Roanoke River Research Articles

Deposited sediment influences occurrence of functional traits of stream fishes

AbstractTo better understand stream‐fish sensitivity to fine sediment, we documented assemblage‐wide responses by selected traits along a sedimentation gradient. We then discuss the management implications of these ‘dose–response’ relations in the contexts of biotic assessments and conservation of sediment‐sensitive species. We identified a spatial gradient in sediment deposition among streams within the upper Piedmont of the Roanoke River basin in North Carolina and Virginia. We assessed fine‐sediment sensitivity of 81 species based on eight species traits stratified by four attributes: food preference, feeding location, spawning substrate and spawning behaviour. We then ranked each trait and scored each species with respect to its sediment sensitivity. Using data from electrofishing surveys during 2018–2019, we calculated proportional abundances of traits observed at 30 sites throughout the study area and grouped species by their aggregate sensitivity scores. We assessed relations between embeddedness and silt cover and occurrences of species and traits using a combination of regression and ordination approaches. All traits tested responded to embeddedness or silt cover, or both. Feeding traits exhibited the strongest responses to embeddedness, while reproductive traits exhibited the strongest responses to silt cover. Our findings indicate that negative responses of the probability of presence for high‐sensitivity traits to embeddedness and silt cover were linear, with no apparent thresholds. Additionally, proportional abundances of species with multiple high‐sensitivity traits were inversely related to embeddedness and silt cover. Overall, our findings regarding population‐level responses to sedimentation were consistent with our findings for trait‐specific responses. Our analysis of species sensitivity to fine sediment corroborated the patterns we saw in our trait‐specific analyses, indicating that population responses to sedimentation can be predicted from combinations of species traits. The ‘dose–response’ relations we documented may be applicable to managing sediment impacts on fishes, especially in the contexts of biotic assessments and conservation of sediment‐sensitive species.

Eastern Continental Divide Origin in the Blacksburg, Virginia Area Determined by Topographic Map Interpretation, USA

Published geology literature addresses only a small fraction of the Blacksburg, Virginia region topographic map drainage divide evidence. This situation probably arises because the accepted geology and glacial history paradigm (accepted paradigm) does not explain most topographic map drainage divide evidence (anywhere). A new and fundamentally different geology and glacial history paradigm (new paradigm) which appears to explain most topographic map drainage divide evidence sees the Eastern Continental Divide in the Blacksburg area as being located along the rim of a continental ice sheet created and occupied deep “hole” with the rim being uplifted as immense and prolonged southwest-oriented meltwater floods flowed across the region. From the new paradigm perspective northwest-oriented New River valley headward erosion into the rising deep “hole” rim (from the deep “hole”) upon reaching the Blacksburg region beheaded and reversed southwest-oriented floodwaters (probably aided by deep “hole” rim uplift) to create today’s northeast- and northwest-oriented New River. Headward erosion of the southeast-oriented Roanoke River valley and subsequently the southeast-oriented James River valley (both from the Atlantic Ocean) then created the Roanoke River-New River and James River-New River drainage divides (both are Eastern Continental Divide segments) and the James River-Roanoke River drainage divide by beheading and reversing southwest-oriented floodwaters which had been flowing in diverging and converging channels (which had been eroded headward in northeast directions along less resistant bedrock units from the New River valley). This scenario explains most through valleys (valleys crossed by drainage divides), barbed tributaries, river direction changes, and water gaps seen on Blacksburg area detailed topographic maps and does not see significant changes taking place since the southwest-oriented floods ended. The accepted and new paradigms are incommensurable which according to Thomas Kuhn means one paradigm should not be used to judge the other.

Using high-frequency monitoring data to quantify city-wide suspended-sediment load and evaluate TMDL goals

Excess sediment is a common reason water bodies in the USA become listed as impaired resulting in total maximum daily loads (TMDL) that require municipalities to invest millions of dollars annually on management practices aimed at reducing suspended-sediment loads (SSLs), yet monitoring data are rarely used to quantify SSLs and track TMDL progress. A monitoring network was created to quantify the SSL from the City of Roanoke, Virginia, USA (CoR), to the Roanoke River and Tinker Creek and help guide TMDL assessment and implementation. Suspended-sediment concentrations were estimated between 2020 and 2022 from high-frequency turbidity data using surrogate linear-regression models. Sixty-one percent of the total three-year SSL resulted from five large storm events. The average suspended-sediment yield from the CoR (58.1 metric tons/km2/year) was similar to other urban watersheds in the Eastern United States; however, the yield was nearly five times larger than the TMDL allocation (12.2 metric tons/km2/year). The TMDL allocated load was modeled based on a predominantly forested reference watershed and may not be a practical target for highly impervious watersheds within the CoR. The TMDL model used daily input data which likely does not capture the full range of SSLs during storm events, particularly from flashy urban streams. The average SSL following the five large storm events doubled that of the CoR’s annual allocated load from the TMDL. The results of this study highlight the importance of using high-frequency monitoring data to accurately estimate SSLs and evaluate TMDLs in urban areas.

