York Bight Research Articles

Surface Velocity Estimation From Satellite Imagery Using Displaced Frame Central Difference Equation

Estimation of surface velocity from satellite imagery with large-scale displacement and longer temporal interval is one of the most challenging remote sensing problems in ocean dynamics. In this paper, a nonlinear inverse model using the displaced frame central difference (DFCD) equation has been created for estimating velocity in an image sequence. Iterative equations with Gauss-Newton and Levenberg-Marquardt algorithms are formulated for solving the nonlinear system of equations. A unified adaptive framework is developed based on the DFCD equations, velocity field modeling, a nonlinear least-squares model, and an algorithm of progressive relaxation of the overconstraint for seeking a flow field in which each vector is consistent with its neighbors. A numerical model is used as a benchmark to examine the accuracy of this new technique. Three sequences of NOAA Advanced Very High Resolution Radiometer (AVHRR) images taken in the New York Bight are also used to demonstrate the performance of the proposed technique. The estimated velocity fields are compared with those measured with the coastal ocean dynamics applications radar array. The experimental results indicate that the new estimator with the DFCD equation has major improvement over the linear inverse model for the simulation and real AVHRR data sets.

Growth and Survival of Hatchery-Produced Atlantic Sturgeon Released as Young-of-Year into the Hudson River, New York

Abstract In 2007, a team of U.S. scientists performed a status review of Atlantic sturgeon Acipenser oxyrinchus oxyrinchus and concluded that the species would likely become endangered (U.S. Endangered Species Act 1973, as amended) in the foreseeable future over much of its range, including populations of the New York Bight, which is comprised of the Hudson and Delaware rivers. Therefore, we evaluated an experimental release of hatchery-produced Atlantic sturgeon that took place in 1994 to determine the value of using stocked fish as a population recovery tool. We obtained recapture data on hatchery fish (identified by presence of pelvic fin removal) from the Atlantic Coast Sturgeon Tagging Database. Our evaluation of retention for a pelvic fin removal mark on hatchery fish showed that 36% of clipped individuals retained a clean fin clip after 49 d. The minimum survival rate for hatchery fish to age 5 was estimated to be in the range of 0.49–0.66% using documented recaptures (N = 24), known number of fish stocked, and results of the pelvic fin removal evaluation. Length and weight-at-age for recaptured hatchery fish at known ages 5–17 were within the range of values reported for wild fish whose ages were estimated by pectoral spine analysis. We also report that one ripe male hatchery fish at age 15 was captured along with other spermiating males at its parental spawning area in the Hudson River in 2009.

Assimilation of HF radar-derived surface currents on tidal-timescales

A surface current observation system based on high-frequency (HF) radar has been developed for Raritan Bay and the coastal waters of New York and New Jersey. An HF radar network provides synoptic surface current maps in near-real-time that can be optimally combined with ocean circulation models using data assimilation (DA) framework to obtain the best possible estimate of a three-dimensional ocean state. A nudging or Newtonian damping scheme has been developed to assimilate HF radar data into an estuarine and coastal ocean circulation model. This model, with an extensive embedded real-time observational network, is called the New York Harbour Observing and Prediction System (NYHOPS). A nudging parameter is introduced into the equations of motion which affects the model dynamics. The data is imparted to neighbouring (three-dimensional) grid points via model dynamics. The impact of HF radar DA is analysed by computing the DA skill score (DAskill) based on the mean-square-error (mse). The DAskill is computed by comparing non-assimilated and assimilated model solutions with in-situ observations of three-dimensional currents, temperature and salinity, which have not been included in the assimilation. A positive DAskill (0∼1) represents an improvement in the model performance by assimilation. HF radar data covering Raritan Bay and the New York Bight (NYB) Apex were assimilated into the NYHOPS model in the model hindcast cycle (–24h to 0h) on a daily forecast basis for a period of 40 days. The DAskill is assessed with respect to the NYHOPS model hindcasts (daily model solutions from –24h to 0h) as well as the first day forecasts (daily model solutions from 0h to 24h). HF radar DA improved the NYHOPS model performance during both the hindcast and forecast periods. The model skill metrics for the near-surface layers in the inner-NJ shelf region shows a hindcast DAskill of 24% (14%) and forecast DAskill of 18% (7%) for horizontal velocities u: east-west component (v: north-south component), and a hindcast DAskill of 33% (38%) and forecast DAskill of 25% (30%) for temperature (salinity). The nudging scheme is robust and efficient for the HF radar DA into the NYHOPS operational forecast model. The NYHOPS-HF radar DA system is capable of importing in the observations and produce useful hindcasts/forecasts with minimum computational expense.

