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Home , Clam, Geoduck, Pacific razor clam

UNITED STATE DEPARTMENT OF THE INTERIOR ~ tewart L. Udall, Secretary John A. Carv!:'r Jr., Under ecretary

l' tanl!:'y ~\. Cain, .L 1.~ . ·i.~ta nt ecretary for FiRh and Wildlife and Park.­ FI, H AND WILDLIFE ERVICE, Clarence F. Pautzk(', Commissioner

RnREAU OF C'OMM~;R I <\f, FI HERlES, Don,dcl L. :'IIcKcrnall, Dhector

Commercial of the North American Pacific Coast

By

MURRAY H, AMOS

Circular 237

Washington, D,C,

April 1966 co TE TS

1 1 1 Commercial Clams of the North American Pacific Coast

By

MURRAY H. AMOS Fishery Biologist (Research)

Bureau of Commercial Fisheries Biological Laboratory Seattle,

INTRODUCTION worn away. The middle layer is generally chalky and composes the bulk of the thickness About 500 different of bivalve of the shell. The inner layer is usually hard nollusks are native to the Pacific coast of and, in some species, iridescent or lustrous. \l orth America. Only nine of these species The two shells are joined at the back by a ippear in commercial markets, although about hinge ligament generally visible from the out­ ~5 specie s are commonly considered edible. side. Concentric rings are laid down on the The other species are either too small, too shells of almost all species as the few in number, or both, to support a com­ grows. A few species also have ridges on the me rcial clam fishery. shell radiating from the hinge to the edge. The commercial harvest of clams along The growth rings vary from indistinct to :he Pacific coast of the and prominent, depending on the species. The ::anada for 1963 (the latest year for which rings may be used to age some species, :omplete data are available) was about since formation of rings is influenced by 5,672,000 pounds worth $463,000 to the fisher­ changing environmental conditions during the men. This harvest yielded about 1,596,000 year. The colder temperature and reduced ?ounds of clam , an estimate based on food abundance of winter slow the growth of a yield of 42 percent from razor clams the clams. The concentric growth rings are and 25 percent meat from all other species. laid down closer together forming a more Jf these totals, Canada produced about 812,000 prominent band often of a different shade pounds of meats and the United States 784,000 from the rest of the shell. While these growth pounds. checks may be used to age the clam, they are not always infallible. Often, for reasons unknov.n, an extra check may appear between HABITAT two true winter checks. Two of the most prominent features of the The common commercial clams are found soft tissues of the clam are the foot and from the intertidal zones of beaches and mud the or "neck. " In digging, the foot flats out to depths of over 30 fathoms. Some, is projected into the substrate and blood is such as the razor, pismo, and bean clams, pumped into a blood sinus, causing the tip prefer the sandy beaches of the open coast of the foot to expand. A set of muscles exposed to the pounding of the surf. Others then contract, pulling the clam toward the live in the quieter waters of protected bays, anchored tip. Some species, such as the inlets, and sounds. Clams usually are buried razor clam, can repeat these actions rapidly in the bottom, from just under the surface and often descend faster than a man can dig t o depths of over 4 feet, depending on the in soft sand. Others, such as the horse clam species; occasionally the littleneck clam, the and , remain virtually immobile once , and the jackknife clam are on the established in the bottom. surface or partially exposed. The siphon consists of two fleshy con­ tractile tubes used to conduct water in and out of the clam. In some species the tubes ANATOMIC FEATURES are joined together to form a single struc­ All clams have two shells composed of three ture; in others they are separated. The in­ layers. The outer layer, or "" coming water brings food and oxygen to the is often varnishlike and sometimes partially clam. The excurrent water carries away waste products and, during spawning season, eggs Note.