About This Project
Although at one time, the Delaware River population of Atlantic sturgeon was the largest on the Atlantic coast today it is the smallest. We hypothesize that this decrease is due to low levels of Dissolved Oxygen (DO) at the nursery area. We will precisely define the threshold of sturgeon larvae to low levels of dissolved oxygen under controlled laboratory conditions. This will provide regulators with new information with which to enact changes to the current DO standard of 3.5 mg/liter.
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What is the context of this research?
Atlantic sturgeon is a relict, iconic, very large, and long-lived species along the Atlantic coast.
They are anadromous and the number of rivers in which they successfully spawn today is greatly reduced.
Early life-stages of fishes, and sturgeons in particular, are hypersensitive to developmental defects from contaminants such as PCBs and dioxins.
The interactive effects of low Dissolved Oxygen (DO) on a background of contaminant exposure are unknown.
The Delaware River has long been beset with sediment-borne contaminants along with low levels of DO in the immediate vicinity of nursery areas of Atlantic sturgeon.
These low levels of DO in the Delaware during the warmer months result from releases from municipal Sewage Treatment Plants and other industrial dischargers.
What is the significance of this project?
It will define threshold values of DO for the survival and normal development of Atlantic sturgeon
If the levels of DO that are toxic to larvae are below current water quality standards, a 24 h average of 3.5 mg/liter DO, regulators will be compelled to reconsider water quality standards and practices at SWT.
What are the goals of the project?
To exactly define levels of DO that are toxic to Atlantic sturgeon larvae that are already contaminated with PCBs and dioxins.
Our ultimate goal is the rebuilding of the Atlantic sturgeon population in the Delaware to levels that can sustain successful recruitment and a future limited fishery.
The embryos are needed for experiments in which they are to be exposed to varying levels of dissolved oxygen and co-stressors common in the Delaware River; PCBs and increasing temperatures
The probe is needed to precisely measure levels of dissolved oxygen to which the embryos and larvae are exposed.
These funds will complement those from the Delaware River Basin Commission and will enable us to extend our previous studies.
Meet the Team
I am interested in the toxicological effects in fishes of exposure to contaminants. My area of focus is fishes in the nearby Hudson River so my research usually looks at the effects of PCBs and dioxins on early life-stage success in terms of survivorship, hatching rate, developmental deformities, and aberrations in behavior. One of my studies on Atlantic tomcod, a common species in the Hudson River, determined that they exhibited dramatic and very rapid evolutionary adaptation to exposure to these chemicals. This study challenged long-held beliefs on the rate of evolution. It was published in the prestigious journal Science garnered international recognition in the popular press such as NPR, Associated Press, New York Times, and even the Economist magazine. To date, I have published more than 40 peer-reviewed papers on the toxicological effects of these contaminants on fishes.
I also have a long history in using DNA approaches to identify the stock
structure of anadromous and marine fishes along the Atlantic Coast
including striped bass, American shad, Atlantic cod, and winter flounder. These studies have resulted in more than 50 peer-reviewed papers on the subject. Currently, most of my work in this area is on federally endangered Atlantic sturgeon where my studies have been used to define their population structure along the entire coast and the vulnerability of individual populations to anthropogenic stressors such as bycatch in coastal fisheries.
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