QL

155

.S63

no.8

11.1

Biological Report 82(11.102)

June 1989

Library

National Wetlands Research Center

I!. S. Fish and Wlldllfz Serwtce

Lafayette, La. 70506

700m

TR EL-82-4

Species Profiles: Life Histories and

Environmental Requirements of Coastal Fishes

and Invertebrates (North and Mid-Atlantic)

BLUE MUSSEL

Coastal Ecology Group

b

Fish and Wildlife Service Waterways Experiment Station

U.S. Department of the Interior U.S. Army Corps of Engineers

Biological Report 82( 11.102)

TR EL-82-4

June 1989

Species Profiles: Life Histories and Environmental Requirements

of Coastal Fishes and Invertebrates (North and Mid-Atlantic)

BLUE MUSSEL

BY

Roger I. E. Newell

Horn Point Environmental Laboratories

University of Maryland

Box 775

Cambridge, MD 21613

Project Officer

David Moran

U.S. Fish and Wildlife Service

National Wetlands Research Center

1010 Gause Boulvard

Slidell, LA 70458

Performed for

Coastal Ecology Group

Waterways Experiment Station

U.S. Army Corps of Engineers

Vicksburg, MS 39180

and

U.S. Department of the Interior

Fish and Wildlife Service

Research and Development

National Wetlands Research Center

Washington, DC 20240
This series may be referenced as follows:

U.S. Fish and Wildlife Service. 1983-19_. Species profiles: life histories and environmental

requirements of coastal fishes and invertebrates. U.S. Fish. Wildl. Serv. Biol. Rep. 82(11). U.S.

Army Corps of Engineers, TR El-82-4.

This profile may be cited as follows:

Newell, R.I.E. 1989. Species profiles: life histories and environmental requirements of coastal fishes

and invertebrates (North and Mid-Atlantic)--blue mussel. U.S. Fish. Wildl. Serv. Biol. Rep.

82(11. 102 ). U.S. Army Corps of Engineers, TR El-82-4. 25 pp.
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 Wetlands Research Center

U.S. Fish and Wildlife Service

NASA-Slidell Computer Complex

1010 Gause Boulevard

Slidell, LA 70458

or

U.S. Army Engineer Waterways Experiment Station

Attention: WESER-C

Post Office Box 63 1

Vicksburg, MS 39 180

. . . 111
square meters (m*)

square kilometers (km’

hectares (ha)

11

10.76

0.3861

2.471

square feet

square miles

acres

liters (1) 0.2642

cubic meters (m3

gallons

35.31 cubic feet

cubic meters (m31 0.0008110 acre-feet

milligrams (mg) 0.00003527 ounces

gr- (g) 0.03527 ounces

kilograms (kg) 2.205 pounds

metric tons (t) 2205.0 pounds

metric tons (t) 1.102 short tons

kilocalories (kcal) 3.968 British thermal units

Celsius degrees (“C) 1.8(“C)+32 Fahrenheit degrees

U.S. Customary to Metric;

inches

inches

feet (ft)

fathoms

statute miles (mi)

nautical miles (nmi)

square feet (ft2)

square miles (mi*)

acres

25.40 millimeters

2.54 centimeters

0.3048 meters

1.829 meters

1.609 kilometers

1.852 kilometers

0.0929 square meters

2.590 square kilometers

0.4047 hectares

gallons (gal) 3.785 liters

cubic feet (ft3) 0.0283 1 cubic meters

acre-feet 1233.0 cubic meters

ounces (02) 28350.0 milligrams

ounces (0~) 28.35 grams

pounds (lb) 0.4536 kilograms

pounds (lb) 0.00045 metreic tons

short tons (ton) 0.9072 metric tons

British thermal units (Btu) 0.2520 kilocalories

Celsius degrees

Mu1 tiply BY To Obtain

millimeters (mm) 0.03937 inches

centimeters (cm) 0.3937 inches

meters (m) 3.281 feet

meters (m) 0.5468 fathoms

kilometers (km) 0.6214 statute miles

kilometers (km) 0.5396 nautical miles

CONVERSION TABLE

Metric to U.S. Customary

Fahrenheit degrees (“F) 0.5556 (“F-32)

iv
CONTENTS

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

CONVERSION TABLE ..........