Structure and dynamics of the midshelf front in the New York Bight

The structure and variability of the wintertime midshelf front in the New York Bight is examined using moored observations of currents and hydrography during 2007. The front is located near the 50 m isobath, inshore of the shelf break front and offshore of estuarine outflow plume fronts. It spans the water column and is the boundary between cooler, fresher, and less dense inner shelf water and warmer, saltier, and denser outer shelf water. The mean hydrographic front slopes upward offshore, and there is an associated equatorward along‐shelf 5–10 cm/s surface‐intensified current jet. The mean across‐shelf circulation is offshore near the surface and onshore at depth. The across‐shelf velocity is convergent and strengthens across‐shelf property gradients with a time scale for gradient doubling of approximately 8 days. Tidal analysis of currents and temperatures suggests that tidal shear dispersion is not an important mechanism for midshelf front formation. The frontal structure and location are roughly consistent with the theory of bottom boundary layer advected fronts, suggesting that multiple estuarine outflows are collectively responsible. Pulses of strong offshore wind cause the breakdown of the across‐shelf thermal wind balance, which has been commonly assumed to hold in shelf environments. Observed shear significantly exceeds thermal wind shear at middepths, where observation of low‐gradient Richardson number indicates the importance of vertical mixing. The response of currents to wind fluctuations is asymmetric, whereby the combination of upwelling favorable and offshore winds or downwelling favorable and onshore winds produces a stronger response than winds from the remaining quadrants.

Genetic mixed‐stock analysis of Atlantic sturgeon Acipenser oxyrinchus oxyrinchus in a heavily exploited marine habitat indicates the need for routine genetic monitoring

Although a previous genetic mixed-stock analysis (gMSA) conducted in the early 1990s showed that marine-captured New York Bight Atlantic sturgeon Acipenser oxyrinchus oxyrinchus almost exclusively originated from the Hudson River, fish from southern U.S. rivers were well represented within this contemporary sample (n = 364 fish), at least during the autumn. Widely distributed spawning stocks are therefore exposed to heavy fishing activity and habitat degradation in this relatively small area, illustrating the need for spatial management across multiple management jurisdictions and routine gMSA to account for temporal change.

Nonlinear inverse model for velocity estimation from an image sequence

[1] Velocity estimation from an image sequence is one of the most challenging inverse problems in computer vision, geosciences, and remote sensing applications. In this paper a nonlinear model has been created for estimating motion field under the constraint of conservation of intensity. A linear differential form of heat or optical flow equation is replaced by a nonlinear temporal integral form of the intensity conservation constraint equation. Iterative equations with Gauss-Newton and Levenberg-Marguardt algorithms are formulated based on the nonlinear equations, velocity field modeling, and a nonlinear least squares model. An algorithm with progressive relaxation of the overconstraint to improve the performance of the velocity estimation is also proposed. The new estimator is benchmarked using a numerical simulation model. Both angular and magnitude error measurements based on the synthetic surface heat flow from the numerical model demonstrate that the performance of the new approach with the nonlinear model is much better than the results of using a linear model of heat or optical flow equation. Four sequences of NOAA Advanced Very High Resolution Radiometer (AVHRR) images taken in the New York Bight fields is also used to demonstrate the performance of the nonlinear inverse model, and the estimated velocity fields are compared with those measured with the Coastal Ocean Dynamics Radar array. The experimental results indicate that the nonlinear inverse model provides significant improvement over the linear inverse model for real AVHRR data sets.

Near-Surface Larval and Juvenile Fish in Coastal Habitats: Comparisons Between the Inner Shelf and an Estuary in the New York Bight During Summer and Fall

Exchanges of fish larvae between the inner continental shelf and estuaries can be critical to the functional significance of these habitats as nurseries. We sampled near-surface fishes on the inner continental shelf off New Jersey and in an adjacent estuary during the summer and fall of 2005 and 2006 to evaluate the occurrence and variation in these connections. Very few of the abundant taxa (Anchoa mitchilli, Brevoortia tyrannus, Urophycis regia, Etropus microstomus, Peprilus triacanthus, and Pomatomus saltatrix) were exclusive to either habitat but some did change in relative habitat affinity among seasons. For some species, this was indicative of a departure from the ocean for estuaries (e.g., Micropogonias undulatus) while others used both habitats during the summer and fall (e.g., Syngnathus fuscus, Scophthalmus aquosus, and A. mitchilli). Together, these observations confirm the high degree of connectivity between the near-surface larval fishes from the inner continental shelf and estuaries.

