Lower Hudson River Research Articles

Successful initial restoration of oyster habitat in the lower Hudson River Estuary, United States

The eastern oyster (Crassostrea virginica), has experienced dramatic declines throughout its range, and most U.S. states along the Atlantic and Gulf of Mexico coasts have restoration programs. Oyster restoration in the Hudson River Estuary has been a focus of management agencies for over two decades. The present project was initiated in 2013 after sampling for replacement of the Tappan Zee bridge determined live oysters would be lost during bridge construction, thus requiring mitigation measures. Preliminary studies identified three areas for pilot studies to inform the design of full‐scale efforts. A pilot study involving deployment of oyster shell‐filled gabions and two styles of Reef Balls, found all substrates supported oyster recruitment and growth but there were higher oyster densities on gabions. Some of the gabions, however, failed structurally necessitating a need for new design. For full‐scale restoration, a total of 422 modified gabions and 881 Mini‐Bay style Reef Balls were deployed across three sites which totaled approximately 2.4 ha (6 ac) in seafloor area. Both substrate types were heavily colonized by oysters and several other species at all three sites, essentially duplicating the findings of the pilot study. The final monitoring event in 2020 indicated a total of approximately 5.8 million live oysters were on the substrates deployed in 2018. This mitigation effort was the largest oyster habitat restoration project in, or north of, the New York Harbor region in recent decades based on restoration area and several oyster metrics of early success.

Movement Ecology of the Imperiled Wood Turtle (Glyptemys insculpta) in a Lower Hudson River Watershed

Knowledge of the spatial ecology of many turtle species is lacking or limited by small sample sizes of study animals, short study periods, or incomplete representation of the species' geographic range, all of which can present barriers to science-based management and conservation. The wood turtle (Glyptemys insculpta) is a declining North American freshwater turtle that is now listed as threatened or endangered in several US states and Canadian provinces. Local-scale knowledge of wood turtle movement patterns and home range sizes is needed for more effective management and regulatory protection, yet the spatial ecology of this species remains undescribed in large portions of its range. We radiotracked 31 wood turtles for 1–5 yrs each in a stream system along the border of New York and Connecticut to describe their movement behavior and inform management efforts in this previously unstudied region. Annual and multiyear 95% minimum convex polygon home range sizes averaged 2.8 (± 3.79 SD) ha and 5.2 (± 7.36 SD) ha, respectively. Males had significantly larger annual and multiyear home ranges than did females, often by severalfold. Overlap of home ranges from one year to the next ranged from 10.5% to 99.7% and averaged 62.6% (± 22.86% SD). Home range centroids shifted 3.8–328.1 m (x̄ = 70.3 ± 80.31 m SD) from year to year and averaged 41.2 m (± 40.56 m SD) from the stream and 138.4 m (± 70.66 m SD) from the nearest road across all individuals. Most turtles' home ranges spanned one or both of the major roads in our study area, illuminating the threat of vehicle collision mortality to the viability of this population. Hibernaculum fidelity was low, with only 15% of turtles hibernating in the same location as in the previous year. Our results suggest that management efforts for wood turtles in western Connecticut and the adjacent region of New York should consider that males (the wider-ranging sex) use an average of 5.3 ha to meet their resource requirements over the course of one annual cycle, buffers of at least 116 m surrounding streams should be protected, habitats that are distant from roads should be prioritized for conservation, and measures that facilitate safe passage beneath roads should be implemented whenever roads are present near occupied wood turtle habitat.

