Chesapeake Horseshoe Crab Spawning Survey 

The AACC Horseshoe Crab Survey of 2026

We conduct the bulk of our surveying at high tide during 3-4 days surrounding the full and new moons in May, June and July. 

We provide training, supplies and other needs. Scroll down below the form and map links to read more details about the program. 

Once you've decided to participate data can be entered on this google form. Take a look at sites we've surveyed.

 We're always happy to get data from new sites to find about more about sites that HSCs visit, but we also want to get complete data sets at sites that we visit each year (sentinel sites).  

If you're interested in providing assistance with scheduled tracking at a sentinel site, please sign up for a specific date in the Survey sign-up sheet with name and contact information. Those sites typically require either permission to access or a code, so we'll work with you on the specifics for those sites. 

Please reach out to tldomanski@aacc.edu for more information. 

The goal of this project is to involve citizen scientists identifying spawning beaches and counting HSCs. There has not been a systematic effort to map all Chesapeake Bay beaches and determine how heavily each beach is utilized. Without this information it is difficult to manage the Chesapeake horseshoe crab population.  

You can participate in multiple ways: 1) spot and report, 2) collecting blood samples for DNA studies on HSCs (directions at hemolymph collection project) , 3) tagging (contact tldomanski@aacc.edu). If you spot a crab that is already tagged that can be reported at https://www.fws.gov/crabtag/ .

All you need to conduct a survey is a willingness to go out looking at your local beach (or contact us to go out to a site in another community that needs volunteers for the survey). 

If you'd like to participate and choose your own site to survey, you are welcome to survey any beach near you where you have access.

To do this:

1) Decide which beach you would like to survey. Any sandy beach, of any size, is a potential spawning beach. It could be at a park, or it could be a neighborhood beach where you have access.

Once you have chosen a beach, decide if you would like to go at night or during the day (or both). More crabs spawn at night, however some beaches are only available during the daytime.

2) Decide on a day, and time. The best time to look for horseshoe crabs is at a high tide in late May, June or July during the full or new moon. We usually survey a beach about 30 minutes before the high tide time. That’s when female crabs emerge from the water with their males for spawning. The chart below the instructions lists the days and times for high tides during this period for the Annapolis area, but more specific high tide information can be found at High Tides on Chesapeake Bay . The information can also be found using the "tide finder" on the Maryland DNR website. 

If you have a smartphone and want to upload the data directly, then you can follow the directions below and put data in the Google Form. If you want to record the data on a hard copy, a form is attached here or you can just write down the information and we are happy to pick it up at your convenience. 

3) Go to this google form.

4) Walk the beach slightly before or at high tide. You don't need to go into the water. You can just count the horseshoe crabs you see along the shoreline and in the very shallow water.  NOTES:  wear waterproof shoes or beach (it gets very annoying very quickly to have wet sand getting into your shoes and please don't go barefoot at night) and take a flashlight or wear a headlamp (we can lend out equipment). 

5) Enter the total males and total females (living). When counting, the larger female is typically buried in the sand, with one or more smaller males over her. Free swimming HSCs are usually males because females typically will definitely have males latched onto their backs (see picture at top of the survey form). 

6)  Also record total dead horseshoe crabs that you see on the beach.

7) If you're interested in collecting additional data, 1) physical parameters (water temperature, salinity or other parameters), 2) collect small volumes of blood (video for collection method below), 3) tag horseshoe crabs, we'll provide additional supplies, training, drop off and pick up materials and samples.  

BELONG TO A GROUP THAT YOU'D LIKE TO ORGANIZE TO TRACK A SITE ALL SEASON?  We'll come out to your site and do training and provide a bit of HSC spawning tshirt swag.  

If you have questions or comments, email klivernoche@aacc.edu or  tldomanski@aacc.edu. For a bit more context see the article in the  Chesapheake Bay Spinsheet magazine and the short summary of some historical data that is included below the survey schedule.