Library

National Wetlands Research Cent@

Us 6. Fish and Wildlife Service

700 Caf~r~

L

Biological Report 82 (11.3 1 )

Lafayette, La. 70506 TR EL-82-4

April, 1985

Species Profiles: Life Histories and

Environmental Requirements of Coastal Fishes

and Invertebrates (Gulf of Mexico)

COMMON RANGIA

QL

155

.S63

no.82-

11.31

Fish and Wildlife Service

Coastal Ecology Group

Waterways ExDeriment Station

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/OBS" series published from 1976 to September 1984. The Biological 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 wildlife needs.
Biological Report 82c11.31)

TR EL-82-4

April 1985

Species Profiles: Life Histories and Environmental Requirements

of Coastal Fisheries and Invertebrates (Gulf of Mexico)

COMMON RANGIA

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

Slidell, 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 requirements of coast.5 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 requirements of coastal fishes and invertebrates (Gulf 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 profiles

are designed to provide coastal managers, engineers, and biologists with a brief

comprehensive sketch of the biological characteristics and environmental requirements 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, life history, ecological role, environmental

requirements, and economic importance, if applicable. A three-ring binder is

used for this series so that new profiles can be added as they are prepared. This

project is jointly planned and financed by the U.S. Army Corps of Engineers and

the U.S. Fish and Wildlife Service.

Suggestions or questions regarding this report should be directed to one

of the following addresses.

Information Transfer Specialist

National Coastal Ecosystems Team

U.S. Fish and Wildlife Service

NASA-Slide11 Computer Complex

1010 Gause Boulevard

Slidell, LA 70458

or

U.S. Army Engineer Waterways Experiment Station

Attention: WESER-C

Post Office Box 631

Vicksburg, MS 39180

iii
CONVERSION TABLE

Multiply

millimeters (mn)

centimeters (an)

meters (m)

kilometers (km)

square meters (m2)

square kilometers (km2)

hectares (ha)

liters (1)

cubic meters (m3)

cubic meters

0.2642 gallons

35.31 cubic feet

0.0008110 acre-feet

milligrams (mg) 0.00003527 ounces

grams (4) 0.03527 ounces

kilograms (kg) 2.205 pounds

metric tons (t) 2205.0 pounds

metric tons 1.102 short tons

kilocalories (kcal) 3.968 British thermal units

Celsius deyrees

inches 25.40 millimeters

inches 2.54 centimeters

feet (ft) 0.3048 meters

fathoms 1.829 meters

miles (mi) 1.609 kilometers

nautical miles (rrni) 1.852 kilometers

square feet (ft2)

acres

square miles (mi')

0.0929 square meters

0.4047 hectares

2.590 square kilometers

gallons (gal) 3.785

cubic feet (ft3) 0.02831

acre-feet 1233.0

Metric to U.S. Customary

BY To Obtain

0.03937 inches

0.3937 inches

3.281 feet

0.6214 miles

10.76 square feet

0.3861 square miles

2.471 acres

1.8("C) + 32 Fahrenheit degrees

U.S. Customary to Metric

ounces (02) 28.35

pounds (lb) 0.4536

short tons (ton) 0.9072

British thermal units (Btu) 0.2520

Fahrenheit degrees 0.5556("F - 32)

liters

cubic meters

cubic meters

grams

kilograms

metric tons

kilocalories

Celsius degrees

iv
CONTENTS

PREFACE .............................................. ..........

CONVERSION FACTORS ................................... ..........

ACKNOWLEDGMENTS ...................................... ..........

NOMENCLATURE/TAXONOMY/RANGE ...

MORPHOLOGY/IDENTIFICATION AIDS

REASONS FOR INCLUSION IN SERIES

LIFE HISTORY ..................

Spawning .................

Larvae and Postlarvae ....

Adult Activity and Feeding

Life Span ................

GROWTH CHARACTERISTICS ........

Growth Rate ..............

Size .....................

THE FISHERY ...................

ECOLOGICAL ROLE ...............

Trophic Level ............

Predators and Parasites . .

Competitors ..............

Spatial Distribution .....

Density ..................

ENVIRONMENTAL REQUIREMENTS ....

Temperature ..............

Salinity .................

Temperature and Salinity .

Oxygen ...................

Substrate ................

Depth ....................

Effects of Pollution .....

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13
ACKNOWLEDGMENTS

We thank Dr. Courtney T. Hackney, University of North Carolina at Wilmington

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 Mills for help in the preparation of the

manuscript.

vi
sinus line

Figure 1. Common rangia.

