Fish and Other Aquatic Resource Trends

in the United States

Fish and Other Aquatic Resource Trends

in the United States

U.S. DEPARTMENT OF AGRICULTURE FOREST SERVICE

A Technical Document Supporting the

2000 USDA Forest Service RPA Assessment

A Technical Document Supporting the

2000 USDA Forest Service RPA Assessment

ANDREW J. LOFTUS AND CURTIS H. FLATHER
Abstract

Loftus, Andrew J.; Flather, Curtis H. 2000. Fish and other aquatic resource trends in the United 

States: A technical document supporting the 2000 USDA Forest Service RPA Assessment. 

Gen. Tech. Rep. RMRS-GTR-53. Ft. Collins, CO: U.S. Department of Agriculture, Forest Service, 

Rocky Mountain Research Station. 50 p.

This report documents the general trends in fisheries and aquatic resources for the nation 

as required by the Renewable Resources Planning Act (RPA) of 1974. The report highlights 

major trends in water quality, specific fish populations, resource utilization, and imperiled 

aquatic fauna. Relationships between land use, water quality, and aquatic species conditions 

are explored. An analysis is provided of a multi-state information sharing initiative (MARIS) that 

the Forest Service has initiated, along with recommendations for the future. The data for the 

report came primarily from existing state and federal agency data. The report concludes with the 

implications of these findings for Forest Service strategic planning.

Keywords: fish resources, national assessment, trends, aquatic species, aquatic habitats, 

threatened and endangered species.

The Authors

Andrew J. Loftus is a natural resources consultant at 3116 Munz Drive, Suite A, Annapolis, MD 21403, 

affiliated with the Conservation Management Institute, Department of Fisheries and Wildlife, Virginia 

Tech University, Blacksburg, Virginia.

Curtis H. Flather is a research wildlife biologist at the USDA Rocky Mountain Research Station, Fort 

Collins, CO.

You may order additional copies of this publication by sending your 

mailing information in label form through one of the following media. 

Please send the publication title and number.

Telephone (970) 498-1392

E-mail rschneider@fs.fed.us

FAX (970) 498-1396

Mailing Address Publications Distribution

Rocky Mountain Research Station

240 W. Prospect Rd.

Fort Collins, CO 80526
Fish and other aquatic resource trends 

in the United States:

A technical document supporting the 

2000 USDA Forest Service RPA Assessment

Andrew J. Loftus and Curtis H. Flather

Contents

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

Purpose. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Federal Authorities in Resource Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Trends and Impacts of Aquatic Habitat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Land and Water Impacts on Aquatic Habitats. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Contaminant Advisories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Wetland Habitats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Trends in Populations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Inland and Freshwater Species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Marine and Estuarine Species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Imperiled Fish and Other Aquatic Species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Causes and Economic Effects of Species Declines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Case Study 1: Midwest Crappie Production in Impoundments . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Case Study 2: Watershed Impacts on Cold Water Habitat in Canyon Creek, Arizona . . . . . . . . . . 15

Case Study 3: Michigan Grayling Restoration: A Lost Opportunity?. . . . . . . . . . . . . . . . . . . . . . . . 17

Case Study 4: Restoring a Declining Lake Superior Lake Trout Fishery . . . . . . . . . . . . . . . . . . . . 18

Case Study 5: Chesapeake Bay Ecosystem Restoration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Case Study 6: Columbia River Salmonids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Case Study 7: Southern Appalachian Aquatic Resources: An Imperiled Ecosystem?. . . . . . . . . . 27

Case Study 8: Atlantic Salmon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Trends in Commercial and Recreational Fishers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Commercial Fishers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Recreational Fishers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

National Survey on Fishing, Hunting, and Wildlife-Associated Recreation. . . . . . . . . . . . . . . . . . . 32

Marine Recreational Fisheries Statistics Survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

State License Sales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Recreational Fishing on Forest Service Lands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Trend Summary and Factors Affecting Participation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Conclusion: Management Implications to Forest Service Strategic Planning . . . . . . . . . . . . . . . . . . . 38

Data and Information Reporting Needs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Other Implications for Forest Service Strategic Planning and Activities . . . . . . . . . . . . . . . . . . . . . 39

Case Study 9: Evaluation of the Multi-State Aquatic Resources Information System (MARIS) 

for Assessing Trends in Aquatic Species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Literature Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Appendix A. Scientific Names of Species Mentioned in the Text. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000. 1

INTRODUCTION

Aquatic resources historically have been a vital component of the development of what is now the United States. 

Native Americans and early settlers relied on fish, water, 

shellfish and other aquatic resources for food and profit 

and as settlement progressed, these resources influenced 

the structure and government of a new nation. The resulting high value of fisheries often contributed to their depletion. For example, the first public schools in this country 

were financed in part through the sale of striped bass1

by act of the Plymouth colony in 1670 (Setzler and others 

1980). However, the pressure to harvest these resources 

combined with increasing land development began to 

take its toll on natural resources. Those same populations 

of striped bass that financed public education became 

subject to early conservation measures in the new colonies when New York and Massachusetts prohibited sales 

during the winter of 1776 (Setzler and others 1980). Like 

the effect that striped bass had on settlement in the northeastern states, every region of this country has in some 

way been shaped by aquatic resources. Similarly, the 

status of the resources has been substantially influenced 

by settlement. 

Today, aquatic resources are no less important to economic vitality and growth than during the past 400 years 

of European settlement. Fish provide a source of protein 

and recreational opportunities for approximately one-fifth 

of all U.S. residents and water is vital for consumption, 

industry, power, and agriculture as well as for healthy 

aquatic ecosystems. 

In balancing the uses of these resources, the vital link 

that aquatic species provide to the overall stability of 

aquatic communities and ecosystems is often overlooked. 

Pacific salmon, for example, play a crucial role in the 

mass transfer of energy and nutrients between the sea, 

freshwater, and terrestrial environments (Allendorf and 

others 1997, Cederholm and others 1999), thereby impacting terrestrial wildlife and freshwater organisms. Decisions that impact these resources have often disregarded 

these ecological relationships. However, the indirect benefits resulting from the ecological roles that aquatic fauna 

play may be greater than the direct benefits resulting from 

consumptive activities (Dailey 1997). 

In many cases, the status of aquatic life is the best 

measure of success in managing the landscape, air, and 

water quality. A true measure of watershed and ecosystem management is reflected in how programs impact the 

diversity and biological integrity of aquatic populations. 

Some policy makers are now recognizing the interactions 

between landscapes and aquatic systems and incorporating them into programs. “Protection of the Chesapeake 

Bay starts on the land as well as the water,” noted Governor Parris Glendening of Maryland during the outbreaks 

of toxic dinoflagellates in portions of the Chesapeake Bay. 

“The crisis surrounding toxic Pfiesteria sharply reminded 

us of the link between our land and our water and the 

effect of water quality on our health and livelihoods.”2

The toxic dinoflagellates that impacted portions of the 

Chesapeake Bay (attributed to a genus Pfiesteria sp.) were 

thought to be completing a phase of their complex life 

cycle that is triggered in part by heightened nutrient loads 

in the waters—in this case from anthropogenic sources. 

Agricultural practices in the surrounding watershed were 

initially linked to these nutrients. Governor Glendening 

was echoing what ecologists, scientists, naturalists and 

others have known for centuries: Actions on the land ultimately affect the condition of the waterways. The condition of the nation’s waterways and the aquatic fauna are 

in fact an indicator of the activities that take place in the 

surrounding watershed and airshed.

Today, many fish species and other aquatic ecosystem 

components face serious threats. Scientists have learned 

much about maintaining and restoring healthy aquatic 

ecosystems as sociologists, managers, and policy makers 

have more clearly identified the benefits that healthy ecosystems provide to people and the national economy. 

Restoring and maintaining healthy ecosystems requires 

political and economic support as well as technical knowledge. Applying these three factors to restore aquatic resources has often resulted in tremendous success as documented in several case studies presented in this report.

PURPOSE

This report is authorized under 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 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. The RPA 

directs that an assessment of resources and utilization 

1 Scientific names of all species mentioned in this report are 

found in Appendix A. 2 State of the State Address, January 21, 1998.
2 USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000.

Loftus and Flather Fish and Other Aquatic Resource Trends in the United States

occurring on all lands be conducted, not just on lands 

managed by the USDA Forest Service. Therefore, case 

studies and population assessments are provided here for 

a variety of lands, including near-shore marine species to 

a limited extent.

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 to make such analyses and determinations is incomplete and difficult to access. This report does focus on the 

general condition of aquatic habitats, species, and usage 

trends as reflected by the results of select surveys and 

data collection efforts. Supplementing this are case studies 

(figure 1) that provide examples of some of the impacts of 

an integrated approach to managing aquatic systems that 

encompasses management of the landscape, fish populations, and human utilization of fish stocks. We highlight 

successes, as well as failures, of fisheries management 

programs that incorporate a holistic land use component. 

Intertwined throughout the document and highlighted in 

special sections are the economic and social importance 

of maintaining healthy aquatic ecosystems.

FEDERAL AUTHORITIES IN 

RESOURCE MANAGEMENT

Federal management of aquatic species, codified in law, 

began to increase in the early 1900s, but it wasn’t until late 

in the century that it began to receive significant attention from the legal community (Bean 1983). A plethora of 

legislation, administrative rules, and supporting judicial 

rulings serves to provide the legal foundation for federal 

interest in fishery resources. Most of this legal foundation focuses on management of habitat on federal lands or 

waters, endangered species, and the interstate commerce 

(interjurisdictional fisheries) and treaty provisions of the 

Constitution.

Figure 1—Location of case studies found in the RPA Fisheries Assessment. Numbers cross-reference case studies as they appear in 

the document. Case Study 9 actually includes the states of Illinois, Iowa, Michigan, Minnesota, Ohio, and Wisconsin. Pacific Coast Rocky Mountain Nort

h

South

Figure 1

2

6

7

9

1

3

4 8

5
USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000. 3

Fish and Other Aquatic Resource Trends in the United States Loftus and Flather

Passage of the Lacey Act (16 U.S.C. 667e) in 1900 set 

the stage for cooperative federal/state management of 

aquatic resources and the process of defining the respective federal and state roles in management of wildlife 

populations (Bean 1983). While the Lacey Act enlists federal enforcement of state game laws in interstate commerce of wildlife, the states themselves retain authority 

over establishing those laws. The Lacey Act, as strictly 

interpreted, applies only to terrestrial wildlife, not to fish, 

and it wasn’t until 1926 when Congress passed the Black 

Bass Act (16 U.S.C. 851-856) that the interstate transportation of fish taken in violation of state law was explicitly 

prohibited under federal authority. These two pieces of 

legislation were subsequently consolidated into a single 

law through the Lacey Act Amendments of 1981 (PL 97-79, 

95, Stat. 1073).

Cases where a fish species migrates through two or 

more states constitutes interjurisdictional fisheries. To 

date, the federal government’s role in such fisheries has 

been primarily to facilitate coordinated state management 

of these species. The Interjurisdictional Fisheries Act of 

1986 (16 U.S.C. 4101; P. L. 99-659, title III, Sec. 302, Nov. 14, 

1986, 100 Stat. 3732) was implemented “(1) to promote and 

encourage State activities in support of the management 

of interjurisdictional fishery resources; and (2) to promote 

and encourage management of interjurisdictional fishery 

resources throughout their range” (16 U.S.C. 4101). Passage of this legislation established a funding mechanism 

for states to receive support on a cost-sharing basis for 

activities involving cooperative interstate management of 

fishery resources.

In most cases, federal legislation works with state programs using incentives to facilitate interstate management of fisheries. The Atlantic Striped Bass Conservation 

Act of 1984 (PL 98-613) combines incentives with a mandate that the Atlantic coastal states implement the conservation and management provisions of the interstate 

fishery management plan for striped bass. Although this 

plan was developed by the states in 1981 under the auspices of the Atlantic States Marine Fisheries Commission 

(ASMFC), full implementation of the plan had not been 

achieved prior to passage of this Act. Following passage 

of this Act (which provides for a federally imposed and 

enforced moratorium on fishing for, or harvesting, striped 

bass in jurisdictional marine waters of a state that is not 

in compliance with the plan), full implementation was 

quickly achieved and maintained. The results of this successful interstate management and habitat restoration on 

striped bass populations are detailed in a later case study.

Based on the success of the Atlantic Striped Bass Conservation Act, in 1993 the Atlantic Coast Cooperative Fishery Management Act (16 U.S.C. 5101) was enacted into 

law. This is similar to the striped bass legislation but 

applies to any species for which the states, under the auspices of the ASMFC, have developed a fishery management plan. Any state that is found out of compliance by 

the ASMFC is referred to the Secretary of Commerce, who 

then begins proceedings for imposing a federal moratorium on fishing for that particular species in that state’s 

waters. 

The history of the federal role in managing aquatic 

species on federal land is founded in the same laws as 

wildlife law. Various legislation such as the Sikes Act 

(16 U.S.C. 670a-670f) and Sikes Act Extension (16 U.S.C. 

670g-670o) for military lands, Classification and Multiple 

Use Act of 1964 (16 U.S.C. 1411-1418 for Bureau of Land 

Management), National Environmental Policy Act of 1969 

(42 U.S.C. 4321-4361), and the National Wildlife Refuge 

Administration Act of 1966 (16 U.S.C. 668dd - 668ee) clearly 

establish the interest of managing resources on various 

federal lands. Significantly, for the USDA Forest Service, 

16 U.S.C. 694 (Fish and Game Sanctuaries on National Forests) provides for the establishment of preserves “devoted 

to the increase” of populations of “fish of all kinds” on 

Forest Service property, but only upon the approval of the 

legislature in the state in which that forest is located.

Federally controlled waters (exclusive of those designated as National Parks, preserves, sanctuaries, or other 

special classifications) generally extend from three miles 

offshore to a distance of 200 miles offshore. The Magnuson 

Fishery Conservation Management Act of 1976 (16 U.S.C. 

1801–1882) claims these waters and the ocean bottom as 

part of the U.S. Territorial Sea. The Magnuson-Stevens Act 

(as amended in 1996) provides for federal management 

of fisheries occurring predominantly in these waters and 

throughout the range of the fish species. The 1996 amendments to this law greatly expand federal responsibility in 

habitat issues that are essential to the life cycle of these 

fish. Federal interest in restoring and enhancing habitat of 

the nation’s coastal waters is also embodied in the Coastal 

Zone Management Act of 1972 (16 U.S.C. 1451-1464), which 

is designed to “preserve, protect, develop and where possible, restore or enhance the resources of the nation’s coastal 

zone for this and succeeding generations.”

The authority for entering into treaties with foreign 

governments is preserved with the federal government 

through Article II and Article III of the U.S. Constitution. 

Many fishery resources migrate through the jurisdictions 

of foreign nations. These species include Pacific salmon, 

Atlantic salmon, and numerous highly migratory pelagic 

species (tunas, billfishes) among others. Achieving coordinated management of these species often requires entering 

into agreements with foreign nations. The International 

Commission for the Conservation for Atlantic Tunas, the 

North Atlantic Salmon Conservation Organization, and 

the U.N. Law of the Sea are just a few of such agreements. 

Additionally, as Native American nations are considered 

sovereign entities, the U.S. government retains the authority to enter into treaties for the management of aquatic 

species that transcend reservation boundaries. 
4 USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000.

Loftus and Flather Fish and Other Aquatic Resource Trends in the United States

TRENDS AND IMPACTS OF AQUATIC HABITAT

Figure 2—Trends in surface water pollutants in the United States, 

1980–1989. Note that an upward trend indicates an increase in 

the concentration while a downward trend indicates a decrease 

in the concentration. An upward trend in dissolved oxygen is typically an indicator of improving water quality while an upward trend 

in other variables is typically an indicator of degrading water quality (Environmental Protection Agency 1996). 

portion of the sites exhibited trends typically associated 

with higher water quality (i.e., higher dissolved oxygen) 

than sites that exhibited reduced water quality (lower dissolved oxygen).

Land and Water Impacts on 

Aquatic Habitats

Many of the changes in the waterways of this nation 

have come through alterations of free flowing rivers, either 

through channelization, damming, diversions, or dewatering. Of the more than three million miles of streams 

in the lower 48 states, only 2% remain in the condition 

that qualify them for potential designation as wild and 

scenic (Wilcove and Bean 1994, Benke 1990); the remaining 98% have dams, water diversions, or significant development (Wilcove and Bean 1994, Benke 1990, Noss and 

Peters 1995), thereby significantly altering those ecosystems from historical conditions. 

One of the most significant threats to the quality of 

aquatic habitat for supporting fish and other aquatic life 

is increased turbidity (Judy and others 1982), most often 

caused by increases in sediment input. Siltation is the 

primary pollution problem threatening U.S. waterways 

(Southern Appalachian Man and the Biosphere [SAMAB] 

1996). While siltation is a natural physical process and 

a certain amount of sediment from natural erosion is 

Status

Although ecologists have long known that aquatic systems can be impacted by forces originating far from the 

habitat where organisms live, only recently has the term 

“ecosystem management” been applied to their management. Trends in both habitat and the broader ecosystem provide the most accurate depiction of the status 

of aquatic systems. Since wetland and terrestrial habitat 

trends are discussed in a companion report (Flather and 

others 1999), the following discussion will detail more of 

the broad aquatic habitat and ecosystem conditions.

While no national survey accurately depicts the true 

condition of the nation’s waterways, analysis of a variety 

of attributes provides a status of water resources and 

in some cases can provide an indication of how water 

resources have changed over time. In the United States, 

there are 3.5 million miles of streams (approximately twothirds perennial), 41 million acres of lakes and reservoirs, 

34,400 square miles of estuaries (excluding Alaska),and 

approximately 300 million acres of wetlands (170–200 million acres of those in Alaska) (Environmental Protection 

Agency 1996). The 191 million acres of National Forest 

System lands contain 128,000 miles of fishable streams 

and rivers, over 2.2 million acres of lakes, ponds and reservoirs, and 12,500 miles of coast and shoreline. Similarly, 

the USDI Bureau of Land Management manages over 

168,000 miles of streams and more than 2.5 million acres 

of lakes and reservoirs. Other federal agencies manage 

lesser amounts of waters (table 1). 

In terms of water quality, 70% of the nation’s assessed 

river miles, lake acres, and estuarine area (square miles) 

can support the “aquatic life use” designated under the 

Clean Water Act (EPA 1996). However, significant physical alterations in water bodies and watercourses including construction of new reservoirs have greatly altered 

aquatic habitat availability and water quality since European settlement. An indication of how six commonly used 

indices of surface water quality have changed during the 

decade of 1980–1989 is provided in figure 2. An upward 

trend for dissolved oxygen is typically a sign of improving water quality while an upward trend in the other constituents is typically a sign of degrading water quality. 

In five of the six parameters (dissolved solids, fecal coliform, suspended sediment, and the nutrients of phosphorous and nitrates), a greater percentage of sites exhibited 

trends in conditions typically indicative of “improved 

water quality” (declining concentrations of these constituents) than those showing degraded conditions. The 

same trend is true for dissolved oxygen, where a greater 

Downward trend No trend Upward trend

% of sites showing changes in concentration levels

Dissolved oxygen

Dissolved solids

Nitrate

Total phosphorous

Fecal coliform

Suspended sediment

Figure 2

13% 84% 3%

22% 73% 5%

8% 86% 6%

11% 87% 2%

0 20 40 60 80 100

6% 85% 9%

14% 78% 8%
USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000. 5

Fish and Other Aquatic Resource Trends in the United States Loftus and Flather

Table 1—Aquatic resources, recreational angling use and associated economic impact on select federal lands. Estimates of Forest 

Service “Angler Use” and “Angler Economic Impact” cannot be compared to other agencies’ estimates for these categories due to 

differences in methodology.

Agency Lakes/ponds/ Angler

(year of estimate) Streams reservoirs Coastal Angler usea economic impact

a Angler use day=4 hours. Freshwater fishing day is any portion of a day spent fishing.

b Sport Fishing Institute 1993a.

c Maharaj and Carpenter 1999.

Bureau of Land 

Management 

(1990)b

National Park 

Service (1989)9

Fish & Wildlife 

Service 

(1986-87)b

Bureau of 

Reclamation 

(1990)b

Bureau of Indian 

Affairs (1991)b

Forest Service 

(1996)c

168,697 miles

33 National Parks, 

18 Recreation 

Areas, 

14 Seashores, 

14 Wild & Scenic 

Rivers with fishing.