ACKNOWLEDGMENTS .........

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NOMENCLATURE, TAXONOMY, AND RANGE

MORPHOLOGY AND IDENTIFICATION . . . .

REASON FOR INCLUSION IN SERIES . . . . .

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

Reproductive Physiology. . . . . . . . . . . .

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

Gametes and Fecundity . . . . . . . . . . .

Reproductive Strategy ..........

Larval Development and Behavior ....

Settlement and Juvenile Development . .

Adults .................

GROWTH CHARACTERISTICS. .....

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

Commercial Shellfisheries ........

Population Dynamics ..........

ECOLOGY ................

Feeding and Nutrition ..........

Predators ................

Parasites and Diseases ..........

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

ENVIRONMENTAL REQUIREMENTS . .

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

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

Substrate and Current ..........

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

Anthropogenic Contaminants. ......

LITERATURE CITED . . . . . . . . . . . .

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V
ACKNOWLEDGMENTS

The blue mussel, Mvtilus edulis is often considered to be the “white rat” of the marine

invertebrate zoologist, due to itxkspread distribution and the ease with which it can be

collected and maintained in the laboratory. As a consequence it has been the subject of intense

scientific investigation over the last two decades. This wealth of information has made my task of

assembling this brief review of the biology of the blue mussel on the Atlantic coast of the United

States particularly challenging. Therefore, within the text I have referenced the major reviews of

various aspects of the biology of the blue mussel where interested readers can obtain more detailed

information. In particular, I draw attention to the book Marine Mussels edited by Bayne --3 (1976a),

which provides a comprehensive treatment of many aspects of the biology of Mvtilus edulis.

I am grateful to Dr. Thomas J. Hilbish, Dr. Victor S. Kennedy, Mr. Carter Newell, and Dr. Ray

J. Thompson for reviewing a draft of this manuscript. Debbie Kennedy drew the illustration of the

blue mussel shell.

vi
Byssal and Pedal Muscle

Retractor Posterior

Umbo

Posteri or

Ventra I

Figure 1. Internal and external characteristics of the blue mussel Mytilus edulis.

BLUE MUSSEL

NOMENCLATURE, TAXONOMY, AND from Labrador to Cape Hatteras, North

RANGE Carolina (Wells and Gray 1960), and it is

Scientific name . . . . .Mvtilus edulis Linne 1758

(Abbott 1975)

Preferred common name . . . . . . . . . . blue mussel

(Figure 1)

Other common names . . . . . . mussel, sea mussel

Class . . . . . . . . . . . . . . . . . . . . . Bivalvia (Pelecypoda)

Order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mytiloida

Family. . . . . . . . . . . . . . . . . . . . . ..*.........Mytilidea

common throughout the North Atlantic and

Mid-Atlantic Regions (Figures 2 and 3). It

is most common in the littoral to sublittoral

zones (~99 m) of oceanic and polyhaline to

mesohaline estuarine environments; however,

it has been found in deeper and cooler

waters (100 to 499 m) that enable it to

penetrate as far south as Charleston, South

Carolina (Theroux and Wigley 1983).

Geographic range: The blue mussel is a widely

distributed boreo-temperate species occurring

in the Arctic, North Pacific, and North

Atlantic Oceans (Seed 1976). On the east

coast of North America, its range extends

MORPHOLOGY AND IDENTIFICATION

The shape of the blue mussel shell is

roughly an elongate triangle; the longest dim-
I

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1

I

I

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I

I

i

I

OSTON

%

- CAPE COD

%

A TLANTIC OCEAN

I3 Coastal distribution 1

0N

MILES

0 so 100

0 50 100

KILOMETERS

Figure 2. North Atlantic distribution of the blue mussel

2
PE cNSYLVANIA

ATLANTIC OCEAN

El Coastal distribution

MILES

KILOMETERS

ORTH CAROLINA

Figure 3. Mid-Atlantic distribution of the blue mussel.

