- REFERENCE COPY Do Not Remove from the Librorv - U. S. Fish and Wildlife hirn ~iologicalReport 82 (11- 31 ) lvorlonolWetlands Research Cenwr TR EL-$2-4 April, 1986 700 Cajun Dome Boulevarrf Latayette,I - Louisiana 70506
Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Gulf of Mexico) COMMON RANGIA
Coastal Ecology Group a Fish and Wildlife Service Watenvavs Ex~erimentStation U.S. Department of the Interior U.S. Army Corps of Engineers This is one of the first reports to be published in the new "Biological Report" series. This technical report series, published by the Research and Development branch of the U.S. Fish and Wildlife Service, replaces the "FWS/OBS1' series published from 1976 to September 1984. The Biolog- ical Report series is designed for the rapid publication of reports with an application orientation, and it continues the focus of the FWS/OBS series on resource management issues and fish and wi Id1 i fe needs. Biological Report 82(11.31) TR EL-82-4 April 1985
Species Profiles: Life Histories and Environmental Requirements of Coastal Fisheries and Invertebrates (Gulf of Mexico)
COMMON RANG IA
Mark W. LaSalle and Armando A. de la Cruz Department of Biological Sciences P.O. Drawer GY Mississippi State University Mississippi State, MS 39762
Project Officer John Parsons National Coastal Ecosystems Team U.S. Fish and Wildlife Service 1010 Gause Boulevard Sl idell, LA 70458
Performed for
Coastal Ecology Group Waterways Experiment Station U.S. Army Corps of Engineers Vicksburg, MS 39180
and
National Coastal Ecosystems Team Division of Biological Services Research and Development Fish and Wildlife Service U.S. Department of the Interior Washington, DC 20240 This series should be referenced as follows:
U.S. Fish and Wildlife Service. 1983-19 . Species profiles: life histories and environmental requi rements of coasts fishes and invertebrates. U. S. Fish Wildl. Serv. Biol. Rep. 82(11). U.S. Army Corps of Engineers, TR EL-82-4.
This profile should be cited as follows:
LaSalle, M.W., and A.A. de la Cruz. 1985. Species profiles: life histories and environmental requi rements of coastal fishes and invertebrates (Gul f of Mexico) - - common rangia. U.S. Fish Wildl. Serv. Biol. Rep. 82(11.31). U.S. Army Corps of Engineers, TR EL-82-4. 16 pp. e PREFACE
This species profile is one of a series on coastal aquatic organisms, principally fish, of sport, commercial , or ecological importance. The profil es are designed to provide coastal managers, engineers, and biologists with a brief comprehensive sketch of the bi01 ogical characteristics and environmental require- ments of the species and to describe how populations of the species may be expected to react to environmental changes caused by coastal development. Each profile has sections on taxonomy, 1 ife history, ecological role, environmental requirements, and economic importance, if appl icabl e. A three-ring binder is used for this series so that new prof il es can be added as they are prepared. This project is jointly planned and financed by the U.S. Any Corps of Engineers and the U.S. Fish and Wildlife Service.
Suggestions or questions regarding this report should be directed to one of the fol 1owing addresses.
Information Transfer Special ist National Coastal Ecosys tems Team U.S. Fish and Wildlife Service NASA-Sl idel 1 Computer Compl ex 1010 Gause Boulevard Sl idel 1 , LA 70458
U.S. Army Engineer Waterways Experiment Station Attention: WESER-C Post Office Box 631 Vicksburg, MS 39180 CONVERSION TABLE
Metric to U.S . Customary Mu1 tiply & To Obtain mil1 imeters (m) inches centimeters (an) inches meters (m) feet ki1 ometers ( km) mi1 es 2 square meters (m ) 10.76 square feet square ki1 meters ( km2) 0.3861 square miles hectares (ha) 2.471 acres liters (1) gal 1ons cubic meters (m3) cubic feet cubic meters acre- feet mil1 igrams (mg) 0.00003527 ounces grams (g) 0.03527 ounces kilograms (kg) 2.205 pounds metric tons (t) 2205.0 pounds metric tons 1.102 short tons ki1 ocal ories ( kcal ) 3.968 British thermal units
Cel sius degrees 1.8("~) + 32 Fahrenhei t degrees
U.S. Customary to Metric inches 25.40 mil1 imeters inches 2.54 centimeters feet (ft) 0.3048 meters fathoms 1.829 meters miles (mi) 1.609 kilometers nautical miles (mi) 1.852 ki1 ometers square feet (ft2) square meters ac res hectares 2 square miles (mi ) square kilometers gal 1ons (gal ) 3.785 1i ters cubic feet (ft3) 0.02831 cubic meters acre- feet 1233.0 cubic meters ounces (02) 28.35 grams pounds (Ib) 0.4536 ki1 og rams short tons (ton) 0.9072 metric tons British thermal units ( Btu) 0.2520 ki1 ocal ories Fahrenheit degrees 0.5556("F - 32) Celsius degrees CONTENTS
Page
PREFACE ...... iii CONVERSION FACTORS ...... v ACKNOWLEDGMENTS ...... v i
NOMENCLATURE/TAXONOMY/RANGE ...... 1 MORPHOLOGY/IDENTIFICATION AIDS ...... 3 REASONS FOR INCLUSION IN SERIES ...... 3 LIFE HISTORY ...... 3 Spawning ...... 3 Larvae and Postlarvae ...... 4 Adult Activity and Feeding ...... 4 Life Span ...... 4 GROWTH CHARACTERISTICS ...... 5 Growth Rate ...... 5 Size ...... 5 THE FISHERY ...... 6 ECOLOGICAL ROLE ...... 7 Trophic Level ...... 7 Predators and Parasites ...... 7 Competitors ...... 7 Spatial Distribution ...... 7 Density ...... 7 ENVIRONMENTAL REQUIREMENTS ...... 9 Temperature ...... 9 Salinity ...... 9 Temperature and Salinity ...... 9 Oxygen ...... 9 Substrate ...... 10 Depth ...... 10 Effects of Pollution ...... 10
LITERATURE CITED ...... 13 ACKNOWLEDGMENTS
We thank Dr. Courtney T. Hackney, University of North Carolina at Wiltnington and Dr. H. Dickson Hoese, University of Southwestern Louisiana, for their critical reviews of the manuscript; T. Dale Bishop and Darryl R. Clark for information and help with the literature search; Mark F. Godcharles, Jake M. Valentine, and personnel of the Alabama State Docks Department and the U. S. Army Corps of Engineers, Mobile District, for providing comments and unpublished reports; Jeanne J. Hartley for her illustration of rangia; and Dr. Robert J. Muncy, Betty Muncy, and Cindy Mil1s for help in the preparation of the manuscript. &
Posterior
periostracum sinus line
Figure 1. Common rangia.
