A Cuticular Secretion of the Horseshoe Crab, Limulus polyphemus: A Potential Anti-fouling Agent.

Solid surfaces placed in the ocean are targets for colonization by all manner of sessile fouling organisms. Although the carapace of the horseshoe crab presents just such an opportunity for colonization, it is usually surprisingly clean of macroscopic colonizers. The dorsal surfaces of the cephalothorax of 8 of 16 randomly chosen animals from the Marine Resources Center at the Marine Biological Laboratory were completely free of macroscopic fouling organisms and in a second sample of 10 randomly chosen animals, 6.09% of the dorsal surface of the cephalothorax was occupied by macroscopic colonizers. In these samples, the commonest fouling organisms were members of the genera Crepidula (a sessile gastropod) and Balanus (barnacles). Some common sessile organisms, such as bryozoans, tunicates, and green algae, were not present on these animals.