Surface currents in Raritan Bay, New Jersey: Importance of HF radar first-order Doppler settings

A surface current observation system based on high-frequency Coastal Ocean Dynamics Application Radar (CODAR) has been developed for Raritan Bay and the coastal waters of New York and New Jersey. This unique oceanographic tool is capable of measuring currents and waves at the ocean surface using resonant Bragg scatter return from transmitted radio signals. Surface current is measured by analysing the high-frequency (HF) radar sea-echo for the Doppler frequency shift where the frequencies of the first-order (FO) Doppler peaks that separate the surface current reflectance from the higher-order receiver signals are empirically determined.The presence of strong currents and horizontal shear in the near-surface flow results in spreading of the FO Doppler region, making it difficult to distinguish FO Doppler peaks from higher-order signals.Differentiating the FO Doppler region using empirical frequency cut-off parameters is one of the important steps in spectral processing of the HF radar receiver signals. The present work focuses on the surface current circulation in Raritan Bay and the New York Bight (NYB) Apex using HF radar observations, and to understand the importance of empirical determination of the FO Doppler region of the HF radar system in a strong, tidally dominated estuarine-ocean circulation.Comparison of HF radar observations with historic mooring observation and three-dimensional ocean model simulation shows that the HF radar system is highly sensitive to FO Doppler region settings. Strong tidal currents and wave-current interaction introduces spreading of the FO Doppler spectrum which results in underestimation of surface currents near the mouth of the New York/New Jersey (NY/NJ) harbour estuary.

Optical complexity in Long Island Sound and implications for coastal ocean color remote sensing

The optical properties of estuaries can vary considerably with the delivery of pigmented materials from surrounding watersheds and marine waters. In this study, optical properties sampled at 158 stations throughout the Long Island Sound (LIS) estuary between 2004 and 2007 show significant regional variability. Chlorophyll, total suspended matter, light absorption, and scattering are exceptionally high compared to other coastal data. Inherent optical properties and sea surface reflectances revealed at least two optical domains: a phytoplankton‐dominated regime in western LIS and New York Bight and a sediment‐dominated regime in central and eastern LIS. Multivariate ordination analysis identified clusters of stations conforming to these optical domains, as well as stations near the Hudson and Connecticut rivers representing optical end‐members in LIS characterized by high chromophoric dissolved material (CDM) and biomass (Hudson River) and high sediment loads (Connecticut River). However, winds, tides, and subtidal estuarine circulation redistribute optical constituents throughout the major basins of LIS and homogenize riverine influence. Ocean color parameters, used to define the spectral quality of optical constituents, such as the spectral slopes of particulate backscattering and CDM absorption, and the chlorophyll‐specific phytoplankton absorption did not cluster and are relatively constant throughout the region at all times of year. Therefore, variability in spectral reflectance in LIS is principally controlled by the relative magnitudes of the optical properties at each station rather than by significant differences in spectral quality of optically significant constituents. Consistency in these ocean color parameters minimizes the necessity for subregional or seasonal “tuning” of ocean color algorithms.

High‐frequency forcing and subtidal response of the Hudson River plume

The Lagrangian Transport and Transformation Experiments (LaTTE) document the physical, biological, and chemical evolution of the Hudson River plume during the spring seasons of 2004, 2005, and 2006. While plume variability due to river discharge, subinertial frequency variability in winds, and ambient shelf circulation are important, the observations show that the plume reacts directly to higher‐frequency forcing as well. Mooring records during 2005 and 2006 show that fortnightly variability in tidal mixing is manifested as fortnightly changes in plume stratification. Diurnal variability related to forcing by the sea‐land breeze system (SLBS) is apparent in the Hudson River plume during the 2005 experiment. The SLBS, while episodic, accounts for ∼15% of the kinetic energy in surface currents in the New York Bight apex during the summer months with individual SLBS events providing up to 50% of the total kinetic energy. Simulations of the plume, using the Regional Ocean Modeling System (ROMS), demonstrate there is a subtidal response to high‐frequency forcing. Spring‐neap variability in tidal mixing modifies the estuary outflow Rossby and Froude numbers, resulting in increased transport (80% of river discharge) in the New Jersey coastal current during spring tides with lower transport (60% of river discharge) during neap tides. SLBS variability results in greater storage of river discharge water in the recirculating bulge region and increases the net transport of freshwater along the Long Island coast while significantly reducing freshwater supplied to the New Jersey coastal current to as little as 30% of the total river discharge.