Using Genomics to Link Populations of an Invasive Species to Its Potential Sources

The introduction and subsequent range expansion of the Northern snakehead (Channa argus: Channidae, Anabantiformes) is one of a growing number of problematic biological invasions in the United States. This harmful aquatic invasive species is a predatory freshwater fish native to northeastern Asia that, following deliberate introduction, has established itself in multiple water basins in the eastern United States, as well as expanding its range into the Midwest. Previous work assessed the population structure and estimated the long-term effective population sizes of the populations present in the United States, but the source of the initial introduction(s) to the U.S. remains unidentified. Building on earlier work, we used whole genome scans (2b-RAD genomic sequencing) to analyze single nucleotide polymorphisms (SNPs) from C. argus to screen the genomes of these invasive fish from United States waters and from three sites in their native range in China. We recovered 2,822 SNP loci from genomic DNA extracted from 164 fish sampled from the eastern United States and Arkansas (Mississippi River basin), plus 30 fish sampled from three regions of the Yangtze River basin in China (n = 10 individuals per basin). Our results provide evidence supporting the Yangtze River basin in China, specifically the Bohu and/or Liangzi lakes, is a likely source of the C. argus introductions in multiple regions of the U.S., including the Lower Hudson River basin, Upper Hudson River basin and Philadelphia (Lower Delaware River basin). This information, in conjunction with additional sampling from the native range, will help to determine the source(s) of introduction for the other U.S. populations. Additionally, this work will provide valuable information for management to help prevent and manage future introductions into United States waterways, as well as aid in the development of more targeted strategies to regulate established populations and inhibit further spread.

Preventing carbon monoxide poisoning in the Hudson River Tunnel in 1921: recounting history

The New York Bridge and Tunnel Commission began planning for a tunnel beneath the lower Hudson river to connect Manhattan to New Jersey in 1919. At 8,300 feet, it would be the longest tunnel for passenger vehicles in the world. A team of engineers and physiologists at the Yale University Bureau of Mines Experiment Station was tasked with calculating the ventilation requirements that would provide safety from exposure to automobile exhaust carbon monoxide (CO) while balancing the cost of providing ventilation. As the level of ambient CO which was comfortably tolerated was not precisely defined, they performed human exposures breathing from 100 to 1,000 ppm CO, first on themselves and subsequently on Yale medical students. Their findings continue to provide a basis for carbon monoxide alarm requirements a century later.

The presence and significance of microplastics in surface water in the Lower Hudson River Estuary 2016–2019: A research note

Microplastics are a major environmental issue of concern. Since 2016, Hudson River Park has collaborated with Brooklyn College to survey microplastics within Park waters between Chambers and 59th Streets in Manhattan. It was hypothesized that microplastic concentration is influenced by proximity to combined sewer overflow (CSO) points, precipitation, and tides. Samples were collected at channel and near-shore locations at downtown and midtown sites. Microplastics were analyzed following NOAA methods via stereo microscope. Concentrations in 2018 were higher than in 2016, 2017 and 2019 ((ANOVA F (1,70) = 5.2, p < 0.03*; post hoc Tukey test p < 0.009*)), and near-shore sites tended to exhibit higher concentrations than channel sites (ANOVA and post-hoc Tukey: p < 0.03*). Microfibers were not fully accounted for and fragments were highly prevalent in all samples (~70%). Additional data will improve the understanding of the presence of microplastics in the Lower Hudson and elucidate the effects of wet weather on plastic concentrations.

The Majestic Nature of the North: Thomas Kelah Wharton's Journeys in Antebellum America through the Hudson River Valley and New England ed. by Steven A. Walton and Michael J. Armstrong