--Revision of Fishery Leaflet 223, dated April 1947. or sperm. Clams usually lie buried in t h e bottom, during cool summers. Certain BritishColumbia hinge ve rtic al, with the siphons protruding butte r clam beds have had only one major above the surface. Their depth in t he sub­ spawning and setting in 20 years, and low strate IS generally related to the length of temperatures are probably a major factor the siphon. The cockle, which has a very in thi s failure to adequately reproduce. short siphon, is usually at or near the sur­ face, whereas the long - necked horse clam may be buried several feet into the bottom. PROPAGATION During low water when the intertidal beds are exposed, the siphons are usually retracted Clams are not now propagated commercially just below the surface and covered with a on the Pacific coast. Recent advances in tech_ thin layer of sand, mud, or fine gravel. niques at the Bureau of Commercial Fisheries The food of the edible clams consists of Laboratory at Milford, Conn., indicate tha detritus from the bottom and drifting mic ro­ propagation soon may become feasible and SCOpiC plant and life ("") in commerc i ally profitable. The Washington State the sea water. Particles are removed from Laboratory at Brinnon, Wash., has the incoming water by motile hairlike struc ­ studied t he cultivation of clams for several tures (cilia) on the gills, passed to the sensi­ years with some succ ess. Also, under the tive palps near the mouth for sorting, and aegis of Victor L. Loosanoff in California, then ingested. From the mouth the food moves efforts are being made to establish true clam through a short esophagus to the stomach. farms based on the work of the Milford and In some species a pouch off the stomach Brinnon labo r ato rie s . contains a flexible transparent rod, the' 'c rys­ In artificial propagation techniques developed tallme style," which is composed of a starch­ to date, mature clams are taken into a hatchery, reducing enzyme. Erosion of the style by whe r e they are induced to spawn in trays of rotatlOn within the stomach frees the enzyme sea water. The fertilized eggs are collected, to assist in digestion. The digested material washed, and placed in containers of sea water 1S then passed to the intestine for absorption, maintained at a c onstant temperature -- usually and the remain1ng waste products empty into about 240 C. (75 0 F.). Under favorable condi­ the outflowing water of the excurrent siphon tions the eggs develop into free-swimming tube. larvae in 12 to 16 hours. The hatched larvae are t hen held in constant-temcferature sea water, 200 C. (68 0 F.) to 30 C. (860 F . ), until metamorphosi s is completed (usually REPRODUCTION within 30 days ) and the larvae take the seden­ tary form of juvenile clams. During this The edible clam s begin spawning in the period the larvae must be fed certain species spr10g as the waters warm. Spawning may of algae and "naked flagellate" protozoans be repeated several times during the spring that have been found acceptable as food. These and 1Oto the summer as portions of eggs food organisms must also be cultured 10 and sperm ripen and are discharged through quantity at the hat che ry. the excurrent siphon tube. Fertilization takes As with all , particularly when in place in the open water, and the eggs hatch dense concentrations, clam larvae are subject 1Oto larvae within a few hours to a few days, to diseases, , and competition with depending on species and water temperature. other forms of . The sea wate r The larvae are free -swimming animals totally used in a shellfish hatchery i s sterilized by unlike the sedentary adults. They gradually exposure to germicidal ultraviolet light. This develop through free-swimming and bottom ­ treatment not only c ontrols bacteria and fung i crawling stages before assuming the adult that are injurious to clam larvae, but also form and "setting" on the bottom, which be ­ protects the cultures from invasion by un­ cOlT'es their permanent habitat. desirable predators and c ompetitors such as The majority of the clams have the sexes small crustaceans, protozoans, rotifers, and separate, that is, separate male and female the larvae of various worms. A number of 1Odlviduals. Some, such as the cockles and antibiotics and other chemicals also are useful the pismo clam, are hermaphroditic, pro ­ in the treatment of larval cultures for dis­ ducing both eggs and sperm, sometimes simul- eases or infestations. To prevent harmful aneously. In a few species of clams, an indi­ bacteria being fed to t he larvae, food organisms vidual may be a male at one life stage and must also be treated with antibiotics or sterile a female at another. cultured in bacteria-free media. In addition, In some years the water along the Pacific other form s of sea life that can utilize the food c.oa"t, part1cularly northward from California, cultures must be prevented from growing and do s not become warm enough to induce spawn- multiplying in the food culture containers . 1n 1n a number of the species of commercial Successful propagation of clams depends on clam Even presumably' well-adapted native fastidious application of t he techniques. Per­ peci may spawn only lightly, or not at all sons interested in attempting clam propagation

2 DORSA L

STOMACH------~ ~--DIGESTIVE GLAND

MOUTH----~ ~------HEA IT ~~~~ PALPS---. ElCURRENT TU BE NTERIOR --- .4 ARTERY TO FOOT ------1 BLOOD SINUS ,..,.--- I NCURRENT TUBE

