Blue crab monitoring Dr. Steven C. Pennings University of Houston

Department of Biology and Biochemistry University of Houston Houston Texas 77204-5513 USA

scpennin@central.uh.edu https://uh.edu/nsm/biology-biochemistry/people/profiles/steven-pennings/ https://orcid.org/0000-0003-4757-7125 Georgia Coastal Ecosystems LTER Project

Dept. of Marine Sciences University of Georgia Athens Georgia 30602-3636 USA

gcelter@uga.edu https://gce-lter.marsci.uga.edu/ Dr. Steven C. Pennings University of Houston

Department of Biology and Biochemistry University of Houston Houston Texas 77204-5513 USA

scpennin@central.uh.edu https://uh.edu/nsm/biology-biochemistry/people/profiles/steven-pennings/ https://orcid.org/0000-0003-4757-7125 Principal investigator Dr. Brian R. Silliman Duke University

135 Duke Marine Lab Rd. Duke University Marine Lab Beaufort North Carolina 28516-9721 USA

brian.silliman@duke.edu https://nicholas.duke.edu/people/faculty/silliman https://orcid.org/0000-0001-6360-650X Co-investigator 2026

The goal of the monitoring is to determine the importance of several factors that may affect use of the marsh by blue crabs. We will use crab traps to estimate the relative abundance of blue crabs in small (1 m width) marsh creeks as a function of 1) time of year, 2) tide height, 3) day versus night high tides, and 4) abiotic conditions (salinity, climate). Crab traps (1-3 per creek) will be deployed in 1-3 creeks for a single high tide, once a week. Traps will be deployed in the upper reaches of the creeks. Traps will be retrieved on the following low tide, and crabs measured, sexed, and released on the spot.

Area 2: Patterns within the Domain (more information)

creek population density LTER NSF GCE Callinectes population studies Overall geographic extent of the research project -81.299522 -81.264378 31.394072 31.371003 2013-10-01

Part of GCE LTER core monitoring efforts

estuary marsh complex Dean Creek - Doboy Sound/salt marsh site at the southern end of Sapelo Island near Dean Creek and the Sapelo lighthouse. A few small creeks are present, but a large creek (Dean Creek) is easily accessed. Upland is composed of small hammocks and some constructed causeways, with sand dune complexes east of Dean Creek and extending to the beach. Upper end of the watershed is affected by a culvert at Beach Road and heavy student use of marsh immediately adjacent to culvert. A hydrographic sonde is deployed in Doboy Sound near Commodore Island approximately 1.5km from this site. GCE6 is also the focus of Sapelo Island Microbial Observatory research on microbial diversity and genomics (http://simo.marsci.uga.edu) -81.299522 -81.264378 31.394072 31.371003 GPS data file (Trimble, Excel) https://gce-lter.marsci.uga.edu/private/registration/files/gps_data/GCE-52-2013_GPS_Initial_crab_trap_deployment.kmz

Creeks at the south end of Sapelo Island with easy road access from the island. For example, we might place traps in tributaries of Dean Creek or Lighthouse Creek. Our first set of traps will be deployed at 31°23'22.24"N; 81°16'49.69"W. We will start by sampling a single creek to ensure that the methodology will work before expanding to additional creeks.

Because traps will be in the upper reaches of very small (1 m channel width) creeks, they will not pose a hazard to navigation, and will not be confused with commercial traps.

We will trap blue crabs, but release them on the spot after counting them. We will be covered by the UGAMI collection permit.