Yesterday's Island Today's Nantucket
Nantucket
Science
Volume 40 Issue 15 • August 12-18, 2010
now in our 40th season

Decked Out Like a Mermaid

by Dr. Sarah D. Oktay
Managing Director UMass Boston Nantucket Field Station

If you are doing a nature walk on island, you are bound to be talking about something you find on a beach named as a mermaid’s fashion accessory.  Whether they are truly bad about leaving their stuff all over the place, or whether their life in a watery realm means even their purses and slippers are ephemeral, we can only guess.  This week we will explore the various items named after the mermaid, including some possible theories for the mermaid herself.

A mermaid is a mythological creature with the head and torso of a women and the tail of a fish. The word is a compound of “mere,” the Old English word for "sea," and maid, a woman.  The male equivalent is a merman.  Mermaid stories have been around for thousands of years.  The first known mermaid stories appeared in Assyria, around 1000 BC. The goddess Atargatis, mother of Assyrian queen Semiramis, loved a mortal shepherd, became pregnant by him, and unintentionally killed him (a really, really “Cold Case” episode). Ashamed, she jumped into a lake to take the form of a fish, but the waters would not conceal her divine beauty.  Thereafter, she took the form of a mermaid—human above the waist, fish below—though the earliest representations of Atargatis showed her as a fish with a human head and legs, similar to the Babylonian Ea.

Much like sirens, mermaids sometimes sing to people and gods and enchant them; distracting them from their work and causing them to walk off the deck or run their ships aground.  Other stories depict them squeezing the life out of drowning men while attempting to rescue them.  They are also said to carry humans down to their underwater kingdoms.  In Hans Christian Andersen's The Little Mermaid, it is said that they forget that humans cannot breathe underwater, while others say they drown men out of spite.  Mermaid stories circle the globe from the Arabian Nights to Britain.  The mermaid, or syrenka, is the symbol for the Polish capitol city of Warsaw.  This website: http://northstargallery.com/mermaids/mermaidhistory2.htm explores the form and use of mermaids in art, literature, as figureheads, on car hoods and bomber planes.

Other related types of mythical or legendary creatures are water fairies (e.g., various water nymphs) and selkies, animals that can transform themselves from seals to humans.  Large “human-ish” creatures such manatees and seals and dolphins were most likely the inspiration for mermaid stories. People often use familiar objects to give us a deeper connection to items we see in nature.  When we imagine an acorn cap or a mushroom used as a tiny umbrella or moss as a soft bed for a fairy or wood nymph we are trying to put ourselves in their shoes.  Mermaid tales were often used to help explain the vagrancies of the sea’s wrath as well as the lure of an ocean voyage for seafaring souls.  The magical underpinning of mermaids is evoked in a beautiful book of children’s poetry called “The Mermaid’s Purse” by the famous English poet (and infamous husband of Sylvia Plath) Ted Hughes.

Mermaid’s slippers are the common slipper shell bivalve whose scientific name is Crepidula fornicata (Linnaeus, 1758), that we talked about in May of this year in this column; they are prolific at Brant Point and at the Jetties, in effect, the shoe stores of the northern beaches.  The slipper shell is a species of medium-sized sea snail, a marine gastropod (Phylum mollusca) in the family Calyptraeidae, which includes the slipper snails, the Chinese hat shells (Calyptraea species), and the cup-and-saucer snails (Crucibulum species).  The Atlantic slipper shell is arched with brown or pink markings and an apex that is bent downward to one side at the back. They live in relatively shallow water (to depths of about 20 feet). The shell is oval, up to 5 cm in length, with a much reduced spire and no operculum.  The large aperture has a shelf, or septum, extending half its length.  On Nantucket one can also find, in much smaller numbers, another species of slipper shell called the Crepidula plana (Say, 1822) or Eastern white slipper shell, which is flatter than the C. Fornicata and has a shorter septum.  Unlike a bivalve (two-part shell) such as the clam or oyster, the slippers have a one-part shell with the creature's foot on the underside along with a shelf that extends about half the length of the shell in the case of the Atlantic slipper.  Slippers shells’ whimsical shape and resemblance to household slippers (for very tiny people) make them a favorite beach combing find for children.

Mermaid’s hair is a term used around the world for a variety of common single cell filamentous (string like) algae.  The genus Cladophora which is found here on Nantucket is one of the many species called “mermaid’s hair.” Under the tide it waves back and forth and looks exactly like green fine hair that could easily be pictured on the head of a young punk mermaid.  In fresh water lakes, Spyrogira is the most common green filamentous algae tagged with the “mermaid hair” moniker.  Some algae identified around the world as mermaid’s hair is actually cyanobacteria or blue-green, single cell prokaryote (no nucleus) microorganisms we know and love as bacteria.  Cyanobacteria (also known as blue-green algae, blue-green bacteria, and Cyanophyta) is a phylum of bacteria that obtain their energy through photosynthesis.  Roughly 3 billion years ago, cyanobacteria began producing atmospheric oxygen that, much later, allowed more complex life forms to emerge. The name "cyanobacteria" comes from the color of the bacteria from the Greek word “kyanós” for blue.