COMMON RANGIA
New Jersey (Woodburn 1962). Before Scientific name ...... Rangia 1956, living common rangia had not cuneata (Gray) (Figure 1) been collected along the Atlantic Preferred common name ...... Common coast (We1 1s 1961) probably because rangia (Andrews 1971; Fotheringham earlier sampling in brackish water and Brunenmeister 1975) areas had been inadequate. Common Other common names ...... Brackish rangia inhabit low salinity (0 to 18 water clam, Louisiana road clam ppt) estuarine habitats (Parker 1966; Class ...... Molluscs Christmas 1973; Hopkins et al. 1973; Order...... Eulamell ibranchia Swingle and Bland 1974). Family...... Mactridae Geol ogical ly, the common rangi a Geographic range: The common rangia is has been found in Pliocene deposits found alonq the Gulf of Mexico coast in the Carol inas and Florida and in (Figure 2)-from northwest Florida to Pleistocene deposits in Chesapeake Laguna de Terminos, Campeche, Mexico Bay and the Potomac River, the Caro- (Dall 1894; Andrews 1971; Ruiz 1975), linas, Florida, the entire north and along the Atlantic coast as far coast of the Gulf of Mexico (Figure north as Maryland (Pfi tzenmeyer and 2), and the north coast of South Drobeck 1964; Gallagher and Wells America (Conrad 1840; Dall 1894; 1969; Hopkins and Andrews 1970) and Maury 1920; Richards 1939).
MORPHOLOGY1 IDENTIFICATION A1 DS 1973, 1976a; Hoese 1973). In turn, this biomass is consumed by fishes, The following description of crustaceans, and ducks (Suttkus et al. common rangia is taken from Abbott 1954; Darnel1 1958; Gunter and Shell (1954) and Andrews (1971, 1981). 1958; Harmon 1962; North Carolina Adults range from 2.5 to 6.0 cm in Bureau of Sport Fisheries and Wildlife length. The valves are obliquely 1965; O'Heeron 1966; Cain 1972; Tarver ovate, thick, and heavy (Figure 1). and Dugas 1973). The shells provide The exterior of the shell is covered hard substrate for epifaunal attachment with a strong, rather smooth (Hoese 1973). periostracum that ranges from light brown to grayish brown to black. The The common rangia was a food item umbones are prominent and are near the of prehistoric Indians (McIntire 1958) anterior end. The shell interior is anu it is still occasionally canned and glossy white with a blue-gray tinge. eaten in New Jersey, Texas, North The pall ial sinus is small but Carolina, and Mexico (Singley 1893; distinct. The posterior lateral tooth Woodburn 1962; Wass and Haven 1970; is long (Figure 1). Dall (1894) U. S. Department of Commerce 1971). mentions that most of the variability Economical ly, common rangi a is more in form is related to the differences important as a source of shells for in the height of the umbones and the road building and in the manufacture of shape of the posterior margin of the many industri a1 products (Tarver and she1 1. Rangi a cuneata var. nasutus Dugas 1973; Swingle and Bland 1974; (Dall 1894)sbeTieved to7Z-T Arndt 1976). Much of this shell rostrate form of R. cuneata (Abbott material is dredged from buried 1954) and may b coiiT'E5 with a deposits in estuaries. * closely re1ated species, the brown rangia (Rangia fiexuosa [Conrad]). LIFE HISTORY The brownranqia is 2.5 to 4.0 cm lona and resembles an elongate comma;; rangia; however, brown rangia can be easily separated from common rangia by The reproductive cycle and the short posterior lateral tooth and environmental conditions necessary for the nondi stinct pal 1i a1 sinus. Brown spawning are well known for common rangi a is found from Louisiana to Texas rangia. The reproductive cycle was and Vera Cruz, Mexico (Andrews 1971), studied in Louisiana by Fairbanks but is much less common than the common (1963), in Virginia by Cain (1975), rangi a. in Florida by Olsen (1976b), and in Campeche, Mexico by Rogers and REASOIVS FOR IIVCLUSION IN SERIES Garcia-Cubas (1981). Most rangia spawned from March to May and from late The common rangi a is an important summer to November in Louisiana and component of estuarine ecosystems from February to June and September to (Parker 1959; Odum 1967; Odum and November in Mexico. In both areas, Copeland 1969; Copeland et al. 1974) spawning may be continuous. accounting, for example, for nearly 95% of the benthic biomass in the James In Virginia, gametogenesis began River Estuary, Vi rgini a (Cai n 1975). in early April and continued throughout In low salinity estuarine areas common the summer; gametes were ripe from May rangia functions as a link between pri- through November. Gametogenesis was mary producers and secondary consumers. initiated when water temperature As a non-selective filter feeder, rose to 15"C, and spawning was rangia transforms large quantities of initiated by a rapid increase or plant detritus and phytoplankton into decrease in salinity (Cain 1975). In * clam biomass (Darnel 1 1958; Olsen 1972, upstream areas of the James River, el6ue~40 (uw op qnoqe) qq6ual ueau aql :SMO[ 104 se aJaM sa6eqs saqe auo 41 -pau~~~uo3uaaq qou seq a4L 1 3uaJa44LP 40 416ual all1 'uol3 e ~6ue~uouuo3 aqq 40 ueds a4~1 a41 -ez!