SANDY BEACHES

by
Edward F. Ricketts
1939



BETWEEN PACIFIC TIDES
PROTECTED OUTER COAST
B. Sandy Beaches

Pages 111 to 112
Second edition

PRESUMABLY because of their usually limited extent, the sandy beaches of the protected outer coast are the most barren of all intertidal areas. They occupy a strange position, biologically speaking. They are distinct, on the one hand, from the typical Pacific sandy beach, which is completely exposed and subjected to violent surf but nevertheless supports a highly specialized fauna, although it is neithr abundant nor greatly varied. In closed bays, sounds, and sloughs, on the other hand, we find the completely protected sandy beaches supporting a fauna both rich and varied. No doubt the total area available for colonization is the chief factor in both the latter cases, for characteristic animals will not develop for a type of region that is representd by small and widely separated areas only, like the sandy beaches in question. Such beaches ordinarily occur in short stretches of a few hundred yards or a few miles, between outcroppings of rock and are almost destitute of life. It might reasonably be asked why such areas are not colonized by the animals of surf-swept beaches; the answer is, apparently, that the animals of surf-swept beaches will not tolerat the more sheltered conditions. The same answer, reversed, would apply to completely protected bay animals, for whom these areas would be too exposed. At any rate, barrenness is the rule, and we have three animals to record from the semi-sheltered sandy beaches, ignoring those forms which may occasionally be washed up from other habitats.

154. A giant beach hopper, Orchestoidea corniculata, is successful in this barren environment, possibly because it lives high up, avoiding the "old devil sea" to which it belongs. During the day it hides in burrows in the sand, coming out at night to feed on decaying seaweed and storm wrack. Occasionally, however, it may be found during the day under piles of seaweed. This beach flea is probably the chief scavenger of the semi-protected beaches. When the waves bring it nothing it must find the food supply rather scanty unless, as is suspected, it turns with equal gusto to detritus originating on land. In appearance, it is very similar to a still larger related hopper of surf-swept beaches (185), but its antennae are not so long.

Smallwood, who has worked with an East-coast beach flea that is similar in form and habitat to our Orchestoidea, believes that the animals' reactions to light do not account for their nocturnal habits, but that keeping out of sight in the daytime is simply a protection against birds.

155. A second and much smaller beach hopper, Orchestoidea benedicti, is the only animal from the surf-swept beaches that is at home here as well. Unlike the larger hoppers, it can be found at will during the day, which seems to upset the bird theory unless its size or flavor are protective factors.

156. So deep down as to be chiefly a subtidal form, especially where the sand is firm, with an admixture of detritus, but sometimes to be seen from the shore, is a lugworm that belongs more properly in the mud flats of protected bays (Arenicola, 310). It is a burrowing animal that breathes by keeping two entrances open to the surface. About one of them characteristic castings of sand will be noticed. On these barren beaches it occurs, so far as we have observed, only where rocky outcrops divert the surf in such a way as to induce the deposition of some silt - the situation to be expected, since the worm feeds by eating the substratum and extracting therefrom the contained organic matter.

BETWEEN PACIFIC TIDES
OPEN COAST
B. Sandy Beaches

Pages 135 to 144
(second edition)
Whereas the animals living on surf-swept shores have solved the problem of wave shock by developing powerful attachment devices, the inhabitants of surf-swept sandy beaches achieve the same end by burying themselves in the sand. Some, like the mole crab and the razor clam, are able to burrow with extraordinary rapidity. Others (Pismo clam) burrow more slowly, depending on the pressure-distributing strength of their hard, rounded shell. These have achieved the necessary great strenth and resistance to crushing, not through the development of such obvious structural reinforcements as ribbing, with the consequent economy of material, but by means of shells which are thick and heavy throughout. Ribbing would provide footholds for the surf-created currents which could whisk the animal out of its securely buried position in a hurry. Natural selection presumably has "bred out" a race of thick- and smooth-shelled clams over which the streaming and crushing surf can pour without effect. In addition the actively burrowing forms particularly, such as Emerita (186), must be provided with a sense of orientation not dependent on sight.

