Per/polyfluoroalkyl substances (PFASs) are ubiquitous, highly persistent anthropogenic chemicals that bioaccumulate and biomagnify in aquatic food webs and are associated with adverse health effects, including liver and kidney diseases, cancers, and immunosuppression. We investigated the accumulation of PFASs in a marine apex predator, the white shark (Carcharodon carcharias). Muscle (N = 12) and blood plasma (N = 27) samples were collected from 27 sharks during 2018-2021 OCEARCH expeditions along the eastern coast of North America from Nova Scotia to Florida. Samples were analyzed for 47 (plasma) and 43 (muscle) targeted PFASs and screened for >2600 known and novel PFASs using liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS). Perfluoroalkyl carboxylates with carbon chain-length C11 to C14 were frequently detected above the method reporting limits in plasma samples, along with perfluorooctanesulfonate and perfluorodecanesulfonate. Perfluoropentadecanoate was also detected in 100% of plasma samples and concentrations were estimated semiquantitatively as no analytical standard was available. Total concentrations of frequently detected PFASs in plasma ranged from 0.56 to 2.9 ng mL-1 (median of 1.4 ng mL-1). In muscle tissue, nine targeted PFASs were frequently detected, with total concentration ranging from 0.20 to 0.84 ng g-1 ww. For all frequently detected PFASs, concentrations were greater in plasma than in muscle collected from the same organism. In both matrices, perfluorotridecanoic acid was the most abundant PFAS, consistent with several other studies. PFASs with similar chain-lengths correlated significantly among the plasma samples, suggesting similar sources. Total concentrations of PFASs in plasma were significantly greater in sharks sampled off of Nova Scotia than all sharks from other locations, potentially due to differences in diet. HRMS suspect screening tentatively identified 13 additional PFASs in plasma, though identification confidence was low, as no MS/MS fragmentation was collected due to low intensities. The widespread detection of long-chain PFASs in plasma and muscle of white sharks highlights the prevalence and potential biomagnification of these compounds in marine apex predators.

Winter flounder Pseudopleuronectes americanus (Walbaum 1792) are a coastal flatfish species of economic and cultural importance that have dwindled to <15, % of their historic abundance in the southern New England/Mid-Atlantic region of the United States, with evidence indicating near-extirpation of certain local populations. This species exhibits intricate behaviors in spawning and migration that contribute to population complexity and resilience. These behaviors encompass full or partial philopatry to natal estuaries, the generation of multiple pulses of larval delivery, and partial migration. The patterns of genetic diversity within and among estuaries and cohorts presented here carry important implications in understanding the susceptibility to demographic shocks, even if the full extent of genetic diversity within and among winter flounder stocks on the US East Coast remains unresolved. Our findings reveal connectivity between estuaries in Long Island, New York, suggesting the potential for genetic rescue of depleted subpopulations. Family reconstruction and relatedness analysis indicate that split cohorts and migration contingents are not the result of genetically distinct lineages. We found no evidence for genetic structure separating these groups, and in some instances, we were able to detect closely related individuals that belonged to different migratory contingents or cohorts. Characterizing the spatial and behavioral organization of this species at the population level is crucial for comprehending its potential for recovery, not only in terms of biomass but also in reinstating the complex population structure that supports resilience. The search for generality in winter flounder spawning and migration behavior remains elusive, but perhaps the lack of generalities within this species is what has allowed it to persist in the face of decades of environmental and anthropogenic stressors.

The ecology and life-histories of white sharks make this species susceptible to mercury bioaccumulation; however, the health consequences of mercury exposure are understudied. We measured muscle and plasma total mercury (THg), health markers, and trace minerals in Northwest Atlantic white sharks. THg in muscle tissue averaged 10.0 mg/kg dry weight, while THg in blood plasma averaged 533 mu g/L. THg levels in plasma and muscle were positively correlated with shark precaudal length (153-419 cm), and THg was bioaccumulated proportionally in muscle and plasma. Nine sharks had selenium:mercury molar ratios in blood plasma >1.0, indicating that for certain individuals the potential protective effects of the trace mineral were diminished, whereas excess selenium may have protected other individuals. No relationships between plasma THg and any trace minerals or health markers were identified. Thus, we found no evidence of negative effects of Hg bioaccumulation, even in sharks with very high THg.

