Geology topics

Jean V. Adams

Publications and source records attributed to Jean V. Adams.

At least 55 records · Page 3Linked to original sources

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

Use of classification trees to apportion single echo detections to species: Application to the pelagic fish community of Lake Superior

Acoustic methods are used to estimate the density of pelagic fish in large lakes with results of midwater trawling used to assign species composition. Apportionment in lakes having mixed species can be challenging because only a small fraction of the water sampled acoustically is sampled with trawl gear. Here we describe a new method where single echo detections (SEDs) are assigned to species based on classification tree models developed from catch data that separate species based on fish size and the spatial habitats they occupy. During the summer of 2011, we conducted a spatially-balanced lake-wide acoustic and midwater trawl survey of Lake Superior. A total of 51 sites in four bathymetric depth strata (0–30 m, 30–100 m, 100–200 m, and >200 m) were sampled. We developed classification tree models for each stratum and found fish length was the most important variable for separating species. To apply these trees to the acoustic data, we needed to identify a target strength to length (TS-to-L) relationship appropriate for all abundant Lake Superior pelagic species. We tested performance of 7 general (i.e., multi-species) relationships derived from three published studies. The best-performing relationship was identified by comparing predicted and observed catch compositions using a second independent Lake Superior data set. Once identified, the relationship was used to predict lengths of SEDs from the lake-wide survey, and the classification tree models were used to assign each SED to a species. Exotic rainbow smelt (Osmerus mordax) were the most common species at bathymetric depths <100 m with their population estimated at 755 million (3.4 kt). Kiyi (Coregonus kiyi) were the most abundant species at depths >100 m (384 million; 6.0 kt). Cisco (Coregonus artedi) were widely distributed over all strata with their population estimated at 182 million (44 kt). The apportionment method we describe should be transferable to other large lakes provided fish are not tightly aggregated, and an appropriate TS-to-L relationship for abundant pelagic fish species can be determined.

Lake Superior↗

USGS2013

A spatial age-structured model for describing sea lamprey ( Petromyzon marinus ) population dynamics

The control of invasive sea lampreys ( Petromyzon marinus ) presents large scale management challenges in the Laurentian Great Lakes. No modeling approach has been developed that describes spatial dynamics of lamprey populations. We developed and validated a spatial and age-structured model and applied it to a sea lamprey population in a large river in the Great Lakes basin. We considered 75 discrete spatial areas, included a stock-recruitment function, spatial recruitment patterns, natural mortality, chemical treatment mortality, and larval metamorphosis. Recruitment was variable, and an upstream shift in recruitment location was observed over time. From 1993–2011 recruitment, larval abundance, and the abundance of metamorphosing individuals decreased by 80, 84, and 86%, respectively. The model successfully identified areas of high larval abundance and showed that areas of low larval density contribute significantly to the population. Estimated treatment mortality was less than expected but had a large population-level impact. The results and general approach of this work have applications for sea lamprey control throughout the Great Lakes and for the restoration and conservation of native lamprey species globally.

Great Lakes↗

USGS2013

Evaluating analytical approaches for estimating pelagic fish biomass using simulated fish communities

Pelagic fish assessments often combine large amounts of acoustic-based fish density data and limited midwater trawl information to estimate species-specific biomass density. We compared the accuracy of five apportionment methods for estimating pelagic fish biomass density using simulated communities with known fish numbers that mimic Lakes Superior, Michigan, and Ontario, representing a range of fish community complexities. Across all apportionment methods, the error in the estimated biomass generally declined with increasing effort, but methods that accounted for community composition changes with water column depth performed best. Correlations between trawl catch and the true species composition were highest when more fish were caught, highlighting the benefits of targeted trawling in locations of high fish density. Pelagic fish surveys should incorporate geographic and water column depth stratification in the survey design, use apportionment methods that account for species-specific depth differences, target midwater trawling effort in areas of high fish density, and include at least 15 midwater trawls. With relatively basic biological information, simulations of fish communities and sampling programs can optimize effort allocation and reduce error in biomass estimates.