FOOT----\:'\ POSTERIOR

VE IN FROM FOOT INTESTINE GILL VENTRAL

Schematic diagram of median section of clam (Mouth and palps displaced anteriorly and one pair of gills removed.) should consult the paper, "Rearing of Bivalve Razor Clam Mollusks," by Loosanoff and Davis (1963). The full reference is given in the last section of The range of the razor clam, patula, this leaflet. is from Pismo Beach, Calif., to the Bering Sea; however, it occurs in commercial quan­ tities only from the Oregon beaches to the HARVESTING western end of the Peninsula. The most productive beds are from Tillamook Most of the annual catch of edible claIns Head to Moclips along the coasts of Oregon is taken by hand with shovels, rakes, or forks and Washington; the Queen Cha rlotte Islands (usually potato forks). Rakes or forks are beaches in ; and the shores preferred for the species found near the sur­ of Cook Inlet, Orca Inlet, the Copper River face because they loosen the ground and do delta near Cordova, and the mainland side not leave mounds or water-filled holes in which of Shelikof Strait in Alaska. In 1963, the U.S. y oung clams may be buried too deeply and commercial fishery for razor clams yielded smothered. For razor clams a special narrow­ 377,000 pounds of meats worth $167,000 to the b laded shovel, known locally as a "clam gun," fishermen. Razor clams represented about i s used. ClaIn dredges are not used as ex­ 48 percent of the total clam meats taken on the t ensively on the Pacific coast as on the Atlantic U.S. Pacific coast. In the same year the British coast for the commercial taking of clams. Columbia razor clam fishery yielded 62,000 pounds of meats (value unspecified). composing about 7.5 percent of the BritishColumbia clam PRINCIPAL SPECIES meat production. Razor clams live in the and In t he following sections a scientific naIne seaward some distance beyond the breaker is given for each species. Unfortunately, the line, on the sandy beaches of the open scientific names of the commercial bivalves coast. Small beds may be found ins ide the are not as well established as might be ex­ mouths of coastal harbors, but growth is pect ed. Several of the species have been usually inferior in these locations. They are variously classified into a number of different not found in the large inland sounds such as species and genera. In general, Ihave followed and the Straits of Georgia. the taxonom ic clas s ific ation gi ven in "Arne rican Spawning of razor clams apparently begins Seas hells" by Abbott (1954). when the water temperature rises to 130 C.