Reviewed by: The Majestic Nature of the North: Thomas Kelah Wharton's Journeys in Antebellum America through the Hudson River Valley and New England ed. by Steven A. Walton and Michael J. Armstrong Paul G. Schneider Jr. (bio) The Majestic Nature of the North: Thomas Kelah Wharton's Journeys in Antebellum America through the Hudson River Valley and New England Edited by Steven A. Walton and Michael J. Armstrong . Albany, NY: State University of New York Press, 2019. 374 pages, illustrated, 7″ x 10″. $90.00 cloth, $34.95 paper, $69.30 e-book. This extensive selection from the personal journals of Thomas Kelah Wharton offers rich rewards to anyone delving into its engaging pages. His fascinating entries, spanning the period May 1832 through October 1834, and June 25 through December 6, 1853, provide contrasting, vivid accounts of his youthful years in New York City and the Hudson River Valley, and his middle-aged journey from New Orleans to Boston nineteen years later. Wharton (1814–62), who over the course of a varied career combined his skills as artist, teacher, and architect-construction superintendent, deserves to be better known, a task that the editors of this volume set out to achieve. A young English immigrant to the United States, Wharton lived in the states of Ohio, New York, and Louisiana over the course of his life. His surviving manuscript journals, in the collections of the New York Public Library, comprise seven volumes dating from 1830 to 1862 (four illustrated with his drawings) in addition to a sketchbook. Associate professor of history at Michigan Technological University, Steven A. Walton, along with retired senior vice president of operations for U.S. News & World Report, Michael J. Armstrong, united in their involvement with the restoration of a Wharton-designed chapel, edited these newly published portions of Wharton's journals. Also included are a selection of Wharton's sketches illustrating his skill as an artist and providing images of some of the scenes and places he mentions. Disappointingly, the small size with which these sketches are reproduced insufficiently conveys their fine detail and artistry. Preparing this publication presented challenges to its editors. First, Wharton himself apparently edited and rewrote portions of his 1830s journals, deleting "several verses" which his "maturer [sic] judgement" suggested be "omitted" (2–3). Based on Wharton's own admission, the editors are right to wonder what else Wharton might have left out from his original notes, and they warn that surviving journal entries are "not an unfiltered composition" (3). Second, in their preface, the editors enumerate many individuals who over the last fifty years directly contributed to the research and transcription efforts culminating in the present work (xiv–xv). Much of this material was assimilated in their preparation of this book; not always as seamlessly as they hoped (xiii). [End Page 398] The resulting volume includes a short, explanatory paragraph on their transcription methodology, an introduction, three chapters comprising the body of Wharton's journal entries, Wharton family genealogical tables, a "Biographical Register" of many of the people mentioned in the journals, an appendix listing Wharton's known artistic and architectural works, endnotes, and an index. Of the three main chapters, the first is an autobiographical sketch penned by Wharton in June 3, 1854 (31). The sometimes confusing and repetitive introduction greatly expands the background of Wharton's life and career. Chapter 2 covers the years 1832–1834 and offers an abundance of firsthand material about New York City and the lower Hudson River Valley in this period. Especially valuable are Wharton's recounted experiences of living in the Hudson River households of imminent physician, scholar, and botanist, Dr. David Hosack; Colonel Sylvanus Thayer, superintendent of West Point Military Academy; and Gouverneur Kemble, wealthy industrialist, patron of the arts, and a founder of the West Point Foundry in Cold Spring, New York. The societal and cultural interconnections among these individuals, in addition to prominent New York City architect, Martin Thompson, under whose direction Wharton studied, is revealed in remarkable detail. Recognizing his natural artistic talents, each of these men became important mentors to Wharton, shaped his career, and became lifelong friends. This portion of Wharton's journal includes descriptions of...

Response to Channel Deepening of the Salinity Intrusion, Estuarine Circulation, and Stratification in an Urbanized Estuary

AbstractModifications for navigation since the late 1800s have increased channel depth (H) in the lower Hudson River estuary by 10–30%, and at the mouth the depth has more than doubled. Observations along the lower estuary show that both salinity and stratification have increased over the past century. Model results comparing predredging bathymetry from the 1860s with modern conditions indicate an increase in the salinity intrusion of about 30%, which is roughly consistent with the H5/3 scaling expected from theory for salt flux dominated by steady exchange. While modifications including a recent deepening project have been concentrated near the mouth, the changes increase salinity and threaten drinking water supplies more than 100 km landward. The deepening has not changed the responses to river discharge (Qr) of the salinity intrusion (~Qr−1/3) or mean stratification (Qr2/3). Surprisingly, the increase in salinity intrusion with channel deepening results in almost no change in the estuarine circulation. This contrasts sharply with local scaling based on local dynamics of an H2 dependence, but it is consistent with a steady state salt balance that allows scaling of the estuarine circulation based on external forcing factors and is independent of depth. In contrast, the observed and modeled increases in stratification are opposite of expectations from the steady state balance, which could be due to reduction in mixing with loss of shallow subtidal regions. Overall, the mean shift in estuarine parameter space due to channel deepening has been modest compared with the monthly‐to‐seasonal variability due to tides and river discharge.