Canadian Journal of Fisheries and Aquatic Sciences↗

USGS2012

Status and trends of prey fish populations in Lake Michigan, 2012

The U.S. Geological Survey Great Lakes Science Center has conducted lake-wide surveys of the fish community in Lake Michigan each fall since 1973 using standard 12-m bottom trawls towed along contour at depths of 9 to 110 m at each of seven index transects. The resulting data on relative abundance, size and age structure, and condition of individual fishes are used to estimate various population parameters that are in turn used by state and tribal agencies in managing Lake Michigan fish stocks. All seven established index transects of the survey were completed in 2012. The survey provides relative abundance and biomass estimates between the 5-m and 114-m depth contours of the lake (herein, lake-wide) for prey fish populations, as well as burbot, yellow perch, and the introduced dreissenid mussels. Lake-wide biomass of alewives in 2012 was estimated at 9 kilotonnes (kt, 1 kt = 1000 metric tonnes), which continues the trend of unusually low alewife biomass since 2004 but represented a 20% increase from the 2011 estimate. The age distribution of alewives larger than 100 mm was dominated (i.e., 84%) by age-2. Record low biomass was observed for several species, including bloater (0.4 kt), rainbow smelt (0.1 kt), deepwater sculpin (1.5 kt), and ninespine stickleback (0.01 kt). Slimy sculpin lake-wide biomass was 0.73 kt in 2012, which was the third consecutive year revealing a decline. Estimated biomass of round goby increased by 79% to 3 kt. Burbot lake-wide biomass (0.5 kt in 2012) has remained below 3 kt since 2001. Numeric density of age-0 yellow perch (i.e., < 100 mm) was only 2 fish per ha, which is indicative of a relatively poor year-class. Lake-wide biomass estimates of dreissenid mussels have continued to increase from 2010, from 12 to 95 kt in 2012. Overall, the total lake-wide prey fish biomass estimate (sum of alewife, bloater, rainbow smelt, deepwater sculpin, slimy sculpin, round goby, and ninespine stickleback) in 2012 was 15 kt, which represented the lowest total biomass of the time series.

Lake Michigan↗

USGS2011

Long-term trends in habitat use of offshore demersal fishes in western Lake Huron suggest large-scale ecosystem change

We estimated mean depths of capture for offshore demersal fish species, grouped into three habitat-based guilds (shallow benthic, pelagic, and deep benthic), using fall bottom trawl data (27–73 m) in the western main basin of Lake Huron from 1976 to 2007. The mean depth of capture of the shallow and deep benthic guilds initially exhibited a trend toward capture in shallower water, switched to a trend toward capture in deeper water in 1991, and changed back to a trend toward capture in shallower water in 2001–2002. Species in the pelagic guild showed a similar pattern, but the initial change point occurred in 1981 for this guild. Individual species in these guilds showed variable patterns of depth distribution, but a feature common to all guilds and all pelagic and deep benthic species was a change to a trend toward capturing fish in shallower water that occurred nearly simultaneously (1999–2002). These common trends suggest that large-scale factors are affecting the habitat use of offshore demersal fish species in Lake Huron. The depth distributions of the three guilds have converged in recent years, indicating that the locations of suitable habitat for offshore demersal fishes may be changing. Our results indicate that the benthic ecology of the western main basin of Lake Huron is undergoing profound changes across a large spatial scale that are affecting the habitat use of offshore demersal fishes. We suggest that these changes are related to recent invasions of exotic species.