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o 5S F.)--usually during the second half of ming, either comlTlercially or for recreatIon, ay and early June in Oregon and Washington, should consult local authorities for regula­ nd 2 to 3 weeks later in Alaska. Spawning tions . ontinues for several weeks; adult females In recent years the take by sports diggers ay each produce 6 million to 10 million has far exceeded the commercial catch on ggs. In years of heavy setting, as many as the principal razor clam beaches of Wash­ ,000 to 1,500 young clams are found per mgton. In 1964, sports dlggers took an estl­ quare foot of beach surface. High mortalities lTlated 2,290,000 pounds of razor clalTls, or re common at the setting stage, however, nearly 11,500,000 individual clams. The com­ ecause young clams are very delicate. lTlercial catch quota for 1964 was 125,000 Razor clams grow at different rates in pounds. ComlTlercial diggers actually took ifferent localities. In t he southern beds in only 30,000 pounds, owmg to a beach closure regon and Washington, initial growth rate following a shipwreck and oil spill. s much higher than in Alaska, but after "everal years the growth rate declines rapidly. lams have a smaller final size and a shorter Pismo Clam ife span in the southern beds than in the orthern beds. By the end of the first winter, Pismo clams, Tivela stultorulTl, inhabit oung clams reach a length of about four- the open coastal beaches from Half Moon Bay, -fths of an inch in the south, but only one­ Calif., to Magdalena Bay, Baja Callfornia, ifth of an inch in the Cordova district of Mexico. This clam, also known as "giant aska. To reach an average size of 4 1/2 tivela" is found from the intertidal zone out ches, clams require 3 1/2 years in the to a depth of 80 feet, and in SOlTle areas is ,outhern beds, but 6 1/ 2 years in the Cordova rare m less than 20 feet of water. The pismo istrict. clam is a relatively sluggish dlgger and The maximwn age for the southern razor seldom burrows deeper than 6 or 7 lnches. -lams is about 13 years, but clams from It usually lives with its hinge verhcal and hlaska may reach 19 years. Age of razor toward the ocean. : lams is determined frolTl the rings on the Several decades ago, pismo clams were shell, although this lTlethod may not always so plentiful they were turned out of the sand ~ rovide the correct age. In younger specimens at low tide by horse -drawn plows and fed to ength i s a fair indicat ion of age. The lengths hogs. Because of this intensive fishery, the Df 2-year-old and 4-year-old razor clams from clam population was severely reduced; no fhe same bed differ greatly, but the lengths commercial for the species is per­ Df 8-year-old and 12-year-old clalTls are lTlitted now by the State of California. Recrea­ almost equal. tional diggers continue to harvest quantities Razor clams are harvested at low tide by of these clalTls under strict regulatlOns c ommercial diggers and, in many places, by governing seasons and bag limits. Chief a large nwnber of tourists and local residents. source of pismo clams for the market are [f the surface siphon holes of the clams are the be:ds on the beaches of Baja Califorma, not easily visible, the diggers strike the Mexico. surface of t he beach with the handles of their Pismo clams spawn in late summer. Vari­ shovels. The vibration causes the clam to ous estimates of the egg productIon of a slngle !retract the siphon and start downward, leaving large female range from IS million to 75 a characteristic hole. At this time the clam million. Each egg measures about 1 360 inch is rapidly spaded out before it can descend in diameter. The growth of the pismo clam beyond reach. shows a definite seasonal rhythm--rapld in I Razor clams can dig down in the sand to a the sumlTler and very slow in the winter. In ~ epth of several feet as fast as 9 inches per general, the species grows very slowly, and minute. The ability to lTlove so rapidly is requires 4 to 7 years to reach a length of £acilitated by the shape of the shell, which 5 inches. Some pismo clams attain an age ~ s slender and tapered, and the presence of estimated as between 20 and 35 years. The a powerful foot or "digger." There is little larger clams reach a length of about 7 evidence that razor clams move horizontally inches . Or m igrate between areas. The shells of the pismo clam are symmetri­ Most of the cOlTlmercial catchof razor clams cal triangular fan shaped. Color is vanable, -s canned. A few clams are marketed fresh, particularly in the juveniles, and ranges from as shucked lTleats, and some are frozen and pale buckskm to dark chocolate. The shells ackaged as . P rotective measures for are thick and covered With the varmshlike aintaining sustained yield from the stocks periostracum also found on razor clams. are promulgated by British Colwnbia and Some shells may be marked With chocolate­ he several States in which razor clams oc­ brown hnes radiating frolTl the hmge to the cur. These regulations may include closed edge of the shell. The thick shells may assist seasons, closed areas, bag lilTlits, and size pismo clams on exposed beaches m retaming limits. Persons wishing to engage in clam- then positions whlle in heavy surf.