~tq~ajJaqje q pz UL~~LMpa~eadde aehJe 1 pa laqs qeqq paq~oda~Aalueq3 'elutb~~~UI -(~aqaumlp ueau U! ud €6) 4 E'PE qe ~a6llahe pue 'q E-gz 'pas013 A~y3lnbaJe sanlen qe aJoqdoq30J$ 3~6elade 'uocqez~~Lq~aj aqq uaqM uoqdls quelequl aqq q6no~qq Jaqje (4) sJnoq 3.8 padolahap 'A~lh~3alqueu a 04 sa3ajopnasd e Lnlse Lq Pale !L l3 .ud 69 lnoqe sapnJqxa Leulue aql '(~~6'1uas 10) seM s66a 40 Jalaurelp a6e~ahe aqq qeq7 ~1116 a47 Jaho squa~~n3AJP! 113 pue paq~oda~syueqJlej '(~961) Ka ~ueq3 suolqeln3LqJe d~ed~1.~6 Aq pal lo~quo3 Kq elut6JlA ul Pup (€961) SYJeqJlej Kq s~ el6ue~ uouuo3 40 6u~paaj euekslnoi ul palpnqs aJaM e ~6ue~uowuro3 40 quaudolahap 40 sa6eqs Kl~eaaql .saqeJqsqns 40 a~~oq3e uah~6 uaqM uaha pol~adqquou-p e Jaho el~enbe ul ahou qou plp sue13 qeqq paq~oda~ (~~6'1)uaslo 'quauLpas aqq uc quauahou .e k6ue~uouwo3 ~e3lq~ah40 A~uo alqede3 aJe et6ue~ uo alqellehe aJe eqep Kqlpun3aj ON qeq3 ~aqsabbns ('186'1) 'Le 7a eJoy LS -el~enbeul sue~340 quauahou a1qq.L 1 PaAJaSqO (€961) SyUPqJ -6~[qqas Jaqje alqqlL ahou et6ue~ uouuo3 aJaM speuo6 qeqq paq~oda~(1~6'1) ule3 'elu~6~!/('~a~la sauep aqq UI .s~eaA E oq z ul qq6ual unuiulu q3ea~ p~no3 .quaquo3 3~ue6~oul 46~4saqeJqs e 7e41 PaJJa4ul (€96'1) SyUeqJlej -qns pa~~aja~dpue 6ulqqas JOJ aqeJqs 'squaua~3u~43~0~6 Lenuue uo eqep uo~j -qns 6ulq3a~as 40 alqede3 aJaM aenJel '(€961 syueq~kej)uu pz SPM 'eue~s~no~ le41 Pa~JodaJ (€961) SyueqJlej '(5L6'1 'U ~PJJJP~~JUO~ay el Ll! sq Lnpe ule3) qqoq JO ~014MO~ 6ulJnp 6u~uu~~saJnqeu 40 qq6ua~ unu!ulu aql '(99~6'1 Aq JO 'apLq 6u~uo3u~ue ul JaqeM uoqqoq uasl0) PPlJolj u! X'Z Pup ('1861 sWn3 aul les aJou aqq ul seaJe uea~qsdn oq -e~xe~)pue s~a6oa) o~lxawu! a-0 aq paq~odsue~qaq Leu Aaq1 -uleq~a3un s 02 paq~oda~SPM UP13 Sly3 Ul ~sl~lp0Jqd as~adslpel6ue~ aLluahn[ aqq MOH -eu.iaq 40 az1uapl3ul aql '(If61 ule3) elul6~~/(ul saleu paJaqunuqn0 saLeua4 'Auo~o3 plo~pAq e oq paq3eqqe (6uol qnq '(1861 seqn3-el3~e~)pue s~a6oa) luu 1 >) sue13 ~leusLeJahas pahJasqo o3lxaW pue (€961 syueq~lej) euelslnoi (~~6'1)asaoH a1l4M ud 5LE se 1 Leus Ul I:IJPaU aq 03 pa3~OdaJaJaM SOLqPJ se salluahnf paq3allo3 (€96'1) syueqJlej xas 'JaleM aqq olu! K~lsa~~psaqaum6 'eue 1s !no1 'u le~q~eq3quod aye1 UI asealaJ P~~UPJuouuuo3 '6uku~eds UI -Jauunsplu u l pa~~n33opol~ad Gul lqqas puo3as w '(5~6~ule3) ud OOE pa6eJahP ' (99L6'1 pue 6uol ud 005 oq OEZ aJaM s~euiue uas 10) 6u lu~eds 6u ~~a66l~q40 papad aqq uaqM q~ewpue ~aquaqdas uaaMqaq -sns .a.ia~- sasea~3ul Aqlu~~es pue aJnq a3e~d yo01 'P~U~~JL/('Jah!a sauep -e~adual -~aquaqda~ul payead 6uku~eds aqq ul aehJeL 40 6ul ~qqas qsow fJaq~ah0~q6no~qq A~npuOJ4 paq~oda~ aJaM 6uiu~edspue saqaueb adl~'epl~olj '(596'1 Aalue43) SA~P UI ' Lej ul qdd 5 qe payead 6ulu~eds L ~aq4eue6aq s~soqd~oweqa~.ud 081 03 -indqno JaqenqsaJJ pasea~3u 43~~paqe SLI qe s 11 16 u le37e pue 'tun la^ aqq aso 1 -13osse qdd oq 01 qnoqe 40 aseaJ3ap 'alqqas 03 ue6aq s~a6~[ahlpad .ud SLl AiluLLes e pa~lnba~Aaqq seaJe ueaJ3s 03 09'1 (pasoqd~oweqau) sJa6~~ahlpad-UMOP U! qnq 'qndqno ~aqe~qsa~4pa3npa~ PUP furl ~LI 03 01'1 aen-lel paMoqun 43~~pa~el3osse qdd s qnoqe 40 asea~3ul Iud OET 03 SL'O aeh-lel pa6ulq-qq6le~qs Kl~u~~ese paJknbaJ sum13 'elul6.i.~~ collected in Louisiana (Table I), to mm, 5 to 9 m, and 4 to 5 mm, estimates of growth rate (Fairbanks respectively (Fairbanks 1963). From 1963; Wolfe and Petteway 1968), the mean height data for clams collected in average life span is about 4 to 5 Lake Pontchartrain, Tarver and Dugas years. A clam of the maximum expected (1973) reported as much as 7.2 m length of 75 mm, reported by Wolfe and growth in a 2-month period. This rapid Petteway (1968) in Chesapeake Bay, growth appeared to be related to warm would be 10 years old. Hopkins et al. temperatures. Annual growth rates have (1973) estimated a maximum life span of been reported to range from 0 to 9.7 mm 15 years. for Vermilion Bay, Louisiana (Gooch 1971) and to be 3 mm in Trinity Bay, Texas (Bedi nger 1974). Wolfe and GROWTH CHARACTERISTICS Petteway (1968) calcul ated the fol lowing von Bertal anffy growth curve for a common rangia population in the Growth Rate Trent River h Carolina: L = 75.62 (1-0.995 e-0.BP65t) The largest Annual growth increments of common predicted length of 75.6 mm would rangia in the Gulf of Mexico are represent 10 years of growth. reported to vary from 0 to 20 mm (Fairbanks 1963; Gooch 1971; Tarver and Size Dugas 1973). Annual growth increments, - estimated for the first 3 years of life Maximum length reported was 94 mm for two populations in Lake for a common rangi a from Grand Gos ier rn Pontchartrain, Louisiana, were 15 to 20 Island, Louisiana (H.D. Hoese, Univ. Table 1. Range of lengths (mm) or heights (mm) of common rangia examined in four areas of Louisiana.
