Assessment of spawning and nursery habitat suitability for American shad (Alosa sapidissima) in the Mattaponi and Pamunkey rivers

Delineation of essential fish habitat is particularly difficult for migratory fish which utilize large expanses of habitat throughout their life history. This study\u27s main objective was the development and evaluation of habitat assessment tools for the early life stages of American shad (Alosa sapidissima) in two coastal plain rivers. to accomplish this, shad spawning and larval nursery habitats were delineated in the Mattaponi and Pamunkey rivers using presence of eggs and larvae (1997--1999) as evidence of habitat use. A watershed habitat assessment protocol was developed and used to rate habitat based on hydrographic, physical habitat, shoreline and land use parameters. These parameters were evaluated for associations with the presence of shad eggs and larvae to corroborate habitat ratings. Values for parameters used in the ratings were obtained from field assessments, long-term data sets and remote sensing in attempts to combine best-available data. Multivariate statistical analyses indicate the importance of hydrographic parameters (current velocity, dissolved oxygen and depth); physical habitat features (sediment type and deadfall); and forested shoreline/land use features to presence of eggs. Larvae were more dispersed than eggs and distinct habitat associations could not be discerned. Morphological features indicate the presence of three distinct regions along the Mattaponi and Pamunkey river gradients. Presence of eggs is typically associated with upstream and mid-river regions, while larvae were dispersed amongst the three regions. Shad eggs and larvae were more abundant on the Mattaponi River than the Pamunkey River, which is concordant with juvenile abundance. Abiotic factors hypothesized to impact spawning location, larval transport, development rates and predator/prey abundance were also examined. Utilizing the juvenile Alosa index (1991--1999) as an estimate of juvenile shad recruitment, correlation with discharge, precipitation and water temperature (March--June) was examined. Hydrographic conditions during May and June appear to most accurately predict juvenile recruitment patterns in the Mattaponi River, however trends in the Pamunkey River were not as consistent. Ultimately, discharge affects transport of weak-swimming larva to variably favorable nursery habitats. A conceptual hydrodynamic model was developed which explores potential impacts of variable habitat exposures on larvae driven by spawning location, habitat suitability, discharge and hatching rates

Composition, distribution, and dynamics of intertidal epibiota on coastal defense structures

Proliferation of artificial structures to protect shorelines has introduced novel habitat to most coastal environments and fragmented natural habitats. These changes can result in disrupted connectivity, habitat homogenization, and altered estuarine landscapes, with uncertain implications for estuarine and marine faunal community structure and function. In estuaries, such as Chesapeake Bay, where soft-bottom habitat dominates and rocky shorelines are rare, the introduction of artificial rocky structure may enhance recruitment of species that are limited by the availability of suitable substrate including native and introduced species (Bilkovic & Mitchell 2013). There is a significant lack of empirical data on the types of epibiotic assemblages that colonize artificial structures, including information on seasonal changes in species composition and abundance and the prevalence of non-native species on offshore breakwaters. Breakwater are shore-parallel structures designed to reduce wave effects. They are typically high-crested rock features that remain partially emerged during all tides. These structures alter the hydrodynamics and physical conditions around them, likely affecting the distribution of epibiota which have planktonic larvae that rely on currents to transport them to suitable substrate for settlement. Considering the extensive and ongoing practice of hardening coastlines, it is imperative to understand the ecological consequences of converting existing coastal habitat to artificial substrate. The SEED funding provided by the WISE Initiative supported the collection of pilot data on the seasonal composition and distribution of colonizing epibiota (oysters, mussels, barnacles, algae) on artificial hard structures (breakwaters). The intent is that research conducted in this SEED grant would support the development of a more extensive proposal to complete a regional project within East Coast estuaries that assesses the implications of introducing artificial structures for erosion control on estuarine species distribution and composition. Our study objective was to document the seasonal composition and distribution of colonizing epibiota on artificial hard structures over the course of a year