Eastern Oyster (&amp;lt;i&amp;gt;Crassostrea virginica&amp;lt;/i&amp;gt;) Filtration Efficiency of Chlorophyll-&amp;lt;i&amp;gt;a&amp;lt;/i&amp;gt; under Dynamic Conditions in the Hudson-Raritan Estuary at Pier 40, New York City

Eastern oyster (Crassostrea virginica) abundance has declined severely over the past century along the Atlantic and Gulf coasts of the United States. For varied reasons, overfishing among the foremost, bivalves no longer make up considerable reefs as was common. While discourse continues on oyster restoration and augmentation, gaps in knowledge of C. virginica and regional environmental interactions remain. Our primary aim was to examine the C. virginica filter feeding of phytoplankton in the Hudson River Estuary, New York City. Secondarily, this study examined the filtration of these oysters in relation to environmental attributes. Chlorophyll-a, the predominant photosynthesizing pigment in red and green algae, is an indicator of phytoplankton productivity in aquatic settings. Crassostrea virginica consumes first-tier plankton from the water column’s seston; thus analysis of chlorophyll-a content allows estimating phytoplankton concentrations, from which oyster filtration efficiency (FE) was quantified. Water conditions (temperature, dissolved oxygen, pH, salinity, turbidity, tide and flow rate) also were recorded. Spectrophotometric determination of chlorophyll-a concentration methodology was derived from the Standard Methods text favored by the US EPA. This project compared real-time Hudson River Estuary (HRE) water samples prior to passing through a contained oyster reef and samples of water post-filtration. This sampling scenario was unique as the contained reef used was fed by HRE water. Most studies on oyster filtration have been laboratory-based, and few assessed oysters in the field. This study took place at Pier 40, the River Project Wetlab, lower Hudson River along Manhattan. The FE of this reef was calculated for two months during various environmental states which can be the basis of future investigations. Statistically significant differences were found between pre- and post-filtration water samples (Z = 4.620, p < 0.001). This study provides a glimpse at how the oysters fare in the HRE environment and expands upon known oyster ecological services and environmental interactions.

GoFish: A versatile nested PCR strategy for environmental DNA assays for marine vertebrates.

Here we describe GoFish, a strategy for single-species environmental DNA (eDNA) presence/absence assays using nested PCR. The assays amplify a mitochondrial 12S rDNA segment with vertebrate metabarcoding primers, followed by nested PCR with M13-tailed, species-specific primers. Sanger sequencing confirms positives detected by gel electrophoresis. We first obtained 12S sequences from 77 fish specimens for 36 northwestern Atlantic taxa not well documented in GenBank. Using these and existing 12S records, we designed GoFish assays for 11 bony fish species common in the lower Hudson River estuary and tested seasonal abundance and habitat preference at two sites. Additional assays detected nine cartilaginous fish species and a marine mammal, bottlenose dolphin, in southern New York Bight. GoFish sensitivity was equivalent to Illumina MiSeq metabarcoding. Unlike quantitative PCR (qPCR), GoFish does not require tissues of target and related species for assay development and a basic thermal cycler is sufficient. Unlike Illumina metabarcoding, indexing and batching samples are unnecessary and advanced bioinformatics expertise is not needed. From water collection to Sanger sequencing results, the assay can be carried out in three days. The main limitations to this approach, which employs metabarcoding primers, are the same as for metabarcoding, namely, inability to distinguish species with shared target sequences and inconsistent amplification of rarer eDNA. In addition, the performance of the 20 assays reported here as compared to other single-species eDNA assays is not known. This approach will be a useful addition to current eDNA methods when analyzing presence/absence of known species, when turnaround time is important, and in educational settings.

