

(Continued)
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Great Plains o Average temperatures have risen throughout the o Projected increases in temperature, evaporation, 

Great Plains, with the largest increases occurring and drought frequency. Agriculture, ranching, and 

in the winter months and over the northern states. natural lands, already under pressure due to an

o Relatively cold days are becoming less frequent increasingly limited water supply, are stressed by

and relatively hot days more frequent. rising temperatures.

o Temperatures are projected to continue to increase. o Climate change is affecting native plant and

o Summer increases are projected to be larger than animal species by altering key aquatic habitats.

those in winter in the southern and central Great Plains. o Shifts in the region’s population from rural areas

o Conditions are expected to become wetter in the north to urban centers will interact with a changing

and drier in the south. climate, resulting in a variety of consequences.

o Projected changes include more frequent extreme

events such as heat waves, droughts, and heavy rainfall.

Midwest/ o Average temperatures have risen in recent decades, o Increasing heat waves, reduced air quality, and

Great Lakes with the largest increases in winter. increasing insect and waterborne diseases during 

o The length of the frost-free or growing season has the summer. 

been extended by one week. o Increase in precipitation in winter and spring, 

o Heavy downpours are twice as frequent as they were more heavy downpours, and greater evaporation

a century ago. in summer would lead to more periods of both

o Both summer and winter precipitation have been floods and water deficits.

above average for the last three decades, the wettest o Increases in heat waves, floods, droughts, insects,

period in a century. and weeds will present increasing challenges to

o A decrease in lake ice, including on the Great Lakes. managing crops, livestock, and forests.

o Since the 1980s, large heat waves have become more o Native species are very likely to face increasing

frequent than any time in the last century, other than threats from rapidly changing climate conditions,

the 1930s. pests, diseases, and invasive species moving

o The observed patterns of temperature increases and in from warmer regions.

precipitation changes are projected to continue.

Southeast o Annual average temperature has risen 2°F since o Increases in air and water temperatures will cause

1970, with the greatest seasonal increase in the heat-related stresses for people, plants, and animals.

winter months. o Decreased water availability is very likely to affect

o A 30 percent increase in fall precipitation over the region’s economy as well as its natural systems.

most of the region but a decrease in fall o Sea-level rise and the likely increase in hurricane

precipitation in South Florida. intensity and associated storm surge will be among

o Summer precipitation has decreased over almost the most serious consequences of climate change.

the entire region. The percentage of the Southeast o Ecological thresholds are likely to be crossed

in moderate to severe drought increased over the throughout the region, causing major disruptions to

past three decades. ecosystems and to the benefits they provide to

o There has been an increase in heavy downpours. people.

o The power of Atlantic hurricanes has increased o Quality of life will be affected by increasing heat

since 1970, associated with an increase in sea stress, water scarcity, severe weather events, and

surface temperature. reduced availability of insurance for at-risk

o The number of very hot days is projected to rise properties.

at a faster rate than average temperatures. 

o Average annual temperatures are projected to rise 

4.5°F to 9°F with a 10.5°F increase in summer.

o Sea-level rise is projected to accelerate, increasing 

coastal inundation and shoreline retreat.

 The intensity of hurricanes is likely to increase.

Table CS5-1—(Continued)

Region Observed trends Key issues for the future

(Continued)
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

Northeast o Annual average temperature has increased by 2°F o Increasing problems for human health, especially

since 1970, with winter temperatures rising twice in urban areas.

this much with more frequent very hot days. o Agricultural production, including dairy, fruit, 

o A longer growing season. and maple syrup, is likely to be adversely affected

o Increase in heavy downpours, less winter as favorable climates shift.

precipitation falling as snow and more as rain. o Severe flooding due to sea-level rise and heavy

o Reduced snowpack, earlier break-up of winter downpours is likely to be more frequent.

ice on lakes and rivers, earlier spring snowmelt o Adverse impacts on winter recreation and the

resulting in earlier peak river flows, rising sea industries that rely upon it.

surface temperatures, and rising sea level. o The center of lobster fisheries is projected to

 continue its northward shift and the cod fishery

on Georges Bank is likely to be diminished.