COMMON RANGIA

NOMENCLATURE/TAXONOMY/RANGE

Scientific name.................Rangia

cuneata (Gray) (Figure 1)

Preferred common name...........Common

rangia (Andrews 1971; Fotheringham

and Brunenmeister 1975)

Other common names............Brackish

water clam, Louisiana road clam

Class.............:............Mollusca

Order.................Eulamellibranchia

Family........................Mactridae

Geographic range: The common rangia is

found along the Gulf of Mexico coast

(Figure 2) from northwest Florida to

Laguna de Terminos, Campeche, Mexico

(Dal1 1894; Andrews 1971; Ruiz 1975),

and along the Atlantic coast as far

north as Maryland (Pfitzenmeyer and

Drobeck 1964; Gallagher and Wells

1969; Hopkins and Andrews 1970) and

1

New Jersey (Woodburn 1962). Before

1956, living common rangia had not

been collected along the Atlantic

coast (Wells 1961) probably because

earlier sampling in brackish water

areas had been inadequate. Common

rangia inhabit low salinity (0 to 18

ppt) estuarine habitats (Parker 1966;

Christmas 1973; Hopkins et al. 1973;

Swingle and Bland 1974).

Geologically, the common rangia

has been found in Pliocene deposits

in the Carolinas and Florida and in

Pleistocene deposits in Chesapeake

Bay and the Potomac River, the Carolinas, Florida, the entire north

coast of the Gulf of Mexico (Figure

2), and the north coast of South

America (Conrad 1840; Dal1 1894;

Maury 1920; Richards 1939).
I /

-.

ul

z

. .
MORPHOLOGY/IDENTIFICATION AIDS

The following description of

common rangia is taken from Abbott

(1954) and Andrews (1971, 1981).

Adults range from 2.5 to 6.0 cm in

length. The valves are obliquely

ovate, thick, and heavy (Figure 1).

The exterior of the shell is covered

with a strong, rather smooth

periostracum that ranges from light

brown to grayish brown to black. The

umbones are prominent and are near the

anterior end. The shell interior is

glossy white with a blue-gray tinge.

The pallial sinus is small but

distinct. The posterior lateral tooth

is long (Figure 1). Dal 1 (1894)

mentions that most of the variability

in form is related to the differences

in the height of the umbones and the

shape of the posterior margin of the

shell. Rangia cuneata var. nasutus

(Dal1 1894)s belied tobe

rostrate form of R. cuneata (Abbott

1954) and may bF coiXiZ?I- with a

closely related species, the brown

rangia (Rangia flexuosa [Conrad]).

The brown rangia is 2.5 to 4.0 cm lonq

and resembles an elongate common

rangia; however, brown rangia can be

easily separated from common ranqia by

the short posterior lateral tooth and

the nondistinct pallial sinus. Brown

rangia is found from Louisiana to Texas

and Vera Cruz, Mexico (Andrews 1971),

but is much less common than the common

rangia.

REASONS FOR INCLUSION IN SERIES

The common rangia is an important

component of estuarine

(Parker 1959;

ecosystems

Odum 1967; Odum and

Copeland 1969; Copeland et al. 1974)

accounting, for example, for nearly 95%

of the benthic biomass in the James

River Estuary, Virginia (Cain 1975).

In low salinity estuarine areas common

rangia functions as a link between primary producers and secondary consumers.

As a non-selective filter feeder,

rangia transforms large quantities of

plant detritus and phytoplankton into

clam biomass (Darnell 1958; Olsen 1972,

1973, 1976a; Hoese 1973). In turn,

this biomass is consumed by fishes,

crustaceans, and ducks (Suttkus et al.

1954; Darnell 1958; Gunter and Shell

1958; Harmon 1962; North Carolina

Bureau of Sport Fisheries and Wildlife

1965; O'Heeron 1966; Cain 1972; Tarver

and Dugas 1973). The shells provide

hard substrate for epifaunal attachment

(Hoese 1973).

The common rangia was a food item

of prehistoric Indians (McIntire 1958)

anu it is still occasionally canned and

eaten in New Jersey, Texas, North

Carolina, and Mexico (Singley 1893;

Woodburn 1962; Wass and Haven 1970;

U.S. Department of Commerce 1971).

Economically, common rangia is more

important as a source of shells for

road building and in the manufacture of

many industrial products (Tarver and

Dugas 1973; Swingle and Bland 1974;

Arndt 1976). Much of this shell

material is dredged from buried

deposits in estuaries.