Mutually beneficial outcomes for hydropower expansion and environmental protection at a basin scale

Reshaping the scale of planning for hydropower development, from reaches to basin-scales, has been recommended as a more effective way to ameliorate the environmental impacts of hydropower. One approach is identifying mutually exclusive areas where development is precluded for conservation purposes and areas of low conservation value that present fewer barriers to development. This strategy, however, is less adoptable in developed countries where hydropower is already widespread and large-scale construction of new dams is unlikely. To broaden the adoption of basin-scale planning, alternative approaches and planning tools are needed for identifying mutually beneficial opportunities for simultaneous increases in hydropower capacity while improving environmental conditions. In this study, we present the Basin Scale Opportunity Assessment as a methodology to improve environmental conditions through either direct (on-site) or indirect (off-site) mitigation. We assess whether direct or indirect mitigation activities lead to optimal results in terms of added hydropower, environmental improvement, and monetary cost at a basin scale. We present two case studies for the Connecticut River and Roanoke River Basins, USA. Significant opportunities for expanding hydropower generating capacity are numerous in both basins. Results suggest that total hydropower capacity could be increased 4 to 7 % in the Roanoke and Connecticut Basins, respectively, without new dam construction and with net improvements in environmental conditions. We found that environmentally and economically optimal win-win strategies for increasing hydropower capacity and improving environmental conditions included improving environmental conditions in rivers downstream of existing dams. Off-site mitigation opportunities, such as dam removal and wetland mitigation, were identified as optimum solutions for achieving net environmental improvements only when they were associated with new hydropower construction. Our results demonstrate that opportunities to increase hydropower capacity and improve environmental conditions are expanded by viewing cumulative benefits at basin scales; however, increasing regulatory flexibility may be required to realize these opportunities.

The unmarked R package: Twelve years of advances in occurrence and abundance modelling in ecology

AbstractSpecies distribution models (SDMs) are widely applied to understand the processes governing spatial and temporal variation in species abundance and distribution but often do not account for measurement errors such as false negatives and false positives.We describeunmarked, a package for the freely available and open‐source R software that provides a complete workflow for modelling species distribution and abundance while explicitly accounting for measurement errors. Here we focus on recent advances inunmarkedfunctionality to support multi‐species, multi‐state, and multi‐season data, as well as support for fitting models with random effects.For illustration, we present an analysis of Acadian FlycatcherEmpidonax virescensabundance on Roanoke River National Wildlife Refuge, North Carolina, USA, over 18 years. We found that Acadian Flycatcher abundance was initially greater in hardwood plantation habitat relative to bottomland hardwood forest along river levees but that abundance declined over time in both habitats.We plan forunmarkeddevelopment to keep pace with advances in hierarchical modelling in ecology, including better handling of continuous‐time data from camera trap and automated recording units and integrated models for multiple data streams.

The Erosional Signature of Drainage Divide Motion Along the Blue Ridge Escarpment

AbstractThe planform rearrangement of river basins is recognized as an important process for landscape evolution. The boundaries of river basins can shift either through gradual drainage divide migration or discrete river captures, but the methods for identifying these processes often rely on topographic evidence that remains otherwise untested. Moreover, efforts to understand the relative importance of either process are hampered by a lack of age constraints on river captures. We use 10Be‐derived erosion rates to test whether, and how, divide motion is occurring at three locations along the Blue Ridge Escarpment in the Appalachian Mountains. In the Pee Dee River basin, we find that the escarpment is migrating inland up to 45 m/Myr, consistent with topographic evidence for gradual divide migration. In the Dan River basin, erosion rates support the topographic evidence for river capture, and we use a forward model of river incision to estimate that the capture likely occurred in the past 12.5 Myr. In the South Fork Roanoke River basin, where the presence of a knickzone has been interpreted as evidence that a river capture initiated a pulse of faster erosion, we instead measure nearly uniform tributary erosion rates above and within the mainstem knickzone. Simulations show that river incision into a more erodible layer of rock, with or without a river capture, could produce the observed topography and erosion rates in the South Fork Roanoke River. Our results show how multiple lines of evidence can illuminate the rates and mechanisms of river basin reorganization.