Alaska o Over the past 50 years, annual average temperature o Longer summers and higher temperatures are

has increased 3.4°F, while winters have warmed by causing drier conditions.

6.3°F, warming at more than twice the rate of the o Insect outbreaks and wildfires are increasing.

rest of the United States. o Lakes are declining in area.

o Earlier spring snowmelt, reduced sea ice, widespread o Thawing permafrost damages roads, runways, 

glacier retreat, and permafrost warming. water and sewer systems, and other infrastructure.

o Projected increases in precipitation with simultaneous o Coastal storms increase risks to villages and

increases in evaporation due to higher air temperatures, fishing fleets.

will lead to drier conditions overall, with reduced soil o Displacement of marine species will affect key

moisture. Average annual temperatures are projected to fisheries.

rise between 5 and 13°F by late this century.

Hawaii and o Small islands are vulnerable to sea-level rise, coastal o Availability of freshwater is likely to be reduced.

U.S. Affiliated erosion, extreme weather events, coral reef bleaching, o Island communities, infrastructure, and

Islands ocean acidification, and contamination of freshwater ecosystems are vulnerable to coastal inundation

resources with saltwater. due to sea-level rise and coastal storms.

o The islands have experienced rising temperatures o Climate changes affecting coastal and marine 

and sea level in recent decades. ecosystems will have major implications for

o Projections for the rest of this century suggest tourism and fisheries.

continued increases in air and ocean surface

temperatures in both the Pacific and Caribbean.

o An overall decrease in rainfall in the Caribbean,

an increased frequency of heavy downpours nearly 

everywhere, and increased rainfall during the summer

months (rather than the normal rainy season in the 

winter months) for the Pacific.

o Hurricane wind speeds and rainfall rates are likely 

to increase. 

o Island coasts will be at increased risk of inundation.

Table CS5-1—(Continued)

Region Observed trends Key issues for the future
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Case Study 6: National Fish Habitat Assessment11 _________

Introduction

The National Fish Habitat Action Plan (NFHAP, www.fishhabitat.org) was formally adopted 

by the states (represented by the Association of Fish and Wildlife Agencies), the U.S. 

Department of the Interior, and the U.S. Department of Commerce in early 2006. The USDA 

Forest Service participates in NFHAP through leadership positions on the National Fish 

Habitat Board, national office staff participation in the Federal Agency Caucus, and Forest 

Service staff participation on various working groups and national fish habitat partnerships.

The focus of the NFHAP “...is to protect, restore and enhance the nation’s fish and aquatic 

communities through partnerships that foster fish habitat conservation and improve the 

quality of life for the American people.”12 This mission will be fulfilled through the following 

actions:

• Protect and maintain intact and healthy aquatic systems.

• Prevent further degradation of fish habitats that have been adversely affected.

• Reverse declines in the quality and quantity of aquatic habitats to improve the overall 

health of fish and other aquatic organisms.

• Increase the quality and quantity of fish habitats that support a broad natural diversity 

of fish and other aquatic species.

An initial task of the NFHAP was the development of the first-ever condition analysis of all 

fish habitats within the United States. This assessment has relied on existing national level 

(and in some cases large regional level) datasets of known stressors to aquatic habitats.

Jelks and others (2008) reported that the number of freshwater fish taxa considered to be 

“imperiled” or extinct in the United States increased 179 percent between 1979 and 2008 and 

nearly doubled in the last 10 years of that period. Human activities were listed as a contributing factor in the majority of these instances. The purpose of the NFHAP assessment approach 

was intended to clarify the potential specific causes on a nationwide scale so that national 

level planning could be more effective and individual partnerships could potentially target the 

most deleterious agents in their watershed for restoring fish habitats.

Methodology

The inland NFHAP assessment focused on streams and rivers of the coterminous United 

States using the 1:100,000 level National Hydrography Dataset Plus (NHDPlus) as the spatial 

framework. To predict the condition of fish habitats, landscape disturbance was analyzed for 

every river through a consistent process. This process assumed that landscape scale patterns 

and human activities for the variables measured correspond to patterns in local scale stressors.