Researchers at the University of California, San Diego (UCSD) and the Scripps Institution of Oceanography (spearheaded by Dennis Carson M.D., professor of medicine and director of the Rebecca and John Moores UCSD Cancer Center) have identified a potent new anti-cancer drug isolated from  a toxic blue-green algae found in the South Pacific. The researchers isolated close to 250 different compounds from the Lyngbya majuscala bacteria, which is also known as "mermaid’s hair."  One of compounds is called somocystinamide A (ScA), and it appears to be a potent agent that can kill tumors and may be delivered to cells using nanotechnology without harming healthy tissue — thereby avoiding a major drawback to traditional cancer therapies such as radiation treatments and chemotherapy drugs. Lyngbya majuscula is known for its toxicity and ability to cause seaweed dermatitis which is why it is called “fireweed” in Australia and “stinging limu” (algae) in Hawaii.  These blue green algae (which has a reddish tint underwater) produces antifungal and cytotoxic agents, including laxaphycin A and B and Curacin A.  Oregon State University researcher Dr. Bill Gerwick first collected the blue-green algae in December 1991.  He named its medicinal compound Curacin A in honor of the island of Curaçao.  Marine plants and animals are often the source of useful compounds from omega-3 acids to AZT (used to treat AIDS patients).

Mermaid’s purses can be found on many island beaches and they are frequent finds off Surfside and CodFish Park in ‘Sconset.  This name is given to the egg cases of many sharks and skates.  This tough, protective purse-shaped egg case contains one fertilized egg.  During ovulation, the female releases oocytes from the ovary.  Then, these oocytes are fertilized by sperm, and the fertilized ova are encapsulated in an egg case in a specialized organ called the nidamental or shell gland.  In all oviparous species and most viviparous species, a yolk sac is packaged in the egg case along with the ovum.  The Skate is a wide, flattish, non-bony (cartilaginous) fish which has “wings” or fin-type projections on the sides of its body and a whiplike tail which it uses as a rudder.  They can weigh up to 100 lbs, but the species we most often find around Nantucket are Little Skates (Latin name, Raja erinacea, Mitchill 1825) which only get to be about 20 inches long at the ripe old age of 8-9 years.  The name Raja erinacea was changed to the currently valid name Leucoraja erinacea in 1825 just to confuse us.  The genus name is derived from the Greek "leukós" meaning “white” and from the Latin "raja" meaning “stingray.”  There are perhaps 6 or 7 other skate species found off Nantucket including the winter, smooth, barndoor, and rosette skates.  Skates are related to stingrays and sharks (subclass Elasmobranchii) and are bottom feeders, where they eat crabs and other crustaceans, worms, bivalves, and small fish. Larger skate species are eaten by humans, but the small ones here are only captured accidentally as by-catch.  Little skates are gray to dark brown above and have a pale underbody.  Small dark spots usually cover the top half of  their body.  These fish are about as wide as they are long and have a flattened, disc-like shape.  Their pectoral fins, which act as modified wings, gracefully propel them through the water.  Three or more rows of thorns run down their back, except in adults where they also run along the midline of their body and tail.

The Skate egg case is a small (3-4 inches long), leathery, rectangular sort of pouch with long, thin, horn-like projections sticking out from each corner. The egg cases are made of keratin, the same substance of which human fingernails are composed.  An egg case forms around each individual skate embryo just before the mother deposits the cases on the sea floor.  The long, curved projections on each corner of the egg case are covered with a gummy material.  The “horns” tend to catch on seaweed or other objects, helping to anchor the egg case to the bottom.  The horns serve to extract oxygen from the water, and to release waste back into the water.  The egg cases are very tough and hard to penetrate, which helps keep out predators like crabs.

When they are first deposited, the egg cases are waterproof because the embryos do not have gills until after three weeks of development.  Then small holes open in the tips of the horns, admitting seawater, and the baby learns to live as an underwater creature.  When the time comes for the young skate to escape its natal confinement (anywhere from 3-15 months depending on the species), the egg case splits open at one end and the juvenile emerges. Then the egg cases wash up on our shores to be found in the wrack line.

Next we find on our beaches the mermaids’ toenail; I always felt bad for mermaids hearing this term used, but it does fit a tiny bit.  The mermaids’ toenail is the word used for the beautiful jingle shells found on Brant Point and various beaches on island.  Jingle shells are the remains of a clam (Anomia simplex), so named because they jingle when you drop them on the rocks. When alive, the jingle shell clam attaches by a short stalk to a rock or other hard surface, and eats tiny organisms that it filters from the water.  People often place several shells onto a string, since they come in many pretty colors and make a nice sound when the wind stirs them.  The lower valve —where the stalk came through — provides a convenient hole for the string! Shells of Anomia simplex are sometimes found as far north as the coast of Nova Scotia and all the way down south to Brazil.  The shells are 1"–2" in diameter and can be found in a range of colors from white to yellow to peach to a dark brown.  Their surface is shiny like frosted nail polish.  Because the clam usually attaches itself to a rock or some other solid object, the upper half, or “valve,” is the shell most often found on beaches, for it frequently washes ashore after the animal dies.

So we have a variety of mermaid related creatures around Nantucket, delighting us year round.  Be sure to keep your eyes open for them when you are at the beach!

References used for this article include the following, accessed August 9th, 2010.
University of California - San Diego (2008, February 20). Novel Highly Potent Anticancer Drug From The Sea Identified. ScienceDaily. http://www.sciencedaily.com/releases/2008/02/080211172554.htm
http://en.wikipedia.org/wiki/Mermaid
http://www.rootsandmedicine.com/curacao/plants.html
http://www.cs.umb.edu/nantucket/stop10.html
http://www.gma.org/fogm/Raja_erinacea.htm#page_69
http://www.yesterdaysisland.com/2010/science/3-hermaph.php
http://www.nefmc.org/skates/meetsum/skate_ID_guide.PDF

 

Nantucket’s most complete events & arts calendar • Established 1970 • © © 2017  Yesterday's Island • yi@nantucket.net