LIFE HISTORY

Spawning

The reproductive cycle and

environmental conditions necessary for

spawning are well known for common

rangia. The reproductive cycle was

studied in Louisiana by Fairbanks

(1963), in Virginia by Cain (1975),

in Florida by Olsen (1976b), and in

Campeche, Mexico by Rogers and

Garcia-Cubas (1981). Most rangia

spawned from March to May and from late

summer to November in Louisiana and

from February to June and September to

November in Mexico. In both areas,

spawning may be continuous.

In Virginia, gametogenesis began

in early April and continued throughout

the summer; gametes were ripe from May

through November. Gametogenesis was

initiated when water temperature

rose to 15"C, and spawning was

initiated by a rapid increase or

decrease in salinity (Cain 1975). In

upstream areas of the James River,

3
Virginia, clams required a salinity

increase of about 5 ppt associated with

reduced freshwater output, but in downstream areas they required a salinity

decrease of about 10 to 15 ppt associated with increased freshwater output.

Spawning peaked at 5 ppt in fall. In

Florida, ripe gametes and spawning were

reported from July through November;

spawning peaked in September. Temperature and salinity increases were suspected of triggering spawning (Olsen

1976b).

In spawning, common rangia release

gametes directly into the water. Sex

ratios were reported to be near 1:l in

Louisiana (Fairbanks 1963) and Mexico

(Rogers and Garcia-Cubas 1981), but

females outnumbered males in Virginia

(Cain 1972). The incidence of hermaphroditism in this clam was reported to

be O.I% in Mexico (Rogers and GarciaCubas 1981) and 2.1% in Florida (Olsen

1976b). The minimum length of mature

adults in Lake Pontchartrain,

Louisiana, was 24 mm (Fairbanks 1963).

From data on annual growth increments,

Fairbanks (1963) inferred that a clam

could reach minimum length in 2 to 3

years. In the James River, Virginia,

Cain (1972) reported that gonads were

mature in clams as small as 14 mm,

which were probably clams in their

second year of life.

No fecundity data are available on

common rangia.

Larvae and Postlarvae

The early stages of development of

common rangia were studied in Louisiana

by Fairbanks (1963) and in Virginia by

Chanley (1965). Fairbanks reported

that the average diameter of eggs was

about 69 pm. Ciliated blastula

developed 8.5 hours (h) after

fertilization, a pelagic trochophore at

26.3 h, and a veliger at 34.3 h (93 pm

in mean diameter). In Virqinia,

Chanley reported that shelled larvae

appeared within 24 h after fertilization. The length of different life

stages were as follows:

straight-hinged larvae 0.75 to 130 pm;

unbowed larvae 120 to 175 pm; and

pediveligers (metamorphosed) 160 to

175 pm. Pediveligers began to settle,

lose the velum, and attain gills at 175

to 180 pm. Metamorphosis began after 7

days (Chanley 1965).

Most settling of larvae in the

James River, Virginia, took place

between September and March when the

animals were 230 to 500 pm long and

averaged 300 pm (Cain 1975). A second

settling period occurred in midsummer.

In Lake Pontchartrain, Louisiana,

Fairbanks (1963) collected juveniles as

small as 375 pm while Hoese (1973)

observed several small clams (< 1 mm

long) attached to a hydroid colony.

How the juvenile rangia disperse

is uncertain. They may be transported

to upstream areas in the more saline

bottom water in an incoming tide, or by

swimming during low flow or both (Cain

1975). Fairbanks (1963) reported that

larvae were capable of selecting substrate for setting and preferred substrates high in organic content.

Adult Activity and Feeding

Common rangia move little after

settling. Fairbanks (1963) observed

little movement of clams in aquaria.

Sikora et al. (1981) suggested that

rangia are capable only of vertical

movement in the sediment. Olsen (1973)

reported that clams did not move in

aquaria over a 4-month period even when

given a choice of substrates.

Feeding of common rangia is

controlled by gill palp articulations

and ciliary currents over the gills

(Olsen 1972). The animal extrudes

pseudofeces from the mantle cavity,

through the inhalant siphon when the

valves are quickly closed.

Life Span

The life span of the common rangia

has not been confirmed. If one relates

the mean length (about 40 mm) of rangia

4
collected in Louisiana (Table l), to

estimates of growth rate (Fairbanks

1963; Wolfe and Petteway 1968), the

average life span is about 4 to 5

years. A clam of the maximum expected

length of 75 mm, reported by Wolfe and

Petteway (1968) in

would be 10 years old.