11 Based on: National Fish Habitat Board, 2010 and Wang and others 2011. 

12 National Fish Habitat Action Plan 2006 available at: http://www.fishhabitat.org/documents/plan/

National_Fish_Habitat_Action_Plan.pdf
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

Datasets representing natural characteristics (catchment elevation and slope, mean annual air 

temperature and precipitation, catchment area, soil permeability rates) and disturbance factors 

that were: (1) meaningful for assessing fish habitat; (2) consistent across the entire study area 

in the way that they were assembled; and (3) representative of conditions in the past 10 years 

were applied to the development of the assessment. Anthropogenic variables were derived 

from 17 datasets representing urban land use, human population density, road density, grazing 

and pasture use, percent row crop agriculture, farm fertilizer applications, ground and surface 

water usage, National Pollution Discharge Elimination Sites, Toxic Release Inventory sites, 

National Superfund sites, and mine density. For rivers in the coterminous United States, these 

variables were collectively analyzed in the categories of:

• Urban/Human settlement (percent urban land use; human population density; road 

density)

• Livestock and grazing (percent pasture and hay in the watershed)

• Agriculture (percent row crop agriculture in the watershed)

• Point source pollution data (numbers of National Pollution Discharge Elimination 

Sites, Toxic Release Inventory sites, and National Superfund sites)

• Habitat fragmentation (numbers of dams and road crossings), and

• Mine density.

Streams were scored according to their condition as indicated by these variables in each 

location.

Although limited data on fish presence were available, data from national sampling programs (EPA’s Environmental Monitoring and Assessment Program, Regional Environmental 

Monitoring and Assessment Program, and NAWQA) and contributed by state agencies were 

used to calibrate the habitat condition scores on an ecologically defined regional basis. Where 

fish data were available, they were analyzed with human disturbance variables to identify the 

response of a set of indicator fish species to the different disturbance variables in each region. 

The resulting condition estimates that corresponded to the sensitivity of regionally specific 

fish groups were then used to determine the final habitat condition score. Stream segments in 

good condition were expected to have a low risk of habitat degradation and streams in poor 

condition a high risk of habitat degradation.

In Alaska and Hawaii, a variation of the methodology was used due to the limited data available in these states. Principal component analysis was employed among the various categories 

of variables to arrive at a single habitat score that indicated the condition of the stream.

For estuaries, habitat stress was measured by river discharge, pollutant levels, eutrophication, and urban, agricultural, and estuarine wetland land cover. A single disturbance score was 

calculated for each estuary based on measures of river discharge, pollution, land cover, land 

cover change, and eutrophication.
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Results13

Nationwide

In the coterminous United States, 27 percent of the stream miles are at high or very high risk 

of current habitat degradation and 44 percent are at low or very low risk (Figure CS6-1). As 

with water quality assessments highlighted elsewhere in this report, urban development, livestock grazing, agriculture, and point source pollution had higher risk of degradation, as did 

areas with high numbers of mines and dams. Rural areas without these disturbance factors 

(for example, Northeast, Southwest, and Pacific Coast States; see Figure CS6-2 for regional 

definitions) were at lower risk of degradation based on the variables analyzed. The estuaries showed a pattern that is consistent with increased human population growth in coastal 

areas—namely that the percent of estuarine area considered at high or very high risk of habitat 

degradation was much greater (53 percent) than inland land areas. Twenty-three percent of 

estuarine area is at low or very low risk.

13 Map-based results can be viewed at http://ecosystems.usgs.gov/fishhabitat/

Figure CS6-1—Relative condition of riverine and near coastal habitat based on the variables analyzed (National Fish Habitat 

Board 2010).
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

Northeast States (New York, Connecticut, Rhode Island, Massachusetts, 

Vermont, Maine, New Hampshire)

Nearly 60 percent of the stream miles in the northeastern states have a low or very low risk 

of habitat degradation and 16 percent have high or very high risk; 44 percent of the estuarine 

area is at high or very high risk. Stream conditions in the northern parts of Maine and New 

Hampshire and the Adirondack Mountain region of in New York is at very low risk of degradation from the factors assessed. The habitats at highest risk of degradation occur in the 

farmlands of northeast New York where row crops and pasture are dominant influences, along 

the Hudson and Connecticut rivers where urbanization and farming occur, and in urban areas 

of the region. Estuarine areas have the lowest risk of degradation along Maine’s coast and the 

highest risk of degradation in Long Island Sound, Massachusetts Bay, and Narragansett Bay, 

where excess nutrients and sources of pollution in the watershed are a key issue.