Lake Huron↗

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

Status and trends of prey fish populations in Lake Michigan, 2008

The Great Lakes Science Center (GLSC) has conducted lake-wide surveys of the fish community in Lake Michigan each fall since 1973 using standard 12-m bottom trawls towed along contour at depths of 9 to 110 m at each of seven index transects. The resulting data on relative abundance, size structure, and condition of individual fishes are used to estimate various population parameters that are in turn used by state and tribal agencies in managing Lake Michigan fish stocks. All seven established index transects of the survey were completed in 2008. The survey provides relative abundance and biomass estimates between the 5-m and 114-m depth contours of the lake (herein, lake-wide) for prey fish populations, as well as burbot, yellow perch, and the introduced dreissenid mussels. Lake-wide biomass of alewives in 2008 was estimated at 8.27 kilotonnes (kt) (1 kt = 1000 metric tons), which was the smallest biomass estimate in the entire time series and 29% lower than the 2007 estimate. Lake-wide biomass of bloater in 2008 was estimated at 3.33 kt, which was the lowest estimate since 1977 and 38% lower than the 2007 estimate. Rainbow smelt lake-wide biomass equaled 0.89 kt, which was only 0.01 kt higher than 2007, which is the lowest estimate in the time series. Deepwater sculpin lake-wide biomass equaled 5.23 kt, which is the fourth straight year of declining biomass. The 2008 estimate is the second smallest in the time series, and 39% lower than the 2007 estimate. Slimy sculpin lake-wide biomass remained relatively high in 2008 (2.75 kt), increasing 25% over 2007. Ninespine stickleback lake-wide biomass equaled only 0.50 kt in 2008, which was 79% lower than the 2007 estimate. The final prey fish, exotic round goby, increased two orders of magnitude between 2007 and 2008, from 0.02 to 4.65 kt. Round gobies now represent 18% of the prey fish biomass. Burbot lake-wide biomass (0.91 kt in 2008) has remained fairly constant since 2002. Numeric density of age-0 yellow perch (i.e., < 100 mm) equaled 0.7 fish per ha, which is indicative of a relatively poor year-class. Lake-wide biomass of dreissenid mussels dropped precipitously in 2008, down to 9.47 kt, and a 96% decline from the 2007 biomass estimate. Overall, the total lake-wide prey fish biomass estimate (sum of alewife, bloater, rainbow smelt, deepwater sculpin, slimy sculpin, round goby, and ninespine stickleback) in 2008 was 25.62 kt, which was the lowest observed since the survey began in 1973.

Lake Michigan↗

USGS2005

Modeling the suppression of sea lamprey populations by use of the male sex pheromone

The suppression of sea lamprey populations, Petromyzon marinus (Linnaeus), was modeled using four different applications of the male sex pheromone: (1) pheromone-baited traps that remove females from the spawning population, (2) pheromone-baited decoys that exhaust females before they are able to spawn, (3) pheromone-enhanced sterile males that increase the proportion of non-fertile matings, and (4) camouflaging of the pheromone emitted by calling males to make it difficult for females to find a mate. The models indicated that thousands of traps or hundreds of thousands of decoys would be required to suppress a population of 100,000 animals. The potential efficacy of pheromone camouflages is largely unknown, and additional research is required to estimate how much pheromone is needed to camouflage the pheromone plumes of calling males. Pheromone-enhanced sterile males appear to be a promising application in the Great Lakes. Using this technique for three generations each of ca. 7 years duration could reduce sea lamprey populations by 90% for Lakes Huron and Ontario and by 98% for Lake Michigan, based on current trapping operations that capture 20 to 30% of the population each year.

Journal of Great Lakes Research↗

USGS2005

Embryonic developmental progression in lake trout ( Salvelinus namaycush ) (Walbaum, 1792) and its relation to lake temperature

Developmental progression of lake trout ( Salvelinus namaycush ) embryos was examined with light and scanning electron microscopy. From this examination, key developmental stages were described in detail. The key developmental stages were then applied to individual lake trout egg lots incubated in constant temperatures of 2, 4, 6, 8, and 10°C. We used Belehradek's, Thermodynamic, and Power models, and also developed the Zero model to determine stage specific developmental rates of lake trout eggs for each background temperature. From the models, hatch dates and staging were predicted for temperature regimes from Lake Superior (1990–91) and Lake Huron (1996–97). Based on the existing lake temperature data and the observed spawning dates, the Zero and the Power models predict that post peak spawning may contribute significantly to overall recruitment success for these years.