Patterns of sediment-associated fecal indicator bacteria in an urban estuary: Benthic-pelagic coupling and implications for shoreline water quality

Estuarine and coastal waterways are commonly monitored for fecal and sewage contamination to protect recreator health and ecosystem functions. Such monitoring programs commonly rely on cultivation-based counts of fecal indicator bacteria (FIB) in water column samples. Recent studies demonstrate that sediments and beach sands can be heavily colonized by FIB, and that settling and resuspension of colonized particles may significantly influence the distribution of FIB in the water column. However, measurements of sediment FIB are rarely incorporated into monitoring programs, and geographic surveys of sediment FIB are uncommon. In this study, the distribution of FIB and the extent of benthic-pelagic FIB coupling were examined in the urbanized, lower Hudson River Estuary. Using cultivation-based enumeration, two commonly-measured FIB, enterococci and Escherichia coli, were widely distributed in both sediment and water, and were positively correlated with each other. The taxonomic identity of FIB isolates from water and sediment was confirmed by DNA sequencing. The geometric mean of FIB concentration in sediment was correlated with both the geometric mean of FIB in water samples from the same locations and with sediment organic carbon. These two positive associations likely reflect water as the FIB source for underlying sediments, and longer FIB persistence in the sediments compared to the water, respectively. The relative representation of other fecal associated bacterial genera in sediment, determined by 16S rRNA gene sequencing, increased with the sequence representation of the two FIB, supporting the value of these FIB for assessing sediment contamination. Experimental resuspension of sediment increased shoreline water column FIB concentrations, which may explain why shoreline water samples had higher average FIB concentrations than samples collected nearby but further from shore. In combination, these results demonstrate extensive benthic-pelagic coupling of FIB in an urbanized estuary and highlight the importance of sediment FIB distribution and ecology when interpreting water quality monitoring data.

Geochronology and geomorphology of the Jones Point glacial landform in Lower Hudson Valley (New York): Insight into deglaciation processes since the Last Glacial Maximum

The glacial deposits at Jones Point, located on the western side of the lower Hudson River, New York, were investigated with geologic, geophysical, remote sensing and optically stimulated luminescence (OSL) dating methods to build an interpretation of landform origin, formation and timing. OSL dates on eight samples of quartz sand, seven single-aliquot, and one single-grain of quartz yield an age range of 14–27 ka for the proglacial and glaciofluvial deposits at Jones Point. Optical age results suggest that Jones Point deposits largely predate the glacial Lake Albany drainage erosional flood episode in the Hudson River Valley ca. 15–13 ka. Based on this data, we conclude that this major erosional event mostly removed valley fill deposits, leaving elevated terraces during deglaciation at the end of the Last Glacial Maximum (LGM). Our analysis supports the earlier 15 ka date for the flood occurrence and suggests that more recent overlying glaciofluvial deposits formed in the lee-side of the Jones Point promontory.

Genomic analyses of Northern snakehead (Channa argus) populations in North America.

BackgroundThe introduction of northern snakehead (Channa argus; Anabantiformes: Channidae) and their subsequent expansion is one of many problematic biological invasions in the United States. This harmful aquatic invasive species has become established in various parts of the eastern United States, including the Potomac River basin, and has recently become established in the Mississippi River basin in Arkansas. Effective management of C. argus and prevention of its further spread depends upon knowledge of current population structure in the United States.MethodsNovel methods for invasive species using whole genomic scans provide unprecedented levels of data, which are able to investigate fine scale differences between and within populations of organisms. In this study, we utilize 2b-RAD genomic sequencing to recover 1,007 single-nucleotide polymorphism (SNP) loci from genomic DNA extracted from 165 C. argus individuals: 147 individuals sampled along the East Coast of the United States and 18 individuals sampled throughout Arkansas.ResultsAnalysis of those SNP loci help to resolve existing population structure and recover five genetically distinct populations of C. argus in the United States. Additionally, information from the SNP loci enable us to begin to calculate the long-term effective population size ranges of this harmful aquatic invasive species. We estimate long-term Ne to be 1,840,000–18,400,000 for the Upper Hudson River basin, 4,537,500–45,375,000 for the Lower Hudson River basin, 3,422,500–34,225,000 for the Potomac River basin, 2,715,000–7,150,000 for Philadelphia, and 2,580,000–25,800,000 for Arkansas populations.Discussion and ConclusionsThis work provides evidence for the presence of more genetic populations than previously estimated and estimates population size, showing the invasive potential of C. argus in the United States. The valuable information gained from this study will allow effective management of the existing populations to avoid expansion and possibly enable future eradication efforts.