River‐of‐origin assignment of migratory Striped Bass, with implications for mixed‐stock analysis

AbstractObjectiveThe Striped Bass Morone saxatilis is an anadromous teleost with a native range extending north from the Gulf of Mexico into Canadian waters. Far‐ranging coastal migrations support one of the most popular recreational fisheries in the United States. Identifying the underlying population genetic structure of the spawning populations and the genetic markers capable of differentiating among them advances our understanding of these economically and ecologically important fish and enables more targeted management to occur.MethodsWe used a restriction site‐associated DNA sequencing approach to identify neutral and adaptive single‐nucleotide polymorphisms (SNPs), and we determined the population genetic structure of 438 adult Striped Bass sampled from nine spawning locations along the Atlantic coast from the Roanoke River, United States, to the Miramichi River, Canada.ResultThe two Canadian populations (Shubenacadie and Miramichi rivers) were genetically distinct from U.S. populations and from each other. Neutral loci differentiated Striped Bass from U.S. waters into four genetically distinct populations: Roanoke River, Hudson–Kennebec River, Upper Chesapeake Bay–Potomac River–Delaware River, and Choptank River (eastern Chesapeake Bay). Outlier loci further differentiated the Delaware River from the Chesapeake Bay tributaries, suggesting that there may be local adaptation in the face of gene flow. We identified 1300 highly informative SNPs (the top 10% [with respect to the genetic differentiation index FST] of the full suite of 13,361 SNPs in our study) capable of assigning fish with at least 90% accuracy to their river of origin; through simulations, we established their applicability for conducting robust mixed‐stock analyses of the coastal migratory Striped Bass fishery.ConclusionThis study demonstrated that neutral and adaptive loci together provide evidence for fine‐scale population structure of migratory Striped Bass, and these loci provide the most informative genetic panel for mixed‐stock analysis of Striped Bass to date, capable of assigning fish to their spawning river of origin.

Generalizing Trends in Upstream American Eel Movements at Four East Coast Hydropower Projects

Abstract Dams impede the upstream migration of juvenile American Eel Anguilla rostrata, limiting their access to freshwater habitat and potentially contributing to population declines across their range. The implementation of fishways at large hydropower dams help restore access to upstream habitat and represents a long-term dataset of American Eel captures. We analyzed the relationships between eel captures and select environmental variables (river discharge, water temperature, and lunar illumination) at four hydropower projects on east coast rivers with a comparable decade of data and sampling techniques: Roanoke Rapids Dam on the Roanoke River in North Carolina, Conowingo Dam on the Susquehanna River in Maryland, Holyoke Dam on the Connecticut River in Massachusetts, and the Moses-Saunders Dam on St. Lawrence River in New York and Canada. The number of eels captured varied among projects, from year to year, and seasonally. American Eel are opportunistic in their upstream movements, with peak movement events associated with high flows, increased water temperature, and low lunar illumination. Our results suggest that systems altered by hydropower dams offer unique challenges to American Eel migrants and that a multitude of factors play a role in the timing of upstream movements.

Predation of the Federally Endangered Roanoke Logperch (Percina rex) by the Invasive Ozark Crayfish (Faxonius ozarkae)

An observed predation of a federally endangered Percina rex (Roanoke Logperch), by an invasive Faxonius ozarkae (Ozark Crayfish), is detailed herein. We observed the predation on 11 August 2021 in the Roanoke River near downtown Roanoke, Roanoke County, VA. The crayfish had recently captured a sub-adult Roanoke Logperch and was dragging it under a cluster of cobbles. Upon observing this behavior, we retrieved the fish, positively identified it, and confirmed it as dead. The initial state of the Roanoke Logperch was nearly undamaged apart from indentations from the crayfish's chelae behind the operculum and near the caudal peduncle. Coloration of the Roanoke Logperch at time of observation indicated the fish had likely recently been captured. A camera was not readily available, so we returned the fish to the cobble cluster until a photograph could be captured. Upon returning approximately one-half hour later, coloration of the fish had begun to fade, and the ventral portion of the fish was partially consumed by the crayfish. Herein we discuss the significance of this observation and the gravity of the continued expansion for this invasive crayfish species, both within the confines of Virginia's waters as well as throughout the eastern United States.