Chesapeake Bay,

Hopkins et al.

(1973) estimated a maximum life span of

15 years.

GROWTH CHARACTERISTICS

Growth Rate

Annual growth increments of common

rangia in the Gulf of Mexico are

reported to vary from 0 to 20 mm

(Fairbanks 1963; Gooch 1971; Tarver and

Dugas 1973). Annual growth increments,

estimated for the first 3 years of life

for two populations . Lake

Pontchartrain, Louisiana, werin15 to 20

mm, 5 to 9 mm, and 4 to 5 mm,

respectively (Fairbanks 1963). From

mean height data for clams collected in

Lake Pontchartrain, Tarver and Dugas

(1973) reported as much as 7.2 mm

growth in a Z-month period. This rapid

growth appeared to be related to warm

temperatures. Annual growth rates have

been reported to range from 0 to 9.7 mm

for Vermilion Bay, Louisiana (Gooch

1971) and to be 3 mm in Trinity Bay,

Texas (Bedinger 1974). Wolfe and

Petteway (1968) calculated the

following von Bertalanffy growth curve

for a common rangia population in the

TFe~t9R9:v~~b.~P~$:)CarolinTahe L ;ai_;,;:

predicted length of 75.6 mm would

represent 10 years of growth.

Size

Maximum length reported was 94 mm

for a common rangia from Grand Gosier

Is1 and, Louisiana (H.D. Hoese, Univ.

Table 1. Range of lengths (mm) or heights (mm) of common rangia examined in

four areas of Louisiana.

__---1-1-

Area Length

--._ll-__

Lake Pontchartrain, LA 38-42 (adults)

l-8 (juveniles)

--_.

Height References

--_-

--- Fairbanks

(1963)

---

m-e 28 Tarver (1972)

m-m 28-44 Tarver &

Dugas (1973)

Lake Maurepas, LA --- 26 Tarver (1972)

___ 25-27 Tarver &

Dugas (1973)

Vermilion Bay, LA

Sabine Lake -

Atchafalaya Bay, LA

31-61

28-57

--- Gooch (1971)

--- Hoese (1973)

5
Southwestern La.; pers. cornn.). Mean

sizes (length, anterior to posterior;

height, umbo to ventral margin)

reported from other Louisiana estuaries

are shown in Table 1. Parker (1960)

and Hoese (1973) reported that the

largest clams were found in the lower

salinity areas of estuaries, whereas,

Tarver and Dugas (1973) found that clam

size increased with salinity. In

Virginia, Cain (1972) noted that clams

living in sand were typically larger

than those living in mud.

THE FISHERY

The foremost commercial value of

common rangia is in the use of fossil

shells for road building material,

oyster cultch, and as a source of

calcium carbonate for the manufacture

of glass, chemicals, chicken and cattle

feed, wallboard, and agricultural lime

(Tarver and Dugas 1973; Swingle and

Bland 1974; Arndt 1976). Clam shells

are harvested by large commercial

hydraulic dredges. By far the,largest

concentrations of living clams are

along the Louisiana coast. The minimum

standing crop of clams estimated to be

between the Atchafalaya River and

Sabine Lake, Louisiana, was between 24

billion and 48 billion clams (Hoese

1973). Because of the relatively slow

growth rate of rangia, Hoese (1973)

suggested that no more than 5% of the

living clam population should be

harvested annually if current

production of fossil shells is to be

maintained; however, at an annual

recruitment of 5% (Fairbanks 1963) the

estimated shell deposits in Lake

Pontchartrain would be nearly exhausted

in 35 years; at 3% Tarver and Dugas

(1973) estimated depletion in 18 years.

The potential sources of common

rangia shell along the gulf coast have

been listed by Arndt (1976). In Texas,

shell occurs in the upper reaches of

San Antonio Bay, Nueces and Lavaca

Bays, Galveston Bay, Trinity Bay, and

Sabine Lake. In Louisiana, deposits

extend from Point au Fer (Atchafalaya

Bay) west to the Texas border,

Calcasieu and Sabine Lakes, and Lake

Pontchartrain. In Mississippi, clams

live in the Pearl River Estuary and

Mississippi Sound; in Alabama, in upper

Mobile Bay; and in Florida in

Choctawhatchee Bay, Tampa Bay, the

Caloosahatchie River (Arndt 1976), and

the upper reaches of Charlotte Harbor

(Woodburn 1962).