Journal of Great Lakes Research↗

USGS2005

Occurrence of Cyathocephalus truncatus (Cestoda) in fishes of the Great Lakes with emphasis on its occurrence in round gobies (Neogobius melanostomus) from Lake Huron

Cyathocephalus truncatus is a pathogenic cestode that is common in many Laurentian Great Lakes fish species, but the depth distribution of this cestode has not been studied. Cyathocephalus truncatus has been reported from 21 fish species and one hybrid representing seven orders and nine families in Lakes Superior, Michigan, Huron, and Ontario. We examined the intestinal contents of six species of fish collected in Michigan waters of Lake Huron, from DeTour to Harbor Beach, in 2001 to 2003 for the presence of this cestode species. Cyathocephalus truncatus was found in five native fish species and the exotic round goby. Prevalence (52%) and mean intensity (4.6 cestodes per infected fish) were highest in bloaters. This is the first reported occurrence of this cestode in round gobies from the Great Lakes. None of the gobies trawled from Lake Huron at depths of 27 to 46 m were infected, but prevalence and intensity of infection in round gobies increased significantly with depth from 55 to 73 m. Our diet study of round gobies indicated that they preyed heavily on amphipods ( Diporeia hoyi ) at depths of 55 to 73 m. Cyathocephalus truncatus was found in eight of 605 D. hoyi obtained by Ponar grab sampling. This suggests that C. truncatus eggs may be released from infected gobies and sink to deep basins with silt bottoms where D. hoyi occur.

Lake Huron↗

USGS2004

Modeling the suppression of sea lamprey populations by the release of sterile males or sterile females

The suppressive effects of trapping adult sea lampreys, Petromyzon marinus Linnaeus, and releasing sterile males (SMRT) or females (SFRT) into a closed system were expressed in deterministic models. Suppression was modeled as a function of the proportion of the population removed by trapping, the number of sterile animals released, the reproductive rate and sex ratio of the population, and (for the SFRT) the rate of polygyny. Releasing sterile males reduced populations more quickly than did the release of sterile females. For a population in which 30% are trapped, sterile animals are initially released at ratio of 10 sterile to 1 fertile animal, 5 adult progeny are produced per fertile mating, 60% are male, and males mate with an average of 1.65 females, the initial population is reduced 87% by SMRT and 68% by SFRT in one generation. The extent of suppression achieved is most sensitive to changes in the initial sterile release ratio. Given the current status of sea lamprey populations and trapping operations in the Great Lakes, the sterile-male-release technique has the best chance for success on a lake-wide basis if implemented in Lake Michigan. The effectiveness of the sterile-female-release technique should be investigated in a controlled study. Advancing trapping technology should be a high priority in the near term, and artificial rearing of sea lampreys to the adult stage should be a high priority in the long term. The diligent pursuit of sea lamprey suppression over a period of several decades can be expected to yield great benefits.

Great Lakes↗

USGS2003

Relative contributions of sampling effort, measuring, and weighing to precision of larval sea lamprey biomass estimates

We developed two weight-length models from 231 populations of larval sea lampreys (Petromyzon marinus) collected from tributaries of the Great Lakes: Lake Ontario (21), Lake Erie (6), Lake Huron (67), Lake Michigan (76), and Lake Superior (61). Both models were mixed models, which used population as a random effect and additional environmental factors as fixed effects. We resampled weights and lengths 1,000 times from data collected in each of 14 other populations not used to develop the models, obtaining a weight and length distribution from reach resampling. To test model performance, we applied the two weight-length models to the resampled length distributions and calculated the predicted mean weights. We also calculated the observed mean weight for each resampling and for each of the original 14 data sets. When the average of predicted means was compared to means from the original data in each stream, inclusion of environmental factors did not consistently improve the performance of the weight-length model. We estimated the variance associated with measures of abundance and mean weight for each of the 14 selected populations and determined that a conservative estimate of the proportional contribution to variance associated with estimating abundance accounted for 32% to 95% of the variance (mean = 66%). Variability in the biomass estimate appears more affected by variability in estimating abundance than in converting length to weight. Hence, efforts to improve the precision of biomass estimates would be aided most by reducing the variability associated with estimating abundance.