2 million acres 

with recreational 

fishing 

opportunities

15,154 perennial 

streams

128,000 miles

2.4 million acres 

of natural lakes;

172,746 acres of 

reservoirs

1.69 million acres 

of reservoirs

985,591 acres of 

natural lakes/

ponds

2.2 million acres

13,054 shoreline 

habitat

12,500 shoreline 

miles

7.2 million angler 

use days

7.5 million angler 

use days

5.4 million angler 

use days

27.1 million angler 

use days

15 million angler 

use days

46.8 million 

freshwater fishing 

days

$220.9 million 

expenditures; 

342.4 million output; 

7,125 jobs

$231.2 million 

expenditures; 

$358.3 million output; 

7,458 jobs

$137.2 million 

expenditures; 

$212.5 million output; 

4,425 jobs

$836.3 million 

expenditures; 

$1.3 billion output; 

26,979 jobs.

$462.4 million 

expenditures; 

$716.7 million output; 

14,912 jobs

$2.9 billion expenditures; 

$8.5 billion output; 

95,718 FTE jobs.

normal, accelerated sediment runoff caused by human 

activities can cause severe negative impacts to aquatic life. 

Land use activities that increase soil erosion will increase 

sedimentation in the waterways and exacerbate negative 

impacts on the aquatic system (see accompanying Case 

Study 1). Between 675 million and one billion tons of 

eroded agricultural soils are deposited in waterways each 

year, causing water damages estimated as high as $16 

billion annually; agriculture is the single largest source 

of this nonpoint pollution in the United States (National 

Biological Survey 1995). There is some indication that 

the sedimentation is improving, however. In nationwide 

sampling, the percentage of sites showing reduced sedimentation (11% ) during the 1980s exceeded the number 

of sites exhibiting worsening sediment conditions (2%), 

although the vast majority (87% ) still showed no change 

(figure 2).

Sediment inputs degrade water quality for both fish 

(Karr 1981) and invertebrates (Penrose and others 1980, 

Lenat and Crawford 1993). Impacts to aquatic habitat and 

biota include excessive siltation on spawning substrate, 

increased water temperatures, nuisance vegetation, low 

dissolved oxygen levels, and unstable stream flows (Pajak 

1990, National Biological Survey 1995). 

One of the principal negative factors related to sediment deposition is nutrient loading, especially nitrogen 

and phosphorous, contained in surface waters via runoff 

(National Biological Survey 1995). Runoff from agricul-
6 USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000.

Loftus and Flather Fish and Other Aquatic Resource Trends in the United States

ture, urban areas, timber-related activities, construction, 

and road building may cause enrichment of waterways 

through the addition of nutrients and sediment within this 

runoff (Klein 1985, Lenat and Crawford 1994). Both sediment and nutrient (nitrogen and phosphorous) indices indicated a greater percentage of sites with improving conditions 

than deteriorating conditions during the 1980s although the 

majority have remained unchanged (figure 2). 

Some land management activities can be implemented 

to reduce both sediment (see Case Study 2) and nutrient 

input into aquatic systems. Studies have shown that riparian “filter strips” reduce nutrients, such as nitrogen and 

phosphorus, in agricultural runoff by up to 80% (National 

Biological Survey 1995). The effect of this on fish populations can be quite dramatic. The addition of filter strips on 

agricultural lands surrounding waterways in Wisconsin 

has the potential to increase the amount of habitat suitable for brook trout by 68%, northern pike by 174%, and 

smallmouth bass by 30% (Pajak 1990, National Biological 

Survey 1995).

Sediment input and runoff can carry with it contaminants from the surrounding watershed that can remain 

trapped in sediments indefinitely, particularly in closed 

lentic systems. The EPA (1998) found that sediment contamination exists in every region and every state of the 

country. More than two-thirds of the 1,363 watersheds 

surveyed have fish consumption advisories and approximately 10% of the sediment underlying U.S. surface 

waters poses potential risks to fish consuming wildlife 

(including humans). Many of these contaminants were 

introduced years ago and persist in the environment 

today. Seven percent (96) of the watersheds surveyed by 

the EPA were classified as “areas of probable concern” 

(figure 3). Such a designation indicates that 10 or more 

sites within the watershed had contaminant levels where 

adverse environmental or health effects “are probable” 

based on a weight-of-evidence approach.

In addition to degradation of waterways through sedimentation, a variety of other human-induced factors 

degrade the quality of aquatic systems. Among landbased activities leading to long recovery times for depleted 

aquatic organisms are channelization, forest spraying, 

mining activity, and timber harvesting activity within 

watersheds (Niemi and others 1990). After an evaluation 

Figure 3—Watersheds of “probable concern” (Environmental Protection Agency 1998). Figure 3
USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000. 7

Fish and Other Aquatic Resource Trends in the United States Loftus and Flather

of numerous studies, Niemi and others (1990) concluded 

that some fish populations still had not recovered from 

declines in over 52 years. The channelization of waterways for purposes such as navigation, flood control, or 

land drainage contributed to the longest of these recovery times and also resulted in increased sedimentation, 

increased variability in flows, and subsequently altered 

habitat conditions precluding restoration of aquatic life.

Contaminant Advisories

In some ways, the quality of waters can be reflected in 

the safety for human consumption of the fish coming from 

those waters. The cleaner the waters become, the fewer 

advisories we would expect to see and conversely, the 

more polluted waters become, the more fish consumption 

guidelines we would expect. However, several problems 

confound this interpretation of fish consumption advisories. The lack of uniform criteria for establishing advisories hinders the comparison of information from various 

state, tribal, and federal agencies, making information difficult, if not impossible, to compare. Second, as technology advances and the ability to detect smaller levels of 

contaminants increases, we may expect scientists to begin 

to detect pollutants that have existed undetected in those 

waters for decades if not centuries. In addition, some 

states are being extremely protective of public health by 

erring on the side of safety and issuing advisories where 

they had not in the past, often as an effort to minimize 

potential litigation. All of these factors, if not accounted 

for in the interpretation of advisory trends, may lead to 

erroneous conclusions regarding the actual trends in the 

quality of our waters.

The U.S. Environmental Protection Agency has taken 

initial steps to catalog and track the number of fish consumption advisories that are issued by state and federal 

agencies each year. The number of water bodies currently 

under an advisory represents 15% of the nation’s total 

lake acres and 5% of the nation’s total river miles. In 

addition, 100% of the Great Lakes and connecting waters 

have advisories for some type of contaminant. In 1996, the 

number of advisories increased from the previous year 

for four of 37 contaminants: PCBs, chlordane, mercury, 

and DDT, although this may only indicate an increase in 

the incidence of detection rather than an increase in contamination. Ninety-six percent of the advisories were for 

mercury contamination (EPA 1996).

Wetland Habitats

Wetlands form a critical link in the life stages of numerous fish. Functions of wetlands include spawning habitat 

for fish, refuge areas and nursery areas for young fish, 

production of food as a basis for aquatic food chains (zooplankton, etc.), flood control, recharging aquifers, erosion 

control, habitat for birds and other animals, and filters 

for sediments, nutrients, and contaminants. The timing of 

inundation is also very important for the survival of particular fish species. To some species, such as the northern 

pike, wetlands serve as spawning and nursery areas for 

a short period of time in the early spring. The absence 

of water from these ephemerally flooded lands in other 

periods of the year does not lessen the usefulness of these 

wetlands to the survival of the species. Furthermore, wetlands fulfill similar vital roles in the life history of most 

fish species in near-shore marine environments. It is estimated that 75% of all estuarine finfish and shellfish species of recreational and commercial value depend on tidal 

marshes for food and habitat (Chambers 1992, Scodari 

1997). Among regions, the value of wetlands to these species may vary, with 18 to 94% relying on wetland habitats 

(table 2; Chambers 1992). Nationwide, the EPA’s Environmental Monitoring and Assessment Program (EMAP), 

which sampled 50% of the nation’s coastal estuaries, 

found that 74% of the estuaries sampled have “healthy” 

aquatic communities (Environmental Protection Agency 

1996).

However, more than one-half of the 221 million acres 

of wetlands that existed in the contiguous United States 

prior to European colonization have disappeared with 

slightly more than 100 million acres remaining today 

(USGS 19973). As is documented in a companion report 

(Flather and others 1999), the rate of wetland loss has 

declined overall and the principal activities contributing 

to wetland loss has shifted from agriculture to urbanization. The majority (85%) of the losses were freshwater 

(palustrine) wetlands.

While the economic benefits of wetlands are not easily 

measured, it is certain that they play a major role in the 

economy of the nation. On the west coast of Florida, each 

additional acre of wetland produced a value of $79.60 

for the recreational fishery based on a willingness to pay 

model (Bell 1989). Raphael and Jaworski (1979) rated the 

net value of habitat such as wetlands for sport fishing 

Table 2—Percent of commercial marine fish species occurring 

in various geographic areas that depend on estuarine habitats 

(Chambers 1992).

Northeast 41 Southwest 18

Chesapeake Bay 78 Northwest 52

Southeast 94 Alaska 76

Gulf of Mexico 98

3 USGS. 1997. National water summary on wetland resources. 

USGS Water Supply Paper 2425 (http://water.usgs.gov/).
8 USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000.

Loftus and Flather Fish and Other Aquatic Resource Trends in the United States

along the Michigan coast as $286/acre. Studies in the 

Chesapeake Bay rated the economic loss that would result 

from an 80% reduction in areas of submerged aquatic vegetation at over $8 million (Kahn and Kemp, 1985).

Although federal programs historically promoted the 

filling or draining of wetlands (Scodari 1997) for the purposes of agriculture, settlement, and other human activities, much has changed in current day legislation. Many 

federal activities are now attempting to reduce the loss 

of wetlands. Major legislation such as Swampbuster, the 

Clean Water Act (and revisions), the Federal Aid in Sport 

Fish Restoration Act, the Coastal Barrier Resource Act, 

and the Coastal Zone Management Act that contain components designed to prevent the destruction of wetlands 

or assist states in implementing programs to prevent the 

destruction of wetlands and restore degraded wetlands. 

Federal agencies are now spending considerable funds 

to reestablish and protect these lands. In 1992, 18 federal 

agencies were conducting wetlands research with expenditures totaling approximately $63 million (see footnote 

3). Since revisions to the Federal Aid in Sport Fish Restoration Act were implemented in 1992, grants have been 

made available through the Coastal Wetlands Conservation Grant Program to states to implement wetlands 

conservation and restoration projects. Twenty-four states 

have received funding between 1992 and 1997 for a total 

of 96 projects which directly affect nearly 52,000 acres. Of 

this total, 42,000 acres have been acquired for protection 

against activities that might degrade them. (USDI Fish 

and Wildlife Service 1997).

TRENDS IN POPULATIONS

Inland and Freshwater Species

There are approximately 800 freshwater fish species 

in the United states (Southern Appalachian Man and the 

Biosphere 1996). While we know that some species such 

as Atlantic and northwest Pacific salmon, paddlefish, and 

sturgeon (Atlantic, shortnose, and lake) have declined, we 

cannot describe beyond select case-by-case scenarios the 

status of the majority of most species. Simply counting 

the number of species, or observing fish assemblages, will 

not necessarily reflect the integrity of ecosystems. There 

are more fish species in the Colorado River today than 

before European settlement due to introductions of nonnative species (Wilcove and Bean, 1990), but this does not 

necessarily indicate a greater biodiversity or ecosystem 

stability. 

Direct measurements allowing the analysis of trends in 

aquatic species populations on a nationwide, or regionwide, basis are generally not available. This is particularly true in freshwater fisheries. Data on aquatic species 

are generally collected as needed for management purposes and long-term data sets, particularly as they relate 

to quantitative status and trends, are rare. Additionally, 

state agencies typically collect the majority of fish population information and each state’s data collection, analysis, 

and management are tailored to their needs. Therefore, 

data may not be compatible with other agencies. Even 

within states, a data system is often not established for the 

purpose of compiling data over larger geographic areas. 

Commonly, trend information is not collected until species are in need of conservation (which therefore tends 

to focus on species in decline) or in cases where the 

attempted restoration of populations is occurring. These 

situations can often provide valuable insight into aquatic 

species’ conditions and the potential (or lack thereof in 

some cases) for restoring specific stocks in contemporary 

aquatic environments (Case Study 3). In select cases of 

inland waters where coordinated management (such as 

recovery efforts) has occurred, better information may 

exist. In the Great Lakes, for example, where lake trout restoration has been a cooperative effort between the states, 

Native American tribes, and the U.S. and Canadian governments, population trends can be documented (Case 

Study 4).

Marine and Estuarine Species

Since this report focuses on species that may be directly 

impacted by land use activities, an in-depth analysis of 

the status of marine fisheries is not provided. However, 

certain life stages of many marine fish species (particularly those occurring near-shore) and all anadromous species can be impacted by land use and therefore, will be 

addressed briefly.

Although some marine fish stocks (mostly high profile or popular species) have been studied extensively 

and much is known about their populations, generally 

quantitative population information on marine fisheries 

is lacking or poor. The National Marine Fisheries Service 

and the regional fishery management councils established 

under the Magnuson Act have begun to conduct better 

assessments and analyses to rectify this. In general, of the 

163 U.S. marine fisheries whose biological status could 

be assessed, 40% were classified as over utilized and 43% 

were fully utilized (USDC 1996) in 1993. Table 3 provides 
USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000. 9

Fish and Other Aquatic Resource Trends in the United States Loftus and Flather

Table 3—Status of select Atlantic fishery resources (USDC 1998a).

Species Stock status

Striped Bass Recovered

Summer Flounder Overfished

Winter Flounder Overfished

Weakfish Overfished

Bluefish Overfished

Scup Overfished

Black Sea Bass Overfished

Atlantic Croaker Overfished

Red Snapper Overfished

Spiny Dogfish Overfished

Gulf of Maine Cod Overfished

the status of some of the high- profile near-shore species 

occurring in the mid-Atlantic.

Management agencies have begun to realize the benefits of cooperatively managing interjurisdictional species 

(see Case Study 5) and in coordinating data collection 

and data management efforts. Additionally, the implementation of federal legislation, particularly on the Atlantic coast, along with cooperative data sharing programs 

between states on the Pacific and Gulf coasts, has fostered cooperative management. Recent amendments to 

the Magnuson Act (now referred to as the Magnuson-Stevens Act) have spurred cooperation between federal and 

state agencies by emphasizing the need for information on 

the “essential fish habitat” parameters for each fish species and requiring that these be incorporated into management plans. Each of these efforts will lead to improved 

refinement of knowledge on the status and trends of 

marine fisheries in general and the factors behind the 

trends.

The status of Pacific salmonids has perhaps received 

more attention, and dedicated fiscal resources, than any 

anadromous fisheries issue in the United States. The range 

of the five species of Pacific salmon that spawn in the 

United States extends from San Francisco Bay, California, 

northward along the Oregon, Washington, British Columbia, and Alaska coastlines, and southward into the coastal 

waters of Japan and Korea in the western Pacific (Groot 

and Margolis 1991). Pacific salmon in the northwest states 

of the contiguous United States are declining and are 

highlighted in Case Study 6. Fifteen distinct population 

segments of Pacific salmon and anadromous trout in the 

Pacific northwest region are listed as either threatened or 

endangered under the Endangered Species Act of 1973 

(table 4; Dandelski and Buck 1998). However, Baker and 

others (1996) noted that the condition of stocks of Pacific 

salmon in southeast Alaska is generally perceived to be 

“good.” Even in this area, the lack of data presents obstacles to evaluating salmon, with only 10% of the “spawning 

aggregates” in southeast Alaska having sufficient data to 

allow status evaluation using escapement (total number 

of salmon returning to spawning areas) indices (Baker 

and others 1996). If we accept the evaluations of 10% of 

the stocks as being a representative sample of the entire 

salmon stocks in this region of Alaska, then several inferences can be made.

Alaskan salmon are currently experiencing high levels 

of productivity and abundance. Since the 1970s, salmon 

harvests in Alaska have greatly increased (figure 4; Baker 

and others 1996). Only two out of 2,296 spawning aggregates surveyed in southeast Alaska were rated as at a 

“high risk of extinction” compared to 146 out of 201 aggregates evaluated in the Pacific northwest (Baker and others 

1996). Using the Washington State Salmon and Steelhead 

Inventory to allow comparable estimates between Alaska 

and Washington, less than 1% of the identifiable salmon 

stocks in southeast Alaska were at high or moderate risk 

of extinction as compared to 15% of the total stocks in 

Washington (Baker and others 1996).

The relatively favorable status of salmon stocks in 

southeast Alaska is primarily attributable to: 1) relatively 

pristine and undeveloped habitats; 2) habitat and salmon 

management policies in Alaska; 3) enhancement by hatcheries; 4) favorable environmental conditions in the streams; 

and 5) favorable marine conditions that have contributed 

to higher survival rates (Baker and others 1996). Alaska’s 

constitution mandates that a sustainable yield of fish be 

maintained, providing somewhat more definitive management authority for closing or restricting a fishery when 

biologists determine this is needed (Baker 1995). At present, the most immediate threat to salmon productivity 

in southeast Alaska is the loss of spawning and rearing 

habitat in natal streams. The activity posing the greatest 

threat to this habitat is logging, although urbanization 

and mining also are having an impact (Baker and others 

1996).

Figure 4—Harvest of Pacific salmon from Alaska waters (Alaska 

Department of Fish and Game. Alaska Commercial Salmon 

Harvest 1970–2995. http://state.ak.us/local/akpages/fish.game/

adfgame).

1974 1979 1984 1989 1994

Year

0

50

100

150

200

250

Harvest (millions of fish)

Chinook Sockeye Coho Pink Chum Total

Figure 9
10 USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000.

Loftus and Flather Fish and Other Aquatic Resource Trends in the United States

® Complete final critical habitat designations for listed ESUs by October 1998® Complete listing assessments for candidate ESUs by December 1998® NMFS issued a proposal to redefine the Snake River fall-run to include the fall Deschutes River populations® Complete final listing determinations and critical habitat designations for proposed ESUs by March 1999® Complete final listing determinations and critical habitat designations for proposed ESUs by March 1999® Complete final listing determination and critical habitat designation for Ozette Lake ESU by March 1999® Complete listing assessments for candidate ESU by March 1999® Complete final critical habitat designations for listed ESUs by March 1999® Complete listing assessment for candidate ESUs by March 1999® Re-assess listing status of Umpqua ESU by August 1998® Complete initial listing determinations for other West Coast populations by December 1998

Table 4—Status of spawning populations of six species of Pacific northwest salmonids (Dandelski and Buck 1998).

Status

(E-Endangered; 

Species Population (ESUa) T-Threatened) FR citation Pending actionsCoho salmon(Oncorhynchus kisutch)Chinook salmon(Oncorhynchus tshawytscha)Chum salmon(Oncorhynchus keta)Sockeye salmon(Oncorhynchus nerka)Steelhead trout(Oncorhynchus mykiss)Sea-run cutthroat trout(Oncorhynchus clarki clarki)

 1. Central CA 2. Southern OR/Northern CA Coasts 3. Oregon Coast 4. Puget Sound/Strait of Georgia 5. Southwest WA/Lower Columbia River 1. Sacramento River Winter-run 2. Snake River Fall-run 3. Snake River Fall-run to include the 

0. Deschutes River populations

 4. Snake River spring/summer-run 5. Central Valley spring-run 6. Upper Columbia River spring-run 7. California Central Valley fall-run 8. Southern Oregon/Northern CA coasts 9. Puget Sound10. Lower Columbia River11. Upper Willamette River 1. Hood Canal summer-run 2. Columbia RiverProposed (T) 1. Snake River 2. Ozette Lake 3. Baker River 1. Southern California 2. South-Central California Coast 3. Central California Coast 4. Upper Columbia River 5. Snake River Basin  6. Lower Columbia River 7. Central Valley 8. Upper Willamette River 9. Middle Columbia River10. Northern California11. Klamath Mountains Province12. Oregon Coast 1. Umpqua River (Oregon)

ThreatenedThreatenedThreatenedCandidateCandidateEndangeredThreatenedProposed (T)ThreatenedProposed (E)Proposed (E)Proposed (T)Proposed (T)Proposed (T)Proposed (T)Proposed (T)Proposed (T)Proposed (T)EndangeredProposed (T)CandidateEndangeredThreatenedThreatenedEndangeredThreatenedThreatenedThreatenedProposed(T)Proposed(T)CandidateCandidateCandidateEndangered

 1. 61 FR 56138 Oct. 31, 1996 2. 62 FR 24588.May 6, 1997 3. 63 FR 42587 Aug. 10, 1998 4. 60 FR 38001 July 25, 1995 5. 60 FR 38001 July 25, 1995 1. 55 FR 12832 April 6, 1990

0. 55 FR 49623 Nov. 30, 19900. 59 FR 13836 March 23, 1994

 2. 57 FR 14653 Apr. 22, 1992 3. 63 FR 11481 March 9, 1998 4. 57 FR 14653 Apr. 22, 1992

0. 59 FR 13836 March 23, 1994

 5. 63 FR 11481 March 9, 1998 6. 63 FR 11481 March 9, 1998 7. 63 FR 11481 March 9, 1998 8. 63 FR 11481 March 9, 1998 9. 63 FR 11481 March 9, 199810. 63 FR 11481 March 9, 199811. 63 FR 11481 March 9, 1998 1. 63 FR 11773 March 10, 1998 2. 63 FR 11773 March 10, 1998 1. 56 FR 58619 Nov. 20, 1991 2. 63 FR 11750 March 10, 1998 3. 63 FR 11750 March 10, 1998 1. 62 FR 43937 Aug. 18, 1997 2. 62 FR 43937 Aug. 18. 1997 3. 62 FR 43937 Aug. 18. 1997 4. 62 FR 43937 Aug. 18. 1997 5. 62 FR 43937 Aug. 18. 1997  6. 63 FR 13347 Mar. 19, 1998 7. 63 FR 13347 Mar.19, 1998 8. 63 FR 11797 Mar. 10, 1998  9. 63 FR 11797 Mar. 10, 1998 10. 63 FR 13347 Mar.19, 199811. 63 FR 13347 Mar.19, 199812. 63 FR 13347 Mar. 19, 1998 1. 61 FR 41514 August 9, 1996

a ESU: Evolutionary Significant Unit 
USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000. 11

Fish and Other Aquatic Resource Trends in the United States Loftus and Flather

Imperiled Fish and Other Aquatic Species

As is documented in Flather and others (1998), fish 

and aquatic species now dominate the list of threatened 

and endangered animal species in the United States. Over 

the last two decades, fish have been listed on the Threatened and Endangered Species list at a rate twice that of 

other vertebrate species while other aquatic species such 

as mussels are imperiled in a greater proportion relative 

to terrestrial species. 