The Louisiana Wildlife and

Fisheries Commission (1968) estimated a

statewide production of about 5 million

cubic yards of clam shell in 1968

compared with 300,000 cubic yards

annually in the mid-1930's. The

maximum annual harvest of shell in the

gulf States was 21.2 million tons in

1967 compared with 468,000 tons in 1912

(Arndt 1976). Of the material dredged

in 1967, an estimated 12.2 million tons

was used in construction and the

remainder for road base, asphalt fill,

poultry grit, cattle roughage, filter

material, and whiting (pigment).

Native Americans used common

rangia as food, as evidenced from shell

deposits in Indian middens along the

gulf coast (Singley 1893; McIntire

1958). The canning of rangia in Texas

under the name of "little neck clams"

by the Givens Oyster Company was

reported by Singley (1893). Rangia

were also canned at Cape May, New

Jersey (Woodburn 1962) and in North

Carolina (U.S. Department of Commerce

1971). Rangia have been collected and

consumed from the Potomac Creek of the

Potomac River, Maryland (Pfitzenmeyer

and Drobeck 1964), to Mexico where Wass

and Haven (1970) reported that this

clam was served with rice as "Paella a

valencianna" in restaurants. The

potential use of this clam as food,

however, is severely limited by

contamination of large potential

sources by pollution (Christmas 1973;

Swingle and Bland 1974). Rangia are

also used as bait for blue crabs

(Godcharles and Jaap 1973).

6
ECOLOGICAL ROLE larvae if coincidental with

spawning.

rangia

Trophic Level

Common rangia serve to link

primary producers and secondary

consumers in estuarine areas. Rangia

are non-selective filter feeders

(Darnell 1958; Olsen 1976a) ingesting

large quantities of detritus and

phytoplankton. Darnell (1958) reported

that gut contents contained 70%

unidentifiable detritus, 10% sand, 17%

algae (possibly Anabaena or

Microcystis) as well as traces of

diatoms, toraminifera, and vascular

plant material. Olsen (1976a) reported

48 species of phytoplankton from

stomach contents of common rangia,

although a large portion of the

material ingested was detritus (46 to

81%, depending on tidal conditions).

Predators and Parasites

Common rangia are preyed upon by

fish, crustaceans, mollusks, and ducks

(Table 2; Suttkus et al. 1954; Darnell

1958; Gunter and Shell 1958; Harmon

1962; North Carolina Bureau of Sport

Fisheries and Wildlife 1965; O'Heeron

1966; Cain 1972; Tarver and Dugas

1973). In addition, moon shell snails

(Polinices spp.) may be predators as

suggested by drill holes in rangia

shells (Hoese 1973). Common rangia are

abundant in the diets of blue catfish,

freshwater drum, spot, black drum,

river shrimp, and blue crab in Lake

Pontchartrain, Louisiana (Darnell 1958,

1961). The smaller rangia are

subjected to the greatest predation

pressure. Clams as large as 40 mm

(length or height), however, are eaten

by fishes such as sheepshead and black

drum (Darnell 1958; Tarver and Dugas

1973). A potential group of predators

not mentioned by the above authors are

the ctenophores (i.e., Mnemioposis)

which sometime appear in tremendous

numbers at certain times of the year

(M.W. LaSalle, pers. observ.). Ctenophores can cause mass mortality of

The common rangia is parasitized

by larvae of fellodistomatid trematodes

(Fairbanks 1963). Cercariae and

sporocysts of this parasite are found

in the gonadal tissue, giving it an

orange coloration and

castration.

effecting

Only large clams are

infected.

Competitors

Potential competitors of common

rangia may be reduced by the wide

range of salinities tolerated by this

clam (Odum 1967). Polymesoda

caroliniana has feeding habits

identical to those of rangia (Olsen

1973, 1976a), but is spatially

separated from rangia; it is found

primarily in intertidal areas or in

small numbers in the shallow nearshore

subtidal areas. In contrast, rangia

live largely in the subtidal zone.

Other potential competitors are

apparently not adapted to fluctuating

salinities.

Spatial Distribution

Common rangia are primarily

restricted to low salinity (< 19 ppt)

estuaries (Maury 1920; Pulley 1952;

Parker 1955, 1956, 1960; Moore 1961;

Parker 1966; Odum 1967; Christmas 1973;

Hoese 1973; Hopkins 1970; Hopkins et

al. 1973; Swingle and Bland 1974).