Figure CS6-2—Regional partitions used in the National Fish Habitat Assessment (National Fish Habitat Board 2010).

Pacific

Coast

Mountain

Southwest

Northern

Plains

Upper

Midwest

Central

Midwest

Central

Mississippi

River

Southern

Plains

Eastern Gulf

of Mexico

Southeast

Atlantic

Mid-Atlantic

Northeast

Alaska

Hawaii
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Mid-Atlantic States (Pennsylvania, New Jersey, Delaware, Maryland, Virginia, 

West Virginia)

Thirty-three percent of the stream miles in this region are at low or very low risk of degradation with 29 percent at high or very high risk. Stream habitat in most of West Virginia is at 

low risk of degradation from the factors assessed, but it should be noted that legacy mining 

and barrier issues have not yet been fully assessed. Areas with the highest risk of degradation include northeast New Jersey, southeast and southwest Pennsylvania, central Maryland, 

and northern Virginia. Row crops, pasture, and urbanization all affect habitats in these areas. 

Chesapeake Bay shows a very high risk of habitat degradation due to excess nutrients and 

a highly altered watershed, while Delaware Bay and other estuaries in the region also show 

a high risk of degradation due to watersheds that are highly altered. Ninety-five percent of 

the estuarine area in the mid-Atlantic states is at high or very high risk of current habitat 

degradation.

Southeast Atlantic States (Georgia, South Carolina, North Carolina)

The greatest proportion (44 percent) of the stream miles in this region are at moderate risk of 

habitat degradation with 33 percent at low or very low risk. With one of the highest population growth rates in the country, this region contains areas of fish habitat at very high risk 

of degradation due to urbanization around the large metropolitan growth areas of Charlotte, 

Raleigh/Durham, and Atlanta. Areas with a low risk of degradation include the mountains of 

western North Carolina and parts of the coastal plain of all three states. Eighty-two percent 

of the estuarine area is at high or very high risk of degradations, influenced by the relatively 

large Albemarle-Pamlico Sound, which has a high risk of impairment due to agricultural 

runoff. Many of the smaller estuaries are generally at low risk of degradation.

Upper Midwest States (Minnesota, Wisconsin, Michigan)

Forty-two percent of the river miles in this region are at moderate risk of habitat degradation, with 29 percent at high or very high risk. Fish habitat in the northern parts of Michigan, 

Wisconsin, and Minnesota are at low or very low risk of degradation from the factors 

assessed. Areas that are at very high risk of degradation occur near large metropolitan areas of 

Minneapolis, Detroit, and Chicago. Streams in southwest Minnesota reported to have a high 

risk of degradation generally due to the effects of row crop agriculture and urbanization.

Central Midwest States (Ohio, Indiana, Illinois, Iowa)

Forty-six percent of the stream miles in this region are at high or very high risk of habitat degradation with 47 percent being at moderate risk. A large proportion of aquatic habitat in Iowa 

has a high risk of degradation from the factors assessed, mainly row crop agriculture. Illinois, 

north central Indiana, and northeastern Ohio also contain areas where habitat has a high risk 

of degradation from agriculture or a very high risk of degradation from urbanization.
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

Central Mississippi River States (Missouri, Arkansas, Kentucky, Tennessee)

Forty percent of the stream miles in this region have a very high predicted risk of degradation and 34 percent have moderate risk from the factors assessed, mainly due to row crop 

agriculture. Areas with a high risk of degradation also occur in southwest Missouri and central 

Kentucky and Tennessee, where pasture is the main source of habitat degradation. Areas 

with low risk of habitat degradation occur in the mountains of eastern Kentucky and western 

Arkansas.

