Geology topics

Martin A. Stapanian

Publications and source records attributed to Martin A. Stapanian.

At least 37 records · Page 2Linked to original sources

USGS2014

Polychlorinated biphenyl congener distributions in burbot: evidence for a latitude effect

We compared the distributions of the congeners of polychlorinated biphenyls (PCBs) detected in whole-body samples of burbot ( Lota lota ) from Great Slave Lake and Lake Erie. Total PCB concentrations in Great Slave Lake burbot were about 1/60 of the concentrations in Lake Erie burbot. Burbot from Great Slave Lake contained a higher proportion of lower-chlorinated (2-6 chlorines) congeners than did burbot from Lake Erie; the reverse occurred for more highly chlorinated (7-9 chlorines) congeners. Hexachloro congeners, followed by pentachloro congeners, dominated the proportions of total PCB in burbot from both lakes. There were no differences between sexes in whole-body samples or between gonad and somatic tissues in the proportions of the 39 congeners and three sets of co-eluters detected in burbot from Great Slave Lake. In contrast, there were distinct sex differences in congener distributions for older burbot from Lake Erie. Our results generally supported a prediction of higher proportions of lower-chlorinated PCB homologs in organisms in remote polar areas. However, the latitudinal effect on PCB congener distribution may be more complex than that portrayed in previous studies.

Lake Erie;Great Slave Lake↗

USGS2014

Polychlorinated biphenyl concentrations of burbot Lota lota from Great Slave Lake are very low but vary by sex

Total polychlorinated biphenyl concentrations (ΣPCBs) in whole fish were determined for 18 ripe female burbot Lota lota and 14 ripe male burbot from Great Slave Lake, a lake with no known point sources of PCBs. In addition, ΣPCBs were determined both in the somatic tissue and in the gonads for a randomly selected subset of five females and five males. Mean ΣPCBs for females and males were 2.89 and 3.76 ng/g, respectively. Thus, males were 30 % greater in ΣPCB than females. Based on ΣPCB determinations for somatic tissue and gonads, ΣPCBs of females and males would be expected to decrease by 18 % and increase by 6 %, respectively, immediately after spawning due to release of gametes. Results from a previous study in eastern Lake Erie indicated that males were 28 and 71 % greater in ΣPCB than females from populations of younger (ages 6-13) and older (ages 14-17) burbot, respectively. Thus, although younger burbot from Lake Erie were about 50 times greater in ΣPCB than Great Slave Lake burbot, the relative difference in ΣPCBs between the sexes was remarkably similar across both populations. Our results supported the contention that the widening of the difference in ΣPCBs between the sexes in older burbot from Lake Erie was attributable to a “hot spot” effect operating on older burbot, as Lake Erie has received PCB point source loadings. Our results also supported the contention that male fish expend energy at a rate between 15 and 30 % greater than that of females. Eventually, these results will be useful in developing sex-specific bioenergetics models for fish.

Great Slave Lake;Northwest Territories↗

USGS2013

Temporal changes and sexual differences in spatial distribution of Burbot in Lake Erie

We used GIS mapping techniques to examine capture data for Burbot Lota lota from annual gill-net surveys in Canadian waters of Lake Erie during late August and September 1994–2011. Adult males were captured over a larger area (3–17% for ≥20% maximum yearly catch [MYC]) than adult females. More males than females were caught in the gill nets in 14 of the 15 study years. Collectively, these results support a hypothesis of greater activity by adult males during summer, when Burbot are actively feeding. The area of capture contracted by more than 60% (for ≥20% MYC) for both sexes during the time period, which is consistent with the documented decrease of the Burbot population in the lake. The sex ratio (females: males) varied over the time series but declined steadily from 0.97 in 2001 to 0.59 in 2011. The overlap in the capture areas of adult males and females was scale dependent. The depth distribution at which adult Burbot were caught did not change over the time series, and there was no difference in the median depths (about 30 m) at which adult male and female Burbot were caught. The last results are consistent with the Burbot's reliance on coldwater habitats. Additional research is recommended, including telemetry to describe daily and seasonal movements and assessment of gender bias in active and passive capture gear.

