Chesapeake Horseshoe Crab Spawning Survey 

The AACC Horseshoe Crab Survey of 2025 is complete.

Thank you to everyone that contributed data. General information about the program is below, and we're already planning for 2026 with additional ways to participate including horseshoe crab rescue from revetments and shoreline sills. For planning, we conduct the bulk of our surveying at high tide during 3 days surrounding the full and new moons in May, June and July. We provide training, supplies and other needs (just ask). We're also excited to partner with any organization that would like to organize a group and needs group training or transportation. Please reach out to tldomanski@aacc.edu for more information. 

The goal of this project is to involve citizen scientists in mapping the spawning beaches of horseshoe crabs throughout the Chesapeake Bay. While there is anecdotal information concerning spawning beaches in the Chesapeake, there has not been any systematic effort to map all 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) If you're also interested in collecting blood samples that will be used for DNA studies on HSCs, take a look at the directions at hemolymph collection project , 3) get involved in 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 spring (high) tide in late May, June or July. This means a full or new moon. We usually survey a beach about an hour 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 https://dnr.maryland.gov/fisheries/pages/tide-finder.aspx . 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. 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)Download the free "Anecdata" app onto your smartphone. Once you have entered your email address, you can search for our project. We are called “Chesapeake Horseshoe Crab Survey”.

4) Walk the beach within an hour of high tide. The app will ask for "weather" - enter conditions. It will also ask for "beach" - type the name of the beach you are surveying. You can enter this information just once, if you like, at the beginning of the survey.

5) If you see a spawning female crab, enter that as an observation. The app will ask you for #females and #males. For example, if you were to see one female with three associated males, you would enter "1" for females and "3" for males. The larger female is typically buried in the sand, with one or more smaller males over her. 

6. If you'd like, take a picture, and submit that as well. There are also data prompts for tag# and carapace width. If you see a crab with a small white circular tag attached (very unlikely), enter the tag number. Don't worry about carapace width.

7. Continue down the beach, and submit each spawning female/male group as a new observation until you've completed a single pass. Done! The program automatically submits username, time, date, and GPS coordinates.

If you have questions or comments, email me tldomanski@aacc.edu .

tagging  https://www.youtube.com/watch?v=5eXexb_30ws