Collecting Cone Shells: Special Handling Required

by B. N. Sullivan

In the last several posts we have been talking about collecting sea shells, and how divers can find shells underwater.

We strongly discourage the taking of live shells from their habitat. Taking live shells depletes populations by preventing the creatures living inside from reproducing. It also can disrupt the ecological balance of the habitat, since these creatures have roles as both predators and prey.

Previously, we offered a few tips on how to figure out if there are creatures living inside a shell. Today we would like to add a word of caution, particularly in regard to Cone Shells (Conidae).

There are hundreds of species of Cone Shells. The shells are attractive, and popular with collectors, but you should know that the snails that build and inhabit Cone Shells are venomous. Handling a live Cone Shell can result in being stung.

The Cone Shell snails are carnivores: some prey on other mollusks, others eat worms, and still others actually prey on fish! The snails have a structure that works a bit like a hypodermic syringe. They produce a venom that contains neurotoxins. They inject the venom into their prey through hollow stingers. (Technically, the 'stingers' are tiny, harpoon-like radula teeth.) Depending on the species, the venom either kills or immobilizes the prey.

There have been numerous cases documenting Cone Shell envenomation in humans. Depending, again, on the Cone Shell species, and also on the site of the sting, the result can range from pain, to paralysis, to death! So, if you see a Cone Shell in the water, understand that it is a venomous creature, and approach it accordingly.

If you are going to handle a Cone Shell to see if it is alive, pick it up carefully by the crown -- that is, the broad end of the cone. The stinging part is in the proboscis, which is at the 'nose' of the cone. Better yet, use something inanimate as a tool to flip over the shell so that its aperture faces upward. You may immediately see some part of the snail, but even if you don't, you should wait for awhile to see if the animal appears and tries to right itself.

If you find shells -- including Cone Shells -- while diving, it's convenient to carry them in a small mesh bag that you can clip to a D-ring on the outside of your vest. In any event, do NOT put a cone shell into your pocket or carry it in your hand, even if you think it is empty -- just in case!

We recommend that divers (and others) who are interested in collecting shells learn something about the creatures that formed the shells and live inside them. An understanding of how and where they live, what they eat -- and what eats them -- not only facilitates knowing where to look for them, it also provides the collector with a better appreciation of how the creature fits into the ecosystem. Today we add another item to this list of reasons to learn something about these creatures: your own self-protection.

About the photos: I took these macro photos of a live Mediterranean Cone Shell (Conus mediterraneus) on a sand flat off the coast of Dhekelia, Cyprus. As far as I know, this is the only Cone Shell species native to the Mediterranean Sea. The shell is relatively small -- about 3 cm (1.25 in). By the way, despite its appearance, that brownish structure sticking out near the wide end of the shell in the second photo is not the 'stinger'. It is the snail's operculum - a sort of lid that the snail uses to close over the shell aperture for protection when it retracts into the shell. The operculum is hard, made of material similar to our fingernails.

Curiously, we have never found an empty Mediterranean Cone Shell, so we have no examples of this shell in our collection. Fortunately, we do have several nice photos of the living species. Some long-time readers of The Right Blue may recall another post featuring this species, from 2007: Muck diving - The tale of the cross-eyed cone shell

Queen Conch - What strange eyes you have!

What: Queen Conch (Strombus gigas).

Click here to learn about the Queen Conch.

Where: I took these photos of the Queen Conch's eyes at Radar Reef,

on the north shore of Cayman Brac.

Click on the photos to enlarge.

Finding Shells Underwater

by B. N. Sullivan

I have been collecting seashells since I was a little girl. Early on, my collecting was limited to shells I found washed up on a beach somewhere, but once I learned to dive, I began looking for shells underwater. Later, when Jerry and I began to dive together, he took up the hobby, too, and over the years, we have amassed quite a respectable shell collection.

We are purists about shell collecting. As I mentioned in the previous post about shell collecting and diving, we do not buy shells, and we do not sell them, or even trade them with other collectors. All of the shells in our collection have been found by one of us.

We also are purists in another sense: we do not take 'live' shells -- that is, shells still occupied by anything living, whether it is the snail that originally secreted the shell, or a hermit crab that has adopted the shell as a home. I cannot say that we never have been tempted to take a live shell; of course we have been. But we don't do it because, over the decades that we have spent in the ocean as divers, we have witnessed a noticeable decline in the number of shells that we see. We know that one of the reasons is that collectors -- and dealers catering to collectors -- have repeatedly harvested live shells before the critters that live in them have had a chance to reproduce.

Many popular dive areas around the world officially prohibit the taking of shells, live or otherwise. There was a time when this kind of rule was encountered only in officially protected areas, such as marine parks or preserves. Nowadays, many dive operators and resorts (and even some municipalities) prohibit divers from collecting any shells, including empties. These 'no-take' rules may seem extreme to some, but in many cases they have arisen because divers (and other people) were taking shells indiscriminately, including those still occupied by their natural residents, and populations were becoming seriously depleted. If you dive in an area that prohibits shell collecting, do follow those rules.

Shell collectors should be conservation-minded, even in areas where collecting is not officially prohibited. We have witnessed plenty of instances of egregious over-collecting. For example, one time we saw a diver climb aboard a boat, carrying twenty-some Marlinspike Augurs (like the shells in the photos on this page). He proudly announced that he had spent his whole dive digging in the sand for them. All of them were alive. Another time, a diver waded ashore with a very large glob of mucus oozing out of the pocket of his BC vest. It turned out that he had collected several large, live cowries and had stowed them in the pocket. In both of those cases, other divers in the party confronted the poachers. The man with the Marlinspike Augurs tossed all but three overboard; the man with the cowries kept his shells, casually announcing to us that "the animals are probably dead by now anyway."