Rangia have been reported from areas as

far as 25 miles upstream in delta

rivers (Swingle and Bland 1974), but

most prefer salinities of 5 to 15 ppt.

Tarver and Dugas (1973) found that

concentrations of clams were highest

adjacent to a potential source of fresh

or salt water, which may be related to

the need for salinity shock required

for spawning (Cain 1973).

Concentrations of clams were greatest

around the periphery of Lake

Pontchartrain and Lake Maurepas (Tarver

1972; Dugas et al. 1974). Dispersion

of adult clams is commonly clumped

7
Table 2. Reported predators of adult and juvenile common rangia.

-- - --

Species/common name Adults Juveniles References

(<5 mm)

-----

Aythya affinis -- lesser scaup duck X 495

mm-- greater scaup duck X 5

mmis -- ring-necked duck X 5

Anasubripes -- American black duck X 5

Anas platyrhynchos -- mallard X 5

Dxyura jamaicensis -- ruddy duck X

Dasyatis sabina -- Atlantic stingray ;

Lepisosteus productus -- spotted gar x" 192

Lepisosteus spatula -- alligator gar X 132

Lepisosteus osseus -- northern longnose gar X 1,2

Dorosoma cepmm -- gizzard shad X 132

Anchoa mitchilll -- southern bay anchovy X 1,2

wfelis -- sea catfish X

IctaIuKPFurcatus -- blue catfish X

Aplodinotus grunniens -- freshwater drum X

Leiostomus xanthurus -- spot X 132

Micro o onias undulatus

+.---

-- Atlantic croaker X 132

ogonias cromis -- black drum X 132

~;M~~w~M;o~~~~$u;~~ X -- sheepshead X 132

X 2

Paralichthys lethostigma -- southern flounder X 192

Cynoscion arenarius -- sand seatrout X 1

Chasmodes bosquianus -- striped blenny X

Penaeus setlferus -- white shrimp X :,2

Macrobrachium ohfone -- river shrimp X

Callinectes saw-- blue crab X X : 2,7

Rhithropanopmrisii -- mud crab X 7'

Thaws haemastoma -- oyster drill X 6

Eli?iices spp. -- moon shell (possible) X 8

References: (1) Suttkus et al. (1954); (2) Darnell (1958); (3) Gunter and Shell

(1958); (4) Harmon (1962); (5) North Carolina Bureau of Sport Fisheries and

Wildlife (1965); (6) O'Heeron (1966); (7) Cain (1972); (8) Hoese (1973)

whereas juveniles may be distributed 818/m2 in Lake Maurepas, Louisian

more uniformly (Fairbanks 1963). (Tarver and Dugas 1973), and 238/m !?

in Vermilion Bay, Louisiana. Average

density of clams from shallow water

Density areas between the Atchaf

4

laya River and

11.1/m for adults,

The density of clams varies

Sabiye Lake was

14/m for juvenile clams > 10 mm, and

greatly (for reasons discussed later). 28/m2 for juvenile clams < 10 mm

The highest density of adult clams was (Hoese 1973). Densities as high as

4

8
129/l?? were reported in Texas bays

(Odum 1967). A mean density of

250/m2 was reported in the Nueces

River, Texas (Hopkins and Andrews

1970). In Lake Pontchartrain,

Louisiana, mean densities ranged from

2.7 to 31/ 2

1

for large clams and 1807

to 1888/m for juveniles (Fairbanks

1963).

ENVIRONMENTAL REQUIREMENTS

A combination of low salinity,

high turbidity, and a substrate of

sand, mud, and vegetation appears to be

the most favorable habitat for the

common rangia (Tarver 1972). This clam

may be one of the few freshwater clams

to become established in brackish water

(Ladd 1951). Conversely, Remane and

Schlieper (1971) considered comnon

rangia as belonging to a marine group

that has become adapted to brackish

L

water.

Temperature

Winter kills in the shallow waters

of Chesapeake Bay suggest that common

rangia had reached its limit of

temperature tolerance there (Gal lagher

and Wells 1969). Cain (1975) reported

that water temperature was the most

important factor stimulating

gametogenesis. He also stated that the

planktonic existence of larvae is

greatly extended by low temperature.

Salinity

Common rangia are concentrated in

areas where salinity seldom exceeds 18

ppt (Maury 1920; Pulley 1952; Parker

1956, 1960; Mogre 1961; Parker 1966;

Odum 1967; Godcharles and Jaap 1973;

Hoese 1973; Swingle and Bland 1974).