Stock composition of Atlantic coastal migratory striped bass using microsatellite DNA analysis

The Atlantic Coast Migratory Stock (ACMS) of striped bass Morone saxatilis is supported by spawning populations in Chesapeake Bay and the Hudson, Delaware, and Roanoke rivers. Spawning success and recruitment differs among these populations and temporally within them and thus their relative abundances shift over time. The ACMS is subject to harvest and other sources of mortality at many Atlantic Coast locales. Effective management of these populations would benefit from knowledge of the relative contributions of these populations to the ACMS. We used microsatellite DNA analysis to measure the extent of genetic differentiation among those populations that contribute to the ACMS and to quantify their contributions to recreational harvest in 2019 at Montauk, New York. We found genetic homogeneity between the Delaware River and Chesapeake Bay populations, but significant allelic differentiation among the Hudson River, combined Delaware River-Chesapeake Bay, and Roanoke River populations. In simulations of single mixture samples, assignment accuracies for the Chesapeake-Delaware, Hudson River, and Roanoke River collections were high at 96 % (95 % CI=0.921, 0.999), 93 % (0.863, 0.979), and 81 % (0.726, 0.866), respectively. Mixture analysis and Individual Based Assignment testing were used to quantify contributions to the 2019 Montauk fishery. Mixture analysis indicated 86 %, 8.5 %, and 5.5 % contributions for the Chesapeake-Delaware, Hudson River and Roanoke River populations, respectively. Similarly, Individual Based Assignments showed the Chesapeake-Delaware population as the largest contributor (78 %), followed by the Hudson River (12 %), and the Roanoke River (10 %). Furthermore, we found no significant differences in relative contributions across the five-month recreational fishing season nor among size-classes of striped bass. Lastly, the risk of consuming a Hudson River striped bass from Montauk containing a considerably high concentration of PCBs is minimal. Future stock composition analysis of Atlantic migratory striped bass would benefit from standardization of the approach, with DNA analysis from collections made at a single strategic location offering advantages.

Untyped Paleoindian Lanceolate Projectile Points in the Upper Roanoke River Basin at Smith Mountain Gap, Virginia

ABSTRACT This paper documents a previously unrecognized Paleoindian presence in the Upper Roanoke drainage (UR) defined by a series of unfluted Early Narrow Lanceolate points (ENLs), some of which resemble Plano types from regions to the west and the northeast. The context of the recoveries is briefly described and discriminant analysis is applied to distinguish ENL forms, as a group, from possible pre-Clovis Early Triangular Lanceolates (ETLs) also found at Smith Mountain and Middle Archaic Guilford Lanceolates, which are common throughout the Piedmont Southeast including the Roanoke drainage. An additional metric study based on plan and sectional landmark ratios of Upper Roanoke ENL forms is used for initial morphometric comparisons to similar, lower Middle Atlantic early lanceolates and Plano types from the American West and Northeast in the Smithsonian National Museum of Natural History Paleoindian Program collection.

Effects of Hydropower Dam Operation on Riverbank Stability

The increasing number of extreme climate events has impacted the operation of reservoirs, resulting in drastic changes in flow releases from reservoirs. Consequently, downstream riverbanks have experienced more rapid and frequent changes of the river water surface elevation (WSE). These changes in the WSE affect pore water pressures in riverbanks, directly influencing slope stability. This study presents an analysis of seepage and slope stability for riverbanks under the influence of steady-state, drawdown, and peaking operations of the Roanoke Rapids Hydropower dam on the lower Roanoke River, North Carolina, USA. Although the riverbanks were found to be stable under all the discharge conditions considered, which indicates that normal operations of the reservoir have no adverse effects on riverbank stability, the factor of safety decreases as the WSE decreases. When the role of fluvial erosion is considered, riverbank stability is found to reduce. Drawdown and fluctuation also decrease the safety factor, though the rate of the decrease depends more on the hydraulic conductivity of the soils rather than the discharge pattern.