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tter Clam diggers in Oregon, Washington, and British Columbia. In addition to the name "native Two species of clams on the Nort h American littleneck, " t his clam is also known as "rock acific coast are now commonly called butter clam," "rock cockle," "bay cockle," "hard lams. The southern specIes, nut­ s hell clam," "Tomales Bay cockle," "ribbed alli, is also known as the "Washington clam, " carpet shell," and "butter clam . " Use of the big clam," and "money shell" (because the common name "butter clam" for this species alifornia Indians used the s hells for money), should be avoided to prevent confUSIon WIth nd is found from San D iego to Humboldt Bay the Saxidomus species. California. The northern species , Saxidomus Littlenecks are usually found in the inter­ ~iganteus, has the common names "Was hington tidal zone , between - 3 and + 4 feet of the "mean lam," "quahog ," "Coney Island," "-," lower low wat er datum plane (O-foot tide nd "great Oreg on" clam. This species ranges level)." They prefer the same type of mixed 'rom Humboldt Bay northward to Alaska. mud- gravel ground as the butter clams and In 1963, the U.S. commercial fishery for often are found intermingled with these species. ~utter clams yielded about 51,000 pounds of They may burrow to a depth of 8 mches but eats worth over $11,700. About 99 percent are usually within 6 inches of the surface, ere taken from the bays and inland sounds and occasionally are on the surface. Little ­ f Washington State. necks are the smallest of the common com ­ British Columbia is by far the largest mercial speCles. Average market size i s about source of butter clams. The 1963 catch was 2 inches, though the largest individuals maybe , 84,200 pounds of meats, or about 84 percent nearly 3 inches long. f the total clam meats taken commercially Littleneck shells are usually cream to gray, 'n Briti shColumbia. Butter clams are marketed often indistinctly mottled with brown. The fresh or canned, whole or minced, and as oval shell has ribs radiating from the hinge howde r or juice. to the edge of the shell, and concentric g rowth Butter clams are dIstributed from the lower lines at right angles to the ribs, resulting evels of exposed tide flats out to depths of in a crosshatched appearance. The edge of over 30 fathoms in some areas. They appear the shell IS not scalloped, however, as in o prefer mixed gravel - mud substrate, though the cockle. hey are also found m sand. They live in the upper 12 inches of the substrate, most com- 0nlY 6 to 10 inches beneath the surface. The Manila Clam shell length of butter clams occasIOnally The Manila clam, Tapes philippinarum, is reaches 7 inches in t he southern species not a native of the Pacific coast of North f:and about 6 inches in the northern species. America. It may have been introduced acciden ­ In commercial catches the usual size landed tally m shipments of Pacific from is 3 to 5 mches. Japan or perhaps planted intentionally by Butter clams can be recognized by the Japanese immigrants. It is now found from l arge external ligament at the hmge; the Brit! h Columbia to northern CalifornIa. The relatively thick egg-shaped shell; the fine, ManIla clam is also called the "Japanese concentriC growth lines that parallel the curva­ littleneck" and "Japanese cockle." ture of the shell; and the relatively short, CommerCIal harvest of thiS species in 1963 black-tipped siphon. The shell color varies totaled 32,600 pounds of meats m British from chalk-whIte to bluish- gray, depending ColumbIa and 119,600 pounds in the State of on t he substrate in which they are located. Washington. The latter catch was worth $62,756 Generally the shells are white and clean to the digge rs. ookmg if t he clams are dug from clean Manila clams usually inhabit the middle gravel or sand; in mud or silt the shells intertidal area, prefer coarse sandy mud often appear brownish or bluish- gray. ThIS substrate, and occur over a somewhat wider color d iffe rence i s related to the substrate tidal range than the littlenecks or butter and IS also noticeable in a number of other clams. Commonly they lie buried 1 to 2 inches species of commercial clams. beneath the surface and can be dug with a rake or fork. They may attain a length of 3 inches, but the average market SIze is nearer 2 inches. Littleneck Clam The shells resemble those of the littleneck clam, but are a more elongated oval. The ribs The native littleneck clam, Protothaca radiating from the hinge are more numerous staminea, is found from Alaska to Mexico, and are not as prominent as in the littleneck but is of commercial importance only in clam. Shell color is highly varIable, but British Columbia and Washington. The U.S. usually is yellowish to buff, with black or catch in 1963 totaled 214,400 pounds of meats brown patterns in lines or mottlmg. The shells worth $107,194 . In the same year the British are generally purple on a portlOn of the m­ Columbia catch was 32,700 pounds of meats. side. The shell bears prominent concentric Li·.tlenecks are also taken by noncommercial growth lines. 7