Age and Growth of Juvenile Atlantic Sturgeon in the Lower Hudson River

AbstractThe precipitous decline of Atlantic Sturgeon Acipenser oxyrinchus oxyrinchus coupled with their recent listing under the U.S. Endangered Species Act necessitates investigations into their population dynamics. Our objectives were to (1) estimate age of juvenile Atlantic Sturgeon by using pectoral spine sections; (2) determine annual growth periodicity in hatchery‐reared and recaptured wild Atlantic Sturgeon to validate our aging method; (3) determine growth rates for recaptured juveniles; and (4) back‐calculate lengths from ages estimated by using pectoral spine sections from captured juveniles. Fish were captured via gillnetting in Newburgh and Haverstraw bays, Hudson River, during fall 2003, spring and fall 2004, and spring and fall 2005. Two readers agreed upon 91% (n = 474) of ages estimated for juvenile Atlantic Sturgeon, establishing a coefficient of variation of 1.7%. Eight year‐classes (ages 1–8) were represented, with age‐4 fish making up the largest age‐class (39%; n = 203) and age‐1 fish being the least represented (&lt;1%; n = 4). Multi‐annual oxytetracycline injections in four cohorts of hatchery‐reared Atlantic Sturgeon (n = 34) demonstrated a two‐part zone for each year of growth, as did four recaptured juveniles that were at liberty for a least 1 year, which exhibited mean growth rates of 0.3 mm/d and 2.4 g/d. We back‐calculated median FLs from annulus positioning in ages 2–8 by using dorsal and ventral lobes of pectoral spine sections and compared the results to actual reported lengths. Dorsal and ventral lobes underestimated the median FLs of all age‐classes except ages 3 and 7, for which lengths were overestimated. We found statistical differences between dorsal‐ and ventral‐derived median FLs, suggesting that both regions must be evaluated. Our overall goal is to provide researchers with a baseline of age and growth data for future work on juvenile Atlantic Sturgeon.

Aquatic environmental DNA detects seasonal fish abundance and habitat preference in an urban estuary.

The difficulty of censusing marine animal populations hampers effective ocean management. Analyzing water for DNA traces shed by organisms may aid assessment. Here we tested aquatic environmental DNA (eDNA) as an indicator of fish presence in the lower Hudson River estuary. A checklist of local marine fish and their relative abundance was prepared by compiling 12 traditional surveys conducted between 1988–2015. To improve eDNA identification success, 31 specimens representing 18 marine fish species were sequenced for two mitochondrial gene regions, boosting coverage of the 12S eDNA target sequence to 80% of local taxa. We collected 76 one-liter shoreline surface water samples at two contrasting estuary locations over six months beginning in January 2016. eDNA was amplified with vertebrate-specific 12S primers. Bioinformatic analysis of amplified DNA, using a reference library of GenBank and our newly generated 12S sequences, detected most (81%) locally abundant or common species and relatively few (23%) uncommon taxa, and corresponded to seasonal presence and habitat preference as determined by traditional surveys. Approximately 2% of fish reads were commonly consumed species that are rare or absent in local waters, consistent with wastewater input. Freshwater species were rarely detected despite Hudson River inflow. These results support further exploration and suggest eDNA will facilitate fine-scale geographic and temporal mapping of marine fish populations at relatively low cost.

