Marine Science Chapters

3.2.6

The Treasures


Now for the 'treasures', the things that are different each time you can get to a minus tide area. There are thousands of species that might be encountered. I picked a few of my favorites to share with you. You never know what treasures will be found on a tidepool trip. In general, several of my favorite treasures are always found, but never all. Each has its own story and mystery, making it truly a 'treasure beneath the sea.'

As you move to the lower depths of the tidepools at a minus tide you may encounter various species of algae.

Sea Lettuce, a common intertidal greel algae Feather Boa kelp mixed with Surf Grass


Especially noticeable in Santa Barbara is the feather boa kelp (Egregia), with its unique growth area looking like an hourglass, and its own species of limpet that feeds on the center strap-like stipe.

Feather Boa Kelp showing hourglass shaped meristem Feather Boa Kelp with limpet on center stipe


Crabs abound as the garbage collectors in the tidepools. From the high intertidal, and very common (but hard to catch) lined shore crab, Pachygrapsus crassipes, to the large male decorator crab, Loxorhynchus crispatus, most crabs will consume anything and thus act to clean up the tidepools.

Lined Shore Crab Large male decorator crab, pyramidal form


A few, like the kelp crab, Pugettia spp., prefer plant material.

Kelp Crab Kelp Crab


Extremely shy by nature, octopods are a delightful tidepool find. They generally hide so it is only the most watchful and observant tidepooler that usually discovers this interesting animal. Once found they can be placed in a pool and observed to change color, shape and skin texture.

Octopus with smooth uniform colored skin Octopus with bumpy blotchy colored skin


Our common species, called the two-spotted octopus, changes from matching its environment to standing out in contrast to it.

Octopus matching its environment Octopus standing out in contrast to its environment


The name (two-spotted octopus) comes from the two fake eyespots, below its inconspicuous real eyes. These fake eyespots can be turned on or off. A close look at the pattern of the fake eyespot is needed to distinguish the two species of the two-spotted octopus (Octopus bimaculoides and Octopus bimaculatus). Octopus bimaculoides' eyespot has a blue chain instead of a starburst.

Octopus stranded in Surf Grass in tidepools Close up of 'eyespot' of the Two-Spotted Octopus


Octopods are masters at blending into their environment by changing color and skin texture in seconds. The octopus can bite with a beak, found in the middle of its eight legs.

Octopus legs and suckers Octopus suckers


A drop of poison is generally delivered with this bite. The poison is enough to paralyze small fish or crabs, but usually does not hurt humans (unless you happen to be allergic to it). It is best to avoid any octopus bites as one never knows if you could have a reaction (similar to a bee sting) that may be harmful.

When stressed, the animal may shoot out a cloud of ink, as a smokescreen, and jet away. It is always a good idea to look around the area where an octopus is discovered because female octopods attach their strings of eggs to a sheltered area in the rocks, often an overhang or small cave. They guard these eggs until they hatch. If you do find an octopus and move it, be sure to replace it in the same tidepool ... in case it was a female guarding eggs.

Octopus releasing ink and jetting away Octopus eggs


Two species of common sea urchins, Strongylocentrotus spp., are annoying to careless tidepoolers and scuba divers who may get their spines lodged under their skin. The spines are not poisonous but should be removed. They can cause serious problems if they lodge near a joint. The smaller and more lavender-colored species are S. purpuratus, also called 'purps', and the larger and usually darker-colored species is S. franciscanus, also called 'frans.' It is mostly the frans that are collected by local sea urchin divers, who harvest them for the five reproductive organs inside. When ripe, these organs are a delicacy in Asia and used in sushi bars they are called uni.

Sea Urchins (both 'purps' and 'frans'


These urchins are pretty strict herbivores and eat mainly kelp, chewing voraciously with five sharp teeth that are on the bottom. These five sharp teeth, called Aristotle's Lantern, are constantly repaired and can be completely replaced in 75 days.