Although there are 111 fish taxa officially listed as 

threatened and endangered under the Endangered Species Act (ESA), far more are considered imperiled (should 

be listed under ESA) by the American Fisheries Society 

(AFS) (Williams and others 1989). Between 1979 and 1989, 

none of the 251 North American fish species identified 

by the AFS as warranting protection because of low populations were removed from their list because of recovery. Ten became extinct, and 16 were removed because of 

better information. According to the AFS list, a total of 364 

fish taxa that warrant protection because of their rarity 

were listed in 1989, with 70% (254) of those coming from 

the United States. One hundred thirty-nine new taxa were 

added to the AFS list during that time frame, although 

41% of those were Mexican fishes that were added because 

new information became available and their habitat continued to decline. Of the fish taxa that changed status 

in the 1979–1989 time period, seven improved and 24 

declined (table 5). An additional 18 were reclassified (but 

remained on the list) due to new information, not because 

of a change in their condition (Williams and others 1989). 

The Nature Conservancy recognized 55% of North 

America’s mussels as extinct or imperiled as compared 

to only 7% of the continent’s bird or mammal species 

(Williams and others 1993, Master 1990). Two hundred 

ninety-seven freshwater mussel species are native to the 

United States and Canada. Of these, 213 are considered 

endangered, threatened, or of special concern and only 70 

are listed as currently stable (Williams and others 1993). 

Twenty-one distinct taxa of mussels are now considered to 

be extinct. The primary factor contributing to the decline of 

mussels is habitat destruction and degradation (Williams 

and others 1993), although other factors such as exploitation may have played a role. Dams are a significant factor 

in altering habitat and changing the physical, chemical, 

and biological environment of streams. Approximately 30 

to 60% of the mussel fauna is destroyed upstream and 

downstream of dams (Williams and others 1993, Layzer 

and others 1993). Erosion caused by deforestation, poor 

agricultural practices, and destruction of riparian habitat 

leads to increased siltation, reducing and eliminating suitable habitat for mussels and other bivalves. Additionally, 

the introduction of nonindigenous species such as zebra 

mussel and Asian clam also negatively impact native 

mussel fauna. The Asian clam was first introduced in the 

Table 5—Changes in the status of species identified as endangered, threatened, or of special concern by the American Fisheries Society from 1979 to 1989. List does not include species 

whose status did not change (Williams and others 1989).

Taxon Change

Improved

 Fish Creek Springs tui chub (Gila bicolor euchila) E to T

 Yaqui chub (Gila purpurea) E to T

 Zuni bluehead sucker 

 (Catostomus discobolus yarrowi) T to SC

 Devils hole pupfish (Cyprinodon diabolis) E to T

 Gila topminnow (Poeciliopsis occidentalis) T to SC

 Spring pygmy sunfish (Elassoma sp.) E to T

 Sharphead darter (Etheostoma acuticeps) T to SC

Declined

 Pallid sturgeon (Acipenser brevirostrum) T to E

 Least chub (Iotichthys phlegethontis) T to E

 White River spine dace (Lepidomeda albivalls) T to E

 Cape Fear shiner (Notropis mekistocholas) SC to E

 Blackmouth shiner (Notropis melanostomus) SC to T

 Oregon chub (Oregonichthys crameri) SC to T

 Mountain blackside dace 

 (Phoxinus cumberlandensis) T to E

 Loach minnow (Tiaroga cobitis) SC to T

 White River sucker (Catostomus clarki intermedius) T to E

 Shortnose sucker (Chasmistes brevirostris) T to E

 June sucker (Chasmistes liorus mictus) SC to E

 Lost River sucker (Deltistes luxatus) SC to E

 Razorback sucker (Xyrauchen texanus) T to E

 Pygmy madtom (Noturus stanauli) T to E

 Alabama cavefish (Speoplatyrhinus poulsoni) T to E

 Preston springfish (Crenichthys baileyi albivallis) T to E

 White River springfish (Crenichthys baileyi baileyi) T to E

 Moorman springfish 

 (Crenichthys baileyi thermophilus) SC to T

 Railroad Valley springfish (Crenichthys nevadae) SC to T

 Desert pupfish (Cyprinodon macularius) T to E

 Striped goodeid (Ataeniobius toweri) T to E

 Rainbow characodon (Characodon laterilis) T to E

 Amber darter (Percina antesella) T to E

 Shoshone sculpin (Cottus greenei) SC to T

SC: Special Concern 

T: Threatened 

E: Endangered

United States in the 1930s and is now the most widespread 

nonindigenous bivalve mollusk in the nation. It settles in 

densities of thousands per square meter (Williams and 

others 1993), thereby crowding out native mussel fauna.
12 USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000.

Loftus and Flather Fish and Other Aquatic Resource Trends in the United States

The geographic distribution of threatened and endangered aquatic species is not uniform across the United 

States. Rather, endangered aquatic species are concentrated in distinct geographic regions (figure 5a). Geographic areas with a concentration of endangered aquatic 

species were identified using the criteria specified in Prendergast and others (1993), namely, an arbitrarily defined 

upper percentile of sample units ranked by species counts. 

To account for the disparity in county area across the 

United States, counties were partitioned into “large-area” 

and “small-area” sets at a threshold of about 910,000 acres. 

This was done because the alternative, a simple conversion to county density (e.g., number of endangered species per unit area), produced an eastern bias and concealed 

known concentrations of endangered species in the arid 

southwest (Hallock 1991). Within each large and small 

area set, counties were ranked according to the number of 

threatened and endangered species that occurred within 

their boundaries. Areas of endangered species concentration were initially identified by mapping the top 5% in 

each of the large-and small-area county sets (i.e., those 

counties where the greatest number of listed species were 

found). Since “endangerment regions” likely do not follow 

county borders, the areal extent of each region of concentration was further defined by mapping the top 20% 

of counties in each of the small-county and large-county 

sets. Counties in this mapping that were contiguous to, or 

formed distinct physiographic clusters with, those counties in the top 5% formed the region of endangered species 

concentration (see Flather and others 1998 for details).

The incidence of endangered fish (figure 5b) and other 

aquatic taxa (figure 5c) is geographically similar to concentrations of all aquatic species (figure 5a) in the arid southwest and the southern Appalachian mountains (see Case 

Study 7). Within these two areas, the current distribution of 

listed species is often restricted to that area, making them 

endemic to that region. These regional endemics are often 

fish. For example, of the total number of listed species occurring in the Southern Appalachians that are endemic to that 

region (see Flather and others 1998), 27% were fish. Similarly, in the Sonoran Basin, 24% of the listed endemic species 

were also fish. Because of the prevalence of endemism in 

these regions, conservation of aquatic diversity will require 

land management activities to address those local factors 

that have contributed to species endangerment.

The ecological impact from the loss of aquatic biota 

can be enormous. For example, Chesapeake Bay oyster 

populations are at less than 1% of their historical abundance. Historical oyster populations in the Bay (pre 1870s) 

could filter a volume of water equal to the entire Bay 

every few days whereas today’s level of oyster populations takes more than a year to filter the same volume of 

water (Horton and Eichbaum 1991). This filtering capability plays an integral role in the cycling of nutrients, 

balance of the planktonic community, and water quality 

attributes such as clarity, nutrient levels, and others.

Causes and Economic Effects of 

Species Declines

In addition to the ecological significance of declining 

species, there is also a significant economic impact. Freshwater mussels once provided an important source of commerce for the United States. In the early 1900s, there were 

more than 2,000 mussel harvesters on the Illinois river, 

whereas there are none today (Wilcove and Bean, 1990). 

Unfortunately, high prices for clam shells on the Asian 

market have increased commercial harvesting pressure 

on already stressed mussel stocks in other areas (Williams 

and others 1993). In Washington and northern Oregon, 

the declining Pacific salmon stocks resulted in the closure of the commercial salmon fishery completely in 1994 

and restrictions on recreational fisheries, creating significant economic impacts (see Case Study 6). On the Atlantic 

coast, the near-collapse of the striped bass stocks resulted 

in complete five-year closures of the recreational, charter, 

and commercial fisheries in Maryland and Delaware and 

a one-year closure in Virginia. Most notably in recent 

years, the collapse of New England groundfish stocks and 

subsequent closures have had significant economic consequences for that region. 

There is generally more than a single causative factor 

behind the decline of aquatic species (Wilcove and Bean 

1994, see Case Study 8). In an examination of 40 taxa of 

North American fishes, Miller and others (1989) determined the most common contributing factors for extinctions are habitat loss (73% of the cases), effects of 

introduced species (68% of the cases), chemical alteration or pollution (38% of the cases), and over harvesting 

(15% of the cases). Causes behind the species declines 

may vary by region, but in the southern Appalachians, 

contamination and modification of aquatic environments 

from mining, reservoir construction, and farming affected 

at least 50% of all listed species in this region (Flather and 

others 1998). An aquatic taxon that is particularly susceptible to these factors is freshwater mussels. Over 50% of 

the mussel fauna in the southern Appalachians are classified by the U.S. Fish and Wildlife Service as threatened, 

endangered, or of special concern or are considered by 

state agencies as being “at risk” (Southern Appalachian 

Man and the Biosphere 1996). Furthermore, Flather and 

others (1998) found that nearly 40% of all the endangered 

species in the southern Appalachian region are clams.
USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000. 13

Fish and Other Aquatic Resource Trends in the United States Loftus and Flather

Figure 5—The geographic distribution of threatened and endangered aquatic species. All maps show counties in percentile classes 

after ranking both large- and small-area counties (to account for differential county area) according to the number of threatened and 

endangered species that occurred within their boundaries (see text for details). Map (a) depicts all aquatic species (fish and non-fish); 

map (b) depicts only fish; map (c) depicts only non-fish aquatic species.
14 USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000.

Loftus and Flather Fish and Other Aquatic Resource Trends in the United States

Background

Crappie populations in Midwest impoundments support some of the most popular sport fisheries in this region 

(Mitzner 1991, USDI Fish and Wildlife Service and Bureau 

of Census 1998). Environmental factors that effect crappie 

populations are of significant interest to fisheries managers and the general public. 

Rathbun Lake in south-central Iowa is one such system. 

This 11,000 acre impoundment was created in 1969–70 

on the Chariton River. Crappie typically composes 80% 

to 90% of the angler creel in Lake Rathbun and harvests 

of 100,000 or more fish were recorded in nine out of 14 

survey years (Mitzner 1991). 

Issue

Between 1980 and 1983, the Iowa Department of Natural Resources investigated the relationships between 

abundance of juvenile crappie and five environmental 

variables to determine what factors controlled population 

growth and subsequent angling success. Factors of water 

storage, turbidity, wind, temperature, and substrate were 

investigated in relationship to crappie reproduction. 

Results

The amount of water in the system (flood water storage) 

was the largest influence on larval crappie abundance, 

with higher volumes (more water) producing higher numbers of juvenile crappie (figure 6). Water storage reservoirs such as Rathbun Lake often fluctuate year to year 

Figure 6—Relationship between reservoir flood storage levels 

and juvenile crappie abundance. Points indicate measurements 

taken in individual years 1972–1979 (Mitzner 1981).

(and also within season). The amount of available water 

impacts many physical characteristics of the habitat of 

larval fish in a particular year, including physical habitat 

availability, water temperature, and water clarity. However, apart from flood water storage, turbidity in the reservoir played the dominant role. In several years of high 

water volume (when high numbers of juvenile crappie 

would be expected) accompanied by high turbidity, low 

numbers of juvenile crappie were measured. Removing 

these years from the analysis doubled the strength of the 

relationship (as measured by r2) between water volume 

and crappie production (Mitzner 1995). Forty-nine percent 

of the variability in crappie abundance was accounted for 

by variations in turbidity during 1980 and 1982 (Mitzner 

1991). At the extreme, no crappie were present in locations in Lake Rathbun with high turbidity (Secchi depths 

less than 2 inches). Crappie abundance increased at a geometric rate as water clarity increased to values above 25 

inches of Secchi disk depth (Mitzner, 1995). 

Turbidity in Rathbun originates from three main sources: 

wave action on the shoreline, suspension of bottom sediments, and runoff from the watershed. Of these factors, 

turbidity was more a function of inflow of silt from the 

watershed than bank sloughing by wind and molar action 

(Mitzner 1987). Correspondingly, a principal factor related 

to turbidity was the inflow of water from the surrounding water basin. An estimated 321,000 tons of sediment 

are delivered to the lake annually from 173,760 acres of 

cropland in the watershed, according to the water quality management plan for Rathbun Lake. Of these croplands, 90,000 acres were classed as critical erosion areas 

and recommended for priority soil conservation practices 

(Mitzner 1987).

Related studies in other watersheds have shown that 

water quality indices were adversely impacted by watershed size and larger ratios between watershed size and 0 5 10 15 20 25 Stor

age (billion cubic meter-days)

0

2000

4000

6000

8000

10000

12000

Juvenile crappie density (#/hectare)

Figure 4

CASE STUDY 1: 

MIDWEST CRAPPIE PRODUCTION 

IN IMPOUNDMENTS

1
USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000. 15

Fish and Other Aquatic Resource Trends in the United States Loftus and Flather

lake surface area (Mitzner 1995) that impacted fish populations. Larger ratios (larger watersheds in relation to the 

size of the lake) in conjunction with shallower depth and 

less steep slopes of the lakes produced poorer bluegill 

populations as measured by a “well-being” index (developed through a composite of growth rate, body condition, and size structure of the population). Subsequently, 

higher bluegill and crappie harvests were associated with 

higher well-being indices. Additionally, agricultural nonpoint source pollution modeling has demonstrated that 

sediment and nutrient loadings are important to the wellbeing indices of panfish populations. Lower sediment and 

nutrient runoff from the watershed produced better panfish populations and angling opportunities. Recommendations from Rathbun Lake and other studies concluded 

that lakes that have already been constructed can benefit 

Background

Canyon Creek, Arizona, is a tributary to the Salt River. 

Base flows originate in natural springs and the total drainage area is relatively small, encompassing approximately 

325 square miles (Morgensen 1986). The soils of this region 

are highly erodible with a high silt content, making the 

activities on watershed extremely influential to the water 

quality of the stream. Predominant land use practices at 

the outset of the rehabilitation initiative in 1986 consisted 

of logging, livestock grazing, and heavy recreational use 

from deepening and reduction in soil and nutrient erosion in the watershed (Mitzner 1995).

The Future

These studies have shown that crappie populations 

in at least one Midwest impoundment are impacted by 

the runoff from the surrounding watershed. Poor land 

use practices in the watershed that contribute to excess 

soil runoff contribute to heavy sediment loads. At the 

same time, improved land use practices that reduce the 

amount of sediments and other runoff into reservoirs 

create improved habitat conditions for fish populations. 

These problems in the water can only be rectified through 

appropriate action on the surrounding watershed.

CASE STUDY 2:

WATERSHED IMPACTS ON 

COLD WATER HABITAT IN 

CANYON CREEK, ARIZONA

(including camping, fishing, and off-road vehicle use). 

Native fish in Canyon Creek include speckled dace and 

desert sucker. Catchable rainbow trout and brown trout 

were stocked beginning in 1948 and sustained a catchand-release fishery only, with no natural reproduction 

before restoration efforts began in 1986.

As a result of the conditions created by year-long cattle 

grazing in the watershed, wildlife and fish resources suffered. Grazing reduced streamside vegetation, particularly the cottonwood and willow that stabilize the banks 

and provide shade to the stream, thereby reducing the 

water temperature. The primary impact from timber harvesting activity on water resources was from the construction of haul roads and skid trails, resulting in large 

sediment input. With the exception of water temperature 

and siltation loads, all water quality parameters were in 

the acceptable range for sustaining coldwater fish populations. This indicated that watershed activities which 

exacerbated these two factors were the primary agents 

responsible for degraded habitat suitability and trout 

reproduction prior to the implementation of a riparian and 

in-stream habitat improvement initiative in 1986 (Morgensen, 1986).

Responses and Results

In 1986, the Canyon Creek Aquatic Habitat Improvement Plan was developed by a team of state, federal, and 

private partners with goals of establishing a quality brown 

trout fishery with a native fish forage base and providing 

a rainbow trout fishery. Management of the creek would 

principally be through riparian management, restrictive 

regulations, and substantially reduced stocking. Since the 

major factors limiting fish growth and reproduction were 

high temperatures due to the lack of shade, high siltation 

2
16 USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000.

Loftus and Flather Fish and Other Aquatic Resource Trends in the United States

from erosion, and lack of pools with adequate depth 

and substrate due to stream scouring (Morgensen 1986, 

Warnecke and others 1996), these factors were targeted 

for improvement. Following a habitat survey in 1986, 

improvements were made to the stream and riparian corridor including reestablishing native vegetation on the 

banks, improving in-stream habitat, and removing cattle 

from the stream and adjacent riparian areas.

Following these modifications, between 1986 and 1994 

the average water temperature was reduced by 9.4° C, 

dropping from an average of 21.7° C in 1986 to 12.3° C 

in 1994 (figure 7). Bank stability, which effects sediment 

loads, markedly improved in four of seven areas, slightly 

improved in two areas, and declined in one area. The 

average stream depth increased in all areas and the average rating of pool habitat quality increased in five of the 

areas while remaining unchanged in the remaining two 

sites. Fish population surveys from 1990–94 indicated that 

brown trout size likely responded to these changes in four 

of five sites (figure 8) and slightly in terms of fish density. Natural reproduction became sufficient to maintain 

a catch-and-release fishery, and over 10% of the population grew to a “trophy” size. Except for a single small 

stocking in 1993, all introductions of hatchery brown trout 

were discontinued. Populations of native desert sucker 

and speckled dace also appeared to increase to higher 

levels although future monitoring is needed to confirm 

this (figure 9).

In August 1992 and January 1993, substantial flooding 

occurred in this watershed, creating the potential to reduce 

the gains that had been made in this stream system. 

Although the floods had a profound effect on the riparian 

corridor, much of the new bank vegetation, primarily willows, withstood and contained the scouring action of the 

flood waters and, as evidenced by the data, appeared to 

have limited impact on the trout populations (Warnecke 

and others 1996).

Figure 7—Water temperature change due to habitat improvement, Canyon Creek, Arizona (Warnecke and others 1996) . Figure 8—Change in brown trout size in Canyon Creek, Arizona, 

following watershed and in-stream improvements (Warnecke and 

others 1996).

Figure 9—Changes in native and non-native fish populations 

in Canyon Creek, Arizona, following watershed and in-stream 

improvements (Warnecke and others 1996).

The Future

Canyon Creek, a stream once negatively impacted by 

the effects of poor land use practices in the watershed and 

unable to sustain wild coldwater species, has benefitted 

from a comprehensive management prescription. Natural 

reproduction of coldwater fish, which had not been possible for over 40 years, is now sustaining a fishery (brown 

trout) and populations of native fish continue to do well. 