Lake Erie↗

USGS2013

Candidate soil indicators for monitoring the progress of constructed wetlands toward a natural state: a statistical approach

A persistent question among ecologists and environmental managers is whether constructed wetlands are structurally or functionally equivalent to naturally occurring wetlands. We examined 19 variables collected from 10 constructed and nine natural emergent wetlands in Ohio, USA. Our primary objective was to identify candidate indicators of wetland class (natural or constructed), based on measurements of soil properties and an index of vegetation integrity, that can be used to track the progress of constructed wetlands toward a natural state. The method of nearest shrunken centroids was used to find a subset of variables that would serve as the best classifiers of wetland class, and error rate was calculated using a five-fold cross-validation procedure. The shrunken differences of percent total organic carbon (% TOC) and percent dry weight of the soil exhibited the greatest distances from the overall centroid. Classification based on these two variables yielded a misclassification rate of 11% based on cross-validation. Our results indicate that % TOC and percent dry weight can be used as candidate indicators of the status of emergent, constructed wetlands in Ohio and for assessing the performance of mitigation. The method of nearest shrunken centroids has excellent potential for further applications in ecology.

Ohio↗

USGS2013

Presence of indicator plant species as a predictor of wetland vegetation integrity

We fit regression and classification tree models to vegetation data collected from Ohio (USA) wetlands to determine (1) which species best predict Ohio vegetation index of biotic integrity (OVIBI) score and (2) which species best predict high-quality wetlands (OVIBI score >75). The simplest regression tree model predicted OVIBI score based on the occurrence of three plant species: skunk-cabbage (Symplocarpus foetidus), cinnamon fern (Osmunda cinnamomea), and swamp rose (Rosa palustris). The lowest OVIBI scores were best predicted by the absence of the selected plant species rather than by the presence of other species. The simplest classification tree model predicted high-quality wetlands based on the occurrence of two plant species: skunk-cabbage and marsh-fern (Thelypteris palustris). The overall misclassification rate from this tree was 13 %. Again, low-quality wetlands were better predicted than high-quality wetlands by the absence of selected species rather than the presence of other species using the classification tree model. Our results suggest that a species’ wetland status classification and coefficient of conservatism are of little use in predicting wetland quality. A simple, statistically derived species checklist such as the one created in this study could be used by field biologists to quickly and efficiently identify wetland sites likely to be regulated as high-quality, and requiring more intensive field assessments. Alternatively, it can be used for advanced determinations of low-quality wetlands. Agencies can save considerable money by screening wetlands for the presence/absence of such “indicator” species before issuing permits.

Ohio↗

USGS2013

Disturbance metrics predict a wetland Vegetation Index of Biotic Integrity

Indices of biological integrity of wetlands based on vascular plants (VIBIs) have been developed in many areas in the USA. Knowledge of the best predictors of VIBIs would enable management agencies to make better decisions regarding mitigation site selection and performance monitoring criteria. We use a novel statistical technique to develop predictive models for an established index of wetland vegetation integrity (Ohio VIBI), using as independent variables 20 indices and metrics of habitat quality, wetland disturbance, and buffer area land use from 149 wetlands in Ohio, USA. For emergent and forest wetlands, predictive models explained 61% and 54% of the variability, respectively, in Ohio VIBI scores. In both cases the most important predictor of Ohio VIBI score was a metric that assessed habitat alteration and development in the wetland. Of secondary importance as a predictor was a metric that assessed microtopography, interspersion, and quality of vegetation communities in the wetland. Metrics and indices assessing disturbance and land use of the buffer area were generally poor predictors of Ohio VIBI scores. Our results suggest that vegetation integrity of emergent and forest wetlands could be most directly enhanced by minimizing substrate and habitat disturbance within the wetland. Such efforts could include reducing or eliminating any practices that disturb the soil profile, such as nutrient enrichment from adjacent farm land, mowing, grazing, or cutting or removing woody plants.

