A04 ASIS Inventory Study Statement of Work_0001.docx

National Park Service U.S. Department of the Interior

Inventory & Monitoring Division

Statement of Work / Objectives NPS Inventory and Monitoring Division

Invasive Crab Inventory at ASIS

Title: Invasive Crab Inventory at ASIS Project Background Oyster reefs are important keystone species in estuarian systems worldwide. They provide important ecosystem services, including provisioning, improving water quality, reducing shoreline erosion, and providing habitat for commercially important fisheries. Because of their importance, they are thought to be good indicators of ecosystem condition. Unfortunately, native oyster reefs are threatened by invasive aquatic species, and their restoration is a top priority.

Marine invasive species are a growing problem for coastal parks, and a likely factor contributing to oyster reef declines. As new introductions increase, related damage to natural resources continue to emerge. ASIS lacks adequate baseline data on invasive species presence within its boundary. Several species such as Green crab (Carcinus manenas) and Asian / Japanese Shore crab (Hemigrapsus sanguineus) have established populations in park jurisdiction and likely impact current native shellfish restoration plans, including reestablishment of oyster reefs. The presence of these species can interfere with regional shellfish aquaculture operations as well as the economically valuable commercial fisheries in the area.

This study will complement recent academic research on the distribution and abundance of oyster spat along the coast of Assateague Island, and support a regional working group’s interest in shellfish restoration within the coastal estuaries. Knowledge of the species distribution and abundance of invasive crabs will guide managers selection of suitable oyster and SAV restoration areas that may have an impact on restoration success. Results from this study will be used primarily to inform a regional shellfish restoration working group facilitated by the Maryland Coastal Bays National Estuary Program.

Measureable Objectives

1. Quantify the abundance of C. manenas and H. sanguineus in the Chincoteague and Sinepuxent Bays and determine the degree to which abundances vary between early and late summer.

2. Identify the spatial distribution of C. manenas and H. sanguineus within the Chincoteague and Sinepuxent Bays and the degree to which abundances vary among habitat types and across space.

Statement of Work The selected contractor will conduct a survey of invasive crabs in Chincoteague and Sinepuxent bays within Assateague Island National Seashore. The target sampling area is positioned between two inlets, Chincoteague Inlet (Virginia) to the south, and the Ocean City Inlet (Maryland) to the north. The bays are bounded to the east by Assateague Island and to the west by the Maryland and Virginia mainland (Figure 1).

Figure 1. Study area for invasive crab inventories at Assateague Island National Seashore.

Specifications

1. The sampling design must specify what methods will be used to survey invasive crabs across the study area.

2. The sample unit is a grid cell; the size of which would be dependent upon the method used for capturing the abundance data. Grid cell size of approximately 0.5 km2 size or less is a reasonable starting point for initial planning (again, dependent upon sampling methodology).

3. Sampling units within sites should be selected randomly to promote statistical inference. Beyond the sampling units within sites, the sites themselves should provide adequate spatial representation and be replicated equally among habitat types.

4. Habitat type is the desired unit of analysis, of which there are three types (rocky substrate, vegetated, and unvegetated habitats). The limiting habitat type is rocky substrate, of which there are approximately 7 areas in the study area. Many more of the vegetated and unvegetated habitat areas are present. It is therefore expected that all areas of rocky habitat would be sampled. And a subset of vegetated and unvegetated habitat type locations would be randomly selected from all potential vegetated and unvegetated areas. For equal sample sizes, each of the 3 types should be represented by 7 sites (i.e., n = 21). Within each of the 21 sites, the more sampling units that are sampled, the greater the precision of the mean abundance estimate per unit. A loose goal would be 3 sampling units for each of the 21 sites is reasonable to achieve a desirable degree of precision.

5. June and September are optimal windows for sampling based on the life, reproduction, and spawning cycles of the species. Notes:

a. The spawning and reproduction cycles of the species of interest is such that their abundance can be expected to increase markedly between early and late summer months.

b. Green crabs are a popular choice of bait of fishers; unused live green crabs are discarded into the waters after fishing expeditions. It is unclear to what extent this can influence species counts, but the timing is likely to coincide with popular fishing seasons, which are late summer weeks in these bays.

6. Because the absence of presence does not necessarily imply true absence, the sampling design proposed by the offeror must describe how sampling effort will be standardized and how imperfect detection will be accounted for.

7. Sampling methods must also include the collection of the following environmental covariate data:

a. Water temperature

b. Dissolved oxygen

c. Salinity

d. pH

e. Chlorohyll a

8. Tidal height and meteorological conditions are continually sampled by ASIS and will be available to the investigator.

9. Collections of specimens should be limited to those necessary to validate the species identifications. Collections require an NPS collection permit. Any collections made during this study are assumed to be consumed in analysis.

10. Analysis and reporting of data must at a minimum:

a. Document the process by which errors are identified and corrected

b. Include distribution maps, and

c. Link detection/non-detection data with measured habitat and water chemistry covariates.

11. It is likely that these data will deviate from traditional parametric assumptions of normality (and homogeneity), as well as having instances where no species are detected in particular sampling plots (i.e., “0”s in the dataset). A mixed model can accommodate these nuances because the user defines the variance structure and link function parameters of the model. Analyses are to be described in detail sufficient for peer review and repetition by independent statisticians.

12. A research permit is required prior to the commencement of any fieldwork. The internet site http://rprs.nps.gov/research/ac/apps/apply/AppInstructions provides for online permit requests.

13. Upon request of the applicant the NPS will provide the following spatial data: geology, wetlands, vegetation classification, soils, park boundary, boundaries for high priority areas, previously used parkwide survey transects. Due to their sensitivity, locations of previously identified rare plant areas will only be disclosed to the successful offeror.

Deliverables The offeror will provide the following to NPS at the conclusion of the study:

1. Report and associated data table(s), spatial data, and map(s) identifying:

a. Sample design

b. Sample methods, locations of survey, level of effort spent, analysis methods.

c. Distribution map of all target species.

d. Environmental variable information collected and used in analysis.

e. An analysis and discussion of results that highlight:

i. The distribution invasive crabs in each of the bays,

ii. Locations of invasive crabs in relation to habitat type and environmental covariates

2. All code (e.g., R, SAS, or other) used to analyze survey data.

3. All observation data for species observations and covariate measurements, submitted in standard Microsoft Excel template (Available at https://irma.nps.gov/DataStore/Reference/Profile/2272660).

4. The report should be provided in a standard Microsoft Word format.

Place of Performance Field work must be completed at ASIS. All other activities associated with analysis and reporting can be conducted at the recipient’s location.

While not a constraint per se, Maryland and Virginia coastal bay waters are rather wind-driven, and weather will greatly influence the timing of sampling within June and September. However, there is no biological/ecological aspect of the study that favors sampling in any week(s) of those months.

Period of Performance Field work is expected to be completed within one year of award.

Deliverables are expected within 18 months of award, with an additional 90 days for review and acceptance of products by NPS staff.

Other Considerations Offeror will be responsible for securing all required park, state, and federal scientific collection permits prior to commencing work.

image1.png image2.emf