Effluents from ten full-scale municipal wastewater treatment plants (WWTPs) that discharge into the Hudson River, surface waters, and wild-caught fish samples were analyzed using liquid chromatography with tandem mass spectrometry (LC/MS/MS) to examine the influence of wastewater discharge on the concentrations of contaminants of emerging concern (CECs) and their ecological impacts on fish. Analysis was based on targeted detection of 41 pharmaceuticals, and non-targeted analysis (suspect screening) of CECs. Biological effects of treated WWTP effluents were assessed using a larval zebrafish (Danio rerio) swimming behavior assay. Concentrations of residues in surface waters were determined in grab samples and polar organic chemical integrative samplers (POCIS). In addition, vitellogenin peptides, used as biomarkers of endocrine disruption, were quantified using LC/MS/MS in the wild-caught fish plasma samples. Overall, 94 chemical residues were identified, including 63 pharmaceuticals, 10 industrial chemicals, and 21 pesticides. Eight targeted pharmaceuticals were detected in 100% of effluent samples with median detections of: bupropion (194 ng/L), carbamazepine (91 ng/L), ciprofloxacin (190 ng/L), citalopram (172 ng/L), desvenlafaxine (667 ng/L), iopamidol (3790 ng/L), primidone (86 ng/L), and venlafaxine (231 ng/L). Over 30 chemical residues were detected in wild-caught fish tissues. Notably, zebrafish larvae exposed to chemical extracts of effluents from 9 of 10 WWTPs, in at least one season, were significantly hyperactive. Vitellogenin expression in male or immature fish occurred 2.8 times more frequently in fish collected from the Hudson River as compared to a reference site receiving no direct effluent input. Due to the low concentrations of pharmaceuticals detected in effluents, it is likely that chemicals other than pharmaceuticals measured are responsible for the behavioral changes observed. The combined use of POCIS and non-target analysis demonstrated significant increase in the chemical coverage for CEC detection, providing a better insight on the impacts of WWTP effluents and agricultural practices on surface water quality.

Post-settlement mortality and growth in flatfish has the potential to profoundly impact year-class strength. However, the abiotic drivers of post-settlement mortality and growth are difficult to disentangle from the effects of predation. Young-of-the-year (YOY) winter flounder Pseudopleuronectes americanus, collected from Shinnecock Bay, NY (USA), were kept in predator-exclusion cages from May through August in 2016 and 2017, with simultaneous recording of dissolved oxygen, temperature and salinity at each caging site. Daily mortality rates in cages were 7 to 5.9 times less than mortality estimated for wild fish from the same area. We modeled the effect of 9 time-varying environmental variables, as well as the effect of cage location and depth, on survival and growth of caged fish using a Cox proportional hazards model with time-dependent covariates. The site that had the best survival in 2016 was not the site that had the best growth within that year, highlighting the potential for trade-offs between survival and growth. We found evidence that environmental conditions can impose both acute and chronic stress to YOY fish in estuarine environments, as well as potential threshold effects that warrant further exploration. Future monitoring efforts and studies of habitat suitability should take into account the degree and duration of exposure to temperature, salinity and dissolved oxygen extremes, not just the average conditions. We argue that risk can more accurately be captured by measuring aspects of the frequency, duration and intensity of both acute and chronic manifestations of environmental stressors, revealing potential thresholds and sublethal effects.

Winter Flounder Pseudopleuronectes americanus, a coastal flatfish species of historically economic and cultural importance, have declined throughout the past few decades within the southern New England and mid-Atlantic region of the United States, reaching a low point of less than 9% of their historic biomass in 2009. Unusually high postsettlement mortality is thought to impose a critical recruitment bottleneck on the population, potentially stalling recovery of Winter Flounder populations despite management measures. Survival and growth during early life history play a key role in the recruitment dynamics of marine fishes. Spatiotemporal differences in these vital rates from young-of-the-year (i.e., age-0) Winter Flounder have been variously linked to environmental gradients, anthropogenic stressors, differences in the timing of settlement, and location. To better understand local declines in recruitment productivity, we assessed vital rates of age-0 Winter Flounder in five different bays in Long Island, New York. A weekly or biweekly beam-trawl survey targeting age-0 Winter Flounder was implemented over five summers. We compared survey-based estimates of age-0 mortality and growth, finding significant differences between locations in growth but not mortality. A consistently high abundance of age-0 Winter Flounder in Shinnecock Bay and Mattituck Creek was prolonged by a secondary settlement pulse later in the season. Hypothesizing that multiple settlement pulses are a bet-hedging strategy against temporally varying environmental conditions, we compared mortality, growth, and occupied habitat conditions between settlement pulses (cohorts), finding differences in growth and habitat occupancy that varied across years.