Long-term costs of maintaining a trophy brown trout fishery without the need for hatchery production likely will 

be lower than if habitat improvements in the watershed 

and riparian areas had not been made. While maintaining 

the habitat improvements, a self-sustaining brown trout 1990 1991 1992 1993 1994 Year

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Density (fish/square mile)

Figure 7

Brown trout Desert sucker Speckled dace

100

150

200

250

300

350

400

450

Length (mm)

Sept 1990 Sept 1992 May 1993 July 1994

Individual sites All sites combined

Sampling period

Figure 8
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-53. 2000 17

Fish and Other Aquatic Resource Trends in the United States Loftus and Flather

population, and a stable native forage fish population are

of paramount importance, public demand is also calling

for a greater increase in the stocked rainbow trout fishery.

Future management is likely to emphasize a diversified

fishery where all of these objectives and user demands

can be accommodated.

Background

Arctic grayling were native to the northern lower and

upper peninsulas of Michigan. Historically, most populations in Michigan were stream dwelling (Nuhfer 1992). By

the late 1930s, grayling stocks in Michigan had been

extirpated (Hubbs and Lagler 1958). Principal reasons for

the decline of these stocks were identified as angler

harvest, introduction of non-native salmonids, and destruction of spawning habitat by extensive logging (Hubbs

and Lagler 1958, Nuhfer 1992) and the associated log

drives in streams which lasted until 1972 (Kelso and

others 1996). Several attempts to reestablish grayling in

various Michigan waters by transplanting stocks thought

to be genetically similar to the original Michigan population failed (Nuhfer 1992).

Response

From 1987 to 1990, the Michigan Department of Natural

Resources studied the linkages between grayling growth,

survival, and reproduction to physical, chemical, and

biotic factors, and assessed the feasibility of restoring

self-sustaining populations. A total of 145,000 grayling

(principally one-year-old fish) were stocked into 13 lakes

and seven river systems in the grayling’s historic range in

Michigan. Stocked waters were chosen based on their

favorable physical, chemical, and biological conditions for

maximizing the survivability of these fish. Selected lakes

had sustained other coldwater fish (trout), were remote,

and contained few other fish species (Nuhfer 1992). Since

Michigan strains had been extirpated, eggs from a lake

population of grayling in Montana and a river population

in Northwest Territories, Canada, were hatched and

raised in Michigan hatcheries before stocking.

Results

In most lakes, arctic grayling grew well during the first

season and even into the second season in certain situations. First year survival was best in lakes where few

other fish species were present and was lowest in lakes

containing larger piscivorus fish such as largemouth bass

and non-native brown trout. Survival after the third year

was only observed in lakes that were closed to fishing

(although grayling harvest was prohibited in all lakes)

and with no competition from other species. There was no

evidence of reproduction in any of the systems although

suitable spawning habitat, based on known spawning

requirements, was available in some systems.

In the seven river systems, most Arctic grayling disappeared within six months. Angler-reported catches indicated a movement of fish away from the original stocking

sites. Nuhfer (1992) hypothesized that some movement

may have been induced by higher water temperatures

compared to historical conditions and resulted in movement of the grayling into areas with higher predator

densities. There was no indication that competition or

predation at the stocking sites contributed to the low

survival in streams. In several rivers, obstructions such

as dams blocked upstream migration that may have

provided more suitable habitat conditions. Higher temperatures in today’s contemporary rivers may provide a

competitive advantage to salmonids over grayling (Nuhfer

1992). Additionally, there were some indications that

grayling in some of the lakes may be susceptible to the

more acidic conditions characterizing today’s waters, This

acidity is exacerbated through input of low pH precipitation in poorly buffered soils of the northern lower and

upper peninsulas of Michigan.

The Future

The original strain of Arctic grayling that inhabited

Michigan waterways has been extirpated and can never

be reestablished. The unique genetic characteristics that
18 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-53. 2000

Loftus and Flather Fish and Other Aquatic Resource Trends in the United States

adapted this strain to the conditions of the lakes and

streams of that region is lost. At the same time, however,

the landscape and water quality conditions to which that

genetic make-up was adapted no longer exist. The results

of this and other studies conclude that river strains of

Arctic grayling that currently survive in conditions

similar to historical Michigan conditions are unlikely to

“either survive well, or reproduce, in contemporary Michigan rivers” (Nuhfer 1992). River strains of Arctic grayling

often undertake long seasonal migrations and therefore

need large, cold, non-fragmented rivers with few competing fish species, particularly salmonids, or predatorysized

non-salmonids. These conditions are rare in today’s

streams. Future management, restoration, and rehabilitation of large river systems may provide opportunities to

recreate these environmental conditions more suitable to

the survival of arctic grayling.

Although grayling survived and grew in lake systems,

no natural reproduction occurred. Thus, self-sustaining

populations of this native species may not be possible

under current environmental conditions. Since grayling

do not survive well in the presence of non-native predators (such as certain species of salmonids), current management regimes may need to be modified in appropriately suited lakes if the establishment of a hatcherybased

grayling fishery is desired.

Background

The fish communities in Lake Superior have undergone

dramatic changes during the past 200 years. These changes

have been attributed to alterations in land use, intentional and unintentional introductions of exotic species,

contamination by toxic chemicals, and other factors (Kelso

and others 1996). Lake trout, which once existed as the

top predator in this system, were decimated by the introduction of the parasitic sea lamprey through the Welland

canal, overfishing, pollution (particularly DDT), and degradation of their spawning habitat due in part to siltation

resulting from extensive logging activities in the 19th and

20th centuries (Schreiner and Schram 1997, Hile and

others 1951, Scott and Crossman 1973). Although native

lake trout were extirpated in the lower Great Lakes,

remnant populations have survived in off shore areas

(primarily three shoals) of Lake Superior (Schreiner and

Schram, 1997, Hansen 1996). Full restoration of the Lake

Superior lake trout population has been a goal of managers since stocks were decimated in the 1950s.

In 1956, the governments of the United States and

Canada formed the Great Lakes Fishery Commission

(GLFC) to develop control techniques for sea lamprey and

to share information to better manage the Great Lakes

fisheries. Development of the chemical lampricide “TFM”

in the 1950s opened the door for sea lamprey control and

the beginning of rebuilding fish populations in the lakes

(Smith and others 1974). To successfully restore lake

trout populations, managers focused on three primary

areas: reducing sea lamprey populations, reducing fishing harvest (the commercial fishery was closed 1962-70),

and restoring spawning habitat. Even though over-fishing and sea lamprey are considered the primary causes of

lake trout declines, spawning habitat restoration and

improved water quality were considered critical to lake

trout rehabilitation and the establishment of a wild,

selfsustaining stock (Schreiner and Schram 1997). Although watershed alterations continue to occur, pollution

from watershed activities has declined, channelization

and new harbor development is decreasing, and hydroelectric facility construction has abated overall in the

Great Lakes (Kelso and others 1996).

Results

When these rehabilitation efforts and extensive stocking

programs began in the early 1960s, wild lake trout abundance steadily increased. By 1994, more than 90% of lake

trout caught in surveys in the Michigan waters of Lake

Superior were of wild (non-hatchery) origin. Eightyfive

percent of the lake trout produced in eastern Wisconsin

and 50 to 90% of the lake trout in Ontario waters of Lake

Superior were of wild origin. Since the early 1970s,
USDA Forest Service Gen. Tech. Rep. RMRS-GTR-53. 2000 19

Fish and Other Aquatic Resource Trends in the United States Loftus and Flather

natural production of lake trout consistently increased

through the mid 1980s (figure 10). Only areas in the

extreme western portion of the lake are lagging in natural

reproduction (Schreiner and Schram 1997). Michigan

now proposes to cut all stocking of hatchery fish; Wisconsin proposes to stop stocking in eastern waters of their

state; and Minnesota will decrease stocking by 30%.

Additionally, contaminant levels continue to decline in

lake trout (DeVault and others 1994). Although populations of wild fish are not yet at pre-1940s levels, when the

fishery sustained a commercial harvest averaging two

million kilograms annually (Hansen 1996), they have

recovered to where stock supplementation can be reduced

or eliminated.

The Future

Environmental management problems still exist and

continue to impact the ecosystem, including chlorine from

paper mills, municipal sewage overflows, heavy metals

from mining activities, atmospheric deposition of contaminants (Schreiner and Schram, 1997), continuing introductions of exotic species, and persistent toxins (Kelso

and others 1996). However, the use of large mesh gill nets

in commercial fisheries has been reduced in Michigan and

Wisconsin, which may improve survival of large (age 7+)

mature lake trout (Hansen and others 1996).

Lake trout in Lake Superior are showing signs of restoration through an integrated management process involving improved environmental conditions and reduced

fishing mortality. While the scenario for the other Great

Lakes differ significantly in some respects, the Lake

Superior lake trout restoration provides encouraging evidence that long-lived species in large systems can successfully be restored using a holistic approach to management.

Figure 10—Wild lake trout abundance (sites combined) in Michigan waters of Lake Superior using unweighted averages of catchper-unit effort. (MA Hansen, pers. comm., College of Natural

Resources, University of Wisconsin, Stevens Point 1998; Hansen

and others 1996).

by Andrew J. Loftus, Loftus and Associates,

Curtis H. Flather, Rocky Mountain Research Station,

and Marjorie S. Adkins, Chesapeake Regional

Information Service Director, Alliance for the

Chesapeake Bay4

Background

The Chesapeake Bay is the largest estuary in the United

States. While the shoreline stretches 195 miles through

Maryland and Virginia, the Bay’s watershed extends

from its northernmost tip in Cooperstown, New York, to

its southern reach in the Tidewater area of Virginia

(Horton and Eichbaum. 1991). This watershed encompasses over 64,000 square miles and is shared by six

states and the District of Columbia (figure 11). The

relative shallowness of the Bay (average depth less than

22 feet) combined with the large watershed area create a

very large watershed to volume ratio (2,743 square km/

m3 of water), making the Bay very susceptible to influences from the landscape

4 Current address: Loftus Consulting, 3116 Munz Drive, Suite

A, Annapolis, MD 21403
20 USDA Forest Service Gen. Tech. Rep. RMRS-GTR-53. 2000

Loftus and Flather Fish and Other Aquatic Resource Trends in the United States

Figure 11—The Chesapeake Bay watershed.

(Horton and Eichbaum 1991). The flora and fauna of the

Chesapeake Bay system are ecologically diverse, with more

than 2,000 plants and animals having been identified from

the Chesapeake Bay region (Lippson and Lippson 1984)

Despite the political complexity of managing the Bay as an

ecosystem, the Chesapeake Bay states recognized in the

early 1980s that this was the only effective way to manage

such a large system. The enormous task of managing the Bay

as an ecosystem not only involves multiple state, federal,

and municipal governments, but requires the general support and participation by the 15 million residents of the Bay

region.

Problem and Response

The Chesapeake Bay has been a center of commerce and an

area of high human growth since its exploration by Captain

John Smith nearly four centuries ago. With its abundant fish

and shellfish resources, easy accessibility by water, proximity to important political seats of power, and natural ports

for shipping, human settlement in the region has been

steady. By the mid 1900s, the impact of four centuries of

intense human habitation and industrialization on the Bay’s

living resources were beginning to be recognized. Prior to

European colonization, nearly all of the watershed was

forested as compared to less than 60% today. Peak storm

flows from the surrounding watershed into the Bay prior to

deforestation, agriculture, development, and urbanization

were likely 25 to 30% lower than today (Horton and Eichbaum

1991). By the 1970s, when agencies such as the Environmental Protection Agency began to focus research efforts on this

as an ecosystem, impacts were already at critical stages.

Nearly all of the historical oyster reefs (which not only

provided oyster habitat but also were important fish

habitat) had disappeared
USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000. 21

Fish and Other Aquatic Resource Trends in the United States Loftus and Flather

due to intense harvesting. Anoxic conditions in 

many parts of the estuary, fueled by high nutrient loads, 

impeded aquatic life and toxic chemicals were still being 

released into the Bay’s waters. The effects of these factors were manifested in the living resources of the Bay 

in many ways: submerged aquatic vegetation (SAV) had 

been depleted, striped bass populations had declined dramatically, spawning runs of migratory American shad 

had disappeared from some river systems, and oysters 

had dropped to a fraction of their historical levels.

No single cause was to blame for these trends, so there 

was no single solution to the problems. The landmark 

1987 Chesapeake Bay Agreement between Maryland, Virginia, Pennsylvania, the District of Columbia, the EPA, 

and the Chesapeake Bay Commission (a tri-state legislative advisory commission) focused on eight primary goals 

embracing an ecosystem approach to management:

1) Provide for the restoration and protection of the living resources, their habitats, and their ecological relationships.

2) Reduce and control point and non-point sources of pollution to attain the water quality condition necessary 

to support the living resources of the Bay.

3) Plan for and manage the adverse environmental effects 

of human population growth and land development in 

the Chesapeake Bay watershed.

4) Promote greater understanding among citizens about 

the Chesapeake Bay system, the problems facing it, and 

policies and programs designed to help it; and to foster 

individual responsibility and stewardship of the Bay’s 

resources.

5) Provide increased opportunities for citizens to participate in decisions and programs affecting the Bay.

6) Promote increased opportunities for public appreciation and enjoyment of the Bay and its tributaries.

7) Support and enhance the present comprehensive, cooperative, and coordinated approach toward management of the Chesapeake Bay system.

8) Provide for continuity of management efforts and perpetuation of commitments necessary to ensure long 

term results.

In 1987, the signatories of the Chesapeake Bay agreement identified excess nutrients as the root of many of the 

problems. These nutrients were fueling excessive growth 

of algae, which was thought to be blocking sunlight and 

inhibiting the growth of submerged aquatic vegetation. 

When the algae died, it sank to the bottom and its decomposition contributed to anoxic conditions in parts of the 

Bay bottom. To address this problem, the partners in the 

agreement established a numerical goal for reducing the 

levels of nitrogen and phosphorous in the Bay’s main 

stem by 40% by the year 2000. Subsequent amendments 

to this agreement extended these reduction targets to the 

tributaries.

Results

Within a decade, 90 of 315 significant municipal plants 

had installed (or were installing) biological nutrient 

removal to remove not only phosphorous but also nitrogen, effectively applying advanced nutrient removal to 

59% of municipal sewage flow by the year 2003 at the 

time of full implementation. Best Management Practices 

(BMP’s) on agricultural lands were implemented on 1.6 

million acres between 1985 and 1996, representing 22% 

of the agricultural land in the three Bay states. Urban 

runoff was curbed by implementing innovative landscape 

and construction technologies developed cooperatively 

by government agencies, citizen’s groups, landscapers, 

and the development community. In 1997 the state of 

Maryland, under the umbrella of the “Smart Growth Initiative” and “Rural Legacy Program,” passed what is perhaps the most aggressive package of legislation for “open” 

land preservation in this region to date. This was designed 

to direct land use patterns in the state through programs 

of financial and political incentives as opposed to regulatory actions. 

Because many of the fish stocks in the Chesapeake Bay 

migrate to Atlantic coastal waters, successful restoration 

and management of these species must be done in concert with other states. The 13 Atlantic states and the District of Columbia have joined under an interstate compact 

to form the Atlantic States Marine Fisheries Commission 

(ASMFC) to develop cooperative fishery and habitat management plans and share data. Until 1984, implementation of fishery management plans developed through the 

ASMFC was voluntary and only marginally successful. 

In 1984, the Atlantic Striped Bass Conservation Act was 

signed into law, which required states to implement and 

enforce the cooperative Atlantic Striped Bass Management Plan. 

Together, the Chesapeake Bay Agreement and the cooperative ASMFC management have had measurable and 

substantial results on the ecosystem. Overall, the levels 

of phosphorous in the Chesapeake Bay declined 16% 

between 1985 and 1992 and are on target for meeting the 

40% reduction goal in 2000. Although it is questionable 

whether the 40% nitrogen reduction goal will be met in 

the time frame specified, levels of nitrogen are declining 

in the major tributaries to the Bay and have stabilized 

in the main portion of the Bay; they are expected to continue to decline as additional nutrient reduction actions 

are implemented. In some areas, submerged aquatic vegetation beds have rebounded 70% since their low levels 

in 1984. By providing fish passage facilities or redesigning artificial obstructions to fish migration, over 330 miles 

of historical habitat have been reopened to migratory 

fish, with plans to open 1,357 miles by the year 2003. 

The goal of reducing chemical releases from Chesapeake 

Bay industries by 65% before the year 2000 was achieved 
22 USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000.

Loftus and Flather Fish and Other Aquatic Resource Trends in the United States

in 1995, a full five years ahead of schedule. Industry 

releases of specific toxins of concern have been reduced 

22% between 1988 and 1997 with a goal to further reduce 

releases and transfers of these materials by 75% by the 

year 2000.

The combined effects of interstate management and a 

cooperative Chesapeake Bay ecosystem restoration program are seen most dramatically with striped bass. Since 

the Chesapeake Bay historically produced 90% of the 

striped bass on the Atlantic coast, the restoration and 

maintenance of healthy spawning and nursery habitat in 

the Bay is of vital importance. Actions of the Chesapeake 

Bay states will be reflected in the status of the striped bass 

population along the entire Atlantic coast. In the 15-year 

period between 1982 and 1997, the Atlantic coast striped 

bass population has rebounded nearly 800% (figure 12). 

Juvenile production has steadily increased with the highest recorded indices of reproduction in 1993 and 1996 in 

over 40 years of surveys. The number of age classes in the 

spawning stock has increased from 2–3 in the early 1980s 

to 3–6 in 1997. Likewise, other fisheries have begun to 

rebound, such as American shad (figure 13). The Susquehanna River stock of American shad had declined to fewer 

than 6,000 fish but by 1997 had rebounded to more than 

200,000. This occurred because of an ongoing moratorium 

on shad fisheries in most of the Chesapeake Bay combined 

with improved fish passage and habitat improvements.

The Future

The Bay jurisdictions and federal partners continue to 

commit large amounts of fiscal resources to address the 

Chesapeake Bay’s problems on an ecosystem basis. Many 

of the relatively inexpensive actions have been completed, 

however, and jurisdictions will be faced with difficult 

financial decisions to continue making advancements in 

the restoration. Maintaining reduced nutrient levels will 

be a challenge due to expected human population growth 

in the area (Chesapeake Bay Program 1997). 

In terms of fisheries management, the tremendous success of the federal striped bass legislation led to similar 

legislation to cover other migratory species. The Atlantic 

Coast Cooperative Fishery Management Act of 1993 mandated states to implement and enforce interstate management plans for other fish stocks. This action will help 

to foster stronger coordinated management between all 

Figure 12—Estimated total population size of Atlantic coast 

striped bass (USDC 1998b).

Figure 13—Estimated population of American shad in the upper 

Chesapeake Bay (C. Markham, pers. comm., Maryland Department of Natural Resources-Fisheries, 580 Taylor Avenue, Annapolis, MD 21401 1997).

Atlantic coastal species that migrate through the Chesapeake Bay.

The Chesapeake Bay, one of the most diverse and 

valuable ecosystems in North America, continues to improve only through the adoption of an intergovernmental ecosystem management approach. It serves as a model 

program for other watershed projects, large or small, to 

follow.

1983 1985 1987 1989 1991 1993 1995 1997

Year

0

10000

20000

30000

40000

50000

# of fish (thousands)

Figure 12

1981 1983 1985 1987 1989 1991 1993 1995

Year

0

50

100

150

200

250

300

350

Number of shad (thousands)

Figure 13

Number of striped bass (thousands) Number of shad (thousands)
USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000. 23

Fish and Other Aquatic Resource Trends in the United States Loftus and Flather

Background

Perhaps no issue in this country has raised the awareness of the interconnectedness between land use and 

aquatic ecosystem health more than salmon declines in the 

Pacific northwest. Although salmon populations range on 

both sides of the Pacific Ocean, their strong tendency to 

home back to natal streams has created numerous distinct 

stocks, each with particular characteristics that have made 

it adapted to its historic river of origin. It is these distinct 

stocks of the five salmon species, as well as steelhead and 

cutthroat trout, that are in danger of continuing declines 

and possible extirpation in the Pacific northwest. 

In general, salmon spawn from late fall to winter in 

clean, gravel areas of streams in the northwest. Residence 

time of the young salmon in the freshwater environment 

varies. As adults, most salmon make long ocean migrations before returning to their natal stream one to seven 

years later to spawn and then die (for complete life history information, consult Groot and Margolis 1991).

