Fish kills, bottom-water hypoxia, and the toxic Pfiesteria complex in the Neuse River and Estuary

Burkholder, JoAnn M.; Mallin, Michael A.; Glasgow, Howard B.

doi:10.3354/meps179301

Cited by 79 publications

(91 citation statements)

References 22 publications

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“…In the riverine segments after Fran, extensive anoxia led to major fish kills (ref. 8 and www.esb.enr.state.nc.us). By contrast, major finfish or shellfish kills in the Neuse River, NRE, or Pamlico Sound were not documented after Floyd (www.esb.enr.…”

Section: Morphometry and Delivery Volumes To The Nre And Pamlico Soundmentioning

confidence: 99%

Comparative impacts of two major hurricane seasons on the Neuse River and western Pamlico Sound ecosystems

Burkholder

Eggleston

Glasgow

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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Ecosystem-level impacts of two hurricane seasons were compared several years after the storms in the largest lagoonal estuary in the U.S., the Albemarle-Pamlico Estuarine System. A segmented linear regression flow model was developed to compare mass-water transport and nutrient loadings to a major artery, the Neuse River Estuary (NRE), and to estimate mean annual versus storm-related volume delivery to the NRE and Pamlico Sound. Significantly less water volume was delivered by Hurricane Fran (1996), but massive fish kills occurred in association with severe dissolved oxygen deficits and high contaminant loadings (total nitrogen, total phosphorus, suspended solids, and fecal bacteria). The high water volume of the second hurricane season (Hurricanes Dennis, Floyd, and Irene in 1999) delivered generally comparable but more dilute contaminant loads, and no major fish kills were reported. There were no discernable long-term adverse impacts on water quality. Populations of undesirable organisms, such as toxic dinoflagellates, were displaced down-estuary to habitats less conducive for growth. The response of fisheries was species-dependent: there was no apparent impact of the hurricanes on commercial landings of bivalve molluscs or shrimp. In contrast, interacting effects of hurricane floodwaters in 1999 and intensive fishing pressure led to striking reductions in blue crabs. Overall, the data support the premise that, in shallow estuaries frequently disturbed by hurricanes, there can be relatively rapid recovery in water quality and biota, and benefit from the scouring activity of these storms.estuaries ͉ fisheries ͉ resilience ͉ volume delivery ͉ water quality

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Section: Morphometry and Delivery Volumes To The Nre And Pamlico Soundmentioning

confidence: 99%

Comparative impacts of two major hurricane seasons on the Neuse River and western Pamlico Sound ecosystems

Burkholder

Eggleston

Glasgow

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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“…If test fish exposed to the samples show signs of disease, and/or if the test fish die (vs maintenance of healthy control fish without exposure to the sample), then water samples from the replicate culture vessels used for the test are examined for the presence of Pfiesteria-like zoospores. The presence of potentially harmful cell densities [≥100 zoospores mL -1 for fish disease, ≥300 zoospores mL -1 for fish death (4,5,8,28,29)] is evaluated as a positive fish bioassay, that is, with presumed actively toxic TPC species present. The dinoflagellates are identified to species using scanning electron microscopy (SEM) of suture-swollen cells and molecular identification using 18S rDNA polymerase chain reaction (PCR) probes (3,4,20,21).…”

Section: Standardized Fishmentioning

confidence: 99%

“…Presumptive counts. Light microscopy is used to assess whether potentially harmful Pfiesteria-like zoospore densities were present in field-preserved water samples that were collected when/where fish were dying, in estuarine or coastal waters with environmental conditions conducive for toxic Pfiesteria activity (4,5,26,29,30). If the samples do not contain ≥300 Pfiesteria-like zoospores mL -1 , then Pfiesteria is ruled out as a cause of fish death.…”

Section: Standardized Fishmentioning

confidence: 99%

“…First set of fish bioassays. Fresh (unpreserved) water samples collected at the same time/area as the above-described preserved samples are used for fish bioassays or for benthic species, water, and surficial sediments (4,5,29). The fish bioassays should yield Pfiesteria-like zoospores in cell densities that, if actively toxic, when collected from the kill (within <3 days, preferably <1-2 days, for appropriately treated samples), will cause fish disease or death within 21 days, usually 4-9 days (4,5,19) (below).…”

Section: Standardized Fishmentioning

confidence: 99%

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The standardized fish bioassay procedure for detecting and culturing actively toxic Pfiesteria, used by two reference laboratories for atlantic and gulf coast states.