Pharmaceuticals and personal care products are emerging contaminants that are increasingly detected in the environment worldwide. Certain classes of pharmaceuticals, such as selective serotonin reuptake inhibitors (SSRIs), are a major environmental concern due to their widespread use and the fact that these compounds are designed to have biological effects at low doses. A complication in predicting toxic effects of SSRIs in nontarget organisms is that their mechanism of action is not fully understood. To better understand the potential toxic effects of SSRIs, we employed an ultra-low input RNA-sequencing method to identify potential pathways that are affected by early exposure to two SSRIs (fluoxetine and paroxetine). We exposed wildtype zebrafish (Danio rerio) embryos to 100 μg/L of either fluoxetine or paroxetine for 6 days before extracting and sequencing mRNA from individual larval brains. Differential gene expression analysis identified 1550 genes that were significantly affected by SSRI exposure with a core set of 138 genes altered by both SSRIs. Weighted gene co-expression network analysis identified 7 modules of genes whose expression patterns were significantly correlated with SSRI exposure. Functional enrichment analysis of differentially expressed genes as well as network module genes repeatedly identified various terms associated with mitochondrial and neuronal structures, mitochondrial respiration, and neurodevelopmental processes. The enrichment of these terms indicates that toxic effects of SSRI exposure are likely caused by mitochondrial dysfunction and subsequent neurodevelopmental effects. To our knowledge, this is the first effort to study the tissue-specific transcriptomic effects of SSRIs in developing zebrafish, providing specific, high resolution molecular data regarding the sublethal effects of SSRI exposure.

Despite large differences in removal efficiencies, all treatment processes investigated were sufficient in preventing short-term behavioral effects in zebrafish larvae.

Pharmaceuticals and personal care products are emerging contaminants that are increasingly detected in surface waters around the world. Despite the rise in environmental detections, measured concentrations are still typically low, raising the importance of environmental risk assessments that focus on ecologically relevant sublethal endpoints, such as altered behavior. Neuroactive pharmaceuticals, like mental health medications, pain killers, etc., may be particularly potent in this regard as they are specifically designed to cause behavioral changes without causing physiologic impairment in mammalian systems. We screened 15 different popular neuroactive pharmaceuticals, ranging from antidepressants (including 3 major antidepressant metabolites), anxiety medications, and pain killers, under three different exposure scenarios (repeated, late acute and early transient exposure) to look for behavioral effects in larval zebrafish using the visual motor response (VMR). Drugs were screened at 0, 1, 10, and 100 μg/L in the repeated exposure scenario, and at 0 and 100 μg/L in the late acute and early transient exposure scenarios. Eight of the 15 compounds tested, specifically the antidepressants amitriptyline, fluoxetine, nor-fluoxetine, paroxetine, sertraline, nor-sertraline, venlafaxine, and the antipsychotic drug haloperidol decreased swimming activity by 25% to 40% under repeated exposure conditions. Five of the compounds (amitriptyline, fluoxetine, nor-fluoxetine, paroxetine, and sertraline) also significantly decreased activity by 17% to 31% in the late acute exposure paradigm. Three compounds (fluoxetine, paroxetine and venlafaxine) significantly altered swimming activity with early transient exposure, however creating a hyperactive response and increasing activity from 24% to 28%, while haloperidol significantly decreased activity by 31%. This paper is, to our knowledge, the first to screen so many neuroactive pharmaceuticals, including major metabolites, in parallel under multiple exposure conditions. We show that antidepressants most consistently alter VMR swimming activity. Additionally, we show that major antidepressant metabolites can potentially alter behavior as much as their parent compounds. Furthermore, we show that the magnitude and direction of behavioral effect is dependent on the exposure duration and period, indicating that a more diverse experimental approach might be needed to more accurately assess the risk these compounds pose to the environment.

Aerial applications of liquid methoprene are used in salt marshes to control mosquitoes by preventing adult emergence. Despite concern about toxicity to non-target organisms, little is known about environmental concentrations after applications, nor methoprene's persistence in salt marsh environments. Aqueous and sediment samples were collected from two marshes receiving weekly applications. Aqueous samples were collected as early as 30 min alter applications and as long as nine days afterwards; sediment samples were taken within hours of application and as long as 19 days post-application. Use of time-of-flight liquid chromatography mass spectral analysis allowed for ultra-low detection limits (0.5 ng/L) in water samples. The data show loss of nearly all methoprene from 1 m deep marsh ditches within 1 day and presence but not accumulation of methoprene in marsh sediments despite repeated applications. Methoprene concentrations observed in salt- marsh mosquito ditches were below those found to be of toxicological significance in other studies. (C) 2018 Elsevier B.V. All rights reserved.