Threats to the salmon life cycle begin in the natal area 

and extend throughout all life stages. Human-induced factors responsible for the decline of Pacific salmon include 

agriculture, dams, fishing pressure, forestry, urbanization, in-stream gravel harvest, irrigation, and dilution of 

native genetic strains through introduction of hatchery 

fish5 (USDC 1996). Additionally, natural climatic effects as 

well as predation by birds, marine mammals, and intro-

 CASE STUDY 6:

COLUMBIA RIVER SALMONIDS

duced fishes play an important role in the survival of both 

adult and juvenile fish.

Problem

While no individual species of Pacific salmon is endangered (Lackey 1996), over 300 distinct native stocks of 

salmon, steelhead, and sea run cutthroat are at risk in 

the Pacific northwest (Allendorf and others 1997, FEMAT 

1993) and 15 distinct population segments are listed under 

the Endangered Species Act (table 4). The largest drainage 

in this region is the Columbia River. This basin historically 

encompasses more than 30 unique sub-basins covering 

approximately 259,000 square miles. Of the current habitat in the basin, 15,000 miles of anadromous fish habitat 

are located on 16 national forests in Washington, Oregon, 

and Idaho. This accounts for over 50% of the remaining 

habitat suitable for salmon in the basin (Federal Register 

1991). Another 1,800 miles are under the administration 

of the Bureau of Land Management (McGinnis 1995).

Despite being the most direct indicator of natural 

spawning trends, estimates for the total number of natural spawners are not available at this time (Anderson 

and others 1996). However, other surrogate estimates 

of abundance provide ample evidence of the decline of 

the Columbia River salmonids. Since 1938, the minimum 

estimated number of salmon and steelhead entering the 

Columbia river has ranged from a high of 3.2 million 

fish in 1986 to a low of 856,500 fish in 1994 (Anderson 

and others 1996). Total escapement (total number of adult 

spawners returning to a segment of stream) of salmon and 

steelhead has declined since 1986, with total escapement 

of spring chinook salmon being the lowest in recorded 

history in 1995 (figure 14). Total escapement of salmon 

and steelhead in 1995 was approximately 700,000 fish, 

with approximately 441,000 of those fish reaching regions 

above the Bonneville Dam (Anderson and others 1996). In 

terms of reproduction, surveys conducted by the Oregon 

Department of Fish and Wildlife in the Snake River drainage since the 1950s indicate that the 1994 redd counts in 44 

streams showed only three redds per stream—the lowest 

ever recorded (Anderson and others 1996).

While there is little disagreement that stocks of Pacific 

salmon have declined, there is substantial controversy 

over the nature and extent of the factors that have contributed to these declines. Reaching historical spawning 

grounds is only the first of many challenges. With 19 major 

dams and 100 smaller projects (McGinnis 1995), only 44 

miles of the 1,240 mile Columbia River remains free of 

hindrance from dam or reservoir (Wilcove and Bean, 1994, 

Moore and Wiley 1991). In the “interior Columbia River 

basin” (the eastern portion of the drainage), over 1,230 

large dams (defined as storage capacity over 62,000 cubic 

meters) block spawning migrations to tributaries (USDA 

5 Pacific States Marine Fisheries Commission. 1997. Factors 

responsible for the decline in salmon abundance and distribution 

in the Pacific northwest. Fact Sheet. (http://www.psmfc.org).

6
24 USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000.

Loftus and Flather Fish and Other Aquatic Resource Trends in the United States

Figure 14—Escapement of four salmon runs in the Columbia River based on dam or weir counts below Bonneville dam (Pacific States 

Marine Fisheries Commission. http://www.streamnet.org).

Forest Service and USDI Bureau of Land Management 

1996).

Once salmon and steelhead do reach spawning habitat, 

a variety of factors impede successful reproduction. As 

reviewed in Anderson and others (1996), the availability 

and quality of spawning habitat is severely restricted by 

inadequate flow levels, high stream temperatures, sedimentation, low pool/riffle ratios and other factors (table 

6). For the eastern portion of the basin, the USDA Forest 

Service and USDI Bureau of Land Management determined that a minimum of 10% of the stream habitat 

(miles) had impaired water quality (table 7). This evaluation did not include an assessment of the habitat quality 

beyond water quality.

Once spawning and hatching occur, salmon and steelhead smolts face many challenges before reaching the sea. 

During their downstream migration, passing through turbines of hydroelectric facilities may impose 10–15% mortality rate per dam on juvenile salmon (Anderson and 

others 1986). Predation by northern squawfish is another 

significant problem for juvenile salmon and steelhead 

(Anderson and others 1986). Furthermore, during the 

downstream migration, juvenile salmon and steelhead 

require specific water temperature and salinity conditions 

to complete the metamorphosis that helps them to physiologically adapt to saltwater. The timing of water releases 

from dams is critical to providing the right mix of temperature, salinity, and flows that ensure survival and delivery 

of migrating salmon to the sea when optimum environmental conditions exist (DiSilvestro 1997).

Responses and Results

Initial attempts by state and federal governments to 

combat declining stocks focused on stocking hatcheryreared fish. However, such stocking programs have greatly 

intermingled distinct stocks of Pacific salmon (Groot and 

Margolis 1991) due to the lack of a scientifically based 

genetics policy. The Mitchell Act served to further promote stocking. However, it should also be noted that 

although salmon stocks have been planted outside of their 

native drainages, those drainages often do not possess 

the physical and chemical parameters in which the original distinct strains of salmon evolved. Extensive efforts 

by multiple state, federal, local, and tribal governments 

Figure 14

1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996

Year

0

100

200

300

400

Number (thousands)

Fall Chinook

1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996

Year

0

100

200

300

400

Number (thousands)

Summer Chinook

1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996

Year

0

100

200

300

400

Number (thousands)

Spring Chinook

1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996

Year

0

100

200

300

400

Number (thousands)

Coho
USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000. 25

Fish and Other Aquatic Resource Trends in the United States Loftus and Flather

Table 6—Major habitat constraints by stock and region. Values are expressed as percentages of total miles identified with constraints 

divided by total miles of spawning and/or rearing habitat (Anderson and others 1996). Spr – spring, Sum – summer, Win – winter.

Flow Gravel In- Inter- Pool-riffle Stream

Levels quantity High stream specific ratio bank

Species/run Columbia River Region low low temperature cover competition low Sediments degraded

Coho Below Bonneville 16.1% 7.6% 29.7% 2.6% 12.4% 9.2% 20.1% 2.7%

Bonneville-Priest Rap 2.3% 0.4% 0.2% 4.6% 0.2% 5.1% 0.4% 0.2%

Snake River a

Priest - Chief Joe 0.2% 0.8% 37.1% 3.5% 8.1%

Fall chinook Below Bonneville 9.3% 6.8% 25.0% 1.4% 16.8% 0.5% 20.4% 15.7%

Bonneville-Priest Rap 9.1% 7.7% 2.2% 5.7% 16.2% 5.6%

Snake River 1.1% 4.4% 2.5% 2.5% 2.5% 22.4%

Priest - Chief Joe 10.7% 6.3%

Spr chinook Below Bonneville 20.9% 8.9% 27.6% 3.3% 11.9% 2.8% 16.9% 4.1%

Bonneville-Priest Rap 11.3% 9.8% 16.3% 10.6% 7.6% 10.2% 10.2% 14.4%

Snake River 7.7% 2.0% 13.4% 5.4% 6.3% 20.4% 8.4%

Priest - Chief Joe 41.3% 8.6% 0.8% 56.4% 12.7% 7.5%

Sum chinook Below Bonneville a

Bonneville-Priest Rap a

Snake River 4.5% 25.5% 2.3%

Priest - Chief Joe 8.6% 8.4% 21.1% 36.7% 24.8%

Sum steelhead Below Bonneville 15.7% 13.8% 22.5% 9.7% 9.2% 5.8% 12.2% 2.8%

Bonneville-Priest Rap 31.7% 12.4% 36.0% 17.9% 10.9% 16.0% 25.3% 40.1%

Snake River 15.2% 2.0% 13.6% 6.2% 0.1% 9.1% 25.8% 13.5%

Priest - Chief Joe 18.6% 6.8% 19.8% 28.0% 13.2% 7.5% 0.1%

Win steelhead Below Bonneville 14.2% 13.0% 20.6% 6.4% 12.1% 5.3% 15.3% 1.9%

Bonneville-Priest Rap 37.4% 6.4% 18.7% 30.1% 40.3% 18.8% 13.0%

Snake River a

Priest - Chief Joe a

a Species/run is not found in this region

and private partners are occurring to restore watersheds 

and aquatic conditions to a state that is more favorable for 

spawning, rearing, and migration of salmon stocks.

Extensive fiscal and personnel resources are being 

invested into resolving the salmon situation. Salmon 

declines have not come without a price to regional economies. In Washington and northern Oregon, the commercial salmon fishery was closed completely in 1994 

(USDC 1996). In 1991, recreational anglers in Washington, 

Oregon, Idaho, and California spent nearly $604 million 

for salmon and steelhead fishing, generating $1.2 billion 

in total economic output, $25 million in state sales taxes, 

$16.2 million in state income taxes, and $76.1 million in 

federal income taxes (table 8). However, this represented 

a decline of 37 to 51% in each category between 1985 

and 1991 (table 8). Overall, the Pacific Northwest salmon 

fisheries each year have produced over $1 billion in personal income and created more than 60,000 jobs (McGinnis 1995).

The Future

The fate of Pacific salmon stocks in the Columbia River 

basin is still uncertain. Returning the Columbia River 

system to its historic conditions is not a feasible solution 

in the short term because much of the electric power in 

the Pacific northwest is generated by these dams as well as 

providing water for irrigation and barge traffic. As McGinnis (1995) stated, “Effective restoration of wild salmon in 

the Pacific northwest is predicated on cooperation between 

myriad stakeholders including watershed management 

councils, the Northwest Power Planning Council, 11 state 

and federal agencies, 13 Indian tribes, eight utilities, and 

numerous fish, forest, and environmental interest groups.” 

Reaching consensus among such diverse groups is just one 

of the complexities of the restoration and management in 

this region. Ongoing revisions in federal policies regarding 

land use, such as the debate within the Forest Service to 

retire roads and halt road building on 33 million acres, have 
26 USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000.

Loftus and Flather Fish and Other Aquatic Resource Trends in the United States

Table 7—Water-quality impaired waters reported by the states and the U.S. Environmental Protection Agency as miles of streams and 

rivers in the portions of states within the Interior Columbia Basin Ecosystem Management Project assessment area. Note: The Utah 

Department of Environmental Quality reports no impaired streams or rivers within the project area in Utah. (USDA Forest Service and 

USDI Bureau of Land Management 1996).

Total Any Temperature Nutrient Sediment/siltation/turbidity Flow 

stream miles impairment impairment impairment impairment impairment

Oregon (1994/96) 75,186 8,123 7,358 280 948 1,263

 Forest Service 2,528 2,464 0 320 134

 BLM 646 570 49 65 78

Washington 49,150 3,962 2,815 33 ND 2,551

 Forest Service 578 204 0 ND 446

 BLM 26 14 0 ND 16

Idaho 98,984 10,024 2,632 3,459 8,812 2,714

 Forest Service 3,000 455 306 2,568 478

 BLM 1,350 513 391 1,187 506

Montana 31,317 3,912 1,051 1,138 3,034 1,791

 Forest Service 1,360 271 99 1,053 556

 BLM 70 20 10 56 45

Wyoming 4,785 71 0 0 46 0

 Forest Service 39 0 0 35 0

 BLM 2 0 0 2 0

Nevada 6,835 175 161 14 0 0

 Forest Service 11 1 9 0 0

 BLM 48 48 0 0 0

TOTALS

 All states 266,257 26,266 14,017 4,922 12,840 831

 Forest Service 7,515 3,395 414 3,976 1,431

 BLM 2,142 1,164 450 1,311 646

a

 ND: No Data

potential ramifications for improving aquatic conditions 

but are extremely contentious among various user groups. 

However, the greatly increased public and scientific awareness of the relationship between the many dynamic factors 

Table 8—Economic impacts of the declines in the recreational fishery for Pacific Northwest salmon and steelhead (American Sportfishing Association. Fact Sheet on Pacific Northwest Salmon and Steelhead Economic Impact. On file with C.H. Flather, Rocky Mountain 

Research Station, 2150 Centre Ave., Fort Collins, CO 80526). 

Change Change 

from from

1991 estimates 1985 1991 estimates 1985

Expenditures $0,603,981,000 –45% State income taxes generated $00,16,187,000 –37%

Economic output $1,200,000,000 –46% Federal income taxes generated $00,76,118,000 –46%

Personal income $00,76,118,000 –46% Jobs (full time equivalents) a $0,000,043,342 –42%

State Sales taxes generated $00,25,000,000 –51%

a

 Salmon and steelhead fishing-related jobs.

affecting salmon populations, including land use, stocking 

impacts, natural climatic impacts, and harvesting implications, provides a stronger basis for managing these and 

other resources in a balanced way in the future.

a
USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000. 27

Fish and Other Aquatic Resource Trends in the United States Loftus and Flather

Background

The Southern Appalachian region of the United States 

may be one of the most ecologically imperiled areas of 

the country. Its proximity to the large and growing population centers throughout the history of the settlement 

of this continent, and its relatively poorly buffered soils, 

have made it susceptible to influences from increasing 

human activities and acidic deposition. 

During 1994–96, a consortium of state and federal agencies (including the USDA Forest Service), regional commissions, and private organizations teamed to conduct a 

comprehensive analysis of the resources in the Southern 

Appalachian Area (SAA). This area consists of parts of the 

Appalachian Mountains and Shenandoah Valley covering portions of eight states from northern Virginia to Alabama. It also contains the headwaters of nine major rivers 

in the Southern Appalachian region.

As human settlement increased in this region in the 

past two centuries, land use in the southern Appalachian 

area has undergone several dramatic changes. These land 

use patterns, in combination with other impacts of human 

settlement, have affected the status and distribution of 

aquatic fauna of this region.

Problem

In the early part of this century, the landscape of the 

southern Appalachians was shaped by agriculture and 

exploitation of timber resources. These activities were not 

CASE STUDY 7:

SOUTHERN APPALACHIAN 

AQUATIC RESOURCES : 

AN IMPERILED ECOSYSTEM?6

6 Synopsis based on Southern Appalachian Man and the Biosphere (SAMAB) 1996.

evenly distributed across the watershed. Prime agricultural lands typically lay in river valley bottoms and lowlands, whereas accessible timber resources were located 

at lower elevations in the mountains or where natural 

streams cut through the mountain ranges. By 1910, logging in this region provided 40% of the lumber in the 

United States. Many of the timber harvesting and agricultural practices resulted in excessive erosion, increased sedimentation in streams, and associated impacts to stream 

habitat. However, by the 1930s and 1940s, government 

acquisition of large tracts of land and subsequent reforestation through programs such as the Civilian Conservation Corp began to repair some of the effects of logging. 

Today, 71% of the land is forested, 22% is used for pasture or is in some herbaceous cover, 3% is cropped, and 

4% is developed or barren (e.g., rock outcroppings). Seven 

national forests and three national parks in the region 

constitute the largest contiguous block of public lands 

east of the Mississippi.

Past effects of land use on aquatic habitats are not 

quickly reversible and, combined with environmental 

pressures from increasing urbanization, are impacting the 

quality of aquatic systems. There are numerous degraded 

streams; more than 20% of stream miles are impacted in 

15 states. Thirty-eight percent of lakes exhibit characteristics of excessive eutrophication. In some watersheds, 

there is a loss of up to 75% of riparian forest. Fifty percent 

of the stream miles in the area show habitat impairment as 

compared to relatively unimpacted reference conditions.

The land use impacts, exploitation of aquatic species, 

and introduction of exotic species are not quickly or easily 

reversed. Seventy percent of the locations sampled in 

the SAA region showed moderate or severe fish community degradation. In states such as Tennessee, native 

brook trout ranges have shrunk to 20 to 30% of their estimated native range since the early 1900s due to activities 

associated with logging, overfishing, and introduction of 

non-native rainbow trout. Although most of the losses 

occurred in the early part of this century, they still continue today, with encroachment of non-native rainbow 

trout and stream degradation being the current primary 

threats (Bivens and others 1985). Whereas streams once 

supported one species of trout, they now support three: 

one native species (brook trout) and two introduced species (brown trout and rainbow trout). One hundred ninety 

other aquatic or semi-aquatic species are endangered, 

threatened, or of special concern in this region, with 57 of 

these being freshwater mussels and 62 being fish. These 

comprise 50% of the mussel species and 45% of the fish 

species in the area.

Two-thirds of the water quality impacts are due to 

nonpoint sources (agricultural runoff, stormwater, landfill, and mining leachate). The Mid-Atlantic highlands, 

which encompasses the SAA, has one of the highest rates 

of acidic deposition in the country (Herlihy and others 

7
28 USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000.

Loftus and Flather Fish and Other Aquatic Resource Trends in the United States

1993). Additionally, 54% of stream miles have high sensitivity to acid deposition. Fifty-nine percent of wild trout 

streams are in areas highly vulnerable to acidification and 

27% are in areas moderately susceptible to acidification. 

Response and the Future

There are signs of improvement to the water quality 

and landscape that hold promise for improving the conditions of aquatic life. Since provisions of the Clean Water 

Act of 1972 were implemented, 75% of the river miles in 

the SAA are now rated as partially or fully supporting 

their designated uses. Within the Southern Appalachian 

area, the Chesapeake Bay drainage has the highest percentage of water bodies that meet water quality standards 

for the protection of aquatic life. Furthermore, terrestrial 

habitat conditions, which greatly influence fisheries and 

have been identified as a major factor influencing ecological integrity of aquatic resources, are improving. In 

the SAA region, soil disturbance related to agriculture 

declined from 1982 to 1992 and current forestry activities 

are so dispersed within the region that the cumulative 

impacts over the region are now considered to be low.

Projections for the SAA provide some hope for improved aquatic systems in the future. Whereas agriculture, 

logging and mining once posed the greatest threats to 

the ecosystem, increasing urbanization in the watershed 

is now a principal factor impacting aquatic habitats and 

fauna in the future. Between 1970 and 1990, human population density in the SAA increased 28% to 101.8 individuals per square mile and will likely continue to increase. 

However, water quality indices have improved. To accommodate future increases in population and urbanization 

will require continued control of sources of pollution 

and siltation from urban landscapes. Increasing programs 

to control point sources of pollution, combined with an 

increasing awareness and application of improved land 

use practices (such as implementing Best Management 

Practices), will contribute to a trend of improving water 

quality and will help to foster improved habitat conditions for supporting aquatic life.

Background

The case of the Atlantic salmon epitomizes the impacts 

that the combined effects of fishing practices, habitat destruction, dilution of genetic stocks, and water quality can have 

on wild fish populations. Atlantic salmon, which was once 

plentiful in the rivers of the Northeast and which provided 

sustenance and commerce for a developing nation, has been 

driven to historically low levels. Despite prior and ongoing 

attempts to restore U.S. stocks, the future of Atlantic salmon 

in U.S. waters remains uncertain.

CASE STUDY 8:

ATLANTIC SALMON

The original range of Atlantic salmon in the United 

States was from the Houstonic River in Connecticut to the 

U.S. tributaries of the lower portions of the St. Johns River 

in New Brunswick, Canada. Historic runs of Atlantic 

salmon numbered in the vicinity of 500,000 fish throughout the New England rivers (Federal Register 1995) and 

Native Americans and early settlers depended on the 

salmon for food (Buck 1993).

Atlantic salmon begin their life cycle in freshwater tributaries of New England rivers. Eggs deposited in gravel 

redds in late fall and early winter begin to hatch in late 

spring. The young stay in these areas, dependent on the 

availability of clean waters and abundant food supply for 

one to three years. Usually after the third year, at which 

time the salmon are five to six inches long, they undergo 

physiological changes to better adapt them for living in 

an ocean environment and begin their seaward migration. In some rivers during these downstream migrations, 

a run of salmon may be reduced by 4 to 20% as the young 

salmon pass through turbines of dams (Buck 1993).

Once in the ocean, the pelagic salmon are highly migratory, spreading throughout waters of the North Atlantic 

and mingling with other stocks of salmon originating in 

river systems of other north Atlantic and Scandinavian 

countries. It is in the open ocean that they are targeted by a 

variety of predators, including marine mammals, sharks, 

tunas, and commercial fishing fleets of many countries.