Eastern Gulf of Mexico States (Florida, Alabama, Mississippi, Louisiana)

Thirty-two percent of the stream miles in this region have a high or very high risk of degradation from the factors assessed; 41 percent are rated as low or very low risk. Much of central 

Florida is at very high risk of habitat degradation due to use of the area as pasture, as is a large 

area in southwestern Louisiana where row crops and pasture both contribute to habitat degradation. Large areas along the Mississippi River and in highly urbanized southeastern Florida 

are at very high risk of degradation. The panhandle of Florida contains areas of habitat with a 

low risk of degradation. The estuaries along most of the eastern Gulf of Mexico have a moderate (53 percent) to low risk of degradation with the exception of Tampa Bay and Pine Island 

Sound, where urbanization and pollution in the watershed negatively affect the estuary.

Southern Plains States (Texas, Oklahoma, Kansas)

Thirty-eight percent of the stream miles in this region are at high or very high risk of degradation, while 31 percent are at low or very low risk. Urbanization in eastern Texas and row crops 

and pasture in western Kansas are responsible for areas with a very high risk of degradation 

due to the factors assessed. Habitat with a very low risk of degradation occurs in central Texas 

and eastern Kansas. Sixty-five percent of the estuarine area of Texas is at high or very high 

risk of degradation due to highly altered watersheds.

Northern Plains States (North Dakota, South Dakota, Nebraska)

Thirty-five percent of the stream miles in this region are at a very high risk of degradation 

from the factors assessed, with heavy concentrations of aquatic habitat in southwest North 

Dakota, central and southeastern South Dakota, and southern Nebraska being impacted by 

row crops, pasture, and road crossings. Conversely, large tracts with low risk occur in north 

central Nebraska and western South Dakota where these factors are not as intense.

Mountain States (Colorado, Idaho, Montana, Utah, Wyoming)

Sixty-four percent of the stream miles in this region are at low or very low risk of degradation with only 17 percent at high or very high levels. The habitats with the highest risk of 

degradation occur in all five states, related to row crops in southeast Idaho, pasture in northern 

Montana, and urbanization in a areas around Denver and Salt Lake City. Areas with a very 

low risk of degradation occur in central Idaho, parts of northwest Montana, and northwest 

Wyoming, particularly where large tracts of parks, wilderness areas, and other protected lands 

occur.
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Southwest States (Arizona, New Mexico, Nevada)

Seventy-six percent of the stream miles in this region were assessed to have low or very low 

risk of disturbance (note that water diversions and drought, common problems in this area, 

were not considered in this analysis). Areas of fish habitat with a very high risk of degradation 

(9 percent of stream miles region wide) occur in southwest Arizona where urbanization, dams, 

and road crossings are of greatest concern. Northwest Arizona, southern Utah, and other parts 

of these states contain areas with a very low risk of aquatic habitat degradation.

Pacific Coast States (California, Oregon, Washington)

Fifty-eight percent of the stream miles in this region are at low or very low risk of disturbance. Overall, 25 percent of the region is at high or very high risk of disturbance, with 

California’s Central Valley, a portion of northeastern Oregon, and eastern Washington 

bearing much of this, principally due to row crops. The western urbanized areas from the 

Canadian border south to Eugene, Oregon, are also at high risk of degradation as well as the 

Los Angeles and San Diego areas. Areas with a low risk of degradation occur in northern 

Washington, central Oregon, and eastern California. With the exception of Puget Sound, estuaries in Washington, Oregon, and northern California have a low risk of degradation, whereas 

the estuaries of central and southern California are generally at high risk of degradation from 

altered flows and watersheds that are highly altered with a high number of pollution sources. 

Fifty-three percent of the estuarine area in the region has a low or very low risk of disturbance 

for the factors considered with 42 percent being at high or very high risk.

Alaska

As indicated earlier, the assessment factors used for Alaska differed from the coterminous 

United States and therefore cannot be directly compared. However, most of Alaskan fish 

habitat is relatively undeveloped, and the state has some of the least disturbed aquatic habitat 

in the country. However, localized areas at risk for habitat degradation exist around metropolitan areas due to the effects of roads and urbanization.