Ecological Indicators↗

USGS2013

Introduction to a special section: Ecology, culture, and management of Burbot

The Burbot Lota lota is the only truly freshwater member of the cod family (Gadidae) and one of only two species of freshwater fish that have a circumpolar range (McPhail and Lindsey 1970; McPhail and Paragamian 2000). Two subspecies of Lota lota have been documented: Lota lota maculosa, which is found exclusively in North America from south of Great Slave Lake in Canada to the southern limit of its range; and Lota lota lota, which is found over the remainder of the species’ Nearctic range and its entire Eurasian range (Hubbs and Schultz 1941; Van Houdt et al. 2003). However, many recent authorities (e.g., Scott and Crossman 1973) do not designate subspecies. Burbot occupy the widest range of depths of all fishes found in the Laurentian Great Lakes basin (i.e., from small streams to at least 300 m in Lake Superior; Boyer et al. 1989). Worldwide, many Burbot populations are threatened or endangered or have been extirpated (reviewed by Stapanian et al. 2010). Due in part to its unpopularity as a sport and commercial fish in much of its range, the species is often ignored in fish management and conservation programs (McPhail and Paragamian 2000; Stapanian et al. 2008, 2010). Even basic information on Burbot ecology, particularly its early life history and spawning habitats and sites, is lacking. This lack of information is particularly troubling because Burbot are an indicator of the health of coldwater systems (Stapanian et al. 2010). Efforts to rehabilitate or restore imperiled populations include culturing early life stages. Burbot larvae are difficult to culture for a variety of reasons, including their delicate body structure, small size at hatch, and live-feed requirement for at least 5 weeks following alimentary tract development.

Transactions of the American Fisheries Society↗

USGS2013

Effects of dreissenids on monitoring and management of fisheries in western Lake Erie

Water clarity increased in nearshore areas of western Lake Erie by the early-1990s mainly as a result of the filtering activities of dreissenid mussels (Dreissena spp.), which invaded in the mid-1980s. We hypothesized that increased water clarity would result in greater trawl avoidance and thus reduced ability to capture fish in bottom trawls during daytime compared to nighttime. We examined this hypothesis by summarizing three analyses on fish data collected in western Lake Erie. First, we used a two-tiered modeling approach on the ration (R) of catch per hour (CPH) of age-0 yellow perch (Perca flavencens Mitchell) at night to CPH during daytime in 1961-2005. The best a priori and a posteriori models indicated a shift to higher CPH at night (R > 1) between 1990 and 1991, which corresponded to 3 years after the dreissenid invasion and when water clarity noticeably increased at nearshore sites. Secondly, we examined effects of nighttime sampling on estimates of abundance of age-2 and older yellow perch, which form the basis for recommended allowable harvest (RAH). When data from night sampling were included in models that predict abundance of age-2 yellow perch from indices of abundance of age-0 and age-1 yellow perch, predicted abundance was lower and model precision, as measured by r-squared, was higher compared to models that excluded data collected at night. Furthermore, the use of only CPH data collected at night typically resulted in lower estimates of abundance and more precise models compared to models that included CPH data collected during both daytime and nighttime. Thirdly, we used presence/absence data from paired bottom trawl samples to calculate an index of capture probability (or catchability) to determine if our ability to capture the four most common benthic species in western Lake Erie was affected by dreissenid-caused increased water clarity. Three species of fish(white perch, Morone americana Gmelin; yellow perch; and trout-perch, Percopsis omiscomaycus Walbaum) had lower mean daytime catchability than nighttime catchability after dreissenids became established, which supported the hypothesis of greater trawl avoidance during daytime following establishment of dreissenids. Results from freshwater drum (Aplodinotus grunniens Rafinesque) were opposite those of the other three species, which may be a result of behavioral shifts due to freshwater drum feeding on dreissenids mussels. Collectively, these three studies suggest that dreissenids indirectly affected our ability to assess fish populations, which further affects estimates of fish densities and relationships between indices of abundance and true abundance.