3
ension (ca. 7-10 cm) is along an anteriorposterior axis from the narrow beaks of the

umbo to the broad posterior shell margin

(Figure 1). The shell has a sculpture of fine

concentric lines and is dark blue to black in

color. The entire outer surface of the shell is

covered by a shiny proteinaceous membrane,

the periostracum. As this protective

periostracum becomes abraded, especially

toward the umbo, the outer, colored, prismatic

calcitic layer sometimes becomes eroded,

exposing the white, inner, prismatic, aragonitic

layer (Carter 1980). Within any blue mussel

population, a few individuals have shells that

are light brown or have stripes of different

shades of brown. The interior of the shell has

a border of dark blue to violet surrounding the

pearly white nacreous layer.

Blue mussels are semi-sessile epibenthic

bivalves that are anchored to a secure

substrate, or attached to other mussels, with

byssus threads secreted from glands in the

animal’s foot. When the valves are closed, the

byssus threads pass through a small notch, the

pedal gape, in the middle of the ventral

junction of the two valves. The blue mussel

can achieve a limited degree of movement by

secreting new threads and adjusting the

lengths of others. This mobility enables the

animal to reposition itself in relation to water

currents (Yonge 1976), to avoid getting

smothered by accreting sediments (Seed 1976),

and to move toward the outer edge of mussel

clumps (Harger 1968).

The interior anatomy has distinctive

characteristics. The posterior adductor muscle

is much larger than the anterior adductor

muscle. In empty shells, the scars of the

posterior adductor muscle and retractor

muscles (both posterior pedal and byssal

[Yonge 19761) are clearly visible (Figure 1).

In the center of the visceral mass is the

darkly pigmented foot, which can be extended

to secrete a new byssus thread. The mantle,

which extends from either side of the visceral

mass, is attached to the entire periphery of

both valves of the shell. New shell growth is

initiated from the mantle margin (Wilbur and

Saleuddin 1983). In two places posteriorly, the

mantle is modified to form an inhalant and

exhalent siphonal aperture to direct feeding

currents into and out from the mantle cavity.

Blue mussel larvae can be identified on

the basis of both their shell morphometrics

and the position of the ligament (for review

and photomicrographs, see Bayne 1976b). More

positive larval identification can be obtained

by scanning electron microscopic examination

of the dentition on the hinge, which is

distinctly different from that of other bivalve

larvae (Lutz and Hidu 1979).

The only species within the North and

Mid-Atlantic Region that can easily be

mistaken for the blue mussel is the horse

mussel, Modiolus modiolus. Unlike the blue

mussel, the horse mussel has umbonal beaks,

which are not at the apex of the shell but

displaced to one side, and by its larger adult

size (lo-15 cm) and heavier and more eroded

shell. Juvenile horse mussels can be

distinguished from blue mussels by periostracal

“hairs” on the posterior margin of the shell.

The horse mussel is usually found in deeper

oceanic water than the blue mussel and does

not penetrate estuaries. The shells of other

species of mussels, such as the ribbed mussel,

Geukensia m, and the hooked mussel,

Brachidontus recurvus, have numerous ridges

radiating from the umbo towards the posterior

shell margin that clearly distinguish them from

the smooth shell of the blue mussel.

REASON FOR INCLUSION IN SERIES

The blue mussel is a common and often

abundant species in the coastal waters of the

North and Mid-Atlantic Regions, where it is an

important prey item for many animals.

Unfortunately, it is precisely these waters that

are affected most by the increased

urbanization of the Northeastern United States

and the disposal of industrial wastes. In

addition to its ecological importance, the blue

mussel is currently the basis of a resurgent

fishery based on wild stocks and a developing

aquaculture industry throughout the North

Atlantic Region.