Embracing dynamic design for climate-resilient living shorelines

As natural marshes are lost to erosion, sea level rise, and human activity, small created marshes, (sometimes with ancillary stabilization structures, and frequently called living shorelines) have gained interest as a replacement habitat; providing both shoreline stabilization and restoration of important ecological functions. These living shorelines enhance ecological function while reducing erosion through the use of marsh plants (Table 1). In all but the lowest energy settings, oyster reefs, low rock structures, or other stabilizing material are frequently used to enhance marsh establishment. Due to their ability to stabilize the shoreline with minimal impact to the ecology, living shorelines are considered a method to increase coastal community resilience to sea level rise (e.g., Sutton- Grier, Wowk, & Bamford, 2015; Van Slobbe et al., 2013) but little consideration is being given to living shoreline resilience under changing climate. Although it has been stated that living shorelines have the capacity to adapt to rising sea levels (e.g., Moosavi, 2017; Sutton- Grier etal., 2015; Toft, Bilkovic, Mitchell, & La Peyre, 2017), their ability to fulfill this potential relies on being designed to incorporate all the processes occurring in natural systems. The extent to which living shorelines can mimic the resiliency of natural marshes and oyster reefs will depend on their setting, design and the type of human maintenance provided. Truly resilient projects will require engineers and ecologists to work together to describe the dynamics of shore line processes under sea level rise and translate this understanding into living shoreline desig

Ecological and erosion protection functions of Chesapeake Bay living shorelines : Comprehensive Monitoring of Ecological and Erosion Protection Functions of Chesapeake Bay Living Shorelines (CMLS), Phase I

Armoring shorelines to prevent erosion, improve access, and accommodate individual landscaping interests can result in fragmentation or loss of habitats, reduction in capacity to moderate pollutant loads delivered to coastal waters, reduction in nekton and macrobenthic integrity (Bilkovic et al. 2005, King et al. 2005, Seitz et al. 2006, Bilkovic et al. 2006, Bilkovic & Roggero 2008), increases in invasive species, such as Phragmites australis (Chambers et al. 1999, King et al. 2007), and disturbance of sediment budgets sustaining adjacent properties. As an alternative to traditional armoring of shorelines, shoreline protection techniques incorporating natural elements from the system are increasingly promoted as not only less harmful to the system, but also beneficial due to their ability to provide or enhance coastal ecosystem services. However, there remains significant uncertainty regarding the benefits and impacts associated with many natural shoreline protection designs because there has been limited scientific investigation of adverse ecological affects associated with many of the current management options (e.g. Carroll 2002, Burke et al. 2005, Davis et al. 2006, Bilkovic & Roggero 2008)

Biofiltration potential of ribbed mussel populations

Our primary study objective was to characterize the ribbed mussel population and estimate their water processing potential along the York River, Virginia

Influence of pH on the distribution and abundance of freshwater snails.

We compared snail populations with pH as a limiting factor in two acidic and two alkaline lakes in Northern Michigan. We estimated populations by the depletion method to determine whether the snails differed in abundance and diversity. The two acidic lakes contained no snails as opposed to the basic lakes which had relatively large snail populations. No species overlap existed between these alkaline lakes. We concluded that pH was a limiting factor in snail distribution.https://deepblue.lib.umich.edu/bitstream/2027.42/54335/1/2771.pd

Johns Point Landing Living Shoreline – Ecological Monitoring : Final Report to Gloucester County

VIMS monitoring activities consisted of three components: • Monitoring of marsh vegetation establishment after planting • Documenting ribbed mussel and oyster recruitment and growth in experimental bags of oyster shell at the living shoreline • Monitoring infaunal communities prior to and after living shoreline implementatio

Ecosystem Approaches to Aquatic Health Assessment: Linking Subtidal Habitat Quality, Shoreline Condition and Estuarine Fish Communities

