Browsing by Author "Hale, Edward A."

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    A satellite-based mobile warning system to reduce interactions with an endangered species
    (Ecological Applications, 2021-05-30) Breece, Matthew W.; Oliver, Matthew J.; Fox, Dewayne A.; Hale, Edward A.; Haulsee, Danielle E.; Shatley, Matthew; Bograd, Steven J.; Hazen, Elliott L.; Welch, Heather
    Earth-observing satellites are a major research tool for spatially explicit ecosystem nowcasting and forecasting. However, there are practical challenges when integrating satellite data into usable real-time products for stakeholders. The need of forecast immediacy and accuracy means that forecast systems must account for missing data and data latency while delivering a timely, accurate, and actionable product to stakeholders. This is especially true for species that have legal protection. Acipenser oxyrinchus oxyrinchus (Atlantic sturgeon) were listed under the United States Endangered Species Act in 2012, which triggered immediate management action to foster population recovery and increase conservation measures. Building upon an existing research occurrence model, we developed an Atlantic sturgeon forecast system in the Delaware Bay, USA. To overcome missing satellite data due to clouds and produce a 3-d forecast of ocean conditions, we implemented data interpolating empirical orthogonal functions (DINEOF) on daily observed satellite data. We applied the Atlantic sturgeon research model to the DINEOF output and found that it correctly predicted Atlantic sturgeon telemetry occurrences over 90% of the time within a 3-d forecast. A similar framework has been utilized to forecast harmful algal blooms, but to our knowledge, this is the first time a species distribution model has been applied to DINEOF gap-filled data to produce a forecast product for fishes. To implement this product into an applied management setting, we worked with state and federal organizations to develop real-time and forecasted risk maps in the Delaware River Estuary for both state-level managers and commercial fishers. An automated system creates and distributes these risk maps to subscribers’ mobile devices, highlighting areas that should be avoided to reduce interactions. Additionally, an interactive web interface allows users to plot historic, current, future, and climatological risk maps as well as the underlying model output of Atlantic sturgeon occurrence. The mobile system and web tool provide both stakeholders and managers real-time access to estimated occurrences of Atlantic sturgeon, enabling conservation planning and informing fisher behavior to reduce interactions with this endangered species while minimizing impacts to fisheries and other projects.
  • Thumbnail Image
    Item
    Environmental drivers of biogeography and community structure in a Mid-Atlantic estuary
    (Oecologia, 2024-02-14) Oleynik, Haley A.; Bizzarro, Joseph J.; Hale, Edward A.; Carlisle, Aaron B.
    Estuaries include some of the most productive yet anthropogenically impacted marine ecosystems on the planet, and provide critical habitat to many ecologically and economically important marine species. In order to elucidate ecological function in estuaries, we must understand what factors drive community dynamics. Delaware Bay is the third largest estuary in the United States and hosts over 200 species of migrant and resident fishes and invertebrates. The Delaware Division of Fish and Wildlife has conducted two long-term trawl surveys at monthly intervals in Delaware Bay since 1966. The two surveys collect data on environmental conditions, species composition, and number of fishes and macroinvertebrates across different size classes and life histories. Using a suite of multivariate approaches including hierarchical cluster analysis, canonical correlation analysis, and permutational multivariate analysis of variance, we characterized the fish and macroinvertebrate community in Delaware Bay and found that community composition and environmental conditions varied across spatial and seasonal scales. We identified four distinct biogeographic regions, based on environmental conditions and community composition, which were consistent across surveys. We found that the community was driven primarily by gradients in temperature and salinity and that abundant, frequently occurring species in the Bay have well-defined environmental associations. Our work represents the first attempt to use an existing historical survey to better understand how environmental parameters influence diversity and distribution of macrofauna within Delaware Bay, providing insight into how abiotic variables, influenced by climate, may impact the Delaware Bay ecosystem and similar estuarine ecosystems worldwide.
  • Thumbnail Image
    Item
    Population Dynamics of Common Nearshore Forage Fishes in the Delaware Inland Bays, USA
    (Estuaries and Coasts, 2022-03-13) McGowan, Andrew T.; Hale, Edward A.; Bartow, Dennis H.; Greco, Michael
    In the Mid-Atlantic, four species of forage fish, Menidia menidia (Atlantic Silverside), Fundulus heteroclitus (Mummichog), Fundulus majalis (Striped Killifish), and Cyprinodon variegatus (Sheepshead Minnow), account for a large proportion of fish abundance in estuarine environments and are important food sources for state and federally managed predatory species. The population dynamics of these species are poorly understood, and factors affecting their populations are largely unclear or unknown. Seine samples were collected in the Delaware Inland Bays over 9 years (2011–2019), with indices and trends in abundance, as well as climatic and biotic drivers of population changes investigated at both combined estuary and individual bay scales. Average interannual decreases in abundance for all four species at the combined estuary scale ranged between 31.9 and 69.2%, while increases ranged between 65.9 and 178.6%, indicating the extreme variability these species show between years. Standardized models of abundance demonstrated long-term declines in abundance for Mummichog and Sheepshead Minnow at both the combined estuary and individual bay scales. Spring discharge affected Mummichog and Sheepshead Minnow abundance, and Sheepshead Minnow showed a strong negative correlation with Summer Flounder abundance. These data quantify the variability in abundance for an important portion of the forage base in Mid-Atlantic estuaries and should be considered as fisheries management shifts away from single-species approaches and recognizes the forage needs of managed species. Results indicate that even commonly encountered species can consistently vary through time and emphasize the need to examine other important but poorly studied forage species.