Although some salmon return to their natal streams 

after only one year at sea, most spend two to three years 

feeding and growing rapidly in the open ocean. Near8
USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000. 29

Fish and Other Aquatic Resource Trends in the United States Loftus and Flather

shore fisheries (including recreational fisheries) as well 

as pollution and stream blockages, take further toll on 

the salmon numbers as they begin to return. If they can 

reach their spawning grounds in the freshwater tributaries, they will spawn, beginning the life cycle for another 

generation.

Problem

As industrial and commercial needs of the United 

States increased during the early parts of the 19th century, 

the construction of dams and water diversions on New 

England Rivers intensified to run the mills and factories 

and transport goods around natural waterfalls. Later, the 

increasing need for electrical power exacerbated the situation as hydroelectric facilities were constructed to harness 

the energy of free flowing rivers (Buck 1993). These water 

diversion activities blocked salmon access to spawning 

habitat and reduced available habitat to only a small fraction of what it was, thereby effectively disrupting the 

Atlantic salmon’s life cycle. On the Connecticut River, for 

example, only 12 years after a dam was erected in the 

lower portion of the river, salmon populations throughout the entire river system were driven to extinction (Buck 

1993). With the exception of the Penobscot River and a 

few other Down East rivers in Maine, salmon runs had 

virtually disappeared from New England by the middle 

19th century (Buck 1993, Federal Register 1995).

In addition, degrading water quality contributed to a 

demise of Atlantic salmon populations. A growing human 

population and increasing industrialization brought with 

it increased waste disposal into rivers. Buck (1993) noted 

that, in addition to dams, “severe pollution and unregulated fishing at the mouth of the Merrimack prevented 

the salmon’s passage and they disappeared completely.”

Unregulated fishing has been the third major cause of 

the salmon’s decline. Although efforts to restore salmon 

extend back as early as 1875, the harvest of returning 

adults prior to their spawning precluded the restoration 

of salmon runs (Buck 1993). States including Maine and 

New Hampshire enacted measures to prohibit the harvesting of salmon once they reached their waters, but 

loopholes in the laws and illicit harvesting undermined 

the effectiveness of these efforts. 

In the 20th century, the increasing size of, and harvesting by, distant water fleets from foreign nations resulted 

in a large escalation of the ocean harvest of salmon, particularly from Denmark. Atlantic salmon harvest increased 

from 132,240 pounds in 1960 to 3,528,604 pounds by 1967 

(Buck 1993) (figure 15). Since salmon stocks originating 

from different natal streams (and different countries) comingle in the ocean, it is not possible to segregate the harvest of salmon originating in different nations in order to 

protect one stock over another.

Figure 15—World catch of Atlantic salmon (Buck 1993).

Responses and Results

Since the 1970s, tremendous progress has been made 

in Atlantic salmon restoration efforts. The North Atlantic 

Salmon Conservation Organization (NASCO) was formed 

in 1984 to provide international management of salmon 

on the high seas. 

Although salmon populations in New England once 

numbered near one-half million fish, by 1996 their abundance was estimated at approximately 4,000 throughout 

the 20 major rivers in the region (Atlantic Salmon Assessment Committee 1997). In September of 1995, the U.S. 

Fish and Wildlife Service published a notice of intent to 

list the populations of Atlantic salmon in seven Down 

East rivers (Sheepscot, Ducktrap, Narraguagus, Pleasant, 

Machias, East Machias, and Dennys Rivers) as threatened 

under the Endangered Species Act of 1973. Adult returns 

to these seven rivers (figure 16) average less than 10% 

of the number of adult returns needed to “fully seed” 

the available habitat (Federal Register 1997). In making 

this proposal, however, the U.S. Fish and Wildlife Service 

determined that populations of Atlantic salmon in the 

Kennebec, Penobscot, Tunk Stream, and St.Croix Rivers 

are persistent and continue to have a genetic link to native 

populations and therefore would be designated as a “Species of Concern.” It was also noted that, primarily due 

to stocking and inter-basin transfers of differing stocks of 

fish, it is unlikely that Atlantic salmon exist in their genetically pure native form in any New England system. South 

1960 1961 1962 1963 1964 1965 1966 1967

Year

0

1000

2000

3000

4000

P

o

u

n

d

s

h

a

r

v

e

ste

d (th

o

u

s

a

n

d

s)

Figure 15
30 USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000.

Loftus and Flather Fish and Other Aquatic Resource Trends in the United States

Figure 16—Population trends of Atlantic salmon stocks proposed for federal protection (Atlantic Salmon Assessment Committee 

1997).

of the Maine river systems, original populations had been 

extirpated completely (Federal Register 1997). Despite the 

available information indicating low populations, the Service withdrew this proposed listing due to the ongoing 

conservation efforts that “substantially reduced threats 

to the species” and that would facilitate rehabilitation in 

these river systems (Federal Register 1997).

In addressing the causes of the salmon decline, the 

Federal Register (1995) noted: 

“One of the predominant land uses of central and 

northern coastal Maine watersheds is the growth 

and harvest of forest products. Forest management 

practices can cause numerous short and long term 

negative impacts on Atlantic salmon. Deforestation 

alters the water retention of watersheds resulting in 

high seasonal runoff followed by inadequate river 

flows. The removal of riparian vegetation reduces 

shading and increases water temperature. Poor logging practices and road construction adjacent to 

streams results in the deposition of substantial loads 

of woody debris and silt into waterways. Insecticides 

used to control insect infestations and herbicides 

used to manage competing vegetation enter waterways and impact salmon. Historic logging practices 

have impacted salmon in these ways, but current 

forest practices due to state and federal laws are not 

now considered a threat to Atlantic salmon.”

The challenges of providing sufficient spawning habitat 

in both quality and quantity still remain, however. The 

Connecticut and Merrimack rivers once provided 40% of 

spawning habitat for salmon in all of New England (Federal Register 1995). On the Merrimack River, comprehen1978 1980 1982 1984 1986 1988 1990 1992 1994 1996

Year

0

50

100

150

200

250

300

350

400

Number of returning wild salmon

1978 1980 1982 1984 1986 1988 1990 1992 1994 1996

Year

0

50

100

150

200

250

300

350

400

Number of returning wild salmon 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996

Year

0

50

100

150

200

250

300

350

400

Number of returning wild salmon

1978 1980 1982 1984 1986 1988 1990 1992 1994 1996

Year

0

50

100

150

200

250

300

350

400

Number of returning wild salmon

1978 1980 1982 1984 1986 1988 1990 1992 1994 1996

Year

0

50

100

150

200

250

300

350

400

Number of returning wild salmon

1978 1980 1982 1984 1986 1988 1990 1992 1994 1996

Year

0

50

100

150

200

250

300

350

400

Number of returning wild salmon

1978 1980 1982 1984 1986 1988 1990 1992 1994 1996

Year

0

50

100

150

200

250

300

350

400

Number of returning wild salmon

All areas combined Narraguagus Pleasant

East Machias Dennys

Sheepscot Ducktrap

Figure 

1978 1980 1982 1984 1986 1988 1990 1992 1994 1996

Year

0

50

100

150

200

250

300

350

400

Number of returning wild salmon

Machias
USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000. 31

Fish and Other Aquatic Resource Trends in the United States Loftus and Flather

sive surveys by the states have quantified the abundance 

and quality of potential spawning habitat in upstream tributaries. This was followed by the initial construction of fish 

passage facilities in the lower portion of the river, but blockages still remain farther upstream. These facilities are in their 

infancy of operation and are still be being refined to provide 

suitable upstream passage. Additionally, passage of smolts 

downstream is a critical component of restoration (Technical Committee for Anadromous Fishery Management of the 

Merrimack River Basin & Advisors to the Technical Committee 1997). Atlantic salmon now return to the river annually as 

a product of hatchery smolt and fry releases but at a fraction 

of their historical level. Since salmon have been extirpated, 

the restoration effort, in addition to relying on obtaining 

upstream fish passage, has relied on stocking hatchery-produced fish of varying ages (Technical Committee for Anadromous Fishery Management of the Merrimack River Basin 

& Advisors to the Technical Committee 1997).

The Future

Although access to historical spawning habitat remains 

a key impediment to Atlantic salmon recovery, evidence 

suggests that low natural survival in the marine environment is now a major factor contributing to the decline 

of Atlantic salmon (Federal Register 1995). If West Greenland and Canadian intercept fisheries were eliminated, 

returns of U.S. Atlantic salmon could potentially double 

(Federal Register 1995). Further, past stocking practices 

and current escapements from commercial aquaculture 

operations may have diluted genetic pools of native fish 

and contributed to the decline. 

The plight of Atlantic salmon continues as attempts at 

recovery are impeded by continued complexities in managing international fisheries; restoring both access to, and 

quality of, natural spawning habitat; and potential factors related to the loss of historic genetic characteristics. 

The elimination of unique genetic strains from some systems means that these stocks will never be reestablished. 

However, genetic stocks that are able to adapt to currentday environmental conditions may be able to survive in 

these same systems. Even though Federal listing under 

the Endangered Species Act was deemed unnecessary at 

this time, conservation efforts by the federal and state 

governments will continue and provide one more step to 

attaining restoration of Atlantic salmon to the rivers of 

New England.

TRENDS IN COMMERCIAL AND RECREATIONAL FISHERS

The RPA Assessment is to include an analysis of present and anticipated uses, demand for, and supply of, 

the renewable resources. Trends in the use of aquatic 

resources reflect several variables, including resource condition, state of the economy, public perception regarding 

the resource, and societal values and desires that may 

change over time. For example, in 1991 the Sport Fishing 

Institute reported that a decline in the number of sport 

fishing license holders in the Great Lakes region was in 

part attributable to heightened reports about contaminants in Great Lake fish. This decline was not related to 

fish abundance or actual increase in contaminant burdens. 

Therefore, interpreting the causes behind changes in participation must be done with care. 

There is no single data source that accurately measures 

the public’s use of fisheries resources. User groups can be 

generally classified as commercial harvesters, recreational 

anglers, subsistence fishers, and “watchable wildlife” participants. Little information on a regional or nationwide 

basis is available for either subsistence fishers or watchable wildlife specifically related to fish. For commercial 

harvesters and recreational anglers, several data sets exist 

and will be discussed below.

Commercial Fishers

The National Marine Fisheries Service (NMFS) is the 

primary source for commercial harvesting data. Commercial harvest of wild stocks of fish is an activity that occurs 

principally in ocean waters and the Great Lakes, and to 

a much lesser degree in freshwater environments other 

than the Great Lakes. Commercial harvesting capacity is 

generally measured in terms of the number of commercial vessels registered. This is problematic since it does 

not accurately reflect either harvesting capacity or time 

spent at sea. In general, it may not accurately reflect the 

condition of the resource since other factors influence participation including market price, government regulation, 

government incentive programs, and weather.

Trends in commercial craft have remained fairly steady 

in the last decade. In 1995, approximately 33,000 vessels in 

excess of five net tons were registered in the United States 

(USDC 1996). Since the time series of data collection began 

in 1964, the number of vessels slowly increased until 1984. 

Since 1990, the number of vessels has remained stable but 

at a lower level than in the earlier time period (figure 17). 

In 1987, the last year of a comparable data set on commer-
32 USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000.

Loftus and Flather Fish and Other Aquatic Resource Trends in the United States

Figure 17—National trends in the number of commercial fishing 

craft, 1965–1995 (X’s). Boats are craft less than 5 net registered 

tons (triangles); vessels are greater than 5 net registered tons 

(circles). Includes Great Lakes fisheries other than tribal fisheries (USDC National Marine Fisheries Service 1971–1997; USDI 

Bureau of Commercial Fisheries 1967–1970).

cial fishing vessels worldwide, U.S. vessels accounted for 

only 3% of the world’s fishing vessels (USDC 1996). U.S. 

commercial seafood harvesting and processing supports 

over 30,000 full time jobs and produces approximately 6% 

of the world’s commercial landings (USDC 1993).

Using the weight or number of individuals harvested 

to reflect trends in populations is also very problematic. 

The same factors that influence commercial harvesting 

capacity also influence total harvest and harvest does not 

necessarily indicate the species’ status. One of the largest 

factors is changes in regulations or incentives governing 

the fishery. If regulations cap the allowable harvest of 

a species, as is becoming more prevalent as more intensive management is evolving to combat declining fisheries, total pounds or numbers of fish harvested would be 

expected to provide a false indication of species status. As 

an example, the declining trend in striped bass harvest in 

the 1980s (figure 18) does not accurately portray the trend 

in the population (figure 12). Moratoriums on fishing 

and other restrictive regulations by the states depressed 

the harvest but such actions allowed the stock size to 

rebound.

Recreational Fishers

Although recreational harvest is not always as readily 

visible as commercial harvest, it often can equal or exceed 

that of the commercial sector of particular fisheries. Information about the status and trends of recreational anglers 

on a nationwide basis are available in the National Survey 

on Fishing, Hunting and Wildlife Associated Recreation (which 

is conducted every five years by the USDC Bureau of 

Census and USDI Fish and Wildlife Service), the Marine 

Figure 18—Commercial harvest of striped bass, 1965–1995 

(USDC National Marine Fisheries Service 1971–1997; USDI 

Bureau of Commercial Fisheries 1967–1970).

Recreational Fisheries Statistics Survey (conducted annually 

by the USDC National Marine Fisheries Service), and the 

number of anglers who bought licenses sold as compiled 

by the U.S. Fish and Wildlife Service. Each survey has its 

strengths and weaknesses and a composite of all three 

can provide general information on status and trends of 

recreational fishing.

National Survey on Fishing, Hunting, and 

Wildlife-Associated Recreation

Every five years the U.S. Fish and Wildlife Service conducts the National Survey on Fishing, Hunting and Wildlife 

Associated Recreation (hereinafter referred to as the National 

Survey). This comprehensive survey provides information on participation, economics, trends in species preference, and angler demographic information related to 

these categories. Unfortunately, changes in survey methodology in certain years (most dramatically in 1991) preclude simple comparisons of most trends for an unbroken 

time series. However, general trend information for specific categories of fishers can be ascertained. 

In 1996 the number of recreational fishers (age 16 and 

older) nationwide declined slightly from 1991, but this 

does not reflect a statistically significant decline (table 

9). Therefore, the number of participants is considered 

to have remained unchanged. Over the last decade, both 

the numbers of anglers and days of participation have 

increased (figure 19). However, values indexed to the initial year of the National Survey demonstrate that while 

the rate of increase in the number of anglers outpaced the 

rate of increase in total U.S. population between 1955 and 

1991, in recent years this gap has begun to narrow (figure 

20). In addition to a declining rate of increase in actual 

numbers of recreational anglers, this trend also highlights 

the declining participation as a function of the entire U.S. 

adult population. 

64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96

Year

0

20

40

60

80

100

120

140

# of commercial craft (thousands)

Figure 17

66 68 70 72 74 76 78 80 82 84 86 88 90 92 94

Year

0

2

4

6

8

10

12

14 Pounds (millions)

Fi

gure 18
USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000. 33

Fish and Other Aquatic Resource Trends in the United States Loftus and Flather

Figure 19—(a) Trends in the number of anglers and (b) Trends 

in the days of angling - for anglers age 12 years older in the 

United States. Dashed lines represent extrapolated estimates 

of participation in fishing activities for 1991 and 1996 based 

on percentage changes applied to 1985 estimates. Freshwater 

anglers and days could not be comparably extrapolated in the 

1991–1996 estimates because of changes in categorization in 

the survey. Data for freshwater could not be extrapolated due 

to changes in survey classification between “freshwater” and 

“Great Lakes” fishing in 1991 (USDI Fish and Wildlife Service 

and USDC Bureau of Census 1993, 1998).

Figure 20—Trends in recreational fishing and population growth 

in the United States, indexed to 1955=100 (USDI Fish and Wildlife Service and USDC Bureau of Census 1998).

In 1996, although the total number of anglers remained 

statistically level from 1991, the number of fishing trips 

increased as did the number of saltwater-oriented anglers 

and trips. The total number of days fishing in the United 

States increased 22% from 1991 to 1996. Regionally, the 

increase in the number of angling trips ranged from 

16% in the Northern RPA region to 37% in the Pacific 

region (table 9). Mirroring this increase, nationwide fishing expenditures increased 37%. Significant to these statistics are the fishing expenditures for boats, 4x4 vehicles, 

campers, vans, and cabins, which increased 123%. 

Marine Recreational Fisheries Statistics Survey 

Each year since 1981, the National Marine Fisheries 

Service has collected information on the recreational fishing participation in saltwater. A combination of telephone 

and intercept surveys are conducted in bimonthly waves 

throughout the year. The sampling universe for the telephone survey (which provides trip estimates) is generally 

considered to be coastal counties. However, changes in 

survey coverage and methodology on the Pacific coast since 

1981 have not been consistent and make data for that region 

difficult to compare over time. Therefore the following discussion applies primarily to the Atlantic and Gulf coasts 

(and excludes Texas, which conducts a separate survey).

Between 1994 and 1996, the number of marine recreational trips declined. However, there are large temporal 

fluctuations in the estimated number of trips (figure 21). 

Recent declines not withstanding, participation in saltwater fishing has increased greatly since 1981. On a regional 

basis, the northern RPA region has experienced a general 

increase since 1992 (figure 22). Much of this is attributable 

to more recreational anglers seeking striped bass, which 

have made a tremendous recovery in the past decade (see 

Case Study 5). The southern region (excluding Texas, which 

does not participate in the survey) has declined slightly 

since 1994, although participation in 1996 is higher than at 

the beginning of the time series in 1981 (figure 22).

State License Sales

Each year, the U.S. Fish and Wildlife Service compiles 

information on fishing license holders in each of the 50 

states and the District of Columbia. The number of license 

holders is “certified” through a review process to ensure 

accurate reporting of statistics. These estimates are then 

used as part of a formula to apportion funds through 

the Federal Aid in Sport Fish Restoration Act (this Act, 

Figure 19

1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000

Year

0

200

400

600

800

1000

1200

1400

D

a

y

s

of p

articip

atio

n (th

o

u

s

a

n

d

s)

Total

Freshwater

Saltwater

1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000

Year

0

10

20

30

40

50

60

P

ers

o

n

s (millio

n

s)

Total

Freshwater

Saltwater

a.

b.

1955 1960 1965 1970 1975 1980 1985 1991 1996 

Year

100

125

150

175

200

225

250

Relative Index Value An

glers

Total U.S. population

Fi

gure 20

Days of participation (millions)
34 USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000.

Loftus and Flather Fish and Other Aquatic Resource Trends in the United States

Figure 21—Trends in marine recreational fishing trips on the 

Atlantic and Gulf coasts of the United States (USDC National 

Marine Fisheries Service 1998: http://st.nmfs.gov).

Figure 22—Trends in marine recreational fishing trips by 

RPA region on the Atlantic and Gulf coasts of the United 

States. Estimates do not include data from Texas participants 

1986–1996 (USDC National Marine Fisheries Service 1998: 

http://st.nmfs.gov).

originally created in 1950 under the popular name of 

the Dingell-Johnson Act, was greatly expanded in 1984 

under the popular name of the Wallop-Breaux Act). While 

license sales information provides fairly reliable information on license holders nationwide, it may be problematic 

since state licensing regulations are not always uniform 

across states (for example, some residents such as younger 

or older persons may be exempt from licensing requirements) and substantial changes in any state licensing program may not necessarily reflect total participation.

Nationwide, license sales declined during the period 

1991–96 (figure 23). Since 1991, license sales declined by 

2.6%, mirroring the slight (but statistically insignificant) 

decline in participation as seen in the National Survey. 

Over the last decade (1986–1996), license sales fluctuated 

on an annual basis but over the period have remained relatively unchanged except for the sharp decline in 1996. 

On a regional basis, there has been a dramatic decrease 

in license sales in the northern region between 1991 and 

1996 (figure 24). Part of the reason may be attributable to 

weather, since this region experienced periods of severe 

flooding (1993 and 1996), and concerns over contaminants 

in fish (Sport Fishing Institute 1991). Similarly, declines in 

1993 license sales in the southern region may be attributable to the high water levels that occurred in that year. 

However, sales in this region have also been declining 

since 1994. In the Rocky Mountain Region, license sales 

have been increasing since 1993. In the Pacific region, part 

of the decline in license sales during the late 1980s and 

early 1990s may be attributable to drought conditions that 

reduced the water supply and fishing opportunities in 

areas such as northern California.

Recreational Fishing on Forest Service Lands

Recreational fishing on Forest Service lands is estimated to be nearly 47 million freshwater angling days 

annually (table 1) with the majority of this taking place on 

inland waters (Sport Fishing Institute 1993b). In the process, anglers spend nearly $3 billion, creating an economic 

impact (as measured by economic output) of $8.5 billion. 