Journal of Great Lakes Research↗

USGS2003

Techniques and methods for estimating abundance of larval and metamorphosed sea lampreys in Great Lakes tributaries, 1995 to 2001

Before 1995, Great Lakes streams were selected for lampricide treatment based primarily on qualitative measures of the relative abundance of larval sea lampreys, Petromyzon marinus. New integrated pest management approaches required standardized quantitative measures of sea lamprey. This paper evaluates historical larval assessment techniques and data and describes how new standardized methods for estimating abundance of larval and metamorphosed sea lampreys were developed and implemented. These new methods have been used to estimate larval and metamorphosed sea lamprey abundance in about 100 Great Lakes streams annually and to rank them for lampricide treatment since 1995. Implementation of these methods has provided a quantitative means of selecting streams for treatment based on treatment cost and estimated production of metamorphosed sea lampreys, provided managers with a tool to estimate potential recruitment of sea lampreys to the Great Lakes and the ability to measure the potential consequences of not treating streams, resulting in a more justifiable allocation of resources. The empirical data produced can also be used to simulate the impacts of various control scenarios.

Journal of Great Lakes Research↗

USGS2003

Selecting Great Lakes streams for lampricide treatment based on larval sea lamprey surveys

The Empiric Stream Treatment Ranking (ESTR) system is a data-driven, model-based, decision tool for selecting Great Lakes streams for treatment with lampricide, based on estimates from larval sea lamprey ( Petromyzon marinus ) surveys conducted throughout the basin. The 2000 ESTR system was described and applied to larval assessment surveys conducted from 1996 to 1999. A comparative analysis of stream survey and selection data was conducted and improvements to the stream selection process were recommended. Streams were selected for treatment based on treatment cost, predicted treatment effectiveness, and the projected number of juvenile sea lampreys produced. On average, lampricide treatments were applied annually to 49 streams with 1,075 ha of larval habitat, killing 15 million larval and 514,000 juvenile sea lampreys at a total cost of $5.3 million, and marginal and mean costs of $85 and $10 per juvenile killed. The numbers of juvenile sea lampreys killed for given treatment costs showed a pattern of diminishing returns with increasing investment. Of the streams selected for treatment, those with > 14 ha of larval habitat targeted 73% of the juvenile sea lampreys for 60% of the treatment cost. Suggested improvements to the ESTR system were to improve accuracy and precision of model estimates, account for uncertainty in estimates, include all potentially productive streams in the process (not just those surveyed in the current year), consider the value of all larvae killed during treatment (not just those predicted to metamorphose the following year), use lake-specific estimates of damage, and establish formal suppression targets.

Journal of Great Lakes Research↗

USGS2003

Classification of lentic habitat for sea lamprey ( Petromyzon marinus ) larvae using a remote seabed classification device

Lentic populations of larval sea lampreys ( Petromyzon marinus ) are suspected of being a major source of recruitment to parasitic stocks in some areas of the Great Lakes, and methods are needed to estimate habitat and population sizes. A deepwater electroshocker has been used to quantitatively assess larval sea lamprey populations in deepwater areas, however a method has not been developed to efficiently identify the most promising locations to sample in this environment. A remote seabed classification device (RoxAnn™) was used to identify soft substrates in a lentic area where sea lamprey larvae have been found in Batchawana Bay (Ontario) in eastern Lake Superior, and related those substrate types to larval distribution and occurrence. Presence of larvae was significantly related to substrate type, distance from the stream mouth, and slope of the lake bottom. Remote seabed classification would be a useful tool in the Sea Lamprey Control Program to identify the most promising locations to conduct larval surveys in lentic areas.

Journal of Great Lakes Research↗