Area Length Height References
Lake Pontchartrain, LA 38-42 (adults) --- Fairbanks (1963) 1-8 ( juveni 1es) ------28 Tarver (1972)
28-44 Tarver & Dugas (1973)
Lake Maurepas, LA --- 26 Tarver (1972)
25-27 Tarver & Dugas (1973)
Vermilion Bay, LA 31-61 .-- Gooch (1971)
Sabine Lake - * Atchafalaya Bay, LA 28-57 --- Hoese (1973) Southwestern La. ; pers. comm. ) . Mean extend from Point au Fer (Atchafal aya sizes (length, anterior to posterior; Bay) west to the Texas border, height, umbo to ventral margin) Calcasieu and Sabine Lakes, and Lake reported from other Louisiana estuaries Pontchartrain. In Mississippi, clams are shown in Table 1. Parker (1960) live in the Pearl River Estuary and and Hoese (1973) reported that the Mississippi Sound; in Alabama, in upper largest clams we.re found in the lower Mobile Bay; and in Florida in salinity areas of estuaries, whereas, Choctawhatchee Bay, Tampa Bay, the Tarver and Dugas (1973) found that clam Caloosahatchie River (Arndt 1976), and size increased with salinity. In the upper reaches of Charlotte Harbor Virginia, Cain (1972) noted that clams (Woodburn 1962). living in sand were typically larger than those living in mud. The Louisiana Wildlife and Fisheries Commission (1968) estimated a statewide production of about 5 million THE FISHERY cubic yards of clam shell in 1968 compared with 300,000 cubic yards The foremost commercial value of annually in the mid-1930's. The common rangia is in the use of fossil maximum annual harvest of shell in the shells for road building material, gulf States was 21.2 million tons in oyster cultch, and as a source of 1967 compared with 468,000 tons in 1912 calcium carbonate for the manufacture (Arndt 1976). Of the material dredged of glass, chemicals, chicken and cattle in 1967, an estimated 12.2 million tons feed, wallboard, and agricultural 1ime was used in construction and the (Tarver and Dugas 1973; Swingle and remainder for road base, asphalt fill, Bland 1974; Arndt 1976). Clam shells poultry grit, cattle roughage, filter are harvested by large commercial material, and whiting (pigment). hydraul ic dredges. By far the largest concentrations of living clams are along the Louisiana coast. The minimum Native Americans used common standing crop of clams estimated to be rangia as food, as evidenced from shell between the Atchafalaya River and deposits in Indian middens along the Sabine Lake, Louisiana, was between 24 gulf coast (Singley 1893; McInt ire billion and 48 billion clams (Hoese 1958). The canning of rangia in Texas 1973). Because of the relatively slow under the name of "little neck clams" growth rate of rangia, Hoese (1973) by the Givens Oyster Company was suggested that no more than 5% of the reported by Singley (1893). Rangi a living clam population should be were also canned at Cape May, New harvested annual ly if current Jersey (Woodburn 1962) and in North production of fossil shells is to be Carolina (U.S. Department of Commerce mai ntained; however, at an annual 1971). Rangia have been collected and recruitment of 5% (Fairbanks 1963) the consumed from the Potomac Creek of the estimated shell deposits in Lake Potomac River, Mary1 and (Pf itzenmeyer Pontchartrain would be nearly exhausted and Drobeck 1964), to Mexico where Wass in 35 years; at 3% Tarver and Dugas and Haven (1970) reported that this (1973) estimated depletion in 18 years. clam was served with rice as "Paella a valencianna" in restaurants. The The potent ia1 sources of common potential use of this clam as food, rangia shell along the gulf coast have however, is severely limited by been 1isted by Arndt (1976). In Texas, contamination of 1arge potential shell occurs in the upper reaches of sources by pol lution (Christmas 1973; San Antonio Bay, Nueces and Lavaca Swingle and Bland 1974). Rangia are Bays, Galveston Bay, Trinity Bay, and also used as bait for blue crabs Sabine Lake. In Louisiana, deposits (Godcharl es and Jaap 1973). ECCILOGICAL ROLE 1arvae if coincidental with rangi a spawning.
Trophic Level The common rangia is parasitized by 1arvae of fellodistomatid trematodes Common rangia serve to link (Fairbanks 1963). Cerc ar iae and primary producers and secondary sporocysts of this parasite are found consumers in estuarine areas. Rangia in the gonadal tissue, giving it an are non-selective filter feeders orange coloration and effecting (Darnel 1 1958; Olsen 1976a) ingesting castration. Only large clams are 1arge quantities of detritus and infected. phytoplankton. Darnel1 (1958) reported that gut contents contained 70% unidentifiable detritus, 10% sand, 17% a1 gae (possibly Anabaena or Potentia1 competitors of common Microcystis) as well as traces of rangia may be reduced by the wide diatoms, foraminifera, and vascular range of salinities tolerated by this pl ant materi a1 . Olsen (1976a) reported clam (Odum 1967). Pol ymesoda 48 species of phytoplankton from carol iniana has feeding habits stomach contents of common rangi a, identical to those of rangia (Olsen although a large portion of the 1973, 1976a), but is spatially material ingested was detritus (46 to separated from rangia; it is found 81%, depending on tidal conditions). primarily in intertidal areas or in small numbers in the shallow nearshore subtidal areas. In contrast, rangia Predators and Parasites live largely in the subtidal zone. m Other potential competitors are Common rangia are preyed upon by apparently not adapted to fluctuating fish, crustaceans, mollusks, and ducks salinities. (Table 2; Suttkus et al. 1954; Darnel1 1958; Gunter and Shell 1958; Harmon 1962; North Carolina Bureau of Sport Spatial Distribution Fisheries and Wildlife 1965; OIHeeron 1966; Cain 1972; Tarver and Dugas Common rangi a are primarily 1973). In addition, moon shell snails restricted to low salinity (< 19 ppt) (Polinices spp.) may be predators as estuaries (Maury 1920; Pulley 1952; suggested by drill holes in rangia Parker 1955, 1956, 1960; Moore 1961; she1 1s (Hoese 1973). Common rangi a are Parker 1966; Odum 1967; Christmas 1973; abundant in the diets of blue catfish, Hoese 1973; Hopkins 1970; Hopkins et freshwater drum, spot, black drum, al. 1973; Swingle and Bland 1974). river shrimp, and blue crab in Lake Rangi a have been reported from areas as Pontchartrain, Louisiana (Darnel1 1958, far as 25 miles upstream in delta 1961). The smaller rangia are rivers (Swi ngle and Bland 1974), but subjected to the greatest predation most prefer salinities of 5 to 15 ppt. pressure. Clams as large as 40 mm Tarver and Dugas (1973) found that (length or height), however, are eaten concentrations of clams were highest by fishes such as sheepshead and black adjacent to a potential source of fresh drum (Darnel1 1958; Tarver and Dugas or salt water, which may be related to 1973). A potential group of predators the need for salinity shock required not mentioned by the above authors are for spawning (Cai n 1973). the ctenophores (e. Mnemioposis) Concentrations of clams were greatest which sometime appear in tremendous around the periphery of Lake numbers at certain times of the year Pontchartrain and Lake Maurepas (Tarver (M. W. LaSal 1e, pers. observ. ). Cteno- 1972; Dugas et al. 1974). Dispersion * phores can cause mass mortality of of adult clams is commonly clumped Table 2. Reported predators of adult and juvenile common rangia.