Use of Acoustic Telemetry to Identify Spawning River and Spawning Migration Patterns of American Shad in the Albemarle Sound, North Carolina

AbstractAmerican Shad Alosa sapidissima is an economically, culturally, and ecologically important anadromous species that undertakes a significant spawning migration, swimming from the ocean into areas far upstream in coastal rivers to reproduce. The species has a large range in the western Atlantic, occurring from Nova Scotia to Florida. However, because American Shad generally return to their natal rivers to spawn, each major river likely has its own spawning stock. Fish that are entering the Albemarle Sound, North Carolina, to spawn primarily ascend one of two rivers at the far western end of the estuary: the Roanoke River or the Chowan River. Determining the current primary spawning river for American Shad in the Albemarle Sound would help inform research efforts and resource management decisions to improve stocks. American Shad were captured in the Albemarle Sound, tagged with sonic transmitters, and tracked using an array of acoustic receivers. Of the 62 fish that made detectable migrations during the six study years, 55 ascended the Chowan River, while only 5 ascended the Roanoke River and 2 entered other rivers. These telemetry results suggest that the Chowan River and its tributaries are the major spawning rivers for American Shad in the Albemarle Sound.

Population Genetic Assessment of Anadromous and Resident Striped Bass (Morone saxatilis) in the Roanoke River System, Eastern United States

Striped bass is the subject of important commercial and sport fisheries in North America. The Roanoke River drainage—especially Smith Mountain Lake, Leesville Lake, and Kerr Reservoir—has popular recreational striped bass fisheries. After construction of five hydroelectric dams, populations became landlocked, declined, and have been supplemented by stocking. A key basis for responsibly augmenting populations is to characterize genetic variation and incorporate the findings into responsible hatchery and stocking practices. Genetic variation at 12 microsatellite DNA loci was evaluated among 837 striped bass representing 16 collections across the native range; populations from rivers in South Carolina, North Carolina, Chesapeake Bay, and Hudson River were screened to provide context for assessing genetic structure within the Roanoke system. Analysis of population genetic differentiation showed landlocked Roanoke River striped bass to be distinctive. Subject to genetic isolation, high M ratios, and relatively low Ne estimates suggest loss of genetic variation, and relatedness analysis showed heightened frequencies of related individuals. These insights into population genetics, demographics, and existing guidelines for broodstock acquisition and mating designs can inform genetically cognizant hatchery management and stocking for striped bass in the Roanoke River drainage. In particular, we recommend the use of larger numbers of breeders and factorial mating designs to increase the genetic diversity of propagated striped bass stocked within the Roanoke River drainage.

Reappraisal of hydrologic alterations in the Roanoke River basin using extended data and improved RVA method

Hydrologic regime changes of the Roanoke River basin under three different scenarios defined based on different periods of post-impact datasets have been studied. For evaluating the degree of hydrologic alterations, the traditional and improved range of variability approach (RVA) which incorporate periodicity [as an index of periodicity (IP)], trend [as an index of trend (IT)], and symmetry [as an index of symmetry (IS)] of the parameters has been used. Comparative analysis of the results obtained with traditional and improved RVA and that obtained with the histogram matching approach (HMA) has also been performed. The overall degree of hydrologic alteration obtained through traditional RVA for Scenarios-I, II, and III was 0.39, 0.42, and 0.40, respectively. The improved RVA method, when applied to the 32 IHA parameters, indicates that many IHA parameters exhibit a higher IP or IT or IS value compared to the corresponding value of the degree of hydrologic alteration (DR), which underscore the inadequacy of the traditional RVA in assessing the degree of alteration in the flow regime of the Roanoke River. Through principal component analysis, the most ecologically relevant hydrologic indicators for understanding eco-hydrology of Roanoke River have been identified, which include Julian date of maximum flow, monthly flow for July and September, and 90-day maximum flow. Analysis of results further reveals that the combination of improved RVA and HMA can better reveal changes in IHAs and provide a better tool for designing strategies to enhance further the ecosystem services available from a managed river system.