Winter Flounder populations have declined throughout the southern New England/Mid-Atlantic (SNE/MA) region since the 1980s, and evidence suggests near extirpation of some local populations. Previous research has focused on the correlation between temperature and declining stock-productivity, supporting the hypothesis that a warming climate is a primary driver of the species decline. Our objective was to critically investigate several potential drivers of Winter Flounder's regional decline and collapse in the SNE/MA region by evaluating them in relation to management actions, spawning stock biomass (SSB), recruitment, productivity (PROD) and fishing mortality (F). Results indicate that the SNE/MA stock has remained below the 40% unfished biomass threshold (B-40%) since 1984, and that F was above the maximum sustainable fishing rate (F-MSY) for most of the period between 1995 and 2010. We found a negative relationship between F and SSB between 1981 and 2000. Correlative analysis between young-of-the-year PROD and a number of biological and physical parameters resulted in 8 (out of 21) significant relationships. However, after correcting for multiple comparisons only two, the abundance of Striped Bass and Summer Flounder, remained significant. The PROD and recruitment analyses did not indicate strong environmental drivers and suggested recruitment compensation during the early 2000s in some surveys. In summary, we did not find evidence of a global environmental driver, such as temperature, explaining the decline of Winter Flounder. Rather, our analysis indicates that long-term overexploitation and failure of management to control harvest rates preceded and was likely a primary driver in the species decline and lack of recovery. Finally, following decades of overfishing, attempts to rebuild the Winter Flounder fishery likely will require a longer-term commitment than management has shown to date.

Freshwater cyanobacterial harmful algal blooms (CyanoHABs) caused by algae in the genus Microcystis have been increasing in frequency and severity in recent decades. Microcystis blooms threaten aquatic organisms through effects associated with the rapid increase of biomass and the production of the hepatotoxin microcystin (MC) by toxic strains. Among fish, effects of blooms are likely to be more severe for early life stages, and physiological impacts on this life stage could significantly impact recruitment and fish populations. This study explores the effects of Microcystis blooms on the development of fish using the model organism, the Japanese medaka (Oryzias latipes), under realistic exposure conditions. Medaka embryos were exposed to natural blooms collected from New York City (USA) lakes, lab cultures of Microcystis, and MC-LR solutions. Field collected samples were more toxic than lab cultures (even when compared at the same algal density or MC concentration), causing decreased survival, premature time to hatch, reduced body length, yolk sac edema, and decreased heart rate, while lab culture exposures only resulted in bradycardia. Heart rate was the most sensitive endpoint measured, being depressed in embryos exposed to both lab cultures and field collected blooms. Generalized linear model analysis indicated bradycardia was statistically associated with both cell densities of blooms and MC concentrations, while single factor analysis indicated that MC concentrations had a stronger correlation compared to cell densities. However, MC exposure could not fully explain the effects observed, as exposures to MC-LR solutions alone were not able to reduce heart rate as severely as algal exposures. Collectively, these experiments indicate that factors beyond exposure to MC or even isolated Microcystis strains influence heart rate of fish exposed to Microcystis blooms. Enhanced mortality, depressed heart rate, and abnormal development observed in response to environmentally realistic exposures of Microcystis blooms could affect success of fish at both individual or population levels.

Large-scale use of dispersants to remediate oil spills has raised concerns about their toxicity to marine organisms. Of particular concern is oxidative stress and resulting membrane damage due to exposure to surfactants in dispersant mixtures. We investigated the potential of the dispersant Corexit 9500® and one of its major components, the anionic surfactant dioctyl sodium sulfosuccinate (DOSS), to induce oxidative stress in larval sheepshead minnows after 24 and 96h exposures, at two sublethal concentrations, the lesser being environmentally realistic for each compound. Corexit exposures elicited only minimal antioxidant responses for most antioxidant components tested, with increased glutathione peroxidase (GPx) and glutathione S-transferase (GST) activities observed only after 96h and at the higher exposure concentration. In contrast, DOSS induced statistically significant increases in the levels of reactive oxygen species (ROS), GPx, and lipid peroxidation, as well as depleted reduced glutathione (GSH) levels at both time points and concentrations. These data indicate that short-term and environmentally realistic exposures to DOSS can impact antioxidant response capabilities, raising concern about its use in oil dispersants and other high volume use products where environmental releases are likely.