Lake Erie↗

USGS2012

A prototype splitter apparatus for dividing large catches of small fish

Due to financial and time constraints, it is often necessary in fisheries studies to divide large samples of fish and estimate total catch from the subsample. The subsampling procedure may involve potential human biases or may be difficult to perform in rough conditions. We present a prototype gravity-fed splitter apparatus for dividing large samples of small fish (30–100 mm TL). The apparatus features a tapered hopper with a sliding and removable shutter. The apparatus provides a comparatively stable platform for objectively obtaining subsamples, and it can be modified to accommodate different sizes of fish and different sample volumes. The apparatus is easy to build, inexpensive, and convenient to use in the field. To illustrate the performance of the apparatus, we divided three samples (total N = 2,000 fish) composed of four fish species. Our results indicated no significant bias in estimating either the number or proportion of each species from the subsample. Use of this apparatus or a similar apparatus can help to standardize subsampling procedures in large surveys of fish. The apparatus could be used for other applications that require dividing a large amount of material into one or more smaller subsamples.

North American Journal of Fisheries Management↗

USGS2011

Trends in Benthic macroinvertebrate community Biomass and Energy Budgets in Lake Sevan, 1928-2004

Water levels of Lake Sevan (Armenia) were artificially lowered by nearly 20 m between 1949 and 1997. Lowered water levels, combined with increased eutrophication, were associated with seasonally anoxic conditions (lasting 1–4 months) near the bottom of the profundal zone each year during 1976–2004. In addition, the extents of the macrophyte zone and of certain substrate types were severely reduced following drawdown. Maximal depth of occurrence decreased by 2–44 m for at least for 50 species of benthic macroinvertebrates between 1982 and 2004 compared to 1937–1961. Species richness of benthic macroinvertebrates declined from 25 to three species at depths where seasonal anoxia occurred. Total biomass increased by a factor of 10 from the period 1928–1948 to 1976–1979 then declined by a factor of 3 to 4 between 1987 and 2004. Energy flow through detritivores was more than tripled during 1976–2004 compared to 1928–1971, a result of increased plankton primary production. In contrast, energy flow through herbivorous benthic macroinvertebrates decreased by a factor of nearly 5, due to reduced areal coverage of macrophytes. Energy flow through filter feeders did not change over the time period examined, but energy flow through the entire zoobenthos community was nearly tripled. The biomasses of Oligochaeta, Chironomidae, and total zoobenthos showed a delayed response to changes in primary production of 7–9, 2, and 2–4 years, respectively. These patterns may provide a basis to predict results of restoration efforts based on the abundance of the zoobenthos in future years as the level of the lake is restored and water quality improves.

Environmental Monitoring and Assessment↗

USGS2011

Influence of dreissenid mussels on catchability of benthic fishes in bottom trawls

Inferring trends in true abundance of fish populations from catch per unit effort data requires either the knowledge of capture probability or the assumption that it is constant, both of which are unlikely contingencies. We developed and validated an index of catchability (a proxy measure for capture probability) from a long-term data set describing nearshore waters of western Lake Erie, and we used the index to test the hypothesis that catchability of four abundant benthic species captured in bottom trawls changed after the invasion of dreissenid mussels. We estimated daytime and nighttime catchability for 1972–1990 (predreissenid period) and 1991–2009 (dreissenid period); we then tested for differences between nighttime and daytime catchability in the predreissenid and dreissenid periods and the nighttime–daytime differential in catchability during the dreissenid period. We also tested relationships between Secchi depth and the catchability index via linear regression. Catchability indices for white perch Morone americana, yellow perch Perca flavescens, and trout-perch Percopsis omiscomaycus did not differ between daytime and nighttime during the predreissenid period. After establishment of dreissenids, all three of these species had lower daytime catchability than nighttime catchability and had positive nighttime–daytime differentials, indicating a shift toward higher nighttime catchability relative to daytime catchability. Changes in catchability indices for freshwater drum Aplodinotus grunniens were opposite the changes observed for the other three species, possibly because the freshwater drum is the only species that actively feeds on dreissenids. Catchability indices were negatively related to water clarity (Secchi depth) for three of the species. Our results are consistent with the hypothesis that catchability of the four most common benthic fish species captured in bottom trawls within nearshore waters of western Lake Erie changed after the dreissenid invasion because of increased water clarity and increased visibility, which led to greater daytime trawl avoidance.