soft-Shell Clam inches from hinge to edge; it weighed 26 ounces and was estimated to be 10 years old. T h e soft - shell clam, Mya arenaria, also The cockle is hermaphroditic, i.e., each indi ­ k nown a s the "eas ter n clam," "mud clam," vidual produces both male and female germ " long - necked clam," "steamer," "nannynose, , , cells. The eggs often are discharged first and a nd "long clam, " is an Atlantic coast species the sperm cells late r in the season, although that was accidentally introduced on the Pacific they may be shed simultaneously. Spawning coast in about 1870 in shipments of eastern begins in the spring and may continue for oyste r s to California and Washington. Later some time. As does the razor clam, the it was planted in a number of places and cockle grows more rapidly in the south than soon s pread along the coast from California in the north . t o Alas ka . For a time this clam supported The shells of the cockle vary from light a commercial fishery, but in recent years brown to gray and often have a variegated has been of commercial consequence only red-brown mottling. The shells are essentially in Oregon, where the 1963 take of 20,800 round, and prominent ribs radiate from the pounds of meats worth $9,735 was reported hinge area. The edge of the shell is strongly a s mixed clams, "principally eastern soft scalloped. clam s . " Soft- shell clams are commonly found in the firme r mud flats though they also inhabit Horse Clam mixed gravel, sand, or mud. The soft-shell clam has a long siphon, which permits it to The horse clam, Schizothaerus nuttalli, is a live 8 to 14 inches beneath the surface. Con­ large clam found from Alaska to San Diego, sequently, a shovel, rather than a fork or Calif. It has many common names, such as r ake, is usually used to harvest it on the "gaper," "empire," "blueneck," "blue," Pacific coast. Soft-shell clams often occur "horseneck," "rubberneck," "bigneck," "otter­ high in the mtertidal zone and farther up-bay shell," "summer," and "great Washington" than other species of bay clams. This dis­ clam. Horse clams are of minor commercial t r ibutlOn reflects a tolerance of low salinities. importance but appear fairly often in sport The shells of the soft-shell clam are chalky­ catches. Commercial production, principally white to bIUlsh-gray, and often appear chalky, from Oregon and California, probably did not as in the butter clam. They may reach a exceed a few hundred pounds of meats in length of 6 mches, though the average market 1963. size is probably 3 to 4 inches. The shell is Horse clams live from the minus tide zone oblong, thin, and brittle - -hence the term (i.e., below the O-foot level) out into deeper "soft shell." This clam is readily identified waters, generally 1 to 3 feet beneath the because one shell (called the "left ") surface of a mud or mud-sand bottom. The has a large spoon-shaped "hmge tooth" that horse clam is the most sedentary of the projects internally at right angles to the commercial clams. The subsurface depth is plane of the shell. estab lS} ed early in the adult life, after which digging ceases. Even if disturbed, the horse clam does not attempt to escape by digging, Cockle de spite the pre sence of a large foot or "dlgger." Horse clams may reach a length of 8 inches The cockle, Clmocardium nuttalli, also known and weigh 4 pounds. The shells are thin and as the "heart cockle," "basket cockle," and cannot completely enclose the body and bulky "cockerel," 1S found from the Bering Sea to siphon. The large siphon, which is capable Mexico. It is most common in British Columbia of great extension, is protected by a tough waters and Puget Sound. The cockle is not brown skm and by two horny flaps at the tip. often in dense enough concentrations to harvest The slphon provides most of the meat from commerClally, though each year a few hundred the horse clam, and is skinned and pounded to a few thousand pounds of meats are obtained. or ground, usually for . The Indians In recent years Alaska has been the chief formerly dried the siphons for winter use. commercial source. The shells are chalky-white, as in the Cockles are found ln the lower tidal zone, butter and soft-shell clams, and often have usually 1 to 3 inches beneath the surface and dark brown patches. The new growth at the often only partlally buried. Cockles have a outer edge of the shell may be covered by a large muscular foot and are active diggers, brown skinlike periostracum. At the posterior but their very short siphons do not allow end the edges of the shell are arched away bur rowing to great depth. The usual substrate from the normal plane of shell growth to i s sand or mud, or a mixture of the two. When accommodate the siphon. There is also a disturbed, the cockle can retract all body parts large pit in the hinge region of the shell, wit hin the shells and close tightly. The aver­ where the hinge ligament is attached. age size of marketed cockles is usually 3 to Many horse clam catches include a closely 4 mches . One specimen was reported as 4-3/4 related clam, the gray- neck, Schizothaerus 11