Unfortunately, comparable estimates across federal agencies are not readily available. In 1993, the Sport Fishing 

Institute compiled the best estimates available of participation on lands of five Department of Interior agencies, 

determining that participation ranged from 5.4 million 

angler use days to 27.1 million angler use days, depending on agency (table 1). 

Trend Summary and Factors Affecting 

Participation

At best, participation in recreational fishing appears to 

be stable between 1991 and 1996 according to the National 

Figure 23—Trends in sport fishing license holders in the United 

States (USDI Fish and Wildlife Service 1997; Maharaj and Athey 

1996).

1980 1982 1984 1986 1988 1990 1992 1994 1996

Year

40

45

50

55

60

65 Number of trips (millions)

Fi

gure 21

1982 1984 1986 1988 1990 1992 1994 1996

Year

14

18

22

26

30

34

38

42

Number of trips (millions) RPA Northern Re

gion

RPA Southern Re

gion

Fi

gure 22

1983 1985 1987 1989 1991 1993 1995 1997

Year

29

29.5

30

30.5

31

License holders (millions)

Figure 23
USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000. 35

Fish and Other Aquatic Resource Trends in the United States Loftus and Flather

Table 9—Regional trends in the number of anglers and angling days for participants age 16 and older, 1991-1996. U.S. totals include 

responses from participants living in the District of Columbia, but regional totals do not (USDI Fish and Wildlife Service and USDC 

Bureau of Census 1993, 1998).

Region Number of anglers a (thousands) Angling days b (thousands)

1991 1996 % change 1991 1996 % change

Total 35,578 35,246 — 511,329 625,893 22.4

(% of population) (18.7) (17.5)

North 15,248 14,625 –4.1 225,271 261,210 15.9

(17.6) (16.5)

South 12,758 12,806 1.4 204,757 256,319 25.2

(21.5) (19.8)

Rocky Mountain 3,049 3,303 8.3 32,968 44,530 35.1

(21.5) (20.5)

Pacific Coast 4,505 4,501 — 48,228 66,149 37.1

(15.3) (14.2)

a Number of anglers based on state-of-residence participation. 

b Angling days based on place where activity occurred.

Figure 24—Trends in sport fishing license holders by region in the United States (USDI Fish and Wildlife Service 1997; Maharaj and 

Athey 1996). Pacific Coast

Rocky Mountain

North

South

Figure 24

1985 1987 1989 1991 1993 1995 

Year

12

12.2

12.4

12.6

12.8

13

13.2

13.4

13.6

License holders (millions)

1985 1987 1989 1991 1993 1995 

Year

3.5

3.7

3.9

4.1

4.3

4.5

License holders (millions)

1985 1987 1989 1991 1993 1995

Year

3.5

3.7

3.9

4.1

4.3

4.5

License holders (millions)

 1985 1987 1989 1991 1993 1995

Year

8.1

8.2

8.3

8.4

8.5

8.6

License holders (millions)
36 USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000.

Loftus and Flather Fish and Other Aquatic Resource Trends in the United States

Survey. Just as relevant though is the fact that, although 

the number of participants is remaining stable, the percentage of the U.S. population that fishes continues to 

decline.

Evaluating the factors that may influence recreational 

fishing participation estimates, and actual participation, is 

difficult. Using license sales as an indication of participation, a survey by the Sport Fishing Institute in 1990 to assess 

the impact of various license fees on license sales revealed 

that the three most significant factors impacting sales were: 

license price, per capita income, and population growth 

(Fedler and Sweezy 1990). While license price had a slight 

negative impact on sales, the depressed sales were generally recouped in a period of a few years. However, whether 

these recouped license sales were anglers returning to fish 

after having dropped out after the increase, or they simply 

reflected increased sales resulting from increased population growth, is a matter of debate.7 The other two factors 

both had positive impacts on license sales. As per capita 

income rose and population increased, license sales in a 

state also increased (Fedler and Sweezy 1990).

Several surveys have been conducted to ascertain causative factors behind the decline in participation. None 

of these surveys indicates that degrading resource conditions are a cause behind the decline. Duda and others 

(1995) found that the largest determinants of male fishing 

decline are increasing age and fewer men growing up in 

rural areas. Among inactive anglers surveyed, the top five 

reasons given for no longer fishing included the amount 

of free time, lost interest, family obligations, work obligations, and having no one to go with (table 10). “Not 

enough game fish” ranked Number 15 with only 5% of 

respondents citing this as a factor for no longer fishing. 

Similarly, a survey conducted annually by the sport 

fishing industry ranked the major reasons for not fishing 

more in 1995 as: no time, no place to go, other interests, 

weather, family issues, and other (unidentified) issues 

(table 11). Consistently over the course of this survey 

(1989–1995), a low number of respondents (0–2%) identified resource conditions (poor water quality, no fish, or 

fish too hard to catch) as a reason for not fishing more. 

Anglers were also asked what attributes of the angling 

experience have degraded or become more difficult than 

in previous years. Under this question, attributes reflective of the quality of the fishing experience became important (table 12). Crowding and competing uses of water 

resources were the most commonly cited factors that 

had made the fishing experience more difficult. Again, 

resource supply indicators (e.g. too few fish) were rarely 

a substantial concern of respondents.

In the 1996 National Survey, respondents were asked 

if they fished as much as they would have liked. Sixty7 Mike Costello, pers. comm., Ohio Division of Wildlife, 10517 

Canal Road SE, Hebron, OH 43025, 1998.

Table 10—Reasons inactive anglers stopped fishing (Duda and 

others 1995).

Reason Percent of responses

Amount of free time 30% 

Lost interest 24%

Family obligations 20%

Work obligations 19%

No one to go with 16%

Personal health 15%

Pollution or litter 12%

Having to travel to go fishing 9%

Not enough access 7%

Not enough places to fish 6%

Fishing endangers fish populations 6%

Interference from others while fishing 6%

Cost of fishing license 5%

Not enough game fish 5%

Cost of fishing equipment 5%

Poor behavior of other anglers 4%

Too many fishermen 3%

Complex regulations 3%

Not enough officers 3%

Not enough trophy fish 2%

Frequent changes in regulations 2%

Finding a place to buy licenses 2%

Creel limit/season length 1%

Strictness of officers 1%

five percent (22,765,000 anglers age 16 and above) of the 

respondents indicated that they did not fish as much as 

desired. Overwhelmingly, the reasons stated were other 

obligations or not enough time (table 13). Factors related 

to resource conditions ranked at 1% or less. Considering 

the results of these individual surveys overall, it appears 

that a combination of factors, led by “competing interests,” are reducing the available time that individuals 

have to spend on recreational fishing. 

This is not to say that resource conditions do not 

play a role in participation. The increasing fishing trips 

for striped bass on the Atlantic coast parallels with 

the increasing abundance of striped bass (figure 25). 

Although the relaxed fishing regulations in 1990 may, 

in part, have contributed to increased trips, regulations 

were substantially more restrictive than pre-1984 and the 

increasing trend in trips began when regulations were 

being tightened prior to 1990. This fact, combined with 

an increase in the incidence of catch-and-release fishing 

(which is largely unaffected by regulatory changes), indicates that factors other than regulatory changes caused 

this large surge in striped bass fishing trips. According 
USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000. 37

Fish and Other Aquatic Resource Trends in the United States Loftus and Flather

Table 11—Trends in reasons anglers provide for not fishing more (Responsive Management 1996).

Reason 1989 1990 1991 1992 1993 1994 1995

No time 80% 80% 75% 74% 73% 70% 78%

No place to go 5% 6% 5% 7% 8% 7% 5%

Other interests NA 3% 2% 13% 20% 6% 8%

Weather 0% 7% 2% 11% 7% 5% 6%

Family issues 6% 6% 6% 8% 7% 4% 4%

Health/age 4% 4% 5% 7% 5% 4% 2%

Too expensive/no money 7% 4% 6% 6% 5% 3% 4%

No one to go with 4% 3% 4% 5% 4% 3% 1%

Other 11% 10% 11% 12% 11% 10% 6%

Fish too hard to catch 1% 2% 1% 2% 1% 2% 1%

No fish to catch NA 2% 1% 1% 1% 2% 1%

Poor water quality NA 1% 1% 1% 1% 1% 0%

Too many other anglers NA NA NA NA NA NA 1%

Not interested 3% 1% 3% 4% 3% 1% 1%

a NA: Not Applicable, insignificant response.

Table 12—Attributes of recreational fishing that are identified as making fishing “more difficult” than in the past (Responsive Management (1996). Blanks represent those situations when the attribute did not appear as survey response for that year.

Attribute (more difficult) 1990 1992 1993 1994 1995

Too crowded 19% 33% 33% 9% 8%

Boats and watercraft NA 10% 12% 9% 9%

Too many jet skis 5%

Too many anglers 9% 15% 11% 12%

Poor behavior of anglers/boaters NA 4% 4% 5% 5%

Weeds in water NA 4% 1% 2% 2%

Water level NA 3% 0% 4% 8%

Litter in water 10% 6%

Litter on land NA 2% 6% 7% 3%

More expensive-licenses 7% 9% 8% 6% 9%

More expensive-equipment NA NA 5% 3% 4%

No place to go NA 2% 1% 6% 7%

Land restrictions NA 8% 4% 6% 5%

Increased regulations 6% 6% 14% 11% 8%

Poor health/age NA 6% 5% 4% 4%

Kids NA 4% 1% 1% 2%

Too few fish -fishing pressure NA 2% 3% 1% NA

 Sport fishing 11%

 Commercial fishing 4%

Too few fish - netting NA 2% 3% 1% NA

Fish are polluted 6% 6% 6% 2% NA

Bugs 3% 3% 4% 2% 2%

Weather 1% 2% 0% 4% 2%

Other 14%

a NA: Not Applicable, insignificant response.

a

a
38 USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000.

Loftus and Flather Fish and Other Aquatic Resource Trends in the United States

Table 13—Reasons anglers did not participate more in fishing 

in 1996 (USDI, Fish and Wildlife Service and USDC, Bureau of 

Census 1998).

Reason Percent of respondents

Family or work obligations 43%

Not enough time 21%

Not enough money/cost too much 4%

Personal health or disability 4%

Weather 3%

No one to fish with 1%

Not enough places to fish/not enough access 1%

Not enough fish 1% Figure 25—Relationship between striped bass population size 

and targeted recreational fishing trips (USDC 1998b; Salz 

1996).

to National Survey estimates of saltwater fishing trips 

directed at specific species (discounting responses of 

“Anything” and “Other”), striped bass-directed trips rose 

from the fourth largest in 1991 to the second position in 

1996 in terms of the percent of days targeting a specific

species (table 14). 

In a companion report, Bowker and others (1999) project that participation in recreational fishing will increase 

by 36% over the next 55 years. Given the recent trends in 

the National Survey and state license sales, this projected 

growth in participation may be optimistic. The model 

used to predict participation patterns (number of participants) is a static logistic regression model incorporating 

age, income, ethnicity, gender, population density, and 

residential proximity to fish resources. However, as is 

evident in the attitudinal surveys referenced previously, 

Table 14—Most sought-after saltwater species (nationwide) by 

anglers (USDI, Fish and Wildlife Service and USDC, Bureau of 

Census 1998).

 Days of fishing a Percent of total

Species (thousands) days of fishing

Flatfish/Flounder/halibutb 28,644 28

Striped Bass 15,023 15

Salmonc 3,976 4

Bluefish 13,190 13

Lingcod 1,900 2

Weakfish 14,245 14

Mackerel 15,108 5

Anything 24,807 24

Other 45,091 44

a Anglers can specify multiple target species on a single trip.

b Likely to include summer flounder, winter flounder, halibut, witch flounder, 

yellowtail flounder, American plaice, windowpane flounder.

c Likely primarily Pacific salmon.

competing interests (either leisure activities or work obligations) are consistently cited as a reason for not fishing 

more. This is a very difficult variable to define, measure, 

or incorporate into projection models.

Bowker and others (1999) also predict that over the 

next 55 years the total U.S. population will increase by 

44%, indicating that the percentage of U.S. residents who 

fish will continue to decline and that days of fishing will 

increase by 27%. This is consistent with the trends exhibited in the last decade in the National Survey.

CONCLUSION: MANAGEMENT 

IMPLICATIONS TO FOREST 

SERVICE STRATEGIC PLANNING

The data needed to complete a comprehensive assessment of the status and trends of freshwater species in the 

United States is not currently accessible. The lack of consistent and reliable aquatic resource information, especially that specific to Forest Service lands, precludes an 

accurate assessment of whether current Forest Service 

management practices are meeting public demand. In 

terms of angling opportunities, if we assume that the reasons stated in broad angler surveys for not fishing (or not 

fishing more) apply to Forest Service lands, then the condition of aquatic resources is not limiting the availability 

of angling opportunities overall. However, some surveys 

have shown that conditions related to access (too many 

anglers or too crowded) are making angling opportunities more difficult to enjoy.

Based on attitudinal surveys, resource condition generally does not seem to be the major concern among users. 1981 1983 1985 1987 1989 1991 1993 1995 199

7

Year

0

5000

10000

15000

20000

25000

30000

35000

40000

45000

Population size (millions)

0

1

2

3

4

5

6

7

8

9

 

Figure 25

Striped bass fishing trips (millions) Striped bass populatio

n

Recreational trips

Population size (thousands)
USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000. 39

Fish and Other Aquatic Resource Trends in the United States Loftus and Flather

8 Loftus, A.J. 1993. Proceedings of a workshop on refining fisheries information systems. Sport Fishing Institute, Washington, 

DC. 41 p. On file with C.H. Flather, Rocky Mountain Research 

Station, 2150 Centre Ave., Fort Collins, CO 80526-1891.

However, as is demonstrated with striped bass, resource 

condition may play a major role in participation rates 

in specific circumstances (figure 25). In Canyon Creek 

(see Case Study 2), although managers were successful 

in establishing a naturally reproducing brown trout population (many in the trophy category) and increasing 

brown trout densities (measured as fish per square meter), 

there was a 75% decrease in angler days between 1989–92 

due in part to substantially reduced stocking of rainbow 

trout (which do not reproduce or overwinter). Finally, the 

reduced Pacific salmon stocks has resulted in millions of 

days of lost fishing opportunities to the recreational, commercial, and subsistence fisheries.

Data and Information Reporting Needs

Despite the expansiveness of aquatic resources on 

Forest Service lands and the impact of Forest Service 

activities on both inland and anadromous fish, an adequate reporting mechanism to document changes in the 

aquatic communities and habitats in a consistent manner 

across Forest Service lands is lacking. In a survey of Forest 

Service line officers and fisheries program personnel, less 

than one-third of respondents thought that monitoring 

and evaluation efforts were adequate to document aquatic 

habitat changes on their Forest alone (Forsgren and Loftus 

1993). The current reporting mechanism is intended to satisfy broad national needs documenting the accomplishments resulting from the expenditure of funds but has 

little meaning to aquatic resource condition. 

This lack of fisheries and aquatic habitat data is not 

unique to the Forest Service, however. As has been noted 

in the management of the Pacific northwest salmon, 

“Management agencies need to improve coordination of 

survey efforts to develop long-term data collection systems. Improved information-sharing between state management agencies and federal lands managers (e.g., Forest 

Service and Park Service) is needed to integrate fisheries 

and habitat data and to ensure that surveys of resources 

by the federal agencies on the lands they control are 

included in escapement monitoring data sets” (Baker and 

others 1996). 

Furthermore, in a pilot study to assess the feasibility 

of compiling information over broad geographic regions, 

Loftus and Waldon (1992) observed a lack of consistent 

reporting formats, data collection, and assessment techniques. The Multi-State Aquatic Resource Information 

System outlined in Case Study 9 of this report is an 

attempt to develop such a system by starting with a 

restrictive and select set of variables. Some federal agencies have made an attempt to develop broad scale measures of aquatic species health. The EPA’s Environmental 

Monitoring and Assessment Program (EMAP) was one 

such attempt to establish standardized monitoring points 

to evaluate relative changes in aquatic resources health 

but was limited in scope and costly to conduct. 

Several national and regional “needs assessments” have 

indicated the utility of developing a shared information 

system for aquatic species. An assessment by the American Fisheries Society in 1984–86 and a NOAA assessment in 1985–86 (Calio Committee) both recommended 

the development “of national and regional fishery information centers accessible to all agencies (federal, state, 

tribal, etc.) to which all agencies contribute operationally 

compatible data, disregarding geopolitical boundaries” 

(Harville 1992). Technological advancements in data sharing capabilities (particularly via the Internet) may reduce 

the necessity of a centralized data warehouse in favor of 

dispersed information accessible via a common system. 

However, the need for shared information to conduct baseline assessments over larger geographic units (as opposed 

to political units) remains. In the views of fishery administrators and technical personnel, such a system would 

serve to demonstrate fisheries status and trends across 

interjurisdictional boundaries; help to develop national 

and regional priorities and budgets to more effectively 

utilize funding and manage resources; eliminate duplication of effort in sampling programs; assist in identifying 

species approaching threatened and endangered status; 

more easily evaluate management activities/research; and 

maximize use of administrative resources.8 Additionally, 

with the increasing interest in developing the capabilities 

for an aquatic Gap Analysis Program, quantitative fisheries information tied to specific geographic locales will 

become a vital data element to develop a statistical-based 

framework for estimates and projections.

Other Implications for Forest Service 

Strategic Planning and Activities

In terms of habitat management, several specific case 

studies have provided recommendations for modifying 

timber harvesting and other forest management practices 

to improve water quality and aquatic system integrity. 

Instances such as the Canyon Creek project highlighted 

earlier and others (Morris and others 1992) indicate that 

most soil erosion from logging results from road construction. The sediment yield from a conventionally harvested 

watershed (using roads) has been shown to be 100 times 

greater than that from an undisturbed control (Morris and 

others 1992). Sediment yield from a site harvested with 

a skyline system (lifting timbers off the land rather than 

extracting with ground-based vehicles) was only three 
40 USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000.

Loftus and Flather Fish and Other Aquatic Resource Trends in the United States

Background

Federal agencies, such as the USDA Forest Service, 

USDA Natural Resources Conservation Service, USDI Fish 

and Wildlife Service, and USDI Geological Survey Biological Resources Division each have a variety of needs for 

times more than an undisturbed control site (Morris and 

others 1992). The Forest Service has acknowledged the 

problem of the deteriorating road system and is developing plans to rectify the problems associated with it. 

The Canyon Creek restoration, Chesapeake Bay success, Pacific salmon management, Southern Appalachian 

Assessment, Atlantic Salmon situation, and Rathbun Lake 

scenario outlined as case studies in this report all clearly 

indicate that changing the management of the surrounding landscape can be substantially beneficial to the aquatic 

ecosystem. Each of these case studies involved different 

anthropogenic influences on aquatic systems. These influences derive from human desires and needs for living 

which, in the process of fulfilling, impacts the landscape 

and aquatic systems. In fulfilling these needs, a more holistic approach to ecosystem management must be implemented that considers both the actual physical aquatic 

habitat as well as the surrounding terrestrial habitat. 

Williams and others (1989) recommended that natural 

resource management agencies manage for the conservation of entire ecosystems rather than individual species. Additionally, they recommended the establishment 

of long-term monitoring programs to provide baseline 

information for future reference to gauge the trend of species conditions.

Modifying Forest Service planning and activities to 

better meet the changing social, demographic, economic, 

and environmental conditions of the next century will 

require stable and consistent sources of information. 

Extensive searches of published literature and agency 

reports reveal that information on the status and trends 

of aquatic species is available primarily on a case-by-case 

basis. This often provides valuable guidance for establishing cause-and-effect relationships for the impact of 

specific Forest Service practices on aquatic species. However, predicting ecosystem change at broad geographic 

scales based on patterns at finer geographic scales is not 

necessarily valid and may result in erroneous conclusions (Lewis and others 1996). Information that indicates 

status and trends on broad geographic scales needs to be 

compiled to more accurately define the overall aquatic 

resource conditions and satisfy the reporting mandates of 

the RPA. Until the time when such information programs 

are established, initiating a comprehensive and accurate 

system for the analysis of the aquatic species status and 

trends in the United States is not likely to be possible.

CASE STUDY 9:

EVALUATION OF THE MULTI-STATE 

AQUATIC RESOURCES INFORMATION 

SYSTEM FOR ASSESSING TRENDS 

IN AQUATIC SPECIES

aquatic species information that are not currently being 

met. These include the need for long-term data sets on 

aquatic species for purposes such as evaluating the effects 

of possible land use or climate change, conducting trend 

analysis on species to fulfill mandates such as the RPA, 

or identifying population trends and potential management scenarios before populations reach critically low 

levels. Compilation of the aquatic assessment component 

of the RPA report and development of USDA farm programs and legislation affecting millions of acres is currently done without the benefit of detailed fisheries data. 