Atlantic coastwide population structure of striped bass Morone saxatilis using microsatellite DNA analysis

Striped bass Morone saxatilis support one of the most popular and important inshore recreational and commercial fisheries along the Atlantic Coast of North America. Populations at both extremes of its distribution are largely resident while those in the center of its range (Hudson River, New York, to Roanoke River, North Carolina) are seasonally migratory, ranging from the Bay of Fundy, Canada, to the Outer Banks of North Carolina. Historically, population abundances of striped bass fluctuated widely, sometimes resulting in the imposition of severe management measures to restrict their harvest. Detailed knowledge of its rangewide population structure would aid in more effective management; however, most genetic studies addressing the structure of the migratory coastal stock have largely failed to achieve this goal. To address this need, we used multi-loci microsatellite DNA analysis. We identified six, and posibly one more, genetically distinct populations across the species’ distribution, including the Miramichi, Shubenacadie, Hudson, Delaware-Chesapeake, Roanoke, and Santee-Cooper rivers. We also report significant genetic differentiation between the Nanticoke and Choptank rivers along the eastern shore of the Chesapeake Bay and collections from tributaries along the western shore of the Bay. The Annapolis and Saint John rivers, tributaries of the Bay of Fundy, historically hosted striped bass aggregations that were extirpated, or nearly so, by anthropogenic stressors in the late 20th century. No specimens with unique genotypes were found in collections from either river; instead the vast majority were admixed with genotypes of Shubenacadie River, Hudson River, Chesapeake Bay, and Roanoke River lineages. Finally, we show in simulations that these genetic markers should be informative in quantifying the contributions of the Hudson River, Chesapeake Bay-Delaware, and Roanoke River to mixed-stock harvests that occur within the range of the coastal migratory stock.

Drift of Larval Darters (Family Percidae) in the Upper Roanoke River Basin, USA, Characterized Using Phenotypic and DNA Barcoding Markers

Larval fish ecology is poorly characterized because sampling is difficult and tools for phenotypically identifying larvae are poorly developed. While DNA barcoding can help address the latter problem, ‘universal’ primers do not work for all fish species. The Roanoke River in the southeastern United States includes seven darters (Family Percide: Tribe Etheostomatini). We made 393 collections of larval fishes in 2015 and 2018, examined darter larvae for morphometric and pigmentation traits, developed PCR primers amplifying darter DNA, and evaluated three gear types for collecting larval darters. Amplified DNA sequences for 1351 larvae matched archived mitochondrial cytochrome oxidase I sequences for darters occurring in the ecosystem. Larval darters were classified to genus with 100% accuracy using the ratio of pectoral fin length to body length; however, identification to species using morphometrics alone was subject to a misclassification rate of 11.8%, which can be resolved by considering pigmentation patterns. Gear-types varied considerably in their capture efficacy for larval darters; most Percina larvae were collected in drift nets. Larval Percina species appeared in the drift before Etheostoma species in both study years. Application of molecular genetic and phenotypic tools to larval fish identification can advance understanding of larval darter ecology.

Microhabitat Comparison of Percina roanoka (Roanoke Darter) and Percina nevisense (Chainback Darter) in the Roanoke River

Microhabitat Comparison of Percina roanoka (Roanoke Darter) and Percina nevisense (Chainback Darter) in the Roanoke River

Commonalities in stream connectivity restoration alternatives: an attempt to simplify barrier removal optimization

AbstractMovement within stream corridors is a basic life history requirement of many aquatic organisms. Barrier removal in streams has become a common practice in the United States aimed to restore organism dispersal and meet conservation objectives; however, there are social and economic costs to the removal of barriers. Accordingly, tools to prioritize barrier removal, particularly optimization techniques, can be used to evaluate cost‐benefit trade‐offs. Many of these techniques, however, require programming experience and are not available to natural resource managers. Furthermore, conservation objectives vary considerably depending on the life histories of organisms under consideration, and these opposing objectives, in conjunction with variant socioeconomic costs, will influence optimization solutions, specifically which barriers to remove. To promote the use of optimization tools, straightforward and open‐access platforms are needed to support use by managers, while also providing general approaches for holistic basin‐scale connectivity restoration. Herein, we use two case studies, White Oak Creek (small watershed) and the Roanoke River Basin (large basin), to explore the divergent outcomes stemming from different conservation objectives and socioeconomic costs used to prioritize barrier removal. We conducted optimization modeling using a widely accessible platform along with an open‐access solver plug‐in to support a wide variety of conservation objectives. We used simple approaches to find commonalities in barriers identified for removal among divergent conservation objectives and provide alternative (i.e., hybrid removal‐passage) strategies for approaching habitat restoration for diverse aquatic communities while increasing social benefits (i.e., hydropower energy). As expected, different conservation objectives aimed to support varied species life histories (e.g., diadromy, large‐river vs. small‐river potamodromy) have very different effects on optimization solutions. In both case studies, however, commonalities in solutions were identified through clustering groups of barriers into general connectivity restoration strategies. Furthermore, strategy types for a given barrier could be predicted with ≥72% accuracy using only four metrics. This suggests that optimization results can be simplified into general standards to support adoption of sustainable basin connectivity criteria strategies. Our framework provides a flexible and open‐access approach to conduct relatively complex optimization modeling for stream barrier prioritization, while examining potential for agreement among divergence conservation objectives.