Burkholder

Marshall

Glasgow

et al. 2001

Environ Health Perspect

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In the absence of purified standards of toxins from Pfiesteria species, appropriately conducted fish bioassays are the "gold standard" that must be used to detect toxic strains of Pfiesteria spp. from natural estuarine water or sediment samples and to culture actively toxic Pfiesteria. In this article, we describe the standardized steps of our fish bioassay as an abbreviated term for a procedure that includes two sets of trials with fish, following the Henle-Koch postulates modified for toxic rather than infectious agents. This procedure was developed in 1991, and has been refined over more than 12 years of experience in research with toxic Pfiesteria. The steps involve isolating toxic strains of Pfiesteria (or other potentially, as-yet-undetected, toxic Pfiesteria or Pfiesteria-like species) from fish-killing bioassays with natural samples; growing the clones with axenic algal prey; and retesting the isolates in a second set of fish bioassays. The specific environmental conditions used (e.g., temperature, salinity, light, other factors) must remain flexible, given the wide range of conditions from which natural estuarine samples are derived. We present a comparison of information provided for fish culture conditions, reported in international science journals in which such research is routinely published, and we provide information from more than 2,000 fish bioassays with toxic Pfiesteria, along with recommendations for suitable ranges and frequency of monitoring of environmental variables. We present data demonstrating that algal assays, unlike these standardized fish bioassays, should not be used to detect toxic strains of Pfiesteria spp. Finally, we recommend how quality control/assurance can be most rapidly advanced among laboratories engaged in studies that require research-quality isolates of toxic Pfiesteria spp.

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“…With exposure to Pfiesteria, fish become lethargic, with episodic hyperexcitability; they also experience respiratory distress, often gulping air at the surface of the water (10,11,20,38,39). They exhibit a poor fright response, disorientation, and loss of balance (44). The fish lose the ability to osmoregulate; in salt water, blood osmotic pressure increases as concentrations of sodium, chloride, and potassium in serum increase toward those in the ambient seawater (39).…”

Section: Effects Of Pfiesteria Toxin In Laboratory Exposuresmentioning

confidence: 99%

Pfiesteria: Review of the Science and Identification of Research Gaps. Report for the National Center for Environmental Health, Centers for Disease Control and Prevention

Samet¹,

Bignami²,

Feldman³

et al. 2001

Environmental Health Perspectives

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The Pfiesteria organism was first identified and named in the early 1990s and its ability to kill fish was documented at the time. Research on the effects of exposure to its toxin on humans is more recent, sparked largely by widely publicized fish kills in the late 1990s and reports of adversely affected persons present at the scenes of the kills. Consequently, the peer-reviewed literature is still limited and substantial research is in progress at institutions in the Atlantic coast states of Maryland, North Carolina, and Virginia, and elsewhere. Dramatic reports of fish kills and illness among persons exposed to water at the time of the kills sparked public concern and reviews by a variety of agencies in the late 1990s. The primary data sources, secondary reviews, and expert panel reports were evaluated by this panel.In approaching its charge, the panel turned to a toxicologically based framework for conducting its review, characterizing the state of the science, and identifying research gaps (Figure 1). Prevention of adverse effects of Pfiesteria will need to be based in an understanding of each element in this framework: the ecological factors that drive concentrations of the organism and its state; the stimuli that lead to toxin production and the nature of the toxin; the mechanism of the toxin's effect on fish; the circumstances and routes of human exposure; and the mechanisms by which human health is adversely affected by the toxin. Sufficient certainty is needed on each of these points to evolve policies that will assure protection of public health and the fish populations. In addition, we need enhanced understanding of the still poorly characterized effects of Pfiesteria on human health.Other reviewers have commented on many elements of this framework; their reviews make clear that there are gaps in scientific understanding, with attendant uncertainty for decision makers, for each of these elements. With substantial research now under way, the panel views the timing of this review as an opportunity to examine the gaps and the extent to which new research findings will set aside uncertainties.Pfiesteria has proved to be a challenging problem. Researchers have referred to the organism as "ephemeral" and "phantom-like."It has multiple forms, transforming itself into a toxin-producing dinoflagellate when it somehow senses the presence of fish. Its toxin apparently destroys the integrity of the skin of fish, allowing the organism to feed; after feeding, the organism transforms into a dormant form. (Throughout this report, we refer to "Pfiesteria toxin," recognizing that the organism may well produce more than one toxin. We use the plural "toxins" in describing the basis for supposing that more than one toxin exists.) There is debate as to whether a pathognomonic lesion occurs in fish. Humans seem to be at risk when their activities lead to contact with toxin-containing water at the time of fish kills. Whether the toxin reaches target tissues by dermal contact or inhalation is unclear. A diffuse syndrome has b...

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Fish kills, bottom-water hypoxia, and the toxic Pfiesteria complex in the Neuse River and Estuary

Cited by 79 publications

References 22 publications

Comparative impacts of two major hurricane seasons on the Neuse River and western Pamlico Sound ecosystems

Comparative impacts of two major hurricane seasons on the Neuse River and western Pamlico Sound ecosystems

The standardized fish bioassay procedure for detecting and culturing actively toxic Pfiesteria, used by two reference laboratories for atlantic and gulf coast states.

Pfiesteria: Review of the Science and Identification of Research Gaps. Report for the National Center for Environmental Health, Centers for Disease Control and Prevention

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