Thomas R. Whittier

Introduced Fish in Northeastern USA Lakes: Regional Extent, Dominance, and Effect on Native Species Richness

Abstract We assessed the effects of nonnative fish on native fish biodiversity, using assemblage data collected during 1991–1996 from 203 randomly selected lakes in the northeastern USA by the Environmental Monitoring and Assessment Program (EMAP) of the U.S. Environmental Protection Agency. An estimated 74% (±17.6%, 95% confidence interval) of the regions 10,608 lakes between 1 and 10,000 ha contain at least one introduced species. Based on our samples, nonnative individuals outnumbered natives in an estimated 31.5% (±11%) of lakes. Regression models indicated that native, introduced, and total species richness were associated with lake surface area, elevation, and lake depth (0.31 ≤ R 2 ≤ 0.81). The intensity of human disturbance in the watershed was positively associated with introduced species richness but not associated with native species richness. The number of nonnative species was a significant variable in the native-species regression models for the entire Northeast and for only one of five sub...

A regional framework for establishing recovery criteria

Effective assessments of aquatic ecosystem recovery require ecologically sound endpoints against which progress can be measured. Site-by-site assessments of end points and potential recovery trajectories are impractical for water resource agencies. Because of the natural variation among ecosystems, applying a single set of criteria nationwide is not appropriate either. This article demonstrates the use of a regional framework for stratifying natural variation and for determining realistic biological criteria. A map of ecoregions, drawn from landscape characteristics, formed the framework for three statewide case studies and three separate studies at the river basin scale. Statewide studies of Arkansas, Ohio, and Oregon, USA, streams demonstrated patterns in fish assemblages corresponding to ecoregions. The river basin study in Oregon revealed a distinct change at the ecoregion boundary; those in Ohio and Montana demonstrated the value of regional reference sites for assessing recovery. Ecoregions can be used to facilitate the application of ecological theory and to set recovery criteria for various regions of states or of the country. Such a framework provides an important alternative between site-specific and national approaches for assessing recovery rates and conditions.

Indicators of Ecological Stress and Their Extent in the Population of Northeastern Lakes: A Regional-Scale Assessment

Article reporting findings from the Environmental Protection Agency (EPA)s Environmental Monitoring and Assessment Program (EMAP) conducted on a sample of lakes in the Northeastern United States from 1991 to 1996.

Evaluation of a Backpack Electrofishing Unit for Multiple Lake Surveys of Fish Assemblage Structure

Abstract We evaluated the effectiveness of a portable, backpack electrofishing unit, used from a small boat, for sampling fish assemblage structure in 11 lakes in the northeastern United States. Samples collected with a boat-mounted, 350-W backpack unit (EF-BP) were compared with samples taken by (1) two 5,000-W electrofishing units, (2) gill nets, (3) trap nets and minnow traps, and (4) seines. The EF-BP was more effective than the nonelectrofishing gears, capturing a mean of 79% of a lakes documented fish species pool. Gill nets, beach seines, and trap nets captured, on average, about 50% of the species; minnow traps were least efficient. With identical transect times, the EF-BP was as effective as a standard barge-mounted electrofishing unit for capturing species and numbers of individuals. At three low-conductivity lakes, the EF-BP collected fewer species and individuals than a semiportable 5,000-W unit but was more effective than any of the nonelectrofishing gears. Analysis of species accumulation c...

Regional Susceptibility of Northeast Lakes to Zebra Mussel Invasion

Abstract The rapid spread of the exotic zebra mussel (Dreissena polymorpha) concerns aquatic resource managers in the United States and Canada. Since 1990, it has been spreading from the Great Lakes into the Northeast. The zebra mussel cannot colonize equally in northeastern lakes in part because soft water causes ion exchange and reproductive problems when [Ca2+] reaches a lower limit of approximately 12 mg/L, and pH drops below 7.3. We used (1) an alkalinity map to conservatively delineate areas expected to be at low risk for zebra mussel invasion and (2) water chemistry data from 344 lakes sampled in the 1991–1994 Environmental Monitoring and Assessment Program (EMAP) to estimate numbers and surface area of lakes at risk in the Northeast (New England, New York, and New Jersey). These lakes were randomly selected from a target population of 11,080 lakes > 1 and < 10,000 ha using a probability design that allowed inference to all lakes in the region with known confidence. An estimated 25% (2,770 SE = 410...