Hawaii

As with Alaska, the assessment factors used for Hawaii differed from the coterminous United 

States and therefore cannot be directly compared. Inland aquatic systems in Hawaii have been 

extensively developed for drinking water and agricultural irrigation. A very cursory analysis 

for those rivers that flow to the ocean was conducted but cannot be compared to the coterminous United States. Areas of urbanization on the islands of Hawaii, Oahu, and Maui are most 

at risk for habitat degradation from the factors assessed. Areas with a low risk of degradation 

occur in higher elevations away from the coast or away from the main urbanized areas.

Use of the Information

The habitat conditions outlined in this report reflect the limited range of variables analyzed 

that represent or are correlated with particular habitat stressors. Some factors very important 

in specific geographic regions may not be included. Factors known to affect the condition of 

aquatic habitats that lacked spatially extensive and consistent collection methods were not 
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USDA Forest Service Gen. Tech. Rep. RMRS-GTR-283. 2012

included in the condition index. For example, although large dams and road crossings (that 

are in the analysis) could be used as surrogate indicators for fish passage obstructions, actual 

smaller scale obstructions (for example, culverts or conversely fishways around dams) are not 

reflected in the analysis nor hydrologic metrics (flow, connectivity, etc.). Neither are some 

of the significant factors leading to species endangerment such as invasive species (Jelks and 

others 2008). However, because large scale stressors to aquatic systems such as urbanization, agriculture, and road building are represented in the analysis, it has utility for evaluating 

major threats to aquatic systems at the geographic scale (1:100K) analyzed.

While the national level compilation of scores at broader spatial units is useful for policy 

makers and planners in assessing national budgetary and program needs, the finer scale watershed analyses will be most useful to on-the-ground efforts to protect, restore, and enhance 

habitats for healthy fish populations. These analyses represent the initial attempt to characterize habitat factors impacting fish populations and will be refined as additional national 

scale data become available. The data download and mapping capability are made available 

to Fish Habitat Partnerships and others through an interactive web tool that will enable these 

partnerships to visualize specific habitat factors influencing the local and catchment watersheds (http://ecosystems.usgs.gov/fishhabitat). It is anticipated that this delivery mechanism 

will facilitate application of the assessment to the implementation of restoration projects and 

likely result in an information exchange that will help to refine data elements for use in future 

assessments.

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Appendix A. Glossary of terms used in the text____________

anadromous—fish that migrate up river from the sea to spawn

at-risk species—a species whose biological and ecological circumstances place it at a 

very high (critically imperiled), high (imperiled), or moderate (vulnerable) risk of 

extinction based on the criteria specified by the conservation ranks developed by 

NatureServe (NatureServe 2010)

best management practices—a practice or usually a combination of practices that are determined by a state or designated planning agency to be the most effective and practicable means (including technological, economic, and institutional considerations) of 

controlling point and nonpoint source pollution at levels compatible with environmental goals (Helms 1998)

biotic—living component of the community

biotic condition—see “index of biotic condition”

biological integrity—state of being capable of supporting and maintaining a balanced 

community of organisms having a species composition, diversity, and functional 

organization comparable to that of the natural habitat of the region (EPA 2006)

catchability—the susceptibility of an organism to be captured by a specific gear type

catch-per-unit-effort—the number of organisms captured per unit of time, space, or measure 

of gear

cyanobacteria—a phylum of bacteria that obtain their energy through photosynthesis – also 

known as blue-green algae

designated use—water quality standards that define the goals for a water body by designating 

its highest attainable uses

diadromous—an organism that migrates between fresh and salt water

distinct population segment—vertebrate population or group of populations that is discrete 

from other populations of the species and significant in relation to the entire species

ecoregion—a geographic area a defined by its environmental conditions (for example, 

climate, landforms, soil characteristics )

ecosystem—a complex set of relationships among the living resources and physical environment of an area

ecosystem services/ecological services—the conditions and processes through which natural 

ecosystems, and the species which make them up, sustain and fulfill human life (Daily 