That the problems faced by sand dwellers on an exposd coast are reasonably baffling is indicated by the fact that few animals are to hold their own under such conditions. While these beaches are not the barren wastes we found the smaller sandy beaches of the protected outer coast to be, they are still sparsely populated in comparison with similar rocky shores. Actually we know of only six or seven common forms that occur in any abundance on heavily surf-swept sand beaches, and two of them are already well along toward extinction as a result of human activities. This reflects a situation quite different from that assumed by most amateur collectors, who would have one but turn over a spadeful of beach sand to reveal a wealth of hidden life.

184. We have already cited several examples, notably the periwinkles, of animals with markedly landward tendencies. On the sand beaches of the open coast there is another, the little pill bug, Alloniscus preconvexus, about 5/8" long. This isopod is an air-breathing form which will drown in sea water. It will be found, therefore, in the highest zone, above the high-tide line, and because of the obvious nature of its burrows it is often one of the first animals to be noticed in this environment. The mole-like burrows are just beneath the surface, and making them the animal humps up the surface sand into ridges. Another air-breather, the isopod Tylos punctatus, a 1/4" to 1/2" oval form resembling Exosphaeroma (198), is restricted to the southern California beaches.

185. During the night, or most noticeably at dusk or at dawn, the foreshore seems to become alive with jumping hordes of the great beach hopper, Orchestoidea californiana (Pl. XXIX). They are pleasant and handsome animals, with white- or old-ivory-colored bodies, while the head region and long antennae are bright orange. The bodies of large specimens are considerably more than an inch long, so that, adding the antenna, an over-all length of 2 1/2" is not uncommon. Like the other beach hoppers, this form avoids being wetted by the waves, always retreating up the beach a little ahead of the tide. These hoppers seem always to keep their bodies damp, however, and to that end spend their daylight buried deep in the moist sand, where they are very difficult to find. Night is the time to see them. Observers with a trace of sympathy for bohemian life should walk with a flashlight along a familiar surfy beach at half-tide on a quiet evening. These huge hoppers will be holding high carnival-leaping about with vast enthusiasm, pausing to wiggle their antennae over likely looking bits of flotsam seaweed. They will rise up before the intruder in great windrows, for all the world like grasshoppers in a summer meadow. Too closely pursued, they dig rapidly into the sand, head first, and disappear very quickly. Ovigerous females have been taken in March in Monterey Bay.

186. Emerita analoga (Pl. XXIX) is the mole crab or sand crab, the "sand bug" of the beach-frequenting small boy. The shell is almost egg-shaped - a contour that is efficient for dwellers in shifting sands where the surf is high, since the pressure is distributed too evenly to throw the animal out of balance........

...taken advantage of by hungry birds as well as curious collectors and bait-gatherers. The latter use the animals in their soft-shelled stag, that is just after they have moulted.

187. At about the mole-crab's level are minute, shrimp-like crustaceans, Archaeomysis maculata, called opossum shrimps because, like other mysids, they retain the young in a marsupial pouch under the thorax. Gills are attached to the legs and hang down in the water. There is a trick to finding these animals, for they are so transparent that they cannot be seen directly with the naked eye. On a sunshiny day, however, they cast shadows on the sand below the smooth runoff of waves dammed back momentarily by a shovel, and so can be located and captured. This form is related to the more visible mysids of the tide pools (60).

188. The bean clam, Donax gouldii (Fig. 67), is common from the San Luis Obispo region to Mexico. This small wedg-shaped clam, averaging an inch in length, is said to have been so common at one time that it was canned commercially at Long Beach. For many years it has not been availabl in commercial quantities, but the individual collector can still find enough for a delicious chowder by combing the sand just beneath the surface. The bean clam's hiding place is commonly revealed by tufts of a hydroid that grows on the shell and protrudes above the surface of the sand. This elongate hydroid, Clytia bakeri, related to Obelia, and occurring also on the Pismo clam, is th only hydroid found on exposed sandy shores.