Transactions of the American Fisheries Society↗

USGS2010

Rehabilitation for bilateral amputation of fingers

We describe reconstructive surgeries, therapy, prostheses, and adaptations for a patient who experienced bilateral amputation of all five fingers of both hands through the proximal phalanges in January 1992. The patient made considerable progress in the use of his hands in the 10 mo after amputation, including nearly a 120% increase in the active range of flexion of metacarpophalangeal joints. In late 1992 and early 1993, the patient had "on-top plasty" surgeries, in which the index finger remnants were transferred onto the thumb stumps, performed on both hands. The increased web space and functional pinch resulting from these procedures made many tasks much easier. The patient and occupational therapists set challenging goals at all times. Moreover, the patient was actively involved in the design and fabrication of all prostheses and adaptations or he developed them himself. Although he was discharged from occupational therapy in 1997, the patient continues to actively find new solutions for prehension and grip strength 18 yr after amputation.

American Journal of Occupational Therapy↗

USGS2010

QuickBird satellite imagery as a tool for restoration and rehabilitation of Lake Sevan, Armenia

Lake Sevan in Armenia is the largest freshwater lake in the Transcaucasus region and is one of the largest high-altitude freshwater lakes in Eurasia (Babayan et al., 2006 ). Armenia is a small (29,743 km 2 ), land- locked country that is comparatively poor in natural resources and nearly surrounded by borders that are blockaded by its neighbors (Babayan et al., 2006 ; Rhoades, 2008 and references therein; CIA, 2010 ). Despite these obstacles, ecological research and environmental restoration efforts continue. For the most part, ecological research in Lake Sevan during the twentieth century was restricted to Soviet-era journals, or was otherwise unavailable to western scientists.

Lake Sevan↗

USGS2010

Worldwide status of burbot and conservation measures

Although burbot ( Lota lota Gadidae ) are widespread and abundant throughout much of their natural range, there are many populations that have been extirpated, endangered or are in serious decline. Due in part to the species’ lack of popularity as a game and commercial fish, few regions consider burbot in management plans. We review the worldwide population status of burbot and synthesize reasons why some burbot populations are endangered or declining, some burbot populations have recovered and some burbot populations do not recover despite management measures. Burbot have been extirpated in much of Western Europe and the United Kingdom and are threatened or endangered in much of North America and Eurasia. Pollution and habitat change, particularly the effects of dams, appear to be the main causes for declines in riverine burbot populations. Pollution and the adverse effects of invasive species appear to be the main reasons for declines in lacustrine populations. Warmer water temperatures, due either to discharge from dams or climate change, have been noted in declining burbot populations at the southern extent of their range. Currently, fishing pressure does not appear to be limiting burbot populations world-wide. We suggest mitigation measures for burbot population recovery, particularly those impacted by dams and invasive species.

Fish and Fisheries↗

USGS2009

Change in diel catchability of young-of-year yellow perch associated with establishment of dreissenid mussels

