We have a guideline here on Dewees which is part of our community ethos to keep our beaches pristine. The guideline (it is part of our community constitution) is that beachcombers should only take three shells home with them. There are three reasons for this:
- shells eventually replenish and renourish our sand
- limiting our shell collection leaves more for the next beachcomber
- a wide variety of animals make their home in and on shells.
The first two reasons are pretty self explanatory, but this week we found several shells demonstrating just how significant a role they serve as habitat for other animals. Hermit crabs are the most common live inhabitant of univalve shells, trading up in size as they grow and outgrow their shells. In addition, a variety of other creatures may build homes on shells– anemones, barnacles, limpets, even corals. In the first photo, an old whelk shell provides a home for a flat-clawed hermit crab, limpets, barnacles, coral, and an anemone on the back. Sponges have bored into the shell, leaving those characteristic honeycomb holes.
There are several types of coral in our waters–including sea whip, star coral, and sea pansies. The first two will grow on abandoned shells, and you can often find very old shells which have supported a variety of sea life. This shell has been engulfed in coral and sea whip, which has also eventually died off.