Tarver and Dugas (1973) reported a

negative correlation (r = 0.71) between

density of clams and salinity and a

positive correlation (r = 0.81) between

clam height and salinity (0 to 6 ppt).

*

Godcharles and Jaap (1973) found a

greater number of size classes and

larger clams at low salinities (0 to

2 ppt) than at higher ones in Florida

and suggested that this range was

optimal.

Common rangia have developed physiological responses to the frequent and

sudden salinity changes present in many

estuaries. Common rangia is an

osmoconformer at salinities greater

than 10 ppt, and an osmoregulator at

lower salinities (Bedford and Anderson

1972a,b; Otto and Pierce 1981a,b). A

number of amino acids (including

alanine, glycine, glutamic and

aspartic) are concentrated at high

salinities suggesting that an amino

acid pool is used for osmoregulation

(Simpson et al. 1959; Allen and Awapara

1960; Allen 1961; Anderson and Bedford

1973; Anderson 1975).

Temperature and Salinity

Cain (1972, 1973, 1974) tested the

combined effects of temperature (8 to

32°C) and salinity (0 to 20 ppt) on

embryos and larvae of common rangia.

Embryos failed to develop at 0 ppt

salinity. The optimum conditions for

embryos were temperatures of 18 to 29OC

and salinities of 6 to 10 ppt.

Larvae survived at all

combinations of temperature and

salinity tested (except at 0 ppt).

They tolerate temperatures of 8 to 32°C

and salinities of 2 to 20 ppt. Growth

of larvae was best at high salinity (10

to 20 ppt) and high temperature (20 to

32°C). Straight-hinged larvae were

found to be more tolerant than embryos

to extremes of temperature and

salinity.

Oxygen

Common rangia can withstand anoxic

conditions as reported by Chen and

Awapara (1969) in studies of

glycolysis; however, rangia are

intolerant of exposure to air (Olsen

1976b).

9
Substrate

Common rangia are found in a wide

range of soft substrates in the

northern Gulf of Mexico. Tenore et

al. (19681, who studied the effects of

clay, silt, and sand substrates on the

common rangia,found clay and silt to be

unfavorable, whereas Cain (1975)

commonly found clams in silty-clay

sediments. Parker (1966) found clams

on sand, silt, and clay sediments where

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

in Alabama (Swingle and Bland 1974).

In Louisiana, the numbers of common

rangia were highest in a mixture of

sand, mud, and vegetation (Tarver

1972), whereas in Alabama, dense

populations lived in compacted sandyclay areas (Swingle and Bland 1974).

In Florida, common rangia were

collected from soft mud (Godcharles

and Jaap 1973; Woodburn 19621, but in

Georgia, clams were found in mud or

soft mud-sand combinations (Godwin

1968).

The importance of organic matter

in the sediment to common rangia is

not clear. Fairbanks (1963), who found

the largest densities of rangia in

highly organic sediments in Lake

Pontchartrain, Louisiana, suggested

the large amounts of associated

bacteria helped to attract and support

clams. High organic content in

sediments was also favorable for rangia

in Vermilion Bay, Louisiana (Gooch

1971). However, no correlation existed

between the abundance of common rangia

and the percentage of organic matter in

the sediment at levels below 10% (Hoese

1973). Few clams were found in

sediments with more than 10% organic

matter in Louisiana (Hoese 1973) and

Alabama (Swingle and Bland 1974).

Mortality of rangia can result from

shell erosion, which can be accelerated

in highly aerated sediments in which

carbonic acids are released (Tarver and

Dugas 1973).

The substrate of some coastal

waters is mainly shells which are often

dredged commercially. For example, the

common rangia makes up much of the hard

substrate of Lake Pontchartrain in

Louisiana. The effects of shell

dredging on the substrate and benthos

are too complex and controversial to

discuss in this profile. See Dugas et

;a. ((lT;&)), Taylor (1978), Sikora et

(1982). ’

and Sikora and Sikora

Depth

The highest concentration of clams

along the gulf coast has been

associated with shallow water areas

less than 6 m deep (Tarver 1972; Hoese

1973; Godcharles and Jaap 1973; Tarver

and Dugas 1973; Dugas et al. 1974).

Tarver and Dugas (1973) observed a

general decrease in density as depth

increased from 2.5 to 4.6 m.

Effects of Pollution

Common rangia are known to

concentrate chemicals such as kepone.

