Bottlenose dolphin research in both Florida Bay and Biscayne Bay:Using dolphins as indicators of estuary health

Jenny Litz1, Laura Engleby2, Joseph Contillo1, Lance Garrison1, John Kucklick3

1NOAA, National Marine Fisheries Service2Dolphin Ecology Project3National Institute of Standards and Technology

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Outline

• Introduction and background

• Florida Bay work by Dolphin Ecology Project

• Biscayne Bay work by NMFS/SEFSC

• Overall conclusions

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Bottlenose dolphins as indicators

• Bottlenose dolphins are long-lived, apex predators and many show patterns of residency within estuaries

• Bottlenose dolphins can serve as biological indicators for ecosystem health and human health

• Marine Mammal Commission (1998): identified bottlenose dolphins as one of the model species for investigations into the effects of environmental contaminants on marine mammals.

• Long-term interdisciplinary studies are important to measure health and population trends over time

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Criteria for a Good Sentinel Species

• Size (Large enough for adequate tissue sample size)• Sensitivity (similar as humans and specific to agent)• Known physiology (need to know “normal” parameters)• Similar physiology to humans• Longevity (long enough life to demonstrate effects over time)• Latent Periods (time between initial exposure and effects short)• Position in the food chain (ideally omnivores top of food chain)• Migration (migrations limited or absent)• Route of toxic exposure similar to humans• Abundance and distribution (abundant enough for sample size)• Ability to propagate in captivityO'Brian DJ, Kaneene JB, Poppenga RH. 1993. The use of mammals as sentinels for

human exposure to toxic contaminants in the environment. Environmental Health Perspectives 99:351-368.

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Criteria for a Good Sentinel Species

Size (Large enough for adequate tissue sample size)? Sensitivity (similar as humans and specific to agent)

Known physiology (need to know “normal” parameters)Similar physiology to humansLongevity (long enough life to demonstrate effects over time)

? Latent Periods (time between initial exposure and effects short)½ Position in the food chain (ideally omnivores top of food chain)

Migration (migrations limited or absent)Route of toxic exposure similar to humans

? Abundance and distribution (abundant enough for sample size)Ability to propagate in captivity

O'Brian DJ, Kaneene JB, Poppenga RH. 1993. The use of mammals as sentinels for human exposure to toxic contaminants in the environment. Environmental Health Perspectives 99:351-368.

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#001 in Aug. 1990 #001 in April 1999

#015 in Oct. 1990 #015 in April 2002

Photo-Identification

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Biopsy Sample Collection

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The Dolphin Ecology Project began Florida Bay work in 1999

Photo-identification catalog presently includes 577 individually identifiable dolphins

Dolphins range throughout the Bay and are present throughout the year

Study area about 2200 Km2

includes ENP and FKNMS

Florida Bay

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Photo-ID surveys: • Conducted in most zones during wet and dry season

• 1999-2000- focus on Eastern, Atlantic, Central Zones

• 2001- expanded effort to include Gulf Transition and accessible portions of Western

Photo-ID surveys were conducted in each of the six zones defined by spatial variation in biotic and abioticfactors

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Marking (May 4-8) Survey routes and sighting locations

Recapture (May 17-21) Survey routes and sighting locations

..

Mark-recapture abundance survey in

Florida Bay• First mark-recapture abundance estimate for Florida Bay and providesbaseline for future

• Conducted in May 2003

• Estimated abundance of 514 (CV=0.17) dolphins

Read, A.J., K.W. Urian, L.K. Engleby, D.M. Waples, and B. Wilson. In review. Abundance of Bottlenose Dolphins in Florida Bay. Bulletin of Marine Science. 27pp

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Florida Bay Biopsy Work

• Concern regarding contaminants, particularly Endosulfan

• Biopsy sampling conducted in 1998 and 2002 for contaminants and genetics

• Results indicate:—Endosulfan was low or non-detectable—PCBs and DDT were lowest for Florida Bay when

compared to other sites in the Southeast

Schwacke L, and others. 2004. Health and risk assessment for bottlenose dolphin (Tursiopstruncatus) populations along the southeast United States coast: current status and future plans. Sorrento, Italy: Paper SC/56/E20 presented to the IWC Scientific Committee. 15 p.

