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'Opihi--The Hawaiian Limpet
The young haole wahine squeamishly eyed the dish set before her. The poi she'd previously experimented with had been disastrous to her taste buds. She wasn't about to make two mistakes in one evening.
Turning to the handsome Hawaiian seated on her right, she asked, "Excuse me, but what is this?"
"That? Why, that's 'opihi ."
"'Opihi?" She had a cute way of simultaneously wrinkling her nose and forehead.
"Mm-hmm. Let's see--I guess the English name for it would be limpet." He liked her green eyes.
"Oh. Is it good?" she asked.
"You bet! Goes great with poi!" he replied enthusiastically.
"Ooh, I can see we differ in taste," she said with a smile.
Flirtatiously, he replied, "Maybe..."
A blush appeared in her cheeks.
"Tell you what," he said. "Tomorrow morning, I'm going to the beach at Kakanui to pick 'opihi. If you like, I can take you with me. It'll be an appropriate time to give you a biology lesson...on limpets, I mean.":
"Hmm, you Hawaiians sure don't waste time, do you?"
"It's all in the aloha spirit. By the way, my name's Keala. What's yours?"
The preceding story is an example of one means of learning about the limpet. However, not all of us are as fortunate as the young woman in regards to being presented with a firsthand experience in discovering the wonders of the limpet. An alternative would be to delve into this subject through diligent reading and research. The goal of this hub is to aid the layman conchologist in his pursuit of shell knowledge.
Just what is a limpet?
Looking very much like a miniature mobile volcano, the limpet is a kind of sea snail which clings tightly to rocks or other surfaces. It belongs to the class Gastropoda, phylum Mollusca. There are three generally recognized families of limpets--the Patellidae and Acmaeidae, limpets which have no opening at the apex of the shell, and the Fissurellidae, limpets which have either a small opening at the apex of the shell or one marked by a slit or notch along the margin.
On the average, the limpet is a small animal, two inches or less in length (although, in some species, the length may be up to 4 inches). Its ribbed, conical shell is very resistant to turbulent wave action and thus enables the limpet to readily adapt to rocky shores. In such an environment, the limpet is successful and abundant as it feeds on algae, minute organic particles, and other vegetation.
Except for shell and foot shape, limpets are essentially like other snails in anatomical terms. Under the protection of its tough, ridged shell, the black limpet has a grey-green oval foot with a large flat adhesive surface. A head with big ear-like tentacles, each bearing an eye near its base, lies at the front of the animal. Lining the shell around its margin is a thin layer of tissue. Throughout this peripheral tissue, or mantle, and lying in the space between it and the foot are many small ciliated gills and short tentacles.
The limpet has a strong homing instinct, spending virtually its entire life at a precise place on a rock, leaving the spot only to feed. It leaves its home when the tide is in and the water not too turbulent, and also when the tide is out at night or if it is sheltered by seaweed.
It feeds by rasping at the algae on rocks, moving around with head and tentacles protruding and swinging from side to side. On the return trip, the limpet tends to retrace its route. It appears to have some sort of instinctive mechanism--an 'opihi GPS, if you will--that guides its way. Experiments have been conducted in which the limpet's tentacles were removed and its outward tracks obliterated. Nevertheless, it still found its way home, even when the journey may cover two or three feet. Now that's a commentary on perseverance!
'Opihi is a delicacy in Hawaii. Very popular as a luau hors d'oeuvre or in family dining, the limpet is usually eaten raw. It can also be combined with a kind of seaweed indigenous to the limpet's habitat to make a delicious soup.
Because of the tremendous year-round demand for 'opihi, the harvesting of limpets is a lucrative business. A gallon of shelled 'opihi sold for $60-80 when I was a young boy fifty years ago. Today, due to higher consumer demand and, sadly, a sharp decline in 'opihi numbers because of over-harvesting, the price per gallon has skyrocketed to $200.
I recall with a nostalgic pull at the heart how my brother and I would accompany our father on daily expeditions to favorite 'opihi hunting grounds and spend several hours scraping the limpet from the rocks. It was during these treks to the rocky beaches that I learned a great deal about the limpet.
For example, provided the rocks were well-splashed and shaded, the tide level did not affect the habitat of the 'opihi. The limpet did not appear to be impacted by temperature fluctuations. It also flourished where the sea is diluted with fresh water from the mountain streams.
I noticed, too, that shells picked where there was greater wave action were thicker than those picked in calm tidepools. In the more turbulent spots, I observed that there was noticeable organic growth on the 'opihi shells which helped the limpet to blend in perfectly with the seaweed on the rocks. This suggested to me that this natural camouflage may have been one of its survival strategies.
Limpets are very difficult to dislodge. They must be taken by surprise. Tools commonly used to pry a limpet from its rock or coral bed are butter knives, screwdrivers, and scrapers. One's fingers are simple not quick or strong enough to capture a limpet.
Besides being a good food source, limpets make good bait for catching fish. Many a time when I ran out of shrimp for bait while hooking small fish with a bamboo pole, I'd simply chip a limpet off of a rock and put small pieces of its foot on the hook. The substitute bait worked beautifully!
Another use for 'opihi would be the crafting of fine jewelry--necklaces, bracelets, charms, brooches, and a host of other adornments. Global online marketplaces like eBay, Amazon, Etsy, Craigslist, and Yardsellr--not to mention thousands of business websites--feature jewelry and other fashion accessories made with the lovely and versatile 'opihi shell.
This next 'opihi tidbit seems so incredible that I've saved it for last. It's a characteristic that would floor even the memorable research team of Masters and Johnson.
Most limpets are monoecious --that is, they possess both well-developed male and female gonads. Both ova and sperrm are produced by two individuals side by side, each displaying identical sexual behavior. What happens is that most limpets start life as males and remain this way until they are one inch long. At two or three years of age, the proportion of females increases as the limpets reverse their sex.
Imagine that! A primitive species feminist movement!
If Adam had been a limpet, he might have had this to say:
I must retrieve
The misused rib*
I gave to Eve.
*rib refers to ribbed shell. Get the rub?