Tampa Bay Dredged Hole Habitat Assessment: Status of Benthic Macrofauna and Sediment Contaminants Final Report David J. Karlen, Barbara K. Goetting, Thomas L. Dix, Sara E. Markham, Kevin Campbell, Joette Jernigan, Julie Christian, Anthony Chacour, Kirsti Martinez, Lyndsey Grossmann, Lauren LaMonica Environmental Protection Commission of Hillsborough County Prepared for: Tampa Bay Estuary Program P.O. # 6861 and # 6863 TBEP Technical Report #03-18 March 2018 Acknowledgements Sediment contaminant analysis and total organic carbon analysis was done by the EPC Chemistry Lab staff: Joe Barron, Erin Blanton, Amanda Driscoll, Kathryn Ecker, Dawn Jaspard, Noel Mesa, Luke Talalaj, Amanda Weronik and Samantha White. Michael Schuman assisted with benthic sample processing. Ed Sherwood (TBEP), Gary Raulerson (TBEP), Gabrielle Nataline (EPCHC), and Nick DeSilva (EPCHC) assisted with field collections. Project Partners included the Florida Wildlife Conservation Commission/Florida Wildlife Research Institute, U.S. Army Corp of Engineers, Tampa Bay Estuary Program, MacDill Air Force Base, and Restore America’s Estuaries. Funding was provided by: The Southwest Florida Water Management District – Cooperative Funding Agreement 16CF000214 (not including McKay Bay dredge hole component) Tampa Bay Environmental Restoration Fund 2015 Grant (not including McKay Bay dredge hole component) Tampa Bay Estuary Program annual work plan (Purchase Orders #6863 and #6861) Environmental Protection Commission of Hillsborough County Pollution Recovery Fund (McKay Bay dredge hole component) U.S. Army Corps of Engineers (In-kind funding) Suggested Citation: Karlen, D.J., B.K. Goetting, T.L. Dix, S.E. Markham, K. Campbell, J. Jernigan, J. Christian, A. Chacour, K. Martinez, L. Grossmann and L. LaMonica. 2018. Tampa Bay Dredged Hole Habitat Assessment: Status of Benthic Macrofauna and Sediment Contaminants, Final Report. TBEP Technical Report #03-18. 105 p. ii Abstract Eleven dredged holes in Tampa Bay were sampled to evaluate their benthic habitat status and provide data for future management decisions. Samples were collected in August 2016 (fall) and March/April 2017 (spring). Sediment grab samples were collected from three sites within each dredged hole and from one reference site outside of the dredged hole during each season. Samples were analyzed for benthic infauna, sediment composition and sediment contaminants (fall only). Results indicated that four of the eleven dredged holes had clean or only low levels of sediment contaminants and supported a healthy benthic community. These included the Skyway Causeway North and South dredged holes in Lower Tampa Bay, The Venetian Isles dredged hole in Middle Tampa Bay and the Georgetown dredged hole in Old Tampa Bay. The Culbreath Bayou North dredged hole in Old Tampa Bay had moderate levels of sediment contaminants but still supported a relatively healthy benthic community. These five dredged holes are recommended to be maintained in their current state. The Culbreath Bayou South, MacDill AFB Beach and MacDill AFB Docks dredged holes all had moderate to high levels of some sediment contaminants and a poor benthic community during the fall season. The Ft. Desoto and Bay Point dredged holes had the lowest rankings due to low bottom dissolved oxygen concentrations and degraded benthic communities. The Bay Point dredged hole in Old Tampa Bay had the lowest ranking overall and may be a good candidate for mitigation. Results from the restored McKay Bay dredged hole indicated that the benthic infaunal community has improved with higher species richness and composition, abundance and higher Tampa Bay Benthic Index scores then during the pre-restoration period. However, low bottom dissolved oxygen during the fall and elevated sediment concentrations of several contaminants including lead, PAH’s and DDT were evident. Periodic monitoring in the future is recommended to continue to evaluate the recovery of this site. iii Table of Contents Acknowledgements ....................................................................................................................................... ii Abstract ........................................................................................................................................................ iii Table of Contents ......................................................................................................................................... iv List of Figures ................................................................................................................................................ v List of Tables ................................................................................................................................................. v Introduction .................................................................................................................................................. 1 Methods ........................................................................................................................................................ 2 Sample Locations ...................................................................................................................................... 2 Field Sampling ........................................................................................................................................... 2 Laboratory Analysis ................................................................................................................................... 4 Data Classification and Analysis ................................................................................................................ 4 Results and Discussion .................................................................................................................................. 5 Bay Point ................................................................................................................................................... 5 Culbreath Bayou North ........................................................................................................................... 12 Culbreath Bayou South ........................................................................................................................... 20 Georgetown ............................................................................................................................................ 26 MacDill AFB Docks................................................................................................................................... 33 MacDill AFB Beach .................................................................................................................................. 41 Venetian Isles .......................................................................................................................................... 49 Ft. De Soto (St. Antoine Key) ................................................................................................................... 57 Skyway Causeway North ......................................................................................................................... 65 Skyway Causeway South ......................................................................................................................... 73 McKay Bay ............................................................................................................................................... 81 Dredged Hole Ranking ............................................................................................................................ 89 McKay Bay Discussion ................................................................................................................................. 92 Conclusions and Management Recommendations .................................................................................... 94 Literature Cited ........................................................................................................................................... 95 Appendix A: Dredged Hole Sample Locations and Sampling Dates ............................................................ 96 iv List of Figures Figure 1. Tampa Bay dredged hole locations. ............................................................................................... 3 Figure 2. Fall 2016 and spring 2017 Bay Point dredged hole and reference sample locations. ................... 5 Figure 3. Fall 2016 and spring 2017 Culbreath Bayou North and South dredged hole and reference sample locations. ........................................................................................................................................ 12 Figure 4. Fall 2016 and spring 2017 Georgetown dredged hole and reference sample locations. ............ 26 Figure 5. Fall 2016 and spring 2017 MacDill AFB Docks dredged hole and reference sample locations. .. 33 Figure 6. Fall 2016 and spring 2017 MacDill AFB Beach dredged hole and reference sample locations. .. 41 Figure 7. Fall 2016 and spring 2017 Venetian Isles dredged hole and reference sample locations. .......... 49 Figure 8. Fall 2016 and spring 2017 Ft. De Soto (St. Antoine Key) dredged hole and reference sample locations. ..................................................................................................................................................... 57 Figure 9. Fall 2016 and spring 2017 Skyway Causeway North dredged hole and reference