Water Quality in Coastal Watersheds is History in Fish Ears

Transcription

1 Water Quality in Coastal Watersheds is History in Fish Ears Roger A. Rulifson Institute for Coastal Science and Policy, and Department of Biology East Carolina University Greenville, NC June 12, 2012

2 The Area in Question

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5 Salinity (ppt) D.O. (Mg/L) % saturation D.O. Temperature (degrees Celsius) Blounts Bay % Saturation D.O. Blounts Bay Air Surface Water (Bottom) Water (surface) Date Date Blounts Bay Salinity Blounts Bay Dissolved Oxygen Surface Bottom Surface Bottom Date Date

6 PH Surface Blounts Bay PH Bottom Date Secchi Depth (m)

7 Nursery Habitat Beck et al. (2001) defined as an area where juvenile fish: occur in high density are successful at avoiding predators grow faster than in other habitats separated from adult habitats Areas that support high recruitment of juveniles to the spawning stock

8 Otoliths Inner ear bones Hearing and balance Daily growth increments Uses Age fish Reconstruct environmental histories Element incorporation Chemical chronology Movement Assumptions - water elements = otolith elements Nucleus

9 Sampling Locations for YOY Striped Bass PASQ PERQ Albemarle Sound BATC Fish & water sample Holding Cage ALLG Map by NCDMF

10 Otolith Preparation Remove [ 15N analysis] Mount light-scope laser left Embed right Section Grind/Polish Observe

11 RESULTS - Water Chemistry Linear discriminant function analysis 84% total correct Canonical discriminant function analysis

12 RESULTS - Otolith Chemistry for YOY Linear discriminant function analysis 76% total correct Striped Bass Canonical discriminant function analysis

13 RESULTS Striped Bass Ontogeny - CHOW - BATC - PERQ - PASQ

14 Nitrogen Isotope Indicates Human Influence Fertilizer Runoff, etc. YOY striped bass otoliths

15 Study Area for Southern Flounder Tar Pamlico River System Pamlico Sound

16 Total Mercury Size class, sex, and location (n = 92) EPA method 7473 Total Hg vs MeHg DMA 80 Direct Mercury Analyzer

17 +110 km = 190 km or 118 miles from Ocracoke Inlet US-17 bridge = 0 km

18 Southern Flounder are Resident in Coastal Watersheds

19 Sr (ppm) Freshwater Residency Otolith Microchemistry Transect across lifetime Strontium correlation with salinity (r = 0.989, p < 0.001) Freshwater: <1000 ppm Estuarine: ppm Marine: >2500 ppm Pamlico Sound Pamlico River Tar River Spawned in ocean; migration inland LONG TERM RESIDENCY Distance (µm)

20 Sr (ppm) Southern Flounder Show Site Fidelity 2 year old female Collected September 10, 2008 near Washington, NC (Pamlico River) January 2006 Spawned at sea April 2007 April 2008 Age 1 Age Transect distance (um) Sept. 2008

21 Salinity (ppt) Sr (ppm) Variation in Sr explained by salinity April 2007 April Transect distance (um) Jan-06 Jul-06 Jan-07 Jul-07 Jan-08 Jul-08 Salinities measured from USGS station , Pamlico River, Washington, NC

22 Total mercury (mg/kg) Freshwater Residency Means Accumulating Elements Mercury Accumulation With Length 0.4 NC Action Level = 0.4 mg/kg MeHg 0.35 Tar River (r = 0.55, p = 0.012) Pamlico River (r = 0.49, p = 0.003) Pamlico Sound (r = 0.39, p = 0.020) a a a b b b b b b Small Median Large Size class

23 Company Quotes from Internet* Company officials say the most feasible way to excavate the limestone deposit 50 to 60 feet underground is to dewater the pit site by pumping out groundwater. The discharge will include water pumped from deep underground and stormwater on the surface. The average discharge would be about 9 million gallons a day, but it could increase to 11 million gallons on some days, company representatives say. Plans call for the water to travel through 11 miles of manmade ditches and discharge into the creek at two points. Paxton Badham, a Martin Marietta vice president, said at public informational meeting in January that the water would be acclimated to the surroundings by the time it reaches the creek.

24 Water Treatment Needed Dr. Richard Spruill, the company s groundwater consultant, said at the public informational meeting that the groundwater is hard water that would have be treated to remove calcium, iron and magnesium to make it useful in public drinking water systems. He said there have been some discussions with area systems about the possibility of using the water. So far no agreements have been reached.

25 River Herring Next on the List for Endangered Species?

26 River Herring Collection Pasquotank North Chowan Perquimans Little NW Yeopim Roanoke SW Scuppernong Alligator

27 Pillai s trace statistic: F = 13.70, df = 32, 452, P < N = % classification

28 Strategic Habitat Areas for River Herring Deaton et al. (2010) North Carolina Coastal Habitat Protection Plan GOOD P O O R GOOD

29 Conclusions Watersheds carry elemental fingerprints unique to the system. Fish residing in the watershed pick up the elements in their hard parts (i.e., bones) and tissues (e.g., mercury). Some species (e.g., flounders) recruit to a watershed and stay there until mature. Human influence is easily seen in watersheds and fish longer term than hurricanes.

30 Acknowledgements Funding provided by NC Fisheries Resource Grants to Rulifson lab Additional funding by the CRFL program (Coastal Recreational Fishing License) Otolith analyses by University of Manitoba, Dr. Norman Halden lab ECU fisheries students NC Division of Marine Fisheries employees NC Wildlife Resources Commission employees Dr. David Evans, NOAA mercury analyses