The New York Bight Jet: Climatology and Dynamical Evolution

Abstract This paper describes the southerly New York Bight (NYB) jet (11–17 m s−1) that develops primarily during the warm season just above the surface offshore (east) of the northern New Jersey coast and south of Long Island (the NYB). Observations from two offshore buoys are used to develop a 9-yr climatology of 134 jet events from 1997 to 2006. There is a seasonal maximum (2.5 events per month) during June and July, with a skew toward the spring months. The wind directions for the jet trace out a nearly elliptical orbit for the 24-h period around the time of jet maximum at ~2300 UTC [1900 eastern daylight time (EDT)] on average. Composites reveal that the NYB jet occurs on days with southwesterly synoptic flow, and the jet is part of a larger-scale (200–300 km) wind enhancement offshore of the mid-Atlantic and northeast U.S. coasts during the early evening hours. High-resolution observations (surface mesonet, aircraft soundings, and a terminal Doppler weather radar) and Weather Research and Forecasting (WRF) model simulations down to 1.33-km grid spacing are used to diagnose the evolution of the NYB jet on 2 June 2007. The NYB jet at ~150 m MSL occurs within the sloping marine inversion near the coast. Low-level trajectories illustrate low-level diffluence and weak subsidence within the jet. A WRF momentum budget highlights the evolving pressure gradient and accelerations during jet formation. The maximum jet winds occur 1–2 h after the peak meridional pressure gradient is established through a geostrophic adjustment process. Sensitivity experiments show that jet occurrence is dependent on diurnal heating and that the concave bend in the southern New Jersey coast limits the southern extent of the jet.

Simulation of Water Age and Residence Time in New York Bight

Abstract The time scales on which river inflows disperse in the coastal ocean are relevant to a host of biogeochemical and environmental processes. These time scales are examined in a modeling study of the Hudson River plume on its entry to the New York Bight (NYB). Constituent-oriented age and residence-time theory is applied to compute two time scales: mean age, which is calculated from the ratio of two model tracers, and residence time, which is calculated using the adjoint of the tracer conservation equation. Spatial and temporal variability associated with river discharge and wind is investigated. High river discharge lowers surface water age and shortens residence time in the apex of the NYB. Easterly winds increase surface water age and extend the duration waters along the Long Island coast remain in the NYB apex. Southerly winds increase age along the New Jersey coast but drive a decrease in age of offshore surface waters and prolong the time that surface waters close to the New Jersey coast stay in the NYB apex. Residence time along the Long Island coast is high in spring and summer because of the retention of water north of the Hudson shelf valley. Patterns of modeled surface water age and an age proxy computed from the ratio of satellite-measured irradiance in two channels show qualitative agreement. A least squares fit gives a statistically significant empirical relationship between the band ratio and modeled mean age for NYB waters.

A Global Optimal Solution With Higher Order Continuity for the Estimation of Surface Velocity From Infrared Images

A global optimal solution (GOS) provides surface velocities from Advanced Very High Resolution Radiometer (AVHRR) remote image sequences using bilinear interpolation algorithms. Although an accurate velocity field can be estimated by GOS from a sequence of infrared images, the field has only first-order continuity. Because an actual coastal ocean has a complex irregular coastland and some ocean studies need vorticity and divergence analysis, which must be extracted from the velocity field, the development of generic GOS algorithms with higher order continuity and smoothed cutouts around these edges is very important. This paper addresses the issues of higher order continuity and smoothed cutouts around coastland edges for using GOS to estimate surface velocities. GOS bilinear polynomials, previously applied to square tiles with first-order continuity, are replaced by surface B-spline functions. The new GOS algorithms can be applied to AVHRR images containing complicated coastal land boundaries, even clouds, to yield smooth velocity fields next to land and higher order continuity velocity fields. The velocity fields obtained through the applications of the first- and higher order GOS techniques to a sequence of two National Oceanic Atmospheric Administration AVHRR images, which were taken from the New York Bight fields, are compared with those measured with the CODAR array. The retrieved velocity fields are used directly to calculate the surface divergence and vorticity. It is found that the angular and magnitude errors of the velocity by the first- and third-order GOSs are quite close for both numerical model data and AVHRR image sequences, and the velocity field estimated by the third-order GOS is globally smoothed.