Species!common name Adults Juveni 1es References (<5 mm)
Aythya affinis -- lesser scaup duck Aythya marila-- greater scaup duck =is -- ring-necked duck Anasubripes -- American black duck Anas p l atyrhynchos -- ma1 1ard mrajamaicensis -- ruddy duck -is sabina -- Atlantic stingray Lepisosteus productus -- spotted gar Lepisosteus spatula -- alligator gar Le isosteus osseus -- northern longnose gar hepmm-- gizzard Shad Anchoa mitchil li -- southern bav anchovv Ariusfais -- Leiostomus xanthurus.- -- sootr - Micro o onias. undulatus -- Atlantic croaker -1%- - . . . -. - - . - .. . . -- black- . .~-. . drum-. X 7rchosar us robatocephalus -- sheepshead X &Iaqo on r om oides -- pinfish ~aralichthyslethostigma -- southern flounder Cvnoscion" arenarius -- sand seatrout Thasmodes bosquianus -- striped blenny Penaeus setiterus~- - ~- -- white shrimo Racrobrachium ohione -- river shr;m~ -am-- blue crab Rhithro~ano~eusharrisii, ~, -~ ~ -- mud crab Thais haemastoma -- o~vsterdrill ElXices spp. -- moon shell (possible) References: (1) Suttkus et al. (1954); (2) Darnel1 (1958); (3) Gunter and Shell (1958); (4) Harmon (1962); (5) North Carolina Bureau of Sport Fisheries and Wild1 ife (1965); (6) OIHeeron (1966); (7) Cain (1972); (8) Hoese (1973) whereas juveniles may be distributed 818/m2 in Lake Maurepas, Louisi an more uniformly (Fairbanks 1963). (Tarver and Dugas 1973), and 238/m 9 in Vermilion Bay, Louisiana. Average density of clams from shallow water Density areas between the Atchaf 1aya River and Sabi e Lake was llll for adults, The density of clams varies 14/m ! for juvenile clams > 10 mm, and greatly (for reasons discussed later). 28/m2 for juvenile clams < 10 m The highest density of adult clams was (Hoese 1973). Densities as high as c. 129/m2 were reported in Texas bays greater number of size classes and (Odum 1967). A mean density of larger clams at low salinities (0 to 250/m2 was reported in the Nueces 2 ppt) than at higher ones in Florida River, Texas (Hopkins and Andrews and suggested that this range was 1970). In Lake Pontchartrain, optimal. Louisiana, mean densities ranged from 2.7 to 311T2 for large clams and 1807 Common rangia have developed phys- to 18881111 for juveniles (Fairbanks iological responses to the frequent and 1963). sudden sal ini ty changes present in many estuaries. Common rangia is an osmoconformer at salinities greater ENVIRONMENTAL REQUIREMENTS than 10 ppt, and an osmoregulator at 1ower sal ini ties (Bedford and Anderson 1972a,b; Otto and Pierce 1981a,b). A A combination of low salinity, number of amino acids (including high turbidity, and a substrate of alanine, glycine, glutamic and sand, mud, and vegetation appears to be aspartic) are concentrated at high the most favorable habitat for the salinities suggesting that an amino common rangia (Tarver 1972). This clam acid pool is used for osmoregulation may be one of the few freshwater clams (Simpson et al. 1959; Allen and Awapara to become established in brackish water 1960; Allen 1961; Anderson and Bedford (Ladd 1951). Conversely, Remane and 1973; Anderson 1975). Schl ieper (1971) considered comnon rangia as belonging to a marine group Temperature and Sal inity that has become adapted to brackish water . Cain (1972, 1973, 1974) tested the combined effects of temperature (8 to 32°C) and salinity (0 to 20 ppt) on Temper ature embryos and larvae of common rangia. Embryos failed to develop at 0 ppt Winter kills in the shallow waters salinity. The optimum conditions for of Chesapeake Bay suggest that common embryos were temperatures of 18 to 2g°C rangia had reached its limit of and salinities of 6 to 10 ppt. temperature tolerance there (Gal 1agher and Wells 1969). Cain (1975) reported Larvae survived at a1 1 that water temperature was the most combinations of temperature and import ant factor st imul at ing salinity tested (except at 0 ppt). gametogenesis. He also stated that the planktonic existence of larvae is They tolerate temperatures of 8 to 32°C and salinities of 2 to 20 ppt. Growth greatly extended by low temperature. of larvae was best at high salinity (10 to 20 ppt) and high temperature (20 to Sal ini ty 32°C). Straight-hinged 1arvae were found to be more tolerant than embryos Common rangia are concentrated in areas where salinity seldom exceeds 18 to extremes of temperature and sal inity. ppt (Maury 1920; Pulley 1952; Parker 1956, 1960; Mogre 1961; Parker 1966; Odum 1967; Godcharles and Jaap 1973; Oxygen Hoese 1973; Swingle and Bland 1974). Tarver and Dugas (1973) reported a Common rangi a can withstand anoxic negative correlation (r = 0.71) between conditions as reported by Chen and density of clams and salinity and a Awapara (1969) in studies of positive correlation (r = 0.81) between glycolysis; however, rangia are clam height and salinity (0 to 6 ppt). intolerant of exposure to air (Olsen Godcharles and Jaap (1973) found a 1976b). Substrate The substrate of some coastal waters is mainly shells which are often Common rangia are found in a wide dredged commercially. For example, the range of soft substrates in the common rangia makes up much of the hard northern Gulf of Mexico. Tenore et substrate of Lake Pontchartrain in al. (19681, who studied the effects of Louisiana. The effects of shell clay, silt, and sand substrates on the dredging on the substrate and benthos common rangia, found clay and silt to be are too complex and controversial to unfavorable, whereas Cai n (1975) discuss in this profile. See Dugas et commonly found clams in silty-clay a1. (1974), Taylor (1978), Sikora et sediments. Parker (1966) found clams al. (1981), and Sikora and Sikora on sand, silt, and clay sediments where (1982). these constituents did not exceed 80, 30, and 65%, respectively. Few clams were collected from hard sand or clay bottoms in Louisiana (Tarver 1972) or The highest concentration of clams in Alabama (Swingle and Bland 1974). along the gulf coast has been In Louisiana, the numbers of common associated with shallow water areas rangia were highest in a mixture of less than 6 m deep (Tarver 1972; Hoese sand, mud, and vegetation (Tarver 1973; Godcharles and Jaap 1973; Tarver 1972), whereas in A1 abama, dense and Dugas 1973; Dugas et al. 1974). populations 1ived in compacted sandy- Tarver and Dugas (1973) observed a clay areas (Swingle and Bland 1974). general decrease in density as depth In Florida, common rangia were increased from 2.5 to 4.6 m. col 1ected from soft mud (Godcharl es and Jaap 1973; Woodburn 1962), but in Effects of Pollution Georgia, clams were found in