Lunsford (1981) reported that peak

kepone levels in common rangia during

summer, in the James River Estuary,

were related to increased metabolism

and feeding rate. The concentration of

kepone was 2 to 4 times greater in

rangia than in the water column

(Lunsford and Blem 1982). The key

factors affecting kepone uptake were

water temperature, dissolved oxygen

concentration, lipid index of clam

tissue, turbidity, kepone concentration

in the water, and the duration of

exposure (Lunsford and Blem 1982).

Kepone is adsorbed by particulate

matter, which enhances its uptake by

filter feeders such as common rangia.

Uptake of oil related products such as

benzopyrene, naphthalenes, and various

aromatic hydrocarbons has also been

reported (Cox 1974; Neff et al. 1976).

All of these compounds were accumulated

primarily in the viscera and fat bodies

of clams under direct exposure and most

were readily released when clams were

.O
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.

11

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16
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17
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18
REPORT DOCUMENTATlON ! 1. “~XMT MO. 2. 2. ~~~pww~ Acc~won NO.

PAGE 1 Biological Report gZ(11.31)

4. ntl. and SuMIfI, % R.Porl Data

Species Profiles: Life Histories and Environmental Requirements

of Coastal Fishes and Invertebrates (Gulf of Mexico) -- Common April 1985

&

Ranqia

7. Author(,)

Mark W. LaSalle and Armando A. de la Cruz

B. fitforming Ot’#w~iz~Cion Name .nd Ad&es,

Department of Biological Sciences

10. Pmisct/Tasb/work Unit No.

P.O. Drawer GY

Mississippi State University

11. bntmCt(C) or Grant(G) No.

Mississippi State, MS 39762 (C)

12. Sponswh# O~anhtlon Name and Address CC)

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

IS. Supplamanta~ Notn

*U.S. Army Corps of Engineers Report No. TR EL-82-4

IL Abatnct Kimit: 2oorrc.r~)

Species profiles are literature summaries of the taxonomy, morphology, range, life

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 salinity (zero to 18 ppt) estuaries along the

northern Gulf of Mexico. The population density of rangia may exceed 1000 clams/m*.

Rangia spawn between March and November, following a sudden rise or fall of salinity

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.

7. Document Analysis l . Descriptors

Estuaries

Clams

Dredging

b. td~ntlfi.n/Q,.n-En&d T.,r,,,

Common rangia Life history

Rangia cuneata Trophic ecology

Salinity requirements Population density

Spawning habits

C. COSATI Field/Grout,

L Availmbllity Statement

Unlimited

. ANSl-239.lSI

19. kcurnty Class (This Report) 21. No. of Pages

Unclassified 16

__-

20. su"'jj@l~'d~i?f~~ 22. Price

OPTIONAL FORM 272 M-7

(Fornnrty NTIS-35)

Der#wtm*nt d Comm8rc*
Species proiiies :

LaSaiie, hark iv.

Research Library

U.S. Department of the Interior

:

National Biological Service

-0 w4

0 Western Energy and Land Use Team

r+--,11,11. rn,,,nc rn__

l LOCatIOns of RegIonal OffIces

Services. Washmgton. UC

X Eastern Energy and Land Use Team

Leetown. WV

+ National Coastal Ecosystems Team

Shdell, LA

REGION 1

Regional Director

U.S. Fish and Wildlife Service

Lloyd Five Hundred Building, Suite 1692

500 N.E. Multnomah Street

Portland, Oregon 97232

REGION 4

Regional Director

U.S. Fish and Wildlife Service

Richard B. Russell Building

75 Spring Street, S.W.

Atlanta, Georgia 30303

REGION 2 REGION 3

Regional Director Regional Director

U.S. Fish and Wildlife Service U.S. Fish and Wildlife Service

P.O. Box 1306 Federal Building, Fort Snelling

Albuquerque, New Mexico 87 103 Twin Cities, Minnesota 55 1 1 I

REGION 5

Regional Director

U.S. Fish and Wildlife Service

One Gateway Center

Newton Corner, Massachusetts 02158

REGION 6

Regional Director

U.S. Fish and Wildlife Service

P.O. Box 25486

Denver Federal Center

Denver. Colorado 80225

REGION 7

Regional Director

U.S. Fish and Wildlife Service

IO1 1 E. Tudor Road

Anchorage, Alaska 99503
DEPARTMENT OF THE INTERIOR

U.S. FISH AND WIlDLIFE SERVICE

As the Nation’s principal conservation agency, the Department of the Interior has responsibility 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 parks and historical places,

and providing for the enjoyment of life through outdoor recreation. The Department assesses 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. abministration.