Sea Urchin underside showing mouth and teeth Se Urchin teeth (Aristotle's Lantern)


The urchin is prey for several fish and some sea otters. In fact, some sea otters feed so exclusively on sea urchins that the purple pigment of the urchin is incorporated into their bones and, when dead, they have lavender-colored skeletons.

Related to sea urchins, several other species of Echinoderms may inhabit the lower tidepools. These include bat stars, Patiria miniata, found in a profusion of colors.

Bat Star in Kelp


Assortment of Bat Stars Assortment of Bar Stars


Remember how the knobby sea stars would evert their stomachs out of their mouths when feeding? Well, the bat star species does it on a regular basis and is easily caught with its gooey stomach everted.

Bat Star underside Bat Star underside with stomach everted


Close up of Bat Star everted stomach


Also found in the lower pools are leather sea stars, Dermasterias imbricata.

Leather Sea Star with female decorator crab Close up of madrepore of Leather Sea Star (and a scar)


Brittle stars, Ophiothrix spiculata may be found under rocks and in rock cracks. Brittle stars are very different than the sea stars we have been talking about. They are filter feeders, often found in great numbers on our ocean bottom, under the sand and in tight spaces. They are called brittle stars because they can drop their legs (or parts of their legs). They regrow these dropped legs but it takes a few months to do this and return to normal.

Brittle Star assortment Brittle Star individual that has regrown the ends of several legs


Abalones (Haliotis spp.) have been revered by man for thousands of years for their yummy flesh and their beautiful shells. In recent years, in Southern California, their numbers have so decreased that they are no longer taken by either sport or commercial means. Their decline is due to a multitude of factors, some natural and some brought on by man. There is a lot of controversy about this decline, but scientists have detailed the life cycle enough to allow mariculture farms to control the broadcast spawning of males and females, fertilize the eggs, raise the planktonic veliger larvae, and get them to settle, becoming baby abalone. These herbivores are grown (fed by kelp) by the thousands in the mariculture farms and sold to gourmet restaurants. Each spring semester I purchase several to show my students what a live abalone is like, including its internal structures, and then I prepare it in lab, giving each student a taste of this expensive delicacy that was once as cheap as hamburger.

Red Abalone


Looking a little like a rabbit, sea hares are a common treasure in Santa Barbara's Coal Oil Point tidepools. They can get up to 16 pounds but are usually more like three to four pounds in the lower pools. Although these slugs appear to be just a big blob, they have a hidden trick beautiful purple ink that can be released if you reach inside the skin flaps on the top and tickle them. In nature this acts as a smoke screen (similar to the octopus's ink).

Sea Hare Sea hare inking


The finest treasures (for me) are the sea slugs, called nudibranchs. For some reason I just love these critters. There are over 100 species in California and each has its own unique and interesting story. Many are brightly colored, but some blend into their surroundings or match their prey (upon which they may live). The most common and most flashy of the nudibranchs is the Spanish shawl, Flabellina iodinea. It is easy to see why it is called the Spanish shawl, as its colors remind one of flamenco dancer shawls. This species also 'dances' occasionally by letting go of the substrate and wildly thrashing its body back and forth, creating the same look as a flashy flamenco dancer's skirt. These are such beautiful creatures - it is hard to imagine that some animals find them toxic.

The Spanish Dancer nudibranch


Many of the slugs (including the Spanish shawl species) feed on stinging animals, like jellyfish and sea anemones. They are capable of keeping the stinging cells alive in their bodies at the tips of all those 'furry' processes, known as cerata. Then, when a predator (like a fish) comes by for a bite of this slug the stinging cells fire and the fish is repelled. The predator is rarely wounded, but it is believed that the predator remembers the flashy colors and never again bothers what it thought was a tasty morsel. So, the flashy color is thus a type of 'warning coloration.'