mud or soft mud-sand combinations (Godwin Common rangia are known to 1968). concentrate chemicals such as kepone. Lunsford (1981) reported that peak The importance of organic matter kepone levels in common rangia during in the sediment to common rangia is summer, in the James River Estuary, not clear. Fairbanks (1963), who found were re1ated to increased met abol ism the largest densities of rangia in and feeding rate. The concentration of highly organic sediments in Lake kepone was 2 to 4 times greater in Pontchartrain , Louisiana , suggested rangia than in the water column the 1arge amounts of associated (Lunsford and Blem 1982). The key bacteria helped to attract and support factors affecting kepone uptake were clams. High organic content in water temperature, dissolved oxygen sediments was also favorable for rangia concentration, 1ipid index of clam in Vermi 1ion Bay, Louisiana (Gooch tissue, turbidity, kepone concentration 1971). However, no correlation existed in the water, and the duration of between the abundance of common rangia exposure (Lunsf ord and Blem 1982). and the percentage of organic matter in Kepone is adsorbed by particulate the sediment at levels below 10% (Hoese matter, which enhances its uptake by 1973). Few clams were found in filter feeders such as comnon rangia. sediments with more than 10% organic Uptake of oil related products such as matter in Louisiana (Hoese 1973) and benzopyrene, naphthalenes, and various Alabama (Swingle and Bland 1974). aromatic hydrocarbons has also been Mortality of rangia can result from reported (Cox 1974; Neff et al. 1976). shell erosion, which can be accelerated A1 1 of these compounds were accumulated in highly aerated sediments in which primarily in the viscera and fat bodies carbonic acids are released (Tarver and of clams under direct exposure and most Dugas 1973). were readi ly re1eased when clams were returned to clean water. Low levels of The effects of low concentrations of these contaminants, however, were contaminants on common rangia are not retained by the clams in each case. known. LITERATURE CITED Abbott, R. T. 1954. American sea- on gulf coast environments. Gulf shells. Van Nostrand, New York. Pub1 ishing Co. , Houston, Tex. 541 pp. Bedford, W. B., and J. W. Anderson. Allen, K. 1961. The effect of salin- 1972a. The physiological response ity on the amino acid concentra- of the estuarine clam, Rangia tion in Rangia cuneata (Pele- cuneata (Gray). I. Osmoregul a- cypoda). Biol. Bull. (Woods Hole) tion. Physiol. Zool. 45: 255-260. 121: 419-424. Bedford, W. B., and J. W. Anderson. Allen, K., and J. Awapara. 1960. 1972b. Adaptive mechanisms of Metabolism of sulfur amino acids the estuarine bivalve, Rangia cuneata, to a sal ini ty stressed environment. Am. Zool . 12: 721. 118: 173-182. (Abstr. ) Anderson, J. W. 1975. The uptake and Bedinger, C. A. , Jr. 1974. Seasonal incorporation of glycine by the changes in condition and gi11 s of Rangia cuneata (Moll usca: biochemical consituents of the Bivalvia) in response to varia- brackish water clam Rangi a cuneata tions in salinity and sodium. (Grav). 1831. Ph. D. Dissertation. Pages 239-258 in F.J. Vernberg, ~ex2-. A&M University, College ed. ~hysiological ecology of Station. 179 pp. estuarine organisms. University of South Carol ina Press, Col umbia. Beyers, R. J., and R. W. Warwick. 1968. The ~roductionof carbon Anderson, J. W., and W. B. Bedford. dioxide by Rangia cuneata. 1973. The physiol ogical responses Contrib. Mar. Sci. 13:45-50. of the estuarine clam, Rangia cuneata (Gray), to salinity. 11. Cain, T. 0. 1972. The reproductive Uptake of glycine. Biol. Bull. cycle and larval tolerances of (Woods Hole) 144: 229-247. ~an~iacuneata in the James River, Andrews, J. 1971. Sea shells of the Virginia. Ph. D. Dissertation. Texas coast. University of Texas ~niiersity of Virginia, Press, Austin. 298 pp. Charlottesville. 250 pp. Andrews, J. 1981. Texas shells: a Cain, T. 0. 1973. The combined field guide. University of Texas effects of temperature and Press, Austin. 175 pp. salinity on embryos and larvae of the clam Rangia cuneata. Mar. Arndt, R. H. 1976. The she1 1 dredging Biol . 21: 1-6. industry of the gulf coast region. Pages 13-48 in A. Bouma, ed. Cain, T. 0. 1974. Combined effects of She1 1 dredgi ngand its inf 1 uence changes in temperature and salinity on early stages of Rangia Darnel 1, R. M. 1958. Food habits of cuneata. Va. J. Sci. 25:30-31. fishes and 1arger invertebrates of Lake Pontchartrai n, Louisiana, an Cain, T. D. 1975. Reproduction and estuarine community. Publ. Inst. recruitment of the brackish water Mar. Sci. Univ. Tex. 5:353-416. clam Rangia cuneata in the James River, Virginia. U.S. Natl. Mar. Darnel 1, R. M. 1961. Trophic spectrum Fish. Cerv. Fish. Bull. of an estuarine community based on 73: 412-430. studies of Lake Pontchartrain, Louisiana. Ecology 42: 553-568. Chanley, P. 1965. Larval development of the brackish water mactrid Dugas, R. J., J. W. Tarver, and L. S. clam, Rangia cuneata. Chesapeake Nutwell. 1974. The mollusk Sci . 6: 209-213. communities of Lakes Pontchartrain and Maurepas , Louisiana. La. Chen, C. , and J. Awapara. 1969. Wildl. Fish. Comm. Tech. Bull. No. Effects of oxygen on the end- 10. 13pp. products of glycolysis in Rangia cuneata. Comp. Biochem. Physiol . Fairbanks. L. D. 1963. Biodemoara~hic 31: 395-401. studies of the clam Rangia Euneata Gray. Tulane Stud. 2001. 10:3-47. Christmas, J. Y. 1973. Cooperative Gulf of Mexico estuarine inventory Fotheringham, N., and S. Brunenmeister. and study. Mississippi Gulf Coast 1975. Common marine invertebrates Res. Lab. , Ocean Springs. of the northwest gulf coast. Gulf Pub'l ishing Co. , Houston, Tex. Conrad, T. A. 1840. On the Silurian system, with a table of the strata Gallagher, J. L., and H. W. Wells. and characteristic fossils: 1969. Northern range extension observations on the genus Gnatho- and winter mortality of Rangia -don with description of a new cuneata. Nauti 1us 83: 22-25. species. Am. J. Sci. 38:92-93. Godcharles, M. F., and W. C. Jaap. Copeland, B. J. , K. R. Tenore, and D. 1973. Exploratory clam survey of B. Horton. 1974. 01 igohal ine Florida nearshore and estuarine regime. Pages 315-35 H. T. waters with commercial hydraul ic Odum, B. J. Copeland, and E. A. dredging gear. Fla. Dep. Nat. McMahan, eds. Coastal ecological Resour. Mar. Res. Lab. Prof. Pap. systems of the U. S. , Vol . 2. The Ser. No. 21. 