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Sentinels in Florida Bay?

Results indicate: —Dolphins in Florida Bay demonstrate high individual site and

foraging tactic fidelity—Bathymetric variation/mudbank habitat has strong ecological

effects on distribution, foraging and potentially social patterns of dolphins

—Strong evidence that dolphins and fish respond to same environmental variables in predictive habitat models

—Modeling results show spatial overlap between high fish abundance and dolphin foraging habitats, thus managers can use foraging dolphins as indicators of productive fish habitats

Work done by Torres from 2002-2005 (summers) investigated top predator (sharks and dolphins) distribution and foraging ecology (Torres, 2007)

(Torres, 2007, Dissertation - Duke University; Torres and Urban, 2005, Estuarine Indicators, Torres et. al. 2008, Ecological Applications)

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The NOAA Fisheries, SEFSC began Biscayne Bay work in 1990, comprehensive sampling in 1994

Over 200 individuals cataloged to date

Study area about 450 km2

includes BNP and BBAP

Biscayne Bay

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Northern BB more extensively developed than southern BB

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BB Social Structure Conclusions

• Social structure was analyzed using measures of Association and multiple statistical methods

• Animals in BB associate non-randomly

• Northern dolphins prefer to associate with northern dolphins and southern with southern

• There are at least 2 and up to 4 overlapping social communities within BB on a north/south axis

Litz, Jenny A. 2007. Social Structure, Genetic Structure, and Persistent OrganohalogenPollutants in Bottlenose Dolphins (Tursiops truncatus) in Biscayne Bay, Florida. A Dissertation. Miami, FL: University of Miami. 140 p.

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Biopsy Samples

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0.042, p≤0.001 0.139, p≤0.001Between BB & FB:

0.015, p=0.0090.046, p=0.067Within BB:microsatellitesmtDNA

FST

0.042, p≤0.0010.456, p≤0.001Jacksonville vs. Atl. *0.042, p≤0.0010.113, p≤0.001Sarasota Bay vs. Gulf #

# Sellas et al., 2005* Caldwell, 2001 University of Miami PhD Dissertation

Samples were: genotyped for gender, sequenced at the maternally inherited mtDNA control region, genotyped at biparentally inherited nuclear microsatellite loci

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• The genetic differentiation between Biscayne Bay and Florida Bay dolphins suggests little mixing of the 2 communities

• Biscayne Bay and Florida Bay communities should be managed as separate biologically relevant stocks

Genetic Structure Conclusions

Litz, Jenny A. 2007. Social Structure, Genetic Structure, and Persistent OrganohalogenPollutants in Bottlenose Dolphins (Tursiops truncatus) in Biscayne Bay, Florida. A Dissertation. Miami, FL: University of Miami. 140 p.

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Persistent Organic Pollutants (POPs)What’s known:Dolphins bioaccumulate lipophilic contaminants in their

blubber layer

Geographic variation has been shown in contaminant profiles between dolphin communities

Compounds measured:94 compounds were measured from blubber biopsies

including 73 PCB congeners, 6 DDT compounds, 6 PBDEs, 6 Chlordanes, and 3 other pesticides: HCB, Mirex, and Dieldrin

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11.9(10.4, 13.6)

14.8(9.0, 24.3)

31.7(28.3, 35.5)

67.7(55.7, 82.3)

545(495, 599)

South BB(n=3)

17.0(15.8, 18.3)

29.6(29.0, 30.3)

49.0(34.0, 70.8)

140(90, 218)

1460(1230, 1720)

North BB(n=3)

14.2(12.0, 16.9)

21.0(14.4, 30.5)

39.4(30.5, 51.0)

97.3(6.2, 143.0)

891(574, 1380)

