Living on Limulus

Conclusions

One of the things I look forward to the most each spring is the horseshoe crabs moving inshore to spawn, because they always bring along something new and interesting to show me. Over the years, I have noticed that the most sluggish are likely to have most of the shell and eyes covered with fouling growth.

Such a thorough covering across the surface of the horseshoe crab may cause it more than a little inconvenience, by interfering with light detection. The thick coating of hitch-hikers seems to presage the final demise of the horseshoe crab. This and their sluggishness are clues that they are suffering and probably won’t survive another season.

I pity them and always peel off the growth from the eyes of heavily infested horseshoe crabs, but it probably doesn’t help them for long, since they undoubtedly grow right back. In spite of it all, the horseshoe crabs struggle on, ambling off into deeper water, disappearing beneath a thickening blanket of bryozoans, barnacles, and whatever else issues from Triton’s wreathed horn. Perhaps, like their terrestrial counterparts, old soldier crabs never die, they just fade away.