1997)

endangered—an animal or plant species in danger of extinction throughout all or a significant portion of its range
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evolutionarily significant unit—a population or group of populations that is substantially 

reproductively isolated from other conspecific populations and that represents an 

important component of the evolutionary legacy of the species

exclusive economic zone—the area of the ocean over which a nation has special rights over 

the exploration and use of marine resources, generally stretching a distance of 200 

nautical miles from its coast

expenditures—money spent on fishing-related recreational trips and equipment in the United 

States and includes money spent by participants for themselves, or the value of gifts 

received by a participant

extinct—a species that no longer exists

federal trust species—species designated as threatened or endangered under the Endangered 

Species Act as well as migratory birds (for example, waterfowl, wading birds, shorebirds, neotropical migratory songbirds)

habitat—the environment of an animal, plant, or other organism

imperiled—at risk of becoming threatened, endangered, or extinct

index of biotic condition—the sum of a number of individual measures of biological condition, such as the number of taxa in a sample, the number of taxa with different habits 

and feeding strategies, etc. (EPA 2006)

Interstate Fisheries Commission—any of three marine fisheries commissions established 

through a compact of states and approved by the Congress for the purposes of coordinating management of interjurisdictional marine resources

invertebrate—an animal without a backbone or spinal column

landscape—physical features of an area of land

lentic—standing water, such as a lake or pond

livebearers—a fish that bear live young rather than depositing eggs

lotic—moving water, such as a stream or river

macroinvertebrate—invertebrate animal large enough to be seen without the aid of a 

dissecting scope

maximum sustainable yield—the theoretical largest harvest that can be taken from a species’ 

stock over an indefinite period without threatening the ability of the stock to replenish 

itself

microcystin—nonribosomal peptides produced by cyanobacteria that can be very toxic for 

plants and animals (including humans)

mycobacteriosis—a generic term that describes a tuberculosis-like disease caused by a group 

of bacteria known as mycobacteria that predominantly affect the visceral organs of 

striped bass and can also cause unsightly skin ulcers
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observed/expected ratio—the number of species observed divided by the number of species 

in a reference condition

overfished—fish population levels that are below that which can replenish itself

overfishing—the rate of fishery removals, or fishing mortality, is too high to sustain the 

current fishing levels and allow the stock to replenish itself—a stock may be subject 

to “overfishing” but not yet be “overfished”

participant—for the National Survey of Fishing, Hunting, and Wildlife-Associated 

Recreation, participant is an individual who reported engaging in recreational fishing 

during the survey year

riparian—a zone or area that is the interface between land and a watercourse (river, lake, or 

stream) that is often characterized by hydrophilic plants

subspecies—an organism identified below the species level on the phylogenetic scale

sustainable—a method of harvesting or using a resource so that the resource is not depleted 

or permanently damaged and is capable of replenishing itself

taxon (pl. taxa)—a taxonomically defined group of organisms

threatened—an animal or plant species likely to become endangered within the foreseeable 

future throughout all or a significant portion of its range

urbanization—a process in which an increasing proportion of a population lives in cities and 

the suburbs of cities
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Appendix B: Scientific names of species 

mentioned in the text _________________________________

American eel—Anguilla rostrata

American lobster—Homarus americanus

American shad—Alosa sapidissima

Asian Carp—Hypophthalmichthys nobilis or Hypophthalmichthys molitrix

Atantic Menhaden ―Brevoortia tyrannus

Atlantic Salmon—Salmo salar

Atlantic Sturgeon—Acipenser oxyrinchus

Black Bass—Micropterus salmoides or Micropterus dolomieu

Brook Trout—Salvelinus fontinalis

Brown Trout—Salmo trutta

Bull Trout—Salvelinus confluentus

Bullhead ―Ameiurus spp.

Catfish ―Ictalurus spp.

Chinook/King Salmon—Oncorhynchus tshawytscha

Chum/Dog Salmon—Oncorhynchus keta

Clams—A marine or freshwater bivalve mollusk of the class Pelecypoda

Cod—Gadus spp.

Coho/Silver Salmon—Oncorhynchus kisutch

Crappie—Pomoxis spp.