All BB(n=6)

Adult Females

69.4(57.1, 84.4)

226(177, 290)

565 (431, 740)

2040(1540, 2700)

8640(6270, 11900)

South BB(n=15)

214(142, 322)

663(484, 520)

1940(1340, 2830)

4260(3290, 5520)

43,300(28,000, 66,900)

North BB(n=16)

124(91, 168)

394(300, 520)

1070(777, 1470)

2980(2370, 3750)

19,900(13,400, 29,400)

All BB(n=31)

Males and Juveniles

∑OtherPesticides∑PBDEs∑Chlordanes∑DDTs∑PCBs

GM(95% CI)

ng/g wet mass

BB Blubber POP Concentrations

Litz, Jenny A., Garrison, Lance P., Fieber, Lynne A., Martinez, Anthony, Contillo, Joseph P., Kucklick, John R. 2007. Fine Scale Spatial Variation of Persistent Organic Pollutants in Bottlenose Dolphins (Tursiops truncatus) in Biscayne Bay, Florida. Environmental Science and Technology 41 (21): 7222-7228.

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ΣPCBs in 31 male/juvdolphins in μg/g wet mass

(NOAA, NS&T Program, 1999)

ΣPCBs in sediments in ng/gdry mass

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# (Hansen et al. 2004) ** (Fair et al. 2003)# # # **

Litz, Jenny A., Garrison, Lance P., Fieber, Lynne A., Martinez, Anthony, Contillo, Joseph P., Kucklick, John R. 2007. Fine Scale Spatial Variation of Persistent Organic Pollutants in Bottlenose Dolphins (Tursiops truncatus) in Biscayne Bay, Florida. Environmental Science and Technology 41 (21): 7222-7228.

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BB POP Conclusions

Baseline POP concentrations for Biscayne Bay dolphins were measured

This is the first time that fine-scale spatial variation of POP concentrations was found in bottlenose dolphins

Bottlenose dolphins in Biscayne Bay are reflective of the bioavailable POPs in the estuary

POP levels found in Biscayne Bay dolphins, particularly PCBs in northern dolphins, are at concerning levels and indicate possible risk of detrimental effects to dolphins and human fish consumers

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Future WorkExpand Photo-ID study area to include Barnes Sound and areas outside the Bay up to 100m depth

Investigate POP levels in dolphin prey species

Investigate potential risk to humans – CDC collaborative pilot study of subsistence fishers in NBB

Comparison of FB and BB catalogs

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Overall Conclusions

• Both Florida Bay and Biscayne Bay dolphins show high levels of site fidelity

• Dolphins are reflective of bioavailable POPs in estuaries on a small spatial scale

• Foraging dolphins are reflective of productive fish habitats in Florida Bay

• Dolphins can be monitored for changes over time – both changes in health and changes in movement patterns

• Bottlenose dolphins can and should be used as indicators in their respective estuaries

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AcknowledgmentsM. Baron, P. Fair, L. Fieber, M. Gaines, C. Hughes, A. Martinez, A. Read, P. Rosel, L. Schwacke, J.Serafy, L. Torres, K. Urian, P. Walsh, D. Waples, J. Wicker, E. Zolman, D.E.P. volunteers and staff, Florida Keys National Marine Sanctuary, Everglades National Park, Biscayne National Park, John Pennecamp Coral Reef State Park, The Hughes Lab (genetics – University of Miami/FAU), The NOAA MMMGL, Lafayette, LA, The NIST Lab, Hollings Marine Lab, Charleston, SC. and all who assisted with photo-ID and biopsy field work!

Funding: NOAA Fisheries, SEFSC; 2001 UM RSMAS Alumni Fellowship; Grants awarded from HBOI from proceeds collected from the sale of Protect Wild Dolphins License Plate as authorized by Florida Statute 320.08058(20); Morse Foundation

Permits: MMPA Permits GA# 779-1633-00 & 911-1466; Annual Biscayne and Everglades National Park Permits