Divers are not the only ones who sometimes engage in excessive collecting. Early one morning as we were preparing to enter the water for a shore dive, we saw a woman sitting near the edge of the water beside a plastic bucket. As we walked past, we were horrified to see that the bucket was half full of assorted cowries. We asked what she was planning to do with all those cowries. She told us she was waiting for the sun to kill them so she could "scrape the muck out of them" with a penknife. She said she had collected them the evening before, while wading in the shallows. It turned out she was a tourist, staying at nearby vacation rental cottage. She told us she did this every year when she visited Hawaii, because she liked to take the shells home to her friends as souvenirs.

As collectors ourselves, we obviously have no quarrel with taking shells, but we do promote prudence in collecting. Don't take live shells; and learn to be satisfied with collecting one or two examples of a given species. If you find a handsome shell that is occupied, do photograph it, but please don't deprive the poor little guy inside of its home.

How to Find Shells

Our success as collectors has grown from an understanding of which critters live where. If you want to collect shells, the first thing you need to do is learn something about the mollusks that create the shells. Learn which kinds live where -- in sand, in rocky rubble, among coral -- then you will know where to look for them. It also helps to learn what they eat. You won't find them where there is no supply of their preferred food.

Learn which other animals eat the snails that inhabit shells. If you discover where a mantis shrimp lives, for example, you may find a small cache of empty shells near the entrance to its burrow (although many will be broken). If you notice an octopus hunting, follow it for awhile and you might be rewarded. We once acquired a large tiger cowrie shell, compliments of an octopus. We watched as the octopus enveloped the tiger cowrie with its body, sucked out the poor snail, and then dropped the empty shell onto the sand. We still have that shell, thank you very much.

Another strategy is to take note of places where empty shells tend to collect naturally, due to the forces of waves, surge, and currents. In reef areas, small conglomerations of shells often can be found near the base of large rocks or coral heads. In inter-tidal zones, waves and surge will carry empty shells along and deposit them among the rocks. Sometimes shells are buried under a bit of sand, so a good technique to use in a likely area is to wave your hand to fan away the top layer of sand to expose the shells.

When you find a shell, how do you know for sure if it has a creature inside? Sometimes it's very easy to see if a shell is empty. If you pick it up and a lot of sand pours out of it, usually that means it is unoccupied.

If you find a shell with its opening facing upward, it probably is not alive, since mollusks and hermit crabs that live inside shells typically move along with the shell on top of them. But the aperture-up rule is not foolproof. Finding out if there's anybody home inside mostly takes patience. You need to leave the shell, aperture up, undisturbed for awhile -- sometimes for as long as 10 or 15 minutes. Wait, and eventually an animal living inside -- whether a snail or a crab -- will poke out, or even try to right itself. The second photo on this page shows that the Marlinspike Augur, which looked to be empty at first, actually had a tiny hermit crab living inside.

Coming up: more stories about certain types of shells and the creatures that live in them.

Shell Collecting and Diving

by B. N. Sullivan

Awhile back, a repairman came to our home.  As he passed through our house on his way to the offending appliance he was there to fix, he screeched to a halt beside a display case in our dining room.  Inside the display case were several hundred small seashells.

He told us he was an avid shell collector and asked if we would mind if he took a moment to look over our collection.  We told him to go right ahead.

He stood there for awhile, quietly reciting the names of the different shell species as his eyes passed over the rows in the display.  It was obvious that he knew something about shells.  At length, he looked up at us and declared, "This is a really beautiful collection!  You must have spent a fortune for these."

Jerry and I exchanged puzzled looks, and then one of us told him we had paid nothing for the shells.  We had found all of them.

The repairman's eyebrows raised in surprise.  He said, "You must be divers -- and you must do a lot of deep dives."

We acknowledged that this was so, but then asked how he knew that.  He said, "You have a lot of shells that are never found on the beach, and a lot of those only live in deep water.  If you didn't buy them, then you must do a lot of deep diving to have so many different deep water species."

Then he looked at the display case again and commented, "Funny, though.  I don't see any cowries. Most divers who collect shells have at least some cowries..."

The cowries were in the next room, we told him,  in a separate display case.  We led him there to see our cowrie collection.  His gaze zeroed in like a laser on a small cowrie in the middle of a row in the display.  He pointed to it and gasped, "You actually found this one?!"

We told him where we had found it, and he shook his head in amazement.  We took the shell out of the display case so that the repairman could have a better look.  As he turned it over in the palm of his hand,  he said he had been trying to acquire an example of that shell species for years.  Several times, he told us, he had seen one for sale at auctions, but he never could afford them.  He said they always sold for more than five hundred dollars.  

Now it was our turn to be amazed!  We never buy shells, nor do we sell them, so we never had thought of  our shells in terms of monetary value -- and the one that was supposedly worth so much wasn't even among the prettiest of our shells!  We do  have lots of very pretty shells, but the most cherished shells in our collection are those  that have a personal story attached to them. 

In the next post, we will give our readers some pointers about how to find shells while diving, and then we will tell about -- and show --  some of our favorite shells.  Stay tuned.

About the Photo: That's our friend Dan, looking for shells among the rocks in a surge area along the coast of Puako, Hawaii.