Last night was the new moon and the new moon means spring tides. Tides are tied (groan) to the lunar cycle, with the highest (and lowest) tides happening every 14 days, at the new and full moons. These large tide swings is referred to as a spring tides. But why is this important you ask? Because Horseshoe Crabs are exceptionally numerous on our beaches during their spring spawning season that runs from March through June, and it is during the spring tides that the mama crabs venture onto the beaches en masse to deposit their eggs in the sand.
Every two weeks during the new and full moon high tides the females come out of the water, often dragging a male attached to her with his hook-like front legs. On the beach she will dig a hole in the sand beneath her to lay her eggs. As she lays her eggs, the attached male (or males) release sperm to fertilize the eggs. The eggs develop under the sand for two weeks until they hatch just in time to catch a ride out on the next high tide. A female may lay as many as 80,000 eggs per season.
It was just to see this wonder of nature’s timing that I visited the heel this morning at the high tide. The crabs were not as numerous as I have seen them at Mitchelville Beach in the past. Mitchelville would have been my preferred place to visit, but the storms and King Tides from last year, especially those in October, have left no beach remaining at the spring tides. I chatted with a number of very friendly people about the crabs, and after observing a crazy woman (ummm, that would be me) on the jetty pulling out crabs that had become wedged in the rocks and releasing them into the waves, a small group of young men joined the effort.
If you would like to read more about these fascinating creatures, just follow this link to my page on Horseshoe Crabs. Below you will find a video of a male clinging to a female’s back as she moves across the sand, as well as a cool one of crabs swimming in the water pooled around the rocks of the jetty at the tides goes back out. We have some clingy males here, too.
UPDATE: I visited the heel again just after the high tide on May 10 and found a crazy number of Horseshoe Crabs, many more than right after the new moon (which should have seen the greatest number). There were so many burrowed deeply into the sand that you had to tread carefully so to not step on them.