189. A razor clam, Siliqua patula

190. The Pismo clam, Tivela stultorum (Pl. XXIX), does not merely tolerate surf; it requires it. Clams removed from their surf-swept habitat to lagoons and sheltered bays to await shipment live but a few days, even though tidal exposure, temperature, and salinity are the same..... The Fish and Game Commission takes an annual census of the animals, based on test counts in strips of beach running from the upper limit of the intertidal zon out to the water line at extreme low water. The results indicate that, despite the present restrictions (fifteen 5-inch clams per person per day, certain areas are closed, and all shipments prohibited), the species is in danger of becoming extinct unless still more stringent restrictions are applied and enforced.

With the exception of man, the Pismo clam's natural enemies are few. .... There is reason for believing that when our own beaches are depleted the coast of Lower California can be called upon to supply large quantities of Pismos. It is to be hoped that the Mexican government, which has shown itself to be wide awake in the matter of conserving wild life, will enact and properly enforce legislation that will help Tivela to hold its own.

191. Although we ourselves have never taken them, E. and C. Berkeley report (1932) from Long Bay.......

192. A good many favorably known food fish, notably striped....... This is the famous grunion, Leuresthes tenuis a smelt about 6" long.

193. The storm wrack and flotsam cast up on sandy beaches is sure to contain the usually incomplete remains of animals from other kingdoms......

In the spring of 1927 the junior writer, aboard a sailing ship a few hundred miles off the coast of central California, sailed for several days through incalculable numbers of purple-sailed "floats"-siphonophores, ... A little later, storms drove tremendous numbers of th creaturs, Vellla lata (Fig. 68), ashore along the California coast-a performanc that is repeated once in every few years. ....Specimens picked up on the beach .... but occasionally a perfect one may be found, with purple zooids trailing below the disc and even with a purple goose barnacle attached.

"Gooseberries," the "cat's eyes" of the fishermen, are occasionally cast up on the beach, where succeeding waves roll them around until they are broken. These are comb jellies or ctenophores, usually Pleurobrachia bachei (Fig. 69).

Great blubber-like masses of the jellyfish Aurelia (330) are often cast up in the fall, but usually so wave-torn as to be scarcely recognizable.

*Any number of other animals may be stranded at times, but those mentioned can b expected fairly regularly. Flotsam timbers, if they have been in the water any length of time, will almost surely have adherent goose barnacles, Lepas anatifera, etc., relatively similar to the Mitella of 160.



Analysis by
Robert 'Roy' Jan van de Hoek
Field Biologist & Geographer
Wetlands Action Network

Ed Ricketts refers to the title of this chapter as "Sandy Beaches." The sandy beaches may be barren in terms of numbers of species, but no one would doubt the beach barren when standing among 10,000, maybe more, sand (mole) crabs, with hundreds of shorebirds, from Willetts, to Whimbrels, to Marbled Godwits, feeding on the hordes of sand crabs. On some beaches such as Zuma on a low tide, the number of Bean Clams can add up to 10,000 or more, if one were to count all of them. And lastly, when a thousand or more Grunion come up on the beach, we would certainly not refer to that stretch of of beach as barren. Yet, an hour earlier or an hour later, after the Grunion run, that beach would look barren. And to know that the birds crowd onto the grunion beach to catch fish is additional proof that the sandy beach is not barren. I have seen Black-crowned Night Heron, perhaps a dozen or more, anxiously awaiting to catch the grunion at San Pedro. Among them, were several Great Blue Heron, also awaiting an opportunistic meal.

In the Introduction, Ed Ricketts discusses sandy beaches on page 6-7 but only briefly under the heading of "Protected Outer Coast" for a brief sentence as follows: "Here on the Pacific we have only two types of shore within this division. They are A. Rocky shores. B. Sandy beaches."

On page 139 (second edition) we learn that George MacGinitie did work at Humboldt Bay because Ed Ricketts had a verbal communication with George MacGinitie regarding clams at Humboldt Bay.