apax. The external appearance of the two poor digger. There is only a small open ng peCles is closely similar. and they appear through the mantle for the foot. VhlC IS o occupy the same habitat; they are not almost vest.g al. sually separated in catch statistics. The The geoduc:~ IS often confused With he ray-neck does not become as large as the horse clam. despite recognizable dlffere ce . :lorse clam. The shell of the geoduck lS more rectangular a ,d gapes on all sides except at the hmge . whereas the horse clam gapes chiefly at the :Jackknife Clam siphonal end; the siphon of the geoduck IS relatively much larger than that of the horse The jackknife clam, Tagelus californianus. clam and does not have horny flaps at the s a south coast species found from Humboldt tip. The shells of the geoduck are whltlsh. ay. Calif., to Panama. In the United States and often covered with a dull yellow-brown It is fished commercially only in the San periostracum. are comparatlv 1) Diego area, where it is used chiefly for fish scarce and protected by personal-use bag ait and brings extremely high prices. The limits and closed areas. 1963 commercial catch was 18.200 pounds The Bodega tellen. Tellina bodegensis. IS bf meats worth $36,073, or about $1.98 per taken commercially in years when it occurs ound. in sufficient abundance. It ranges from th Jackknife clams are inhabitants of mud or Queen Charlotte Islands, British Columbia, ud-sand bottoms and intertidal areas of inner to Cape San Lucas, Baja California. but is bays, sloughs, and estuaries. Unlike the other harvested only from certain bays of Oregon. species of clams discussed in this circular The Bodega tellen occupies sandy beaches they establish a permanent vertical burrow, along the open coast but is usually most usually 15 to 20 inches long. The top of the abundant in coarse shifting sand near the burrow is about 4 inches beneath the surface. entrance to bays. It attains a length of 2 1/2 The clams fit snugly in their burrows but to 3 inches. The shell is relatively heavy. can move up and down rapidly. Jackknife white, and oblong. with numerOus distinct clam s are furthe r distinguished by having concentric lines. The siphonal end of the two siphons. each with a single tube. shell is bent slightly to the right; the opposite The shells of the jackknife clam may reach (ante rior) end is round. The se clams are a length of 4 1/2 inches. They are thin, flat. excellent diggers and burrow rapidly when and much elongated. A clam 4 1/ 2 inches disturbed. long is only about I 1/4 inches wide. The Another clam, which occasionally appears m shells are grayish-white and usually are harvestable quantities. is the bean clam, covered with a dull brown periostracum. Donax gouldi. It is found from Pismo Beach. Calif., to Cape San Lucas, Baja Califorma, in the sandy beaches of the open coast. Bean other Species clams are small. usually not much over 1 inch long. Population density varies widely; Of the remaining 25 or more species of in some years they are extremely abundant. edible clams, few ever appear in commercial In years of great abundance they are col­ markets. The most prominent of these non­ lected and steamed for broth. The shells camme rcial species is the geoduck (pronoWlced are heavy and strongly concave, WIth fa.nt "goyduk," or, more commonly. "goo-ee-duck"), ridges radiating from the hinge to the edge. Panope generosa, found from Alaska to Mexico. Shell color is highly variable, usually whlte, The name geoduck is apparently derived from yellow, orange, or bluish-purple. the transliteration "gweduk," the Nisqually The wedge clam, Donax callfornlcu.§, also Indian term for this clam. This is the largest appears in widely varyingpopulatlondenSltles. clam of the North American Pacific coast It is found in bays and inlets from Goleta, and may reach a weight of 8 pounds, though Cal1f., to Magdalena Bay, Baja California. 3 pounds is more common. One geoduck, Adult \'I.·edge clams are usually about I Inch dredged from 30 fathoms, was reported by the long. The shells are thm and wed e -snaped; Washington State Department of Fisheries to indistinct ridges radiate from the hinge ar a. have weighed 20 pounds. Shells of large geo­ The wedge clam shells are generallyyellowlsh ducks are generally no larger than those of because of the r-eavy penostracum. \\ hf're he large horse clams, though the weight of the pe riostracum is worn away. the hel s are whole animal may be nearly twice that of the buff. In years of great abundance, wedge clams horse clam. are collected for use In broth, Geoducks are found in sandy mud bottoms The remainmg edible clams are generally from the lowe r low tide level out to 30 fathom s taken only mCldentally in diggmg for at er or more. Because they are usually bUrled 3 to clams. An excellent source of mformat on 4 feet or more in the substrate, considerable on these species IS 'Comma mar digging is required for their capture. Contrary bIvalves of Califorma b John E. F ch to popular belief, the geoduck is an extremely (1 Q531.