Marine slugs also have interesting reproductive habits. They are hermaphroditic, but must mate with another individual. Their reproductive pore is on the right side of their body so they must position themselves just right. Eventually they get together, cross-fertilize and then separate to lay their fertilized eggs. The eggs hatch as planktonic larvae.

Two Spanish Dancers Spanish Dancers lining up to mate.  Note white penis emerging from right side.


There are many other beautiful nudibranchs and a few related slugs, like Janolus barbarensis, Hermissenda crassicornis, Triopha catalinae, Anisodoris nobilis, Acanthodoris rhodoceras, Diaulula sandiegensis, and Berthellina engeli.

Janolus


Hermissenda Triopha


Anisodoris Acanthodoris


Diaulula


Berthellina Berthellina


And finally the two species I did my Master's Degree research on, Corambe pacifica and Doridella steinbergae, that live on the encrusting bryozoa (white patches) on kelp and are so camouflaged that they are nearly impossible to see. They not only look like the bryozoa, they eat it and lay their eggs on it. Below is a picture of a kelp frond (about a foot across) with these white patches and then a close-up (about an inch across) of the white patch with my slugs.

Bladder kelp with encrusting white


Corambe on bryozoa


Nudibranchs are, in my opinion, the beauties of the sea. An assortment of nudibranchs is just a delight to find in a tipepool.

Nudibranch assortment in a tidepool with kelp


As the water recedes during low tides there are some fish that get trapped in the tidepools. These are mostly small sculpins, blennies and kelpfish, but occasionally a large fish is there, like the cabezon. They just wait out the low tide, that may only be an hour or two at the lower levels, and then go about their business.

Cabezon trapped in tidepool Cabezon


Looking up from the water a tidepooler will almost always see numerous shorebirds, like the snowy egret and godwits.

Snowy Egret Godwits


Occasionally there will be a seal or sea lion hauled out on the tidepool rocks, basking in the sun. It is especially common to see harbor seals at the downcoast end of Carpinteria State Park, where there is a harbor seal rookery. Each March there are numerous babies born here - you can observe them from the cliffs just downcoast from the oil pier.

Harbor Seals at Carpinteria


A unique treasure for me is the presence of my students in the tidepools, discovering new things and understanding the complex dynamics that create our complicated shorelines with the four distinct zones.

SBCC students doing transects at Devereux SBCC students waving to their teacher


SBCC students doing a quadrat study at Devereux SBCC students doing a transect study at Devereux SBCC students doing a transect study at Devereux


As one gets ready to leave the tidepools there is always a chance of catching the blow of a migrating whale. Especially from the months of January to April, the California gray whale is migrating to and from its breeding grounds in Baja and passing Santa Barbara. This whale feeds on zooplanktonic crustaceans in the Bering Sea, off Alaska, each summer. In the fall it leaves to travel along the coastline to Baja for its winter mating and birthing. Then it returns north each spring. Occasionally tidepoolers have been surprised as they look up from the tidepools and see a gray whale breaching nearby.

Gray Whale surfacing to breathe


Gray Whale breaching off of Santa Barbara


With all the thousands of possible treasures in the tidepools, these are but a few of the visible ones. It is the indicator species (covered earlier in this lesson) that one can always count on being present in the tidepools (three from the splash zone, three from the high tide zone, one from the mid tide zone, and three from the low tide zone). These become like old friends to the returning tidepooler. The 'treasures' change with each tidepool trip - something that makes tidepooling a unique experience each time. Enjoy the tidepools if you ever get a chance, no matter where you are. In California there is a State Law that prohibits the removal of any animal from the tidepools unless you have a permit. Permits (fishing licenses) allow only the taking of food items and are highly regulated. A scientific collecting permit is required for all other critters and these must be obtained from the California State Department of Fish and Game only if there is a good reason. Many other areas in the world have similar rules so always be sure to be knowledgeable if you must take something from the tidepools. A good 'rule of thumb' in nature is to leave only footprints and take only memories and photographs.




 Copyright and Credits
(Revised 6 August 2007)
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