HOW HIGH CAN FERRITIN LEVEL BE? A RARE CASE OF EHRLICHIOSIS-INDUCED HLH WITH REACTIVATION OF EBV

SESSION TITLE: Critical Care 3 SESSION TYPE: Fellow Case Report Posters PRESENTED ON: 10/09/2018 01:15 PM - 02:15 PM INTRODUCTION: Hemophagocytic lymphohistocytosis (HLH) is often under recognized which leads to high mortality and morbidity. Prompt recognition and treatment can decrease mortality. We present a case of HLH triggered by infection with Ehrlichia with reactivation of EBV. CASE PRESENTATION: A 28-year-old man with no past medical history presented with fever, chills, generalized musculoskeletal pains, nausea, vomiting, loose stools and headache. He went to hiking at Roanoke river and Greenway a week prior to presentation. Physical exam revealed blood pressure 123/69 mmHg, pulse 96/min, temperature 103 F, respiratory rate 36/min. Pertinent physical examination findings include cervical lymphadenopathy, generalized muscle tenderness with bilateral shin petechiae. Laboratory data revealed leukopenia 0.9, platelets 17, transaminitis (AST-457, ALT- 96), CK- 8663, fibrinogen 162, and ferritin 61,437. He was admitted for neutropenic fever and was empirically started on vancomycin, cefepime and doxycycline for tick borne infection. Bone marrow biopsy was performed due to concern for HLH revealed histocytes with intracellular RBC and WBC’s. Further workup is negative for any autoimmune disease, malignancies, but positive for IgG EBV and Ehrlichia. PCR for EBV DNA was positive with viral load 2096 copies/ml (normal < 200 copies/ml). Received a dose of Etoposide and Decadron but he started to improve clinically. Doxycycline was continued and rest of the antibiotics and chemotherapy was discontinued. Patient was discharge in stable condition and completed total 14 days of doxycycline treatment. Patient remained asymptomatic one month after hospital discharge. DISCUSSION: HLH is a life-threatening disorder characterized by unregulated hyperimmune response to antigen which results in phagocytosis of white cells, RBCs and platelets by mononuclear macrophages. It was first described in 1952 by Farquhar and Claireaux. Secondary causes of HLH is seen in adults from autoimmune diseases, infections and malignancies. Viral infections are the most common triggers: EBV, CMV, HIV. Elevated ferritin >10,000 μg/L has been demonstrated to be 90% sensitive and 96% specific for HLH (3). If left untreated mortality is high with median survival less than 2 months. HLH-1994 treatment protocol recommended an 8-week induction with IV dexamethasone and etoposide, and HLH-2004 protocol added cyclosporine to help prevent relapse.Most patients respond to early initiation of doxycycline 100 mg twice daily in Ehrlichiosis induced HLH and can be continued 4-5 days after clinically resolution of symptoms. If refractory then can use chemotherapeutic agents like etoposide, cyclosporine, intrathecal methotrexate, methylprednisolone. CONCLUSIONS: HLH should be in differential diagnosis in patients who present from endemic regions of tick borne infections with fever, cytopenia’s and especially with high ferritin levels (> 500 μg/L). Reference #1: Ehrlichia-Induced Hemophagocytic Lymphohistiocytosis: A Case Series. Zaher K et al. Blood 2014 124:4105 Reference #2: Ehrlichiosis-Induced Hemophagocytic Lymphohistiocytosis Presenting As Septic Shock - An Immune Response Gone Haywire And Its Lessons For The Icu Setting. N. G. Holtzman et al. Am J Respir Crit Care Med 189;2014: A6737 Reference #3: Hemophagocytic lymphohistiocytosis: review of etiologies and management. Melissa R George. J Blood Med. 2014; 5: 69–86. Published online 2014 Jun 12. https://doi.org/10.2147/JBM.S46255 DISCLOSURES: No relevant relationships by Venkateswara Kollipara, source=Web Response No relevant relationships by Umar Sofi, source=Web Response