As part of a large study examining the toxicity of the Corexit® family of oil spill dispersants on aquatic vertebrates, we examined effects on the liver in an in vitro study using the rainbow trout liver cell line (RTL-W1). We exposed RTL-W1 cells to the dispersant Corexit 9500 and its major surfactant components and measured their cytotoxic effects as well as modulation of activity of CYP1A, one of the major enzymes responsible for organic contaminant metabolism. The anionic surfactant DOSS was found to be the most cytotoxic with a 24h EC50 of 10mg/L, as compared to 45 to 91mg/L for the non-ionic surfactants, Tween 80 and 85 and Span 80. The EC50 for Corexit was intermediate between these compounds at 29mg/L. Corexit 9500 and the non-ionic surfactants Tween 80 and 85, but not DOSS or Span 80 knocked down CYP1A activity induced by benzo[a]pyrene, a model agonist, demonstrating the potential of these compounds to compromise the ability of exposed organisms to metabolize petroleum hydrocarbons or other CYP1A substrates.

The growing incidence of hypoxic regions in coastal areas receiving high volumes of anthropogenic discharges requires more focused risk assessment of multiple stressors. One area needing further study is the combined effect of hypoxia and oil exposure. This study examined the short-term sublethal effects of co-exposure to hypoxia and water accommodated fractions (WAF) and chemically enhanced WAFs (CEWAFs) of Southern Louisiana Crude oil on detoxification, antioxidant defenses and genotoxicity in early life stage sheepshead minnow (Cyprinodon variegatus). CYP1A induction (evaluated by measuring EROD activity), activity of a number of key antioxidant enzymes (GST, GR, GPx, SOD, CAT, and GCL), levels of antioxidants (tGSH, GSH, and GSSG), evidence of lipid peroxidation (evaluated using the TBARS assay), and DNA damage (evaluated using the comet assay) provided a broad assessment of responses. Contaminant detoxification pathways induced by oil exposure were inhibited by co-exposure to hypoxia, indicating a maladaptive response. The interactive effects of oil and hypoxia on antioxidant defenses were mixed, but generally indicated less pronounced alterations, with significant increases in lipid peroxidation not observed. Hypoxia significantly enhanced DNA damage induced by oil exposure indicating the potential for significant deleterious effects post exposure. This study demonstrates the importance of considering hypoxia as an enhanced risk factor in assessing the effects of contaminants in areas where seasonal hypoxia may be prevalent.

Oxygenated polycyclic aromatic hydrocarbons (oxyPAHs) are directly discharged into the atmosphere with exhaust gas from diesel engine automobiles and industry and are also generated by photo-oxidation and/or microbial metabolism of parent polycyclic aromatic hydrocarbons (PAHs). They are widely distributed in environment, especially around urban areas. We evaluated the effects of exposure to oxyPAHs as acenaphthenequinone (ANQ), 7,12-benz(a)anthracenequinone (BAQ), 1,4-naphthoquinone (NAQ), and 9,10-phenanethrenequinone (PHQ) in Japanese medaka (Oryzias latipes) embryos. ANQ (>2720 μg/L) caused caving in the yolk sac, and BAQ (>22.4 μg/L) caused tanning of the oil droplet. Additionally, NAQ (>314 μg/L) and PHQ (>734 μg/L) stopped development of medaka embryos beginning 2 days after the start of exposure. The hatched larvae from embryos exposed to ANQ, BAQ, NAQ, or PHQ at 518, 9.86, 36.5, or 80.7 μg/L, respectively, exhibited incomplete development of the cephalic region, incomplete palate, unabsorbed and hypertrophied yolk sac, tubular heart, altered axial curvature, and poor swimming ability. These symptoms were similar to those observed in blue sac disease, which is caused by exposure to PAHs.

Toxic risks of sediments collected from seven sites in Tokyo Bay were evaluated using Japanese medaka embryos. Those sediments with slight pore water were placed in grass petri dishes without overlying water. The most remarkable effect in the field sediment was to cause hatching delay in embryos, and the longest time until hatching took was 12.5 ± 1.6 days post-fertilization (dpf), although that in control group was 10.1 ± 0.7 dpf. A significant delay in hatching was observed at four sites. Because total carbon concentrations were relatively high in sediments at three of these four sites, several chemicals were expected to be residues in these sites and could cause their delay. Although extreme mortality was not observed at all sites, sediments collected from the site close to Kawasaki city induced 10 % mortality. Polycyclic aromatic hydrocarbon (PAH) concentrations were remarkably high at this site compared with other sites, and thus PAH toxicities could be causing the mortality. Concentration of heavy metals such as cadmium, copper, lead, and zinc in sediments were also determined, but no clear relationship was found between toxicities to embryos and the distribution of their concentrations.