Premigration Patterns of Growth, Condition, and Resource Use by the Spring-Spawned and Summer-Spawned Cohorts of Juvenile Bluefish in the Hudson River Estuary, New York

AbstractIn fish populations with multiple age-classes of similar size and close proximity, interactions between age-classes may be an important source of density-dependent population structuring if there is a disparity in competitive ability, creating a competitive bottleneck. However, intercohort competitive interactions within a single year-class have rarely been investigated and may have implications for recruitment success. Bluefish Pomatomus saltatrix produce at least two cohorts (spring- and summer-spawned) of offspring each year, and juveniles of this species are abundant in the lower Hudson River estuary, New York, during summer and early autumn. Our objectives were to evaluate the potential for a competitive bottleneck between these spring and summer cohorts by assessing the cohort-specific growth, condition, and patterns of resource use prior to the autumn migration in 2008 and 2009. The size advantage gained by the spring cohort resulting from earlier hatching dates was maintained throughout bo...

Historical sources of polychlorinated biphenyls to the sediment of the New York/New Jersey Harbor

Using dated sediment cores, polychlorinated biphenyl (PCB) congener concentrations in the New York/New Jersey Harbor and Lower Hudson River were investigated using Positive Matrix Factorization. Of the seven factors resolved, six represent Aroclors in various stages of weathering. Factor 1 resembles Aroclor 1242 and is consistent with the Upper Hudson River PCB signal associated with the General Electric capacitor plants near Hudson Falls, NY. This factor is the dominant source of PCBs in the upper layers of the sediment core collected in the Lower Hudson River. Factor 2 (Aroclor 1248) was the dominant PCB component in the core depths corresponding with around 1970, but it has decreased more rapidly since its peak (estimated half-life of about 5 years) than factor 1 (half-life of about 14 years), suggesting that PCBs from the Upper Hudson have delayed the recovery of the Harbor from PCB contamination. The seventh factor, comprised of PCBs 206, 208, and 209, was greatest in concentration in the deepest core slices and is thought be associated with inadvertent production of PCBs during the manufacture of titanium dioxide and/or with foundry waxes containing PCBs. PCB 11, which is thought to be associated with the use of color organic pigments, was examined separately and was detected in sediment throughout the Harbor. Its maximum concentrations generally occurred at the same depth as the maximum total PCB concentrations, suggesting that PCB 11 concentrations decreased after the mid-1970s.

Re-visiting projections of PCBs in Lower Hudson River fish using model emulation

Remedial decision making at large contaminated sediment sites with bioaccumulative contaminants often relies on complex mechanistic models to forecast future concentrations and compare remedial alternatives. Remedial decision-making for the Hudson River PCBs Superfund site involved predictions of future levels of PCBs in Upper Hudson River (UHR) and Lower Hudson River (LHR) fish. This study applied model emulation to evaluate the impact of updated sediment concentrations on the original mechanistic model projections of time to reach risk-based target thresholds in fish in the LHR under Monitored Natural Attenuation (MNA) and the selected dredging remedy.The model emulation approach used a combination of nonlinear and linear regression models to estimate UHR water PCBs as a function of UHR sediment PCBs and to estimate fish concentrations in the LHR as a function of UHR water PCBs, respectively. Model emulation captured temporal changes in sediment, water, and fish PCBs predicted by the mechanistic model over the emulation period. The emulated model, using updated sediment concentrations and a revised estimate of recovery rate, matched the trend in annual monitoring data for white perch and largemouth bass in the LHR between 1997 and 2014.Our best predictions based on the emulated model indicate that the projected time to reach fish tissue risk-based thresholds in the LHR will take decades longer than the original mechanistic model projections.

Contaminant bioaccumulation dynamics in young-of-the-year bluefish subpopulations in New York Bight with a special reference to the condition and nursery area fidelity subsequent to recruitment