15

SANITARY CONTROL State Department of Fisheries suggested im­ provements. Clams, like all other shellfish, are subject o rigid sanitary regulations and inspection by tate and Federal health authorities. Em­ SELECTED REFERENCES loyees of shucking houses must undergo fre­ uent medical examinations; pe rsons carrying ABBOTT , R . TUCKER. ontagious diseases are not permitted to 1954. American . D. VanNostrand handle fresh clams. The shucking houses Co., Inc., , 541 p. a nd their equipment are also inspected peri­ BANNOT, P AU L. I dically by Municipal and State sanitary au- 1940. The edible bivalves of California. horities. Clams opened in the shucking houses Calif. Fish Game 26(3):212-239. iilre examined, and samples are tested at CALIFORNIA DEPARTMENT OF FISH AND intervals for disease organisms. GAME. Certain laws prohibit the removal of clams 1963. The California marine fish catch for from waters in which they are exposed to 1961. Its Fish Bull. 121,56 p. excessive amounts of bacteria or toxic sub­ DEPARTMENT OF FISHERIES OF CANADA. stances. State health or fishery authorities 1962. British Columbia catch statistics - sometimes find it necessary to close shell_ 1961. Dep. Fish. Can., 164 p. fish beds to fishing. These closures should FITCH, JOHN E. be closely observed. Persons wishing to dig 1953. Common marine bivalves of Cali­ for clams should consult with the appropriate fornia. Cali£. Dep. Fish Game, Fish authorities and also watch for emergency Bull. 90, 102 p. closures, which can occur at any time. FRASER, C. McLEAN. 1929. The spawning and free-swimming larval periods of Saxidomus and Paphia. CLAM FISHERY REGULATIONS Trans. Roy. Soc. Can. (Sec. 4) 23:195- 198. The clam fisheries, as with all other fish­ 1931. Notes on the ecology of the cockle. eries within territorial waters, are regulated Trans. Roy. Soc. Can. (Sec. 5) 25:59-72. by the bordering States. In most States a FRASER, C. McLEAN, and P, SMITH, special fishery agency has been established 1928. Notes on the ecology of the butter and directed to promulgate and enforce laws clam. Trans. Roy. Soc. Can. 22:271- for the protection of the resource. In some 286. States enforcement may be by the State police JOHNSON, MYRTLE E., and HARRY J. SNOOK. or by cooperative effort of State police and 1927. Seashore animals ofthe Pacific coast. State wardens. The State fishery agencies MacMi llan Co., New York, 659 p. may require licenses for commercial clam­ LOOSANOFF, VICTOR L., and HARRY C. mers and sometimes for recreationaldiggers. DAVIS. They also may establish closed seasons, 1963 . R earing of bivalve mollusks. In F. S. bag limits, and size limits for each species. Russell (editor), Advances in ~ar i ne Persons interested in digging for clams b iology 1: 1-136. Academic Pre s s, should ask their State fishery agency about London and New York. existing laws relating to the species they LYLES, CHAR LES H. intend to take. 1965. Fishery statistics of the Unit e d States - 1963. Bureau of Commercial Fisheries, Statisti cal D igest 57, 5 2 2 p. ACKNOWLEDG MENTS MARRIAGE, LOWELL D. 1954. The bay clams of Oregon. F i sh An earlier leaflet on Pacific coast com­ Comm. Oreg., Contr. 20, 47 p. mercial clams was prepared in 1947 by QUAYLE, D. B. Victor L. Loosanoff under the title, "Com_ 1941. The edible molluscs of British Col um­ mercial clams of the Pacific coast of the bia. Rept. B.C, Fish. Dep. - 1940, J 85- United States." Much of it is incorporated J87. in the present leaflet. Additional information RICKETTS, EDWARD F., and JACK CALVIN. included in this paper came from the follow­ 1952. Between Pacific tides. 3d ed. Stan­ ing publications: "Washington State shellfish," ford University Press, 502 p. by the Washington State Department of Fish­ TAGELBERG, HERB C, eries; "Bay clams of Oregon," by Lowell D. 1964. Growth and ring formation of Wash­ Marriage of the F ish Commission of Oregon; ington razor clams. Wash. Dep. F i sh" and "Common marine bivalves of California," Fish. Res. Pap. 2(3):69-103. by John E. Fitch of the California Department WASHINGTON STATE DEPARTMENT OF of Fish and Game. Kenneth K. Chew of the FISHERIES. University of Washington College of Fisheries 1964. Washington State shellfish. Wash. ana Cedric E. Lindsay of the Washington State Dep. Fish., 16 p. Olympia, Wash.

17 "EY OUTH, F K W., H. C. and H. B. HOLMES. 1 25. Growth and age at maturity of , Slhgua a (Dixon). Bur. of Fish. Bull. 41:Z0~1~_U~r=JI

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