Atlantic Sturgeon Vessel‐Strike Mortalities in the Delaware Estuary

AbstractThe Atlantic Sturgeon Status Review Team has recommended that the Secretary of Commerce list the New York Bight distinct population segment of Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus), which includes the Delaware River and Hudson River populations, as threatened under the federal Endangered Species Act. Between 2005 and 2008, a total of 28 Atlantic sturgeon mortalities were reported in the Delaware Estuary. Sixty‐one percent of the mortalities reported were of adult size and 50% of the mortalities resulted from apparent vessel strikes. The remainder of the mortalities were too decomposed to ascertain the cause of death, but the majority were likely the result of vessel strikes. For small remnant populations of Atlantic sturgeon, such as that in the Delaware River, the loss of just a few individuals per year due to anthropogenic sources of mortality, such as vessel strikes, may continue to hamper restoration efforts. An‐egg‐per‐recruit analysis demonstrated that vessel‐strike mortalities could be detrimental to the population if more than 2.5% of the female sturgeon are killed annually. We report on our observations of vessel‐strike mortalities in the Delaware Estuary, discuss the possible implications for the Delaware River population, and recommend further research.

Potential on-shore and off-shore reservoirs for CO 2 sequestration in Central Atlantic magmatic province basalts

Identifying locations for secure sequestration of CO(2) in geological formations is one of our most pressing global scientific problems. Injection into basalt formations provides unique and significant advantages over other potential geological storage options, including large potential storage volumes and permanent fixation of carbon by mineralization. The Central Atlantic Magmatic Province basalt flows along the eastern seaboard of the United States may provide large and secure storage reservoirs both onshore and offshore. Sites in the South Georgia basin, the New York Bight basin, and the Sandy Hook basin offer promising basalt-hosted reservoirs with considerable potential for CO(2) sequestration due to their proximity to major metropolitan centers, and thus to large industrial sources for CO(2). Onshore sites are suggested for cost-effective characterization studies of these reservoirs, although offshore sites may offer larger potential capacity and additional long-term advantages for safe and secure CO(2) sequestration.

Towards an integrated observation and modeling system in the New York Bight using variational methods. Part II: Repressenter-based observing strategy evaluation

As part of an effort to build an integrated observation and modeling system for the New York Bight, this study explores observing strategy evaluation using a representer-based method. The representer of a single observation describes the covariance between the observed quantity and ocean state errors at all locations at any time within the assimilation window. It also describes the influence of the observation on control variable correction in a 4D variational data assimilation system. These properties hold for the combination of representers that is associated with a group of observations and functions of model variables that combines model variables (e.g. salt flux). The representer-based method is used here to identify which of a set of proposed tracks for an autonomous coastal glider is better for predicting horizontal salt flux within the Hudson Shelf Valley in a 2-day forecast period. The system is also used to compare different observation strategies. We show that a glider that traverses a regular transect influences a larger area than a continuously profiling mooring, but the mooring carries stronger influence at the observation location. The representer analysis shows how the information provided by observations extends toward the dynamically upstream and how increasing the duration of the analysis window captures more dynamical connections and expands the area of influence of the observations in data assimilation. Overall, the study demonstrates that the representer methodology can quantitatively contrast different observational strategies and determine spatial patterns and temporal extent of the influence of observations, both of which are helpful for evaluating the design of observation networks.