Crustaceans—Aquatic arthropods of the class Crustacea

Cutthroat Trout—Oncorhynchus clarkii

Darters—A small North American fish of the genera Etheostoma, Ammocrypta, or Percina

Eurasian watermilfoil—Myriophyllum spicatum

Finfish—An aquatic vertebrate of the class Osteichthyes with two sets of paired fins and 

several unpaired fins

Flatfish—An aquatic vertebrate of the order Pleuronectiformes

Halibut (Pacific)—Hippoglossus stenolepis

Herring—Clupea spp.

Horseshoe Crab—Limulus polyphemus

Lake Trout—Salvelinus namaycush
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Largemouth Bass—Micropterus salmoides

Pacific Salmon—fish of the genus Oncorhynchus

Panfish—A generic name referring to a small fish suitable for frying, in this case generally 

Perca spp., Pomoxis spp., or Lepomis spp.

Pink/Humpback Salmon—Oncorhynchus gorbushca

Pollock—Theragra spp.

Pupfish—Cyprinodon spp.

Quagga Mussel—Dreissena rostriformis bugensis

Rainbow Trout—Oncorhynchus mykiss

Round Goby—Neogobius melanostomus

Salmon (Pacific, western, northwestern)—Oncorhynchus spp.

Sardines—Fish of the family Clupiedae

Scallops—Placopecten magellanicus

Sea Lamprey—Petromyzon marinus

Sea-run Cutthroat Trout―Oncorhynchus clarkii clarkii

Shellfish—An aquatic shelled mollusk or crustacean

Smallmouth Bass—Micropterus dolomieu

Snails—An aquatic or terrestrial mollusks of the class Gastropoda

Snapping Turtle—Chelydra spp.

Sockeye Salmon—Oncorhynchus nerka

Spiny Waterflea—Bythotrephes longimanus

Steelhead Trout—Oncorhynchus mykiss

Striped Bass—Marone saxatilis

Summer Flounder—Paralichthys dentatus

Trout—Any of several chiefly freshwater game fish of the genera Oncorhynchus, Salvelinus, 

or Salmo

Walleye—Sander vitreus

Walleye Pollock—Theragra chalcogramma

Weakfish—Cynoscion regalis

White Bass—Morone chrysops

Yellow Perch—Perca flavescens

Zebra Mussel—Dreissena polymorpha 
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Status of the biological condition of wadeable streams, by ecoregion in the 

United States based on Macroinvertebrate Index of Biotic Condition (MIBC) 

(USEPA 2006).

Stream miles Condition (% of stream miles)

 Region (x 1000) Good Fair Poor

Nationwide 671.1 28 25 42

Northern Appalachians 97.9 13 15 45

Southern Appalachians 178.4 21 24 55

Coastal Plains 72.1 36 23 39

Upper Midwest 36.5 28 31 39

Temperate Plains 100.9 26 36 37

Southern Plains 19.3 22 20 54

Northern Plains 13.4 30 13 50

Western Mountains 126.4 46 28 25

Xeric West/Southwest 26.0 42 15 39

Appendix C: Source Data for Figure 3____________________
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Fish and other aquatic resource trends in the United States: A technical document supporting the Forest Service 2010 RPA Assessment

Appendix D: Source Data for Figure 4____________________

Macroinvertebrate taxa loss determined by the ratio of observed number of species to the number of 

species expected at least-disturbed reference sites (O/E ratio) in wadeable streams by ecoregions in 

the United States (USEPA 2006).

Percent of stream miles with:

Stream miles >50% 20% – 50% 10% – <20% <10%

 Region (x 1000) taxa loss taxa loss taxa loss taxa loss

Nationwide 671.1 13 26 12 41

Northern Appalachian 97.9 19 17 14 23

Southern Appalachian 178.4 16 36 13 30

Coastal Plains 72.1 15 38 12 32

Upper Midwest 36.5 5 31 18 45

Temperate Plains 100.9 10 17 12 58

Southern Plains 19.3 15 15 20 42

Northern Plains 13.4 12 16 6 60

Western Mountains 126.4 5 18 10 63

Xeric West/Southwest 26.0 15 35 10 34

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