Oyster larval transport/hydrodynamic modeling at Tangier/Pocomoke Sound, Virginia | W81EWF 22 SOI 0023

Grant Opportunity FAQs: Oyster Larval Transport and Connectivity Modeling for Tangier and Pocomoke Sounds

1) What is the purpose of this grant opportunity?

This opportunity supports research that helps guide the next phase of oyster restoration in the Chesapeake Bay. The focus is on the more open, mainstem waters around Tangier Sound and Pocomoke Sound near the Virginia/Maryland border, using modeling to produce decision-relevant information that can directly inform restoration planning.

2) What geographic area is the project focused on?

The work is centered on Tangier Sound and Pocomoke Sound in the Chesapeake Bay, specifically the larger, more exposed mainstem region near the Virginia/Maryland border.

3) Why is restoration attention shifting to Tangier and Pocomoke Sounds now?

After major progress restoring oysters in 10 tributary rivers (five in Virginia and five in Maryland), planners are turning to the larger and more exposed Tangier/Pocomoke region. Historical records indicate this area experienced a dramatic decline in oyster reef habitat, making it a major priority for understanding where restoration could be successful at scale.

4) What evidence is given for historical oyster reef loss in the Tangier/Pocomoke area?

Surveys from the late 1800s documented about 2,252 hectares of oyster reefs in the Tangier/Pocomoke region. By the 1980s, only about 630 hectares remained. That change represents an estimated 72 percent loss of reef habitat.

5) What is the core scientific question the opportunity is trying to answer?

The central scientific need is to understand oyster larval transport and connectivity across the region using hydrodynamic and biophysical modeling. The goal is to determine how currents and related hydrodynamic processes move oyster larvae, where larvae are likely to settle, and how different reef locations may be connected through larval dispersal.

6) Why does the opportunity emphasize hydrodynamics and larval transport?

The opportunity is grounded in the idea that oyster reefs are not randomly distributed. Local hydrodynamics, especially currents that move oyster larvae, likely played a major role in where reefs historically persisted and where reefs could be successfully rebuilt today. Modeling these processes is intended to improve restoration site selection.

7) What does "connectivity" mean in this project context?

Connectivity refers to the way oyster populations in different locations may be linked by larval movement. If larvae produced in one area are transported by currents to another area where they settle, those reefs and sub-populations are connected as part of a broader network.

8) What is a metapopulation, and how does it relate to oyster restoration here?

The opportunity describes oyster populations as potentially functioning like a connected network (a metapopulation). In this framing, some reefs act as consistent larval producers (sources), while other reefs depend on incoming larvae (sinks) because local conditions do not allow them to sustain themselves without outside replenishment.

9) What are "source" reefs and "sink" reefs?

Source reefs are locations that consistently produce larvae that can disperse to other areas. Sink reefs are locations that rely on larvae arriving from elsewhere because local conditions may not support self-sustaining reproduction and recruitment.

10) What types of modeling are expected under this opportunity?

The opportunity calls for hydrodynamic and biophysical modeling, with simulations designed to map larval movement, likely settlement patterns, and system-wide connectivity across Tangier and Pocomoke Sounds.

11) What practical decisions is the modeling expected to inform?

The modeling outputs are intended to help planners prioritize where to build oyster reefs. The emphasis is not just on whether a site looks suitable locally, but on how each site could strengthen recruitment and long-term persistence across the broader Tangier/Pocomoke system.

12) Why is site selection described as such a critical factor?

The opportunity states that site selection is one of the biggest determinants of whether a large-scale reef build will provide lasting ecological benefits. This project aims to improve site selection by adding a connectivity-based perspective to restoration planning.

13) What are the three main objectives of the anticipated work?

The opportunity describes three closely related objectives:

1. Characterize oyster larval transport dynamics across the Tangier/Pocomoke region, including whether the relatively open area still has consistent circulation features or "favorable currents" that concentrate larvae and promote settlement.
2. Identify likely source and sink areas to create a connectivity-based framework for deciding where reefs should be constructed to maximize population-level benefits (not just isolated site-by-site gains).
3. Estimate the oyster population size required to create a detectable, region-wide improvement in recruitment, helping define what "enough restoration" looks like at regional scale.

14) What does the opportunity mean by "favorable currents"?

In this description, "favorable currents" are consistent circulation features that can concentrate larvae and increase the likelihood that larvae settle in certain places. Even though the area is relatively open, the project expects that persistent transport patterns may still exist and may matter for where reefs can thrive.

15) What is meant by a "connectivity-based framework" for restoration planning?

It refers to prioritizing restoration locations based on how sites function within the regional larval network (for example, whether a site produces larvae that seed other reefs, or whether it depends on larvae arriving from elsewhere). This approach is intended to maximize population-level outcomes across Tangier and Pocomoke Sounds rather than focusing only on isolated, local site performance.

16) What is the "population threshold" question and why is it described as novel?

The opportunity highlights a challenging, novel objective: estimating the oyster population size needed to create a detectable, region-wide improvement in recruitment. The description notes that determining a population threshold that measurably influences recruitment at the regional scale has not previously been done, and this work would help clarify how much restoration is needed to move beyond individual reefs and influence the broader system.

17) What kind of outcome is the project expected to deliver?

The overall intent is to produce decision-relevant modeling outputs. These outputs should directly inform where and how to invest in oyster reef restoration in Tangier and Pocomoke Sounds so that new reefs meaningfully contribute to recruitment and long-term recovery across the region.

18) Who is offering the funding?

The funding is offered by the Department of Defense, Engineer Research and Development Center.

19) What is the funding mechanism for this opportunity?

The opportunity is offered under a discretionary cooperative agreement.

20) What is the funding opportunity number?

The funding opportunity number is W81EWF 22 SOI 0023.

21) How many awards are anticipated?

The opportunity indicates an anticipated single award.

22) What is the maximum funding amount available?

The stated award ceiling is $100,000.

23) What is the activity category and CFDA listing provided?

The activity category is Science and Technology and other Research and Development. The CFDA listing provided is 12.630.

24) When was the opportunity created and what was the original closing date?

The opportunity was created June 9, 2022, and the original closing date was August 9, 2022.

25) Who is eligible to apply?

Eligibility is listed as "Others," with additional eligibility details referenced in the full announcement.

26) What makes this opportunity different from tributary-focused restoration work?

This opportunity targets a larger, more open and exposed mainstem region (Tangier and Pocomoke Sounds) after progress in 10 tributary rivers. The work is framed around understanding region-wide larval transport and connectivity to support restoration at a broader spatial scale where historical reef losses were substantial.

27) What region-wide restoration benefit is the modeling trying to support?

The modeling is intended to help identify which restoration sites are most important for sustaining recruitment across the broader system, improving the likelihood that restored reefs persist and contribute to long-term recovery throughout Tangier and Pocomoke Sounds.