In the Chesapeake Bay, there is currently no comprehensive assessment of aquatic habitat heterogeneity or understanding of the effects of multiple stressors on the viability of these habitats. To assess the use of side-scan sonar technology with specially designed classification software, QTC SIDEVIEW developed by Quester Tangent Corporation as a tool to define subtidal nearshore habitat, two representative watersheds of the Chesapeake Bay were surveyed. Relationships between subtidal habitat and shoreline condition as well as linkages of habitat condition to fish community indices were assessed. Side-scan technology had the ability to image habitat at a resolution of less than 1 meter. Automated seabed classification shows promise as a delineation tool for broad seabed habitat classes. In the James River, relationships between shoreline condition and fish community indices were observed, while no association with bottom type was reflected in the data possibly due to the limited availability of vertical structure in this system. Observed relationships and habitat mapping protocols have the potential to be extrapolated to additional watersheds in the coastal plain, and become tools for future development of habitat indices and ecosystem management

Assessing Larval American Shad Growth and Survival with in situ mesocosm experiments in three differing habitats within a coastal estuary

Habitat can be defined as the place where the organism lives including all its physical, chemical and biological dimensions (Odum 1971; Hoss and Thayer 1993). These dimensions include water quality, physical structure, flow regime and biotic interaction. Essential fish habitat (EFH) is further defined as “those waters and substrate necessary to fish for spawning, breeding, feeding, or growth to maturity” (Magnuson-Stevens Act, 16 U.S.C. 1801 et seq.) With new mandates to identify and protect EFH for all species managed under fisheries management plans, evaluation of fish habitat has become a priority. The methods used to identify and define essential fish habitat have ranged from intensive microscale sampling to coarse macroscale delineations. Historically, assessment of fish habitat occurred on small scales and addressed water quality, physical structure and prey/predator interactions. With increases in geographic information systems (GIS) capabilities, large-scale depictions of fish distributions have been completed, however, these surveys often lack the detail necessary to describe the processes driving distribution. Research at both scales is necessary to accurately define and describe essential fish habitat. Macroscale assessments of fish distribution, linked with process-oriented experiments will elucidate the driving forces behind distribution and allow for a more complete identification of essential habitat

Shallow Water Fish Communities and Coastal Development Stressors in the Lynnhaven River

Coastal development pressures in the Mid-Atlantic have been attributed to significant negative impacts to aquatic ecosystems. The Lynnhaven River watershed, located in the southernmost extent of the Chesapeake Bay and encompassing Virginia Beach, is an example of a shallow-water tidal system under intense development pressure that is confronted with multiple and often conflicting coastal management issues. Rapid development in and around the City of Virginia Beach over the past few decades has led to the loss of natural buffers and habitat (e.g. oyster, wetlands and seagrasses), increased sedimentation, and degraded water quality. The Lynnhaven Ecosystem Restoration Project, led by U.S Army Corps of Engineers, is an effort to collaborate with State and federal partners over a 5-year period to identify and implement the most effective strategies for improving water quality, restoring oysters and seagrasses, and managing siltation. Limited quantitative information exists on the nekton assemblages utilizing shallow water habitats, such as tidal creeks, within the Lynnhaven River restoration area. To document nekton composition, and to investigate potential effects of development stressors, such as dredging and shoreline modification, three sets of paired dredged and undredged tidal creeks were surveyed in the Western Branch of the Lynnhaven River. Fish communities were sampled with multiple gear types once per month for three months (August, September, October, 2006). Abundance, average length and weight, diversity, and fish community indices were estimated for each creek and time period, and dredged compared with undredged systems for resemblance in fish composition and abundance. Tidal creeks within Lynnhaven Bay support diverse and similar fish communities. Slight differences in community structure among creeks may be attributable to the location and size of watersheds. The effects of dredging were not apparent in fish community responses measured as abundance, biomass, diversity, and fish community indices. However, anthropogenic effects may be obscured in the shortterm by the background variability of physical and water quality features of Lynnhaven Bay estuary, and long-term or cumulative effects are not quantifiable due to the dearth of historic information on fish communities. Available historic information may indicate a shift in fish community structure that could be associated with coastal development pressures, such as shoreline alteration and habitat loss of wetlands and oyster reefs. Accordingly, restoration and preservation of critical nursery habitats may augment fish productivity in Lynnhaven Bay