Realizing the capability to provide regional fishery analyses will create the opportunity to include land use or 

management provisions, which benefit identified fisheries resources, into federal programs that are regional in 

scope.

Recognizing the value in the aquatic species information that was already being collected by the states, the 

USDA Forest Service combined with several other federal 

agencies and private organizations to investigate mechanisms through which agencies could share information 

on the quantitative status and trends of aquatic species. 

Between 1990 and 1993, this initiative completed a pilot 

project involving several Midwestern states that successfully demonstrated that a regional effort was possible (and 

identified some of the problems that could be expected). 

As a result of that project, a more focused effort was initiated in late 1994 involving six states (figure 26) to imple9
USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000. 41

Fish and Other Aquatic Resource Trends in the United States Loftus and Flather

Figure 26—States participating in the Multi-state Aquatic Resources Information System initiative.

ment a useful and workable information sharing system 

using state-of-the art Internet technology. The Multi-State 

Aquatic Resources Information System (MARIS) is based 

on the premise that states currently control the majority 

of aquatic species information collected, and that helping states to strengthen the computerization and management of their information will facilitate the sharing of 

information with other agencies in the long run. 

How It Works

The MARIS initiative links aquatic databases of several 

states and provides that information through a common 

format via the Internet (figure 27). Each individual state 

retains their information on a server within their state. 

For the initial development of the system, the states constructed a standard “MARIS” format to which these data 

could be automatically converted based on a list of variables that were generally common to each state database 

(tables 15–17). The common “quantitative” variable for 

the initial system development was determined to be 

catch-per-unit-effort. Since lookup tables and conversion 

programs are constructed, states are able to maintain their 

data in any format and database software/hardware platform that they desire. MARIS data sets are constructed 

from individual state data sets using these conversion 

programs and look-up tables. All variables are linked 

through a series of geographic locator codes to facilitate 

compatibility with other external databases such as land 

use/land cover.

When a “client” submits a query to the MARIS central 

server, this is broken into separate queries to be sent 

to the individual states where the information resides. 

The responses of these individual queries are then compiled by the MARIS server and a consolidated response is 

returned to the original client. Linking the MARIS information (quantitative information on aquatic populations) 

to existing physical/chemical databases, land use databases, GIS systems, and other databases will allow the 

capability to evaluate effects of factors such as land use 

patterns on aquatic systems on a large scale.
42 USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000.

Loftus and Flather Fish and Other Aquatic Resource Trends in the United States

Figure 27—Application of the dispersed data set form of information sharing utilized by MARIS.

Application

To evaluate the applicability of the MARIS system and 

identify areas for refinement, queries were made to the 

MARIS server that required a multi-state response. At 

present, Internet linkages have been made with four of 

the MARIS state servers but the state fisheries information also currently resides on the MARIS home server at 

the University of Illinois. 

The unique characteristic of MARIS is the ability 

to compile and compare quantitative information regarding the status of fish populations from several jurisdictions. Therefore, information was gathered regarding the 

catch-per-unit effort/time (number of fish caught over a 

standard period of time, or CPUETN) and the catch-perunit-effort/area (weight of fish caught over standard unit 

of area, or CPUESB).

In this initial evaluation of trend analysis, a species was 

chosen which: 1) had not been intensively managed through 

either extensive stocking or extirpation; 2) occurred in at 

least three of the MARIS states; and 3) had data reported for 

at least three years. Using these criteria, black crappie and 

white crappie were chosen from the available data. These 

data were further refined by selecting only those water 

bodies that had records for at least three years within a 

five-year time span. Once data were selected and screened, 

correlation and Least Absolute Regression (LAD; Slauson 

and others 1991) analyses were conducted to determine if 

there were any relationships between crappie abundance 

and time (measured as year of sampling) within lakes.

MARIS Server

State Server

Database

Client
USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000. 43

Fish and Other Aquatic Resource Trends in the United States Loftus and Flather

Table 15—Variables and variable characteristics found in MARIS waterbody description file.

Field name Data type Description 

MWBCODE Text Master Waterbody Identification Code, unique code for each waterbody within state

STATE Text State Postal Code Abbreviation

LAKENAME Text Geographic Place Name

MANAGE Text State Management Location Code (wildlife district)

LATITUDE Number Latitude at Lake Outfall (decimal degrees)

LONGITUDE Number Longitude at Lake Outfall (decimal degrees)

FIPSCODE Text County FIPS Code (3 digits)

SECTION Text Section in which lake exists

TOWNSHIP Text Township in which lake exists 

RANGE Text Range in which lake exists 

USGSHYDR Text USGS Hydrologic Unit

WATERTYPE Text Waterbody Type (1=Lake, 2=Stream, or 3=Impoundment)

MEANDEPTH Number Mean depth of lake (m, 3 digit rounded)

MAXDEPTH Number Maximum depth of lake (m, 3 digit rounded)

AREA Number Surface area of lake (ha)

SHORELINE Number Lake Shoreline length (km, 4 digits)

WATERSHED Number Lake Watershed Area (ha)

LITTORAL Number % Littoral Zone (state specific)

WINTERKILL Text Evidence of winter fishkill (Y/N)

PUBLICACCESS Text Public access possible (Y/N)

Table 16—Variables and variable characteristics found in MARIS water quality description file.

Field name Data type Description 

MWBCODE Text State Master Water Body Identification Code

SAMPLEDATE Date/Time Date of data collection

ALKALINITY Number Alkalinity (mg/l)

CONDUCTIVITY Number Conductivity (mmhos)

PH Number Lake pH

LITTORAL Number Lake Littoral zone, expressed as % of total surface area of lake, where maximum 

depth < state-defined reference depth.

SECCHI Number Mean secchi disk (transparency) read (m)

WATERTEMP Number Surface Water Temperature (°C)

Results and Discussion

Only four of the six MARIS states currently have data 

available. At the time of the analysis, data from Iowa were 

in the process of being entered into their system. Information from Minnesota was entered and made available but 

had not yet been made accessible via the MARIS server. 

Of the four states whose information was available, only 

three (Illinois, Ohio, and Wisconsin) had records of crappie status under the criteria established. Wisconsin had 

data for black crappie. The measure of relative abundance 

common to all three of these states was CPUETN and 

therefore was used for the trend analysis.

Since the use of desktop computers for data entry is a 

relatively recent advancement (within the last decade) in 

most states, a great deal of historical trend information 

is not yet computerized. It has only been fairly recently 

that data in the states has been made available in standard formats and computerized. Despite this, in some 

cases the MARIS states, either with assistance from federal agencies or on their own, have invested in entering all 

of their available historical data. For our query of crappie 

trends, Wisconsin data extend from 1964–1992, although 
44 USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000.

Loftus and Flather Fish and Other Aquatic Resource Trends in the United States

Table 17—Variables and variable characteristics found in MARIS catch and effort description file.

Field Name Data type Description

MWBCODE Text State Master Water Body Identification Code, unique code for each water body

SPECIESCODE Text 3-letter code assigned each species

SAMPLEDATE Date/Time Date of data collection

GTMAJ Text Major Gear Type

GTMIN Text Minor Gear Type (state specific)

TOTCATN Number Total number of fish caught in sample (6 digits max)

TOTCATW Number Total weight of fish caught in sample (kg, 6 digits max)

EFFTIME Number Total duration of sampling effort

STDTIME Text Time units for sampling effort (H=hours,D=days)

EFFSPACE Number Total lake area sampled

STDSPACE Text Space units for sampling effort (ex. km)

CPUETN Number Catch Per Unit Effort Time (total number of fish caught per standard unit of time)

CPUESN Number Catch Per Unit Effort Space (total number of fish caught per standard unit of area)

CPUETB Number Catch Per Unit Effort Time Biomass (total weight of fish caught per standard unit of time)

CPUESB Number Catch Per Unit Effort Space Biomass (total weight of fish caught per standard unit of area)

TARGET Text Species or species group code of fish targeted if the sampling effort was directed at a

specific taxa.

the majority of the data is found in the 22-year time span 

from 1971–1991. Illinois data extend from 1983 to 1991 

and Ohio data from 1987 to 1996. However, states are still 

in the process of computerizing their data. Ohio is one 

such state and data were available for only one waterbody. This, combined with the restrictive nature of the 

requirements of the query, resulted in seven lakes for Illinois, one lake for Ohio, and 15 for Wisconsin that met the 

criteria for black crappie. For white crappie, 15 lakes in 

Illinois and one in Ohio met the criteria. 

We tested for temporal trends in both species by regressing catch-per-unit-effort against year using Least Absolute Regression (LAD; Slauson and others 1991). LAD was 

chosen because it has greater power than least squares 

regression for asymmetric error distributions and it is 

more robust to the influence of a few outlying observations (Cade and Richards 1996). Although the MARIS data 

sets incorporate several geographic locator codes such as 

latitude/longitude and hydrologic unit, no attempt was 

made in this analysis to link fish population trends to 

external data sets for assessing the impact of variables 

such as environmental conditions, land use changes, or 

regulatory changes. The only attempt to factor out external influences was in the criteria for the choice of species 

(as discussed previously). Therefore, the causative factors 

behind the significant trends were not examined.

From this analysis, it can be seen that three out of 

15 lakes in Illinois exhibited significant (P<.10) negative 

trends in catch-per-effort for white crappie. Two out of 

these 15 Illinois lakes and the single lake in Ohio exhibited significant positive slopes for this variable (table 18). 

For black crappie catch-per-effort, two out of seven lakes 

exhibited significant positive slopes in Illinois. In Wisconsin, four out of 15 lakes exhibited significant positive 

slopes while one exhibited a significant negative slope for 

black crappie (table 19).

The information in this basic analysis can be used to 

point to areas of further investigation, including evaluating factors of lakes with similar trends, such as geographic 

dispersion of lakes, land use changes in the surrounding 

watershed, and management changes. The multi-state 

nature of the information expands the geographic scope 

beyond political boundaries and allows analysis on a geological, watershed, and ecotype classification basis. In 

addition, by making data available from multiple states, 

this approach expands the number of lakes (sample size) 

for which agencies or researchers have data available for 

conducting analysis. 

More importantly, since this was the first assessment 

of the application of the MARIS system, several areas of 

potential improvement were noted. Requiring the return 

of metadata (information about data records, data quality measures, collection techniques, analysis, etc.) with 

records would help to reduce the incidence of misinterpretation of data and assist in determining appropriateness of comparisons of records from several sources. 

Creating structured reports (as opposed to free form queries) would reduce potential errors in interpretation by 

preventing queries of invalid comparisons. Bringing data 

from all states on-line would result in more comprehensive analysis capability and help to pinpoint geographicbased trends. This extended analysis capability would 
USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000. 45

Fish and Other Aquatic Resource Trends in the United States Loftus and Flather

Table 18—Comparison of trends in white crappie in select MARIS states as measured by catch-per-unit-effort by year (CPETN). Period 

is time span of sampling records. For significant slopes (P<.10), P-values are denoted by *.

State Lake name N Slope P-value CDa Period

IL Beaver Dam Lake 12 –0.50 0.75 0.03 1985–1991

IL Braidwood Lake 26 0.00 1.00 0.00 1984–1991

IL Clinton Lake 17 2.42 0.21 0.11 1985–1991

IL Coffeen Lake 13 6.02* 0.04 0.22 1986–1991

IL Dawson Lake 15 0.67 0.75 0.01 1984–1988

IL Forbes Lake 22 –4.35* 0.00 0.13 1985–1991

IL Lake Jacksonville 22 –0.87 0.18 0.05 1985–1991

IL Lake Sangchris 18 –0.17* 0.04 0.09 1984–1991

IL Lake Shelbyville 39 0.70 0.12 0.04 1984–1991

IL Lake Springfield 36 –7.34 0.22 0.04 1984–1991

IL Lincoln Trail Lake 13 –0.12 0.44 0.08 1983–1991

IL Mill Creek lake 16 0.00 1.00 0.00 1983–1991

IL Pittsfield Lake 31 4.60 0.33 0.02 1984–1991

IL Siloam Springs Lake 25 1.00* 0.05 0.09 1985–1991

IL Waverly Lake 10 –3.07* 0.02 0.28 1984–1991

OH Delaware Lake 55 4.99* 0.00 0.25 1987–1996

a CD=Coefficient of Determination

Table 19—Comparison of trends in black crappie in select MARIS states as measured by catch-per-unit-effort by year (CPETN). Period 

is time span of sampling records. For significant slopes (P<.10), P-values are denoted by *.

State Lake name N Slope P-value CDa Period

IL Beall Woods Lake 11 2.00 0.27 0.06 1985–1990

IL Beaver Dam Lake 12 –0.67 0.68 0.04 1985–1991

IL Lake Shelbyville 25 0.33* 0.09 0.04 1984–1991

IL Lincoln Trail Lake 31 –0.28 0.32 0.02 1983–1991

IL Spring Lake (South) 21 2.37 0.35 0.03 1986–1991

IL Walnut Point Lake 22 0.60* 0.01 0.05 1982–1991

IL Weldon Springs Lake 21 0.13 0.62 0.01 1985–1991

OH Delaware Lake 55 –3.00 0.78 0.00 1987–1996

WI Black Lake (Birch) 8 13.75* 0.05 0.10 1986–1992

WI Chequamegon Waters Flowageb 10 0.09 0.20 0.04 1966–1992

WI Day Lake Flowageb 8 –0.43 0.75 0.02 1971–1977

WI Kathryn Lake 11 0.94 0.55 0.02 1985–1992

WI Kegonsa lake 5 0.46 0.68 0.10 1976–1988

WI Long Lake 7 0.23* 0.10 0.33 1970–1992

WI Mendota Lake 6 0.83 0.34 0.24 1977–1983

WI Mineral lake 7 –1.26 0.76 0.01 1968–1990

WI Minnesuing Lake 7 –0.59* 0.05 0.27 1964–1976

WI Mondeaux Flowageb 28 6.09 0.01 0.10 1971–1992

WI Park Lake 11 0.47 0.39 0.07 1970–1988

WI Sailor Lake 10 2.46 0.17 0.18 1985–1991

WI Spillerberg Lake 6 8.33* 0.04 0.60 1986–1991

WI Twin Lake (East) 7 –0.73 0.85 0.04 1970–1990

WI Waubesa Lake 6 0.41 0.74 0.14 1968–1984

a CD=Coefficient of Determination

b Includes species identified simply as Pomoxis spp and assumed to be Pomoxis nigromaculatus.
46 USDA Forest Service Gen. Tech. Rep. RMRS–GTR–53. 2000.

Loftus and Flather Fish and Other Aquatic Resource Trends in the United States

also be enhanced by filling in the geographic gaps which 

exist in the MARIS region by bringing on additional states. 

Additionally, as resources allow, historical data should be 

entered into the state systems.

Conclusion

There are multiple advantages to a MARIS-type system. 

Since states retain direct control of the data, updates or 

corrections to data sets are easier, there is no need to reformat data to accommodate specified format and software, 

and states control exactly what data are made available. 

Additionally, this provides a single primary point of contact for state-based information. Database administration 

is reduced dramatically as compared to a “central database” system. Additionally, there is no additional data management being conducted by third parties, thereby taking 

advantage of the current expertise of state agency staffs 

and improving the value and quality of the information.

It is important to note that these data queries were completed without contacting any of the state agencies but 

rather through the MARIS remote query process. Refining this system and expanding its scope of geographic 

coverage and content will facilitate gathering information 

for programs such as the RPA. 

These initial six states, because of their data system technology and expressed willingness to work together and 

with the federal agencies, are establishing a template for 

data sharing. This template is likely to be adopted by other 

states across the country who recognize the need and advantages of compatible information systems. In the process, 

the states are strengthening their own internal information 

systems through the funding brought by the federal agencies that allows states to convene and share expert advice/

technologies and that provides funds for equipment acquisition, data entry services, and consultation services of a leading university computer research facility. The evaluation of 

this system has demonstrated that this type of dispersed 

information system can be successfully used to analyze 

aquatic species trends across geopolitical boundaries. Considering the value of multi-state data over periods of several 

years, promoting this method of data acquisition and compilation, both for historical data and future data collection, 

can be extremely beneficial to evaluating status and trends 

over long time periods and broad geographic scales.

ACKNOWLEDGMENTS

We would like to thank the following individuals for 

their assistance and for providing information contained 

within this report: Gene Buck, Congressional Research Service; Michael Hansen, College of Natural Resources at 

the University of Wisconsin, Stevens Point; Jack Holcomb, 

U.S. Forest Service, Region 8; Paul Pajak, U.S. Fish and Wildlife Service, Hadley, Massachusetts; Larry Mitzner, Iowa 

Department of Natural Resources; Larry Stolte, U.S. Fish 

and Wildlife Service, Nashua, New Hampshire; Richard 

Bennett, U.S. Fish and Wildlife Service, Hadley, Massachusetts; Wilson Laney, U.S. Fish and Wildlife Service, Raleigh, 

North Carolina; Carol Markham, Maryland Department 

of Natural Resources; Larry McEachron, Texas Parks and 

Wildlife Department; Stan Allen and Duane Anderson, 

Pacific States Marine Fishery Commission; Jeff Waldon, 

Conservation Management Institute, Virginia Tech University; Joe Janisch and the staff at the Arizona Department 

of Fish and Game; and Marjorie Adkins, Alliance for the 

Chesapeake Bay. The manuscript benefitted from reviews 

of earlier drafts provided by: Lane Eskew, U.S. Forest Service, Rocky Mountain Research Station; Hal Schramm, 

American Fisheries Society Fisheries Management Section/

Mississippi Cooperative Fish and Wildlife Research Unit; 

William Taylor and Kurt Newman, Department of Fisheries and Wildlife Michigan State University; Gil Radonski, 

fishery consultant, Swansboro, North Carolina; Vishwanie 

Maharaj, American Sportfishing Association; Clayton J. 

Edwards, U.S. Forest Service, North Central Forest Experiment Station, Rhinelander, Wisconsin; Kathryn Staley, Wildlife Institute, Natural Resources Conservation Service; Rudy 

King, U.S. Forest Service, Rocky Mountain Research Station; 

Dave Darr, U.S. Forest Service, Resource Valuation and Use 

Research; and Linda Langner, U.S. Forest Service, Resource 

Program and Assessment. Special thanks to Michael S. 

Knowles, Materials, Communication and Computers, Inc. 

of America, for database administration and analysis support, and Joyce Van De Water, U.S. Forest Service, Rocky 

Mountain Research Station, for graphics assistance.

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American plaice Hippoglossoides platessoides

American Shad Alosa sapidissima

Arctic Grayling Thymallus arcticus

Atlantic Salmon Salmo salar

Asian Clam Corbicula fluminea

Atlantic Croaker Micropogonias undulatus

Atlantic Sturgeon Acipenser oxyrhynchus

Black Crappie Pomoxis nigromaculatus

Black Sea Bass Centropristis striata

Bluefish Pomatomus saltatrix

Brook Trout Salvelinus fontinalis

Brown Trout Salmo trutta

Chum salmon Oncorhynchus keta

Cod Gadus morhua

Coho salmon Oncorhynchus kisutch

Chinook salmon Oncorhynchus tshawytscha

Crappie Pomoxis spp.

Cutthroat trout Oncorhynchus clarki clarki

Desert Sucker Catostomus clarki

Halibut Hippoglossus hippoglossus

Lake Sturgeon Acipenser fulvescens

Lake Trout Salvelinus namaycush

Largemouth Bass Micropterus salmoides

APPENDIX A—Scientific names of species mentioned in the text.

Common name Scientific name Common name Scientific name

Lingcod Ophiodon elongatus

Mackerel Scomber scombrus

Paddlefish Polyodon spathula

Northern Pike Esox lucius

Red Snapper Lutjanus campechanus

Rainbow Trout Oncorhynchus mykiss

Scup Stenotomus chrysops

Sea Lamprey Petromyzon marinus

Shortnose Sturgeon Acipenser brevirostrum

Smallmouth Bass Micropterus dolomieui

Sockeye salmon Oncorhynchus nerka

Speckled Dace Rhinichthys osculus 

Spiny Dogfish Squalus acanthias

Steelhead trout Oncorhynchus mykiss

Striped Bass Morone saxatilis

Summer Flounder Paralichthys dentatus

Weakfish Cynoscion regalis

White Crappie Pomoxis annularis

Windowpane flounder Scophthalmus aquosus

Winter Flounder Pleuronectes americanus

Witch flounder Glyptocephalus cynoglossus

Yellowtail flounder Pleuronectes ferrugineus

Zebra Mussel Dreissena polymorpha
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