1. Assessing Linkages between Nearshore Habitat and Estuarine Fish Communities in the Chesapeake Bay Donna Marie Bilkovic*, Carl H. Hershner, Kirk J. Havens, Marcia R. Berman, David Stanhope and Lyle Varnell Center for Coastal Resources Management Virginia Institute of Marine Science

2. Atlantic Slope Consortium (ASC) ASC Estuarine Indicator Research Programs in the United States Research Institutes involved include: Pennsylvania State, Smithsonian Environmental Research Center, East Carolina University and Virginia Institute of Marine Science

3. “Our suite of indicators will produce integrated assessments of the condition, health and sustainability of aquatic ecosystems based on ecological and socioeconomic information compiled at the scale of estuarine segments and small watersheds, with clear linkages and connections to larger scales”. Brooks et.al., 2001 Stated GOAL of the Atlantic Slope Consortium website: www.asc.psu.edu

4. Can nearshore habitat be linked with fish community integrity, and are these accurate indicators of aquatic ecosystem health? Study Objectives  Develop and test fish community metrics that assess the health of shallow-water estuarine systems in the Mid-Atlantic  Assess relationships among shoreline condition, subtidal habitat, and fish community metrics  Assess potential relationship between watershed land use and shallow-water estuarine fish communities*. * Relationship between watershed land use and riparian land use observed for agricultural, forested and developed landscapes

6. Sampling Locations and Watershed Land Use on the Chesapeake Bay 166,000 km 2 watershed 18,804 km of shoreline 320 km long 5.5 to 56 km wide only 6.5 m average depth 15 million people live in basin

7. Watershed Selection  25 Watersheds selected  Salinity regime = oligo-mesohaline  At least three watersheds in each land use class were sampled  Land use categories 1) forested 2) agricultural 3) developed Selection Criteria

8. 5 SITES per watershed were sampled… At each SITE we assessed  Habitat Condition Shoreline (alteration) Subtidal (physical structure)  Biotic Communities Fish Prey species  Water chemistry/physical

9. Habitat Assessments

10. Eight metrics were assessed for consistency as indicators of aquatic ecosystem health based on fish community structure and function. Fish Community Metrics Reference Species Richness/Diversity Measures Species Richnessthis paper Proportion of benthic-associated speciesDeegan et al. 1997 Number of dominant species (90% of total abundance)Deegan et al. 1997 Number of resident speciesDeegan et al. 1997 Fish Abundance Ln AbundanceDeegan et al. 1997 Trophic Composition Trophic IndexJordan and Vaas 2000 Nursery Function Number of estuarine spawning speciesDeegan et al. 1997 Number of estuarine nursery species Deegan et al. 1997

11. Statistical Analyses Assessment of applicability and consistency of metrics Comparison among Fish Community Index scores, shoreline condition and subtidal habitat measures Comparison of Fish Community Index with overall watershed land use patterns

12. Fish Community Metrics Assessment  Metrics were combined into an aggregate index by summing standardized individual metric values.  All but one of the examined fish community metrics was positively and highly correlated (r>0.5) with the summed metrics.  Total abundance was excluded from the final fish community index (FCI).

13. All Significant positive relationships

14. Except…

15. Additionally, we examined the metrics using PCA… which indicated that the use of all the metrics, with the exception of total abundance, is supported for the development of a multi- metric FCI of the nearshore in coastal plain estuarine ecosystems.

16. Fish Community Metrics Assessment  Metrics were combined into an aggregate index by summing standardized individual metric values.  All but one of the examined fish community metrics was positively and highly correlated (r>0.5) with the summed metrics.  Total abundance was excluded from the final fish community index (FCI).

17. Do Fish Respond to Variations in Nearshore Condition?

18. Fish Community and Habitat Comparisons p<0.001; all different FCI scores were significantly different among all subtidal habitat categories. Higher scores were associated with increasing abundance of subtidal habitat p=0.003; High vs.Minimal FCI scores were significantly lower at sites with highly altered shorelines versus minimally altered shorelines.

19. Watershed Land Use versus Fish  FCI scores were significantly lower in developed and agricultural watersheds versus forested watersheds. p=0.03

20. Increased shoreline condition was associated with increased available Subtidal structure (shelter for fish). Habitat Comparisons

21. Developed Forested Agricultural Highly Altered Unaltered Moderately Altered Minimal Habitat Abundant Habitat Moderate Habitat

22.  Seven of eight tested Fish Community Metrics were included in a final index, and may be useful indicators of biotic integrity in shallow water estuarine systems.  Linkages could be discerned between FCI scores and not only local habitat influences, but also on a larger watershed scale. Thus, HABITAT CONDITON shows promise as an indicator of estuarine health.  Linkages existed among habitat at various scales (e.g. Decreases in FCI scores were evident with developed watersheds and shorelines which were subsequently linked with the loss of subtidal habitat structure)  Future management tools? Summary

23. Ongoing continuous shoreline surveys extract information on shoreline condition (land use, structures, bank condition etc.) for comparison with biotic communities GPS Continuous Survey  Assessment of shoreline condition impacts on fish communities at multiple spatial scales  Acoustic habitat mapping in the nearshore and comparison of specific habitats with biota  Explore temporal trends in fish communities indices  Examine additional biological communities in association with shoreline condition (e.g. benthic macroinvertebrates). http://ccrm.vims.edu/gis/gisdata.html Future Research

24. For instance…a metric measuring benthic community health increased as shoreline and watershed land use exhibited more natural conditions

25. Thanks to: Colleagues at SERC, Penn State, ECU and VIMS; funding source: Environmental Protection Agency, STAR Program