Congener-Specific Analysis of PCB Accumulations in Chesapeake Bay Striped Bass (Morone saxatilis) William Gardner University Maryland Eastern Shore, Princess Ann, MD Department of Natural Science, Living Marine Cooperative Science Center Introduction Polychlorinated biphenyls (PCB) threaten the ecological and economic value of Chesapeake Bay striped bass (Morone saxatilis). In terms of the former, PCBs are known endocrine disruptors and have been linked to declines in wild fish populations. In terms of the latter, the state of Maryland has issued both statewide advisories for striped bass caught in the Chesapeake Bay and in Maryland’s Atlantic coastal waters. Data used to generate the statewide Chesapeake Bay advisories suggest that striped bass are exposed to sources both inside and outside the estuary. However, data is lacking for assessing the PCB levels in young striped bass maturing within their natal subestuaries. Furthermore, the state of Maryland has adopted no consumption advisories for striped bass captured in its coastal waters. This management decision is based predominantly on PCB levels in striped bass capture in New York Coastal waters, due to insufficient data elsewhere. As of result of these data gaps, the main focus of this research has been to further our understanding as to when and where striped bass are exposed to quantities of PCBs sufficient enough to cause accumulations to warrant a health advisory. Striped Bass Fishery It is estimated that 50 – 90 percent of the Atlantic coast striped bass migratory stock are spawned in tributaries of the Chesapeake Bay (Fig 1). In 2008 recreational and commercial landings were more than 25.6 million and 7.1 million lbs, respectively (NOAA 2009). Striped Bass Migrations Adult striped bass migrate from the Atlantic Ocean into freshwaters of the Chesapeake Bay to spawn in the early spring. After spawning, migratory striped bass exit the Chesapeake Bay and generally move northward along the Atlantic Coast (Fig. 2). They spend most of the summer and early autumn in New England shore waters. In late autumn, striped bass return to the Chesapeake Bay region. Chesapeake Bay striped bass generally over-winter off the coast of North Carolina. Figure 2. Striped Bass Migrations Susquehanna River Patuxent River Choptank River Potomac River Nanticoke River Rappahannock River York River James River Chester River Pocomoke River Figure 1. Chesapeake Bay spawning rivers Maryland’s PCB Advisories Maryland has issued both statewide and coastal PCB advisories for striped bass Table 1). Data used to generate these advisories suggest that striped bass are being exposed to PCB both inside and outside of the Chesapeake Bay (J. Beaman, MDE, 2005). The research proposed here has evolved from uncertainties regarding the drivers behind these advisories. The statewide advisories rely on data collected from legally harvestable fish. Thus, data is lacking for accessing PCB levels in young striped bass maturing within their natal sub estuaries. Furthermore, the USEPA has classified several of these areas as having “insufficient or inconclusive data” (Fig. 3). Secondly, Maryland’s coastal advisories is based on limited data, largely from New York coastal waters (MDE 2007 and ECASCAW 2008).Waterbody Table 1. PCBs (risk driver) Allowable Meal/Year Chesapeake Bay and Tributaries < 28” May 16 – Dec 15 > 28” April 15 – May 15 General Population 8 oz meals Women 6 oz meals Children 3 oz meals AVOID MD Coastal waters 12AVOIDAVOID Region of Concern- area with probable adverse effects Area of Emphasis- area of potential adverse effects Area of Low Probability for adverse effects Area with insufficient or Inconclusive Data Historically Low Levels of Chemical Contamination Congener-Specific PCB Data PCBs are a class of chemical consisting of 209 possible congeners with varying degrees of chlorination (Fig. 3). Congener- specific PCB data can lead to the identification of likely sources through fingerprinting techniques. This involves matching the congener pattern present in biota with known sources in the environment, while accounting for environmental weathering and bioaccumulation processes. The resulting PCB signature will not be a direct reflection of the source but rather a descriptive component. Congener-specific PCB data in the Chesapeake Bay is limited (Liebert 2006). Hypotheses Specifically, we will test several hypotheses: 1.PCB levels measured in striped bass (1 to 3 yrs) will not be discernable between Chesapeake Bay subestuaries. 2.PCB concentrations in Chesapeake Bay striped bass collected in the aforementioned subestuaries will be similar to published values (> 313 ng/g) of fish taken from known contaminated areas. 3.Whether PCB accumulations are occurring mainly within the Bay or in marine habitats will be accomplished by comparing PCB concentrations in out-migrating sub-adults with adults over-wintering in NC’s coastal waters. 4.Will PCB concentrations measured in striped bass overwintering (NC) be similar to published values for fish taken from NY’s Coastal water (400 ng/g)? 5.We will also test the hypotheses that fish size, age and lipid content will influence PCB levels, and we will asses their relative importance. Figure 4 Fig 3. Methods Fifthteen striped bass ages 1 to 3 yrs will be collect from natal Chesapeake Bay subestuaries and twenty-five 3 to 5 yrs will be collect in the Bay’s lower mainstem. Thirty striped bass > 3 yrs will be collected in the winter off the coast of North Carolina deep water trawl nets during NOAA-funded LMRCSC winter survey (Fig. 5) PCB analysis will be carried out at the NOAA/NMFS) James J. Howard Marine Sciences Laboratory (Fig. 5) according to previously described methods (Dockum 2009, Williams 2006). The statistical approach undertaken will follow U.S. EPA recommendation for testing fish tissue data (U.S. EPA 2000). Objective The objective of this study will be to characterize the effects of spatial variation and life history traits on PCB accumulations in Chesapeake Bay striped bass. Figure 5. Sample collection and analysis utilizing NOAA resources Figure 6. PCB congener accumulations in Upper Bay mainstem striped bass ng/g Figure7. PCB congener accumulations in Choptank striped bass Figure 8. PCB congener accumulations in Pocomoke River striped bass ng/gLocationn Weight (g) Length (cm) Lipid content (%) PCBs (ng/g) *Upper Chesapeake Bay, Rock Hall **Pocomoke River, Bullbegger **Choptank River, Tred Avon Preliminary Results Table 2. Preliminary PCB Data for striped bass collected in Maryland waters * Area Not Characterized due to historically low levels ** Area of Insufficient or Inconclusive Data LocationAge(yrs) Length (cm) Weight (g) Lipid content (%) PCBs (ng/g) Atlantic Coast, NC Cape Hatteras, (n=40) Table 3. Preliminary PCB Data for striped bass collected in North Carolina’s coastal waters Conclusions Preliminary results showed average PCB concentrations were 7.0, 8.3, and 3.7 (ng/g) for young striped bass collected in the Upper Bay mainstem, Pocomoke River and Choptank River, respectively (Table 2). These levels are below levels observed in “regions of concern”. Although PCB levels were similar in magnitude from all three natal subestuaries, spatial differences in PCB congener accumulation patterns were visually apparent (Fig. 6, 7, & 8) (suggestive of localized sources). Striped bass collected from NC’s coastal waters ranged in age from 3 to 10 (yrs) with a mean PCB concentration of (ng/g) (Table 3), which is well below level observed in NY’s coastal water. This may argue for less-restrictive coastal advisories in MD’s water.