A comparison of impoundments and natural drainage lakes in the Northeast USA

We classified 235 randomly selected lentic waterbodies (>1 ha) in the Northeast USA as human created, or natural. We compared geographic extent and distribution, morphology and hydrology, trophic state, and fish assemblage metrics of impoundments and natural drainage lakes. We estimated that 46% of the 10 608 (±1695; 95% CI) lentic waterbodies in the region were impoundments or quarries; 68% of Uplands lakes and 26% of Lowlands lakes were natural. Impoundments were smaller, shallower, had shorter water residence times, and were in watersheds with greater human activity than were natural drainage lakes. More than half (55%) of Lowlands impoundments were eutrophic, accounting for 67% of eutrophic or hypereutrophic lentic waterbodies in the Northeast. An estimated 90% of eutrophic lakes and impoundments were <23 ha. Impoundments had greater proportions of fish species and individuals tolerant of human disturbance, and greater proportions of non-native species and individuals than did natural drainage lakes. We discuss some management implications of the differences between impoundments and natural drainage lakes.

DISTRIBUTIONS OF LAKE FISHES IN THE NORTHEAST — II. THE MINNOWS (CYPRINIDAE)

Abstract We discuss the distribution and native status of 24 minnow species (family: Cyprinidae) collected at 203 randomly selected lakes in the northeastern USA (New England, New York, New Jersey) by the Environmental Monitoring and Assessment Program (EMAP). Twenty-four species were collected during the summers of 1991–96. Only golden shiner was frequently collected, occurring in 71% of the sampled lakes. Fallfish, creek chub, and common shiner were also common. The remaining species were taken in <10% of the lakes. Physical (surface area, depth, elevation), chemical (pH, total phosphorus), and watershed disturbance characteristics of the lakes show distinct species-specific patterns. Evidence suggests that native minnow biodiversity has declined over the last 150 years as a result of changing biotic, physical, chemical, and watershed characteristics.

DISTRIBUTIONS OF LAKE FISHES OF THE NORTHEAST USA — III. SALMONIDAE AND ASSOCIATED COLDWATER SPECIES

Abstract We present distributional maps and discuss native status for fish species characteristic of coldwater lakes, sampled from 203 randomly selected lakes in the northeastern USA (New England, New York, New Jersey). Eleven coldwater fish species from four families (Salmonidae, Osmeridae, Gadidae, Cottidae) were collected during the summers of 1991 to 1996 by the Environmental Monitoring and Assessment Program (EMAP). The most widespread species were brook trout and rainbow smelt, collected at 23% and 18% of the sampled lakes, respectively. Stocked (put-and-take) rainbow trout occurred at 10% of the lakes, while the remaining fish species (brown trout, landlocked Atlantic salmon, lake trout, Arctic char, lake whitefish, cisco, burbot, slimy sculpin) were collected at less than 6% of the lakes. We also provide comparative data on physical (surface area, depth, elevation), chemical (pH and total phosphorus), and watershed characteristics of the lakes where these species were collected.

FIRST RECORDS OF REDEAR SUNFISH (LEPOMIS MICROLOPHUS) IN NEW ENGLAND

We report the first records of redear sunfish Lepomis microlophus in the northeastern United States, north of Pennsylvania. During the summer of 1991, the US EPAs Environmental Monitoring and Assess? ment Program (EMAP; Whittier and Paulsen 1992) conducted a pilot survey of 19 lakes in New England. At two lakes in northeastern Vermont the field crew identified an unknown Lepomis. As part of EMAPs quality assurance procedures, samples of all species were routinely vouchered and sent to the Museum of Comparative Zoology (MCZ) at Harvard University to verify field identifications, and for archiving. Field notes were not sent with the vouchers. At the museum, KEH identified redear sunfish L. microlophus (Gunther) and pumpkinseed L. gibbosus (Linnaeus) from among the Lepomis vouchers from these two lakes. Dr. Reeve Bailey at the University of Michigan con? firmed the L. microlophus identifications and noted that, based on scale counts, the specimens originated from the eastern U.S. population and

DISTRIBUTIONS OF LAKE FISHES IN THE NORTHEAST — IV: BENTHIC AND SMALL WATER-COLUMN SPECIES

Abstract Using data collected at 203 randomly selected lakes in eight states in northeastern USA, we present maps of distributions and native status for 28 fish species: 15 benthic species in five families, 11 small water-column feeders in six families, and two large piscivores. Brown bullhead and white sucker were among the most widespread lake-dwelling fishes, and were collected in 69% and 56% of the sampled lakes. Banded killifish, American eel, and yellow bullhead were collected in 26%, 19% and 17% of sampled lakes respectively. The remaining species were collected in <8% of the sampled lakes. Many of the species that were uncommon in this survey have limited distributions in the Northeast or are more commonly found in streams than in lakes. Seven species discussed in this article are Mississippian and were only collected in Cross Lake, NY. We also present a summary of the extent, geographic distributions, and native status of all 88 fish species collected in the EMAP – Northeast Lakes Project.