1. Non-native mussels have increased water clarity in many lakes and streams in North America and Europe. Diel variation in catchability of some fish species has been linked to visibility during survey trawls (used to measure escapement). 2. Water clarity increased in nearshore areas of western Lake Erie by the early 1990s, following passage of legislation in 1972 to improve water quality (e.g. reduce phosphorus loading) and the invasion of dreissenid mussels ( Dreissena spp. ) beginning in 1987. 3. We hypothesised that increased water clarity in Lake Erie resulted in decreased catchability of young-of-year (age-0) yellow perch ( Perca flavescens Mitchill) during daylight compared to during night. We used a two-tiered modelling approach to test this hypothesis on the ratio ( R ) of catch per hour (CPH) during night to CPH during daylight in bottom trawl surveys conducted during 1961-2005. 4. First, we examined seven a priori models. The first model, the 'null' model, represented no change in R over time. Three more models tested whether the timing of the change in R was associated with passage of water quality legislation only, dreissenids only (two-period models) and both legislation and dreissenids (three-period models). Three additional models included a 3-year lag before the effects of legislation, dreissenids or both occurred. Secondly, all possible two- and three-period models with a minimum of 2 years per time period were explored a posteriori . The a posteriori procedure determined the temporal transitions to higher R that were best supported by the data, without regard to a priori hypotheses. 5. Night CPH was greater than daylight CPH in 3 of 11 years during 1961-72, in 10 of 15 years during 1973-87, and in 14 of 18 years during 1988-2005. During 1991-2005 night CPH exceeded daylight CPH in all years except one, and night CPH was more than twice daylight CPH in 10 years during this period. 6. The best a priori model had two periods, with a break between 1990 and 1991, corresponding to 3 years after the dreissenid invasion. Similarly, the best two- and three-period a posteriori models both had breaks between 1990 and 1991. The results supported our hypothesis that age-0 yellow perch exhibited a transition to lower catchability during daylight compared to night, and the timing of the transition coincided with the establishment of dreissenid mussels. 7. The most plausible mechanism for our results was increased visibility of the trawl during daylight, resulting in increased avoidance of the trawl. These results have potential applications wherever non-native mussels have increased water clarity.

Freshwater Biology↗

USGS2009

Ages and lengths of yellow perch Perca flavescens , white perch Morone americana , and lake whitefish Coregonus clupeaformis in commercial trap nets in western Lake Erie

We collected samples of yellow perch (Perca flavescens) and white perch (Morone americana) in spring, and of lake whitefish (Coregonus clupeaformis) in autumn, from commercial trap nets set in western Lake Erie in 2008. The yellow perch sample (N = 153) was dominated (72%, of the total sample) by the 2003 year class, followed by the 2005 year class (12%). The white perch sample (N = 201) was dominated by the 2005 year class (39% of the total sample), followed by the 2003 year class (23%). The lake whitefish (N = 99) sample was dominated by the 2003 year class (75%) followed by the 2001 year class (10%). For yellow perch (both sexes in spring, analyzed separately) and lake whitefish (males in autumn), mean total length at age 5 was the same for the 2001 year class (calculated from historical data) and the 2003 year class.

Lake Erie↗

USGS2009

Surveillance and status of fish stocks in western Lake Erie, 2008

The Lake Erie Biological Station has conducted bottom trawl assessments of fish populations in western Lake Erie near East Harbor State Park, Ohio each summer and autumn since 1961. The catches of most age-0 forage fishes in 2008 were less than their 15-year means. Mean densities for five species exceeded the long term mean. Mean density of age-0 white perch Morone americana was more than double last year’s mean and the long-term mean. Densities of both yellow perch Perca flavescens and walleye Sander vitreus were at or above their long term mean. Catches of round goby Neogobius melanostomus (all ages combined) exceeded the previous five years, but were substantially below the species’ 13-year (1996-2008) mean. For five species, mean total lengths of age-0 individuals captured in 2008 were greater than their respective 20-year means. During 1988-2007, the frequency of occurrence for yellow perch diet items was highest for benthic invertebrates and zooplankton during the summer and benthic invertebrates in autumn. During summer zooplankton and benthic invertebrates were frequently consumed by white perch. Benthic prey for white perch occurred more frequently in the last 5-10 years.

Lake Erie↗

USGS2007

Restoration and rehabilitation of native species in the Great Lakes: Overview

The Laurentian Great Lakes have undergone many changes, both abiotic and biotic, since the early 1900s. Some positive changes have been the relatively recent recovery of some native species and habitats and a concentrated effort toward the recovery of others. The papers in this issue address some of these recoveries and recovery efforts. In addition, an objective of this issue was to communicate ideas and attention to additional research needs. To this end, authors were encouraged to provide novel analyses and hypotheses based on examination of long-term data and reviews of appropriate literature.

Journal of Great Lakes Research↗