Contaminant bioaccumulation dynamics was examined in young-of-the-year (YOY) bluefish subpopulations (Pomatomus saltatrix) in the New York Bight ecosystem, and the results were used to assess (i) effects of habitat quality in terms of levels of PCBs and pesticides on bluefish condition and (ii) fidelity of YOY bluefish to different subestuaries that served as the nurseries subsequent to recruitment during their first summer. Total PCBs and p,p′-DDE body burdens increased with fish length, but concentrations generally increased only poorly to moderately, which suggested steady-state contaminant uptake commensurate with aggressive feeding and dilution related to rapid growth characteristic of YOY bluefish within a subestuary. High condition factors paired with elevated contamination levels in bluefish from the Lower Hudson River, as compared with bluefish from Newark Bay with poor condition factors paired with elevated contamination levels, suggested that PCBs and pesticides alone may not determine condition in these fish. We found dissimilar patterns of prominent PCB congeners in bluefish from adjacent subestuaries (e.g., Newark Bay and Lower Hudson River) suggesting separate contaminant sources. Total PCB normalized fingerprints of PCB congeners permitted statistical discrimination among YOY bluefish specimens from various estuaries with a potential to differentiate subpopulations on scales to less than 20 km. This unexpected fidelity to nursery estuaries may have implications for the management strategies.

Partial migration of striped bass: revisiting the contingent hypothesis

ABSTRACT: Partial migration, by which contingents within populations undertake divergentmigrations, is common in marine fishes but remains poorly documented. Intrapopulation groups offish with similar seasonal migration behaviors were noted early in the fisheries literature and haveattracted increased interest for their role in population resilience to environmental change andfishing. Here, we used acoustic telemetry to test historical hypotheses on contingent structure forstriped bass Morone saxatilis in the Hudson River, New York (USA), which harbors one of thelargest populations of this species. Season and region of release were used as design elements toevaluate 3 principal contingents. In total, 51 implanted striped bass were detected in New YorkHarbor (NYH), Hudson River, and other estuarine and coastal receiver arrays from June 2010through December 2011. Multivariate analyses of >500000 recoveries confirmed predictions of3 broad contingent behaviors, viz. those that principally utilized (1) the Upper Hudson RiverEstuary, (2) the NYH and Lower Hudson River Estuary, and (3) coastal waters, but commingled inupper Hudson River spawning habitats during late spring. All contingents occupied NYH, buttheir transit routes into and out of the harbor varied significantly. Further behavioral diversity wasobserved within contingents, including size-specific differential migration, multiple natal origins(natal divergence), and non-annual (skipped) spawning. Contingent structure within HudsonRiver striped bass likely distributes the influences of regional fisheries, pollution, and other en -vironmental forces, promoting stability and persistence in the overall population.KEY WORDS:

Geographic variability in amoeboid protists and other microbial groups in the water column of the lower Hudson River Estuary (New York, USA)

In comparison to other groups of planktonic microorganisms, relatively little is known about the role of amoeboid protists (amebas) in planktonic ecosystems. This study describes the first geographic survey of the abundance and biomass of amebas in an estuarine water column. Samples collected in the lower Hudson River Estuary were used to investigate relationships between ameba abundance and biomass and hydrographic variables (temperature, salinity, and turbidity), water depth (surface and near bottom), distance from mid-channel to shore, phytoplankton biomass (chlorophyll fluorescence) and the occurrence of other heterotrophic microbial groups (heterotrophic bacteria, nanoflagellates, and ciliates) in the plankton. Although salinity increased significantly towards the mouth of the estuary, there were no significant differences in the abundance or biomass of any microbial group in surface samples collected at three stations separated by 44 km along the estuary's mid-channel. Peak biomass values for all microbial groups were found at the station closest to shore, however, cross-channel trends in microbial abundance and biomass were not statistically significant. Although ameba abundance and biomass in most samples were low compared to other microbial groups, clear patterns in ameba distribution were nevertheless found. Unlike other microbial groups examined, ameba numbers and biomass greatly increased in near bottom water compared to surface samples. Ameba abundance and biomass (in surface samples) were also strongly related to increasing turbidity. The different relationships of ameba abundance and biomass with turbidity suggest a rising contribution of large amebas in microbial communities of the Hudson estuary when turbidity increases. These results, emphasizing the importance of particle concentration as attachment and feeding surfaces for amebas, will help identify the environmental conditions when amebas are most likely to contribute significantly to estuarine bacterivory and C-flux.