77 pp. Conservation Foundation, Washing- ton, D.C. Godwin, W. F. 1968. The distribution and density of the brackish water COX, 8. A. 1974. Responses of the clam, Rangia cuneata in the marine - crustaceans Mysidopsis Altamaha River, Georgia. Ga. Fish a1 myra Bowman, Penaeus aztecus Game Comm., Mar. Fish. Div. Ives , and Penaeus setiferus Contrib. Ser. No. 5:l-10. (Linn. to ~etroleumhvdrocarbons. ~h.D. - ~issertation. Texas A&M Gooch, D. M. 1971. A study of Rangia University, College Station. 182 cuneata Gray, in Vermilion Bay, PP. Louisiana. M. S. Thesis. Univer- sity of Southwestern Louisiana, Dall, W. H. 1894. Monograph of the Lafayette. 48 pp. genus Gnathodon Gray (Rangia Des- moulin~~c.U.S. Natl. Mus. Gunter, G., and W. E. Shell, Jr. 1958. 17: 89-106. A study of an estuarine area with water-level control in the Louisi- Lunsford, C.A., and C. R. Blem. 1982. ana marsh. Proc. La. Acad. Sci. Annual cycle of Kepone residue 21: 5-34. and lipid content of the estuarine clam, Rangia cuneata. Estuaries Harmon, B. G. 1962. Mollusk as food 5: 121-130. of lesser scaup along the Louisi- ana coast. Trans. N. Am. Wildl. Maury, C. 3. 1920. Recent mollusks of Conf. 27: 132-138. the Gulf of Mexico and Pleistocene and Pliocene species from the Gulf Hoese, H. D. 1973. Abundance of the States. Bull. Am. Paleontol. 8:l- low salinity clam, Rangia cuneata 115. in southwestern Louisiana. Proc. Natl . Shellfish. Assoc. McIntire, W. G. 1958. Prehistoric 63: 99-106. Indian settlements of the changing Mississippi River Delta. La. Hopkins, S. H. 1970. Studies on the State Univ. Coastal Stud. Ser. brackish water clams of the genus 1: 1-128. Rangia in Texas. Proc. Natl. Shellfish. Assoc. 60: 5-6. Moore, D. R. 1961. The marine and (Abstr. ) brackish water mol lusca of the state of Mississippi. Gulf Res. Hopkins, S. H., and J. D. Andrews. Rep. 1:l-58. 1970. Ra~giacuneata on the east coast: thousand mile range Neff, J. M. , B. A. Cox, D. Dixit, and extension or resurgence? Science J. W. Anderson. 1976. 167 : 868-869. Accumulation and release of petroleum derived aromatic Hopkins, S. H., J. W. Anderson, and K. hydrocarbons by four species of Horvath. 1973. The brackish marine animals. Mar. Biol. water clam Rangia cuneata as 38: 279-298. indicator of ecological effects of sal ini ty changes in coastal North Carolina Bureau of Sport waters. U.S. Army Engineer Fisheries and Wildlife, North Waterways Exp. Stn. , Vicksburg, Carolina Wildlife Resources Miss. Contract Rep. No. Commission, and Virginia DACW39-71-C-0007. Commission of Game and Inland Fisheries. 1965. Back Ladd, H. S. 1951. Brackish-water and Bay-Curri tuck Sound data report. marine assemblages of the Texas Vol. 1. 84 pp. coast with special reference to mollusks. Publ. Inst. Mar. Sci. Odum, H. T. 1967. Biological circuits Univ. Texas. 2:12-164. and the marine systems of Texas. Pages 99-157 -in T. A. Olsen and F. Louisiana Wildlife and Fisheries Com- J. Burgess, eds. Pollution and mission. 1968. The history and marine ecology. John Wiley and regulation of the she1 1 dredging Sons, New York. industry in Louisiana. La. Wildl. FishComm. 32pp. Odum, H. T. , and B. J. Copeland. 1969. A functional classification of the Lunsford, C. A. 1981. Kepone distri- coastal ecological systems. Pages bution in the water column of the 9-86 H. T. Odum, B. J. James River Estuary - 1976-78. Copeland, and E. A. McMahan, eds. Pestic. Monit. J. 14:119-124. Coastal ecological systems of the U.S. Rep. Fed. Water Pollut. abundance of Rangia cuneata. U.S. Control Admin., Washington, D. C. Fish Wildl. Serv. Bur. Commer.-. . Fish. Circ. 246: 35-36. OIHeeron, M. K. 1966. Some aspects of the ecology of Rangia cuneata Parker, R. H. 1955. Changes in the (Gray). M.S. Thesis. Texas A&M invertebrate fauna, apparently University, College Station. 71 attributable to salinity changes, PP. in- the bays of central Texas. J. Paleontol . 29: 193-211. Olsen, L. A. 1972. Comparative functional morphology of feeding Parker, R. H. 1956. Macro- mechanisms in Rangia cuneata invertebrate assemblages as (Gray) and Polymesoda carom indicators o f sedimentary (Bosc). Proc. Natl. Shellfish. environments in east Mississippi Assoc. 63: 4. (Abstr. ) delta region. Am. Assoc. Petrol. Geol . Bull. 40: 295-376. Olsen, L. A. 1973. Food and feeding in relation to the ecology of two Parker, R. H. 1959. Macro- estuarine clarns, Rangia cuneata invertebrate assemblages of (Gray) and Polyrnesoda carol iniana central Texas coastal bays and (Bosc). M. S. Thesis. Florida Laguna Madre. Am. Assoc. Petrol. State University, Tal lahassee. Geol. Bull. 43: 2100-2166. 102 pp. Parker, R. H. 1960. Ecology and Olsen, L. A. 1976a. Ingested material distributional patterns of marine in two species of estuarine bi- macro-invertebrates, northern Gulf valves: Rangia cuneata (Gray) and of Mexico. Pages 302-337 in F. P. Polymesoda carol iniana (Bosc). Shepard, ed. Recent sediments of Proc. Natl. Shellfish. Assoc. northwest Gulf of Mexico. Am. 66: 103-104. (Abstr. ) Assoc. Petrol. Geol. Bull. Tulsa, Okl a. Olsen, L. A. 1976b. Reproductive cycles of Polymesoda carol iniana Pfitzenmeyer, H. T., and K. G. Drobeck. (Bosc) and Rangia cuneata (Gray) 1964. The occurrence of the with aspects of desiccation in the brackish water clam, Rangia adults and ferti 1ization and early cuneata, in the Potomac River, larval stages in Polymesoda -- Mary1 and. Chesapeake Sci. 1iniana. Ph. D. Dissertation. 5: 209-215. Florida State University, Tal la- hassee. 116 pp. Pulley, T. E. 1952. An illustrated check list of marine mollusks of Otto, J., and S. K. Pierce. 1981a. Texas. Tex. J. Sci. 4:167-199. Water balance systems of Rangia cuneata: ionic and amino acid Remane, A. , and C. Schl ieper. 1971. regulation in changing salinities. Biology of brackish water. John Mar. Biol. 61:185-192. Wi ley and Sons, New York. 372 pp. Otto, J., and S. K. Pierce. 1981b. An Richards, H. G. 1939. Marine interaction of extra- and intra- Pleistocene of the gulf coastal cellul ar osmoregul atory mechani sms plain: Alabama, Mississippi and in the bivalve mollusc Rangia Louisiana. Am. Assoc. Petrol. cuneata. Mar. Biol . 61: 192-198. Geol . Bull. 50: 297-316. Parker, J. C. 1966. Bottom fauna Rogers, P. , and A. Garcia-Cubas. 1981. study -- distribution and relative Evolution gonadica a nivel histologico de Rangia cuneata Rangia cuneata Gray in coastal (Gray, 1831) de la Laguna Pon, waters of Alabama. Ala. Mar. Campeche, Mexico (Moll usca: Resour. Bull. 10: 9-16. Bivalvia). Am. Inst. Cienc. del Mar. Limnol., Univ. Nat. Auton, Tarver, J. W. 1972. Occurrence, dis- Mexico. 8: 1-20. tribution and density of Rangia cuneata in Lakes Pontchartrain and Ruiz, H. E. 1975. Estudio ecologico Maurepas, Louisiana. La. Wildl. preliminar de las almegas Fish. Comm. Tech. Bull. No. 1. 