Towards an integrated observation and modeling system in the New York Bight using variational methods. Part I: 4DVAR data assimilation

Four-dimensional variational data assimilation (4DVAR) in the Regional Ocean Modeling System (ROMS) is used to produce a best-estimate analysis of ocean circulation in the New York Bight during spring 2006 by assimilating observations collected by a variety of instruments during an intensive field program. An incremental approach is applied in an overlapped cycling system with 3-day data assimilation window to adjust model initial conditions. The model-observation mismatch for all observed variables is reduced substantially. Comparisons between model forecast and independent observations show data assimilation improves forecast skill for about 15 days for temperature and salinity, and 2–3 days for velocity when the model is forced by a concatenation of successive 24-h meteorological forecasts. These time scales for forecast improvement due to data assimilation may be less in practice with real-time multi-day forecast meteorology. Tests that limit the data used to certain subsets show that assimilating satellite sea surface temperature data improves the forecast of surface and subsurface temperature, assimilating in situ temperature and salinity data from gliders improves the subsurface temperature and salinity forecast, and assimilating HF-radar surface current data improves the velocity forecast yet degrades the subsurface temperature forecast – an effect that is attributed to the lack of cross-variable covariance in the univariate background error covariance used here. During some time periods the convergence for velocity is poor as a result of the data assimilation system being unable to adjust for errors in the applied winds because surface forcing is not among the control variables. The capability of a 4DVAR data assimilation system to reduce model-observation mismatch and improve forecasts in the coastal ocean is demonstrated, and the value of accurate meteorological forcing is highlighted.

Spring and Summer Larval Fish Assemblages in the Surf Zone and Nearshore off Northern New Jersey, USA

Larval fish use of surf zone and nearshore habitats at northern latitudes has received little attention. Consequently, potential impacts of beach nourishment and other forms of disturbance are not well understood. This study, on a northwestern Atlantic coastline spanning May through July over 4 years, demonstrates that recently hatched larvae are common in both surf zone and nearshore habitats. Taxonomic compositions of surf zone and nearshore assemblages were similar to each other and those from an adjacent estuary. An influence of upwelling events was apparent in coincident changes in abundance and/or size of several species in the surf zone. Other changes over the late spring–summer transition, including buoyancy-driven flows from the Hudson River plume, demonstrate the dynamic nature of larval fish assemblages in the New York Bight area.

Expanded Range and New Host Species of Mycobacterium shottsii and M. pseudoshottsii

Mycobacterium shottsii and M. pseudoshottsii are recently described mycobacteria commonly isolated from Chesapeake Bay striped bass Morone saxatilis. However, their distribution in striped bass outside of the Chesapeake region and their ability to infect alternative hosts have not been described. Mycobacteria identified as M. shottsii (based on fatty acid methyl ester analysis and multigene sequencing) were isolated from striped bass collected in Albemarle Sound, North Carolina, and white perch Morone americana in the Rhode River, Maryland, and detected in striped bass from the New York Bight off Long Island, New York. Mycobacterium pseudoshottsii were isolated from white perch in the Rhode and Corsica rivers, Maryland, and detected in striped bass in the New York Bight. This work demonstrates that these mycobacteria can be found outside of the Chesapeake Bay as well as in hosts other than striped bass.

Dichelesthium oblongum (Copepoda: Dichelesthiidae) infestation in wild-caught Atlantic sturgeon, Acipenser oxyrinchus oxyrinchus

Abstract Fast, M. D., Sokolowski, M. S., Dunton, K. J., and Bowser, P. R. 2009. Dichelesthium oblongum (Copepoda: Dichelesthiidae) infestation in wild-caught Atlantic sturgeon, Acipenser oxyrinchus oxyrinchus. – ICES Journal of Marine Science, 66: 2141–2147. Atlantic sturgeon were sampled in autumn 2007 and 2008 along the New York Bight. The fish were examined for the presence of external parasites, and blood, fin, and opercula biopsies were collected for subsequent serum analysis and histopathological evaluation. Dichelesthium oblongum, a parasitic copepod, was observed on 93% of the sturgeon sampled (77 out of 83) between Rockaway and Jones Beaches, NY, and Sandy Hook, NJ. During the course of the examinations, grossly visible lesions associated with the attachment and feeding of juvenile stages of D. oblongum were noted on the operculum, pectoral, dorsal, and anal fins of infested fish. Significant differences were observed between the level of infestation and serum chemistry across sampling sites, such that the most heavily infested fish were caught off Jones Beach (15.8 ± 2.79 lice fish−1), higher infestations than at Rockaway Beach (8.86 ± 0.89 lice fish−1) and Sandy Hook (5.31 ± 1.40 lice fish−1). Animals from Jones Beach also indicated ion loading (i.e. sodium, calcium, and magnesium), possibly as a result of stress or water loss through D. oblongum infestation compromising the epithelial barrier. The interaction of the environment and parasite with host life-history characteristics are discussed in terms of their ecological significance to this threatened fish species.