8 comerci a1 es del si stema 1agunar de PP. Terminos, Campeche, Rangia cuneata (Gray, 1831). Tesi s professional , Tarver, J. W., and R. J. Dugas. 1973. Univ. Nat. Auton, Mexico, 80 pp. A study of the clam Rangia (cited in Rogers and Garcia-Cubas cuneata, in Lake Pontchartrain and 1981). Lake Maurepas, Louisiana. La. Wildl. Fish. Comm. Tech. Bull. No. Sikora, W. B., J. P. Sikora, and A. 5. 97pp. McK. Prior. 1981. Environmental effects of hydraulic dredging for clam shells in Lake Pontchartrain, Taylor, J. L. 1978. Evaluation of Louisiana. Publ. No. LSU-CEL-81- dredging and open water disposal 18. U.S. Army Corps of Engineers, on benthic environments: Gulf New Orleans District. Contract Intracoastal Waterway -- Apal a- Rep. No. DACW29-79-C-0099. 140 chicola Bay, Florida to Lake PP. Borgne, Louisiana. Contract Report to U.S. Army Corps of Sikora, W. B. , and J. P. Sikora. 1982. Engineers, Mobile District, Ecological characterization of the Mobile, Ala. 51 pp. benthic community of Lake Pont- chartrain, Louisiana. Publ. No. Tenore, K. R., D. B. Horton, and T. W. LSU-CEL-82-05. U. S. Army Corps Duke. 1968. Effects of bottom of Engineers, New Orleans substrate on the brackish water District. Contract Rep. No. bivalve Rangia cuneata. Chesapeake DACW29-79-C-0099. 214 pp. Sci. 9:238-248. Simpson, J- K- and J. U.S. Department of Commerce. 1971. Awapara. 1959. Free amino acids Fishery statistics of the United in some aquatic invertebrates. States 1968. U.S. Gov. Print. Biol. Bull. (Woods Hole) 117:- Off., Washington, D.C. Dig. 62. 371-381. 189 pp. Singley, J. A. 1893. Contributions to Wass, M., and D. 1970. Marsh the natural history of Texas. clams believed potential food Part I. Texas mollusca. Annu. Bull. Va. Inst. Mar. Sci. Rep. Geol. Sur. Tex. 4:297-343. 2:supply. 1. Suttkus, R. D. , R. M. Darnell, and J. H. Darnell. 1954. Biological Wells, H. W. 1961. The fauna of study of Lake Pontchartrai n. oyster beds, with special (annual report 1953-54). Tulane reference to the salinity factor. University, New Orleans, La. 59 Ecol . Monogr. 31: 239-266. PP. Wolfe, D. A. , and E. N. Petteway. Swingle, H. A. , and 0. G. Bland. 1974. 1968. Growth of Raygia cuneata Distribution of the estuarine clam Gray. Chesapeake Sci . 9: 99-102. Woodburn, K. D. 1962. Clams and vicinity. Fla. Board Conserv. oysters in Charlotte County and Mar. Lab. (FBCML) No. 62. 29 pp. SOY72 -101 REPORT OOCUMENTATlON 1. "Emcn 2. 3. nb~~*~sAccesston NO PACE I Bi01 oqi ca1 Report 82( 11.3114 - I 4. mle and S,MI~I~ L n.0.( 0.t. Species Profiles: Life Hi stories and Environmental Requirements April 1985 of Coastal Fishes and Invertebrates (Gulf of Mexico) -- Common 6. Ranqia Authoris) 7. C.rforrnin. Onsnlzation nast. I L - - - - -. .rm.-. Mark W. LaSalle and Armando A. de la Cruz 1 e. C.rformln( Orlanlzatlon Nama and Mdrass 1 10. ~mi~/~asr~wor~tUnit NO. I Department of Bi 01 ogical Sciences 1 I P.O. Drawer GY Mississippi State University Mississippi State, MS 39 762 1% sVon~n(Orlanlutlon Name and Addma National Coastal Ecosystems Team U.S. Army Corps of Engineers Fish and Wildlife Service Waterways Experiment Station U.S. Department of the Interior P.O. Box 631 Washington, DC 20240 Vicksburg , MS 39180 *U.S. Army Corps of Engineers Report No. TR EL-82-4 1L Abctnc( (Uml(: 100 word.) Species profiles are 1iterature summaries of the taxonomy, morphology, range, 1ife history, and environmental requirements of coastal aquatic species. They are designed to assist in environmental impact assessment. The common rangia (Rangia cuneata) is a common inhabitant of shallow, low sal inity (zero to 18 ppt) estuaries along the northern Gulf of Mexico. The population density of rangia may exceed 1000 clams/m2. Rangia spawn between March and November, following a sudden rise 'or fa1 1 of sal inity of 5 to 10 ppt. Juvenile clams develop rapidly, settling after about 7 days. Juveniles tolerate salinity and temperature extremes of 2 to 20 ppt and 8 to 32 "C. The growth rate of clams ranges from zero to 20 mm per year depending on conditions. Clams may live 15 years or more, attaining a maximum length of about 94 mm. Rangia are found in a wide range of substrate from sand to soft mud. Rangia are filter feeders, ingesting large amounts of detritus and phytoplankton, and are the prey of a large number of fish, crustaceans, mollusks, and ducks. Deposits of fossil shell material are dredged for a number of industrial purposes. Estuaries Clams Dredging b. IdentlRenlOp.n.Endad Terms Common rangi a Life history Rangia cuneata Trophic ecology Sal inity requirements Population density Spawni ng habits C. COUTl Fialdltmup 1L Avallablllty Statamant 19. kcurbty Class (Th~sRewrO 21. No. of Paacs Unl imited Unclassified 16 -- 20. Suur'%F13rn*Fd P. ?rice Sea ANSI-239.18) OCTIONAL FORM 272 (4-71 (Forrmrly NTIS-35) D.par(ment ol Commarca . REGION 1 REGION 2 REGION 3 - - Reejonal Director Regional Director Regional Director u.5. Fish and Wildlife Service U.S. Fish and Wildlife Service U.S. Fish and Wildlife Service Lloyd Five Hundred Building, Suite 1692 P.O. Box 1306 Federal Building, Fort Snelling 500 N.E. Multnomah Street Albuquerque, New Mexico 87 103 Twin Cities, Minnesota 55 Ill Portland, Oregon 97232 REGION 4 REGION 5 REGION 6 Regional Director Regional Director Regional Director U.S. Fish and Wildlife Service U.S. Fish and Wildlife Service U.S. Fish and Wildlife Service Richard B. Russell Building One Gateway Center P.O. Box 25486 75 Spring Street, S.W. Newton Corner, Massachusetts 02 158 ,Denver Federal Center Atlanta, Georgia 30303 Denver, Colorado 80225 REGION 7 Regional Director U.S. Fish and Wildlife Service 101 1 E. Tudor Road Anchorage, Alaska 99503 ------a OF THE ....-..-.7 U.S. FISH AND WILDLIFE SERVICE As the Nation's principal consewation agency, the Department of the Interior has mpon- sibility for most of our.nationally owned public lands and natural resources. This includes fostering the wisest use of our land and water resources, protecting our fish and wildlife, preserving theenvironmental and cultural values of our national park and historical places, and providing for the enjoyment of life through outdoor recreation. The Department as- sesses our energy and mineral resources and works to assure that their development is in the best interests of all our people. The Department also has a major responsibility for American Indian reservation communities and for people who live in island territories under U.S. administration.