LIFE HISTORY

ReDroductive

The blue mussel is diecious, though rare

instances of hermaphroditism have been

4
reported (Seed 1976). Mussels generally

produce gametes and are ready to spawn by

the time they are one year old; however, when

adverse environmental conditions (e.g.,

prolonged periods of exposure to air) cause a

slow rate of growth, sexual maturity is

sometimes not attained until the second year.

Although the gonad is situated within the

visceral mass it extends during the

reproductive period into the mantle, which also

becomes swollen with gametes.

Previtellogenesis (i.e. formation of oogonia and

spermatogonia) occurs during the period from

winter through early spring when food

availability is generally low and feeding

activity is further depressed by low water

temperatures. Energy for gametogenesis during

this period is supplied from nutrient reserves

of glycogen, which are sequestered during the

post-spawning period and stored in the

vesicular cells specialized cells in the

connective tissue of the mantle (reviewed by

Gabbott 1983). The blue mussel sequesters a

separate nutrient reserve in the digestive gland

to supply the energy that sustains metabolic

energy demands during the period of reduced

food intake in the winter. Vitellogenesis, the

final stage of gametogenesis when the

spermatocytes and oocytes are formed, usually

occurs over a comparatively short period of a

few weeks in the late spring, during which the

nucleus enlarges and lipids are synthesized and

stored in the egg yolk (for review see Sastry

1979). Energy for vitellogenesis is supplied

from the remaining glycogen reserves, from

lipid reserves stored in adipogranular cells in

the mantle, and from freshly ingested food

material (Gabbott 1983). The ripe gametes are

then ready to be spawned; if their release is

delayed, they degenerate and are resorbed by

hemocytes.

Gametogenesis, spawning, and nutrient

storage are linked in an integral process

termed the reproductive cycle. This cycle in

any blue mussel population is the result of a

complex balance between exogenous factors

such as food availability, temperature, salinity,

and duration of exposure to air and

endogenous factors such as nutrient reserves,

hormonal cycle, and genotype (Seed 1976;

Sastry 1979). Interaction between these

factors ensures the synchrony of gamete

development within the population. Such

synchrony is essential for an oviparous species

and ensures that larvae are in the water at

the optimum time for their growth and survival

(Sastry 1979).

The timing of the various components of

the reproductive cycle differs greatly between

various blue mussel populations within the

North Atlantic and Mid-Atlantic Regions

(Figure 4: Newell et al. 1982). Newell et al.

(1982) concluded that latitude and water

temperature were not as important as food

availability in governing the reproductive cycle

of the blue mussel along the east coast of the

United States. Thus, it is impossible to

predict the timing of the reproductive cycle

for any particular population. For

environments in which variations in physical

factors are not large --especially those that

influence patterns of phytoplankton production

- it is likely that the reproductive cycle for

the blue mussel is probably rather constant

from year to year (Newell et al. 1982). In

habitats where annual variations in

environmental factors are large, such as in

estuaries with annually variable freshwater

inputs and year to year variations in water

temperature, the reproductive cycle of Mvtilus

edulis can be expected to vary (Thompson

1979,1984a; Lowe et al. 1982).

Soawning

When sperm and eggs are fully ripe they

are released from the follicles in each gonad

into a series of genital canals that gradually

combine into a common gonoduct that opens

on the genital papilla (Bayne 1976b). Eggs and

sperm are liberated via the exhalent siphon

directly into the water column, where

fertilization occurs. About 10,000 spermatozoa

are shed for each ovum spawned (Thompson

1979).

The exact factors that stimulate the first

mussels within a population to spawn are

unknown. However, a prerequisite is the

presence of fully-ripe gametes that are ready

to be liberated. If the gametes are ripe,

spawning may be stimulated by a slight

increase in water temperature or change in

salinity, mechanical disturbance as a result of

wave action, desiccation, or even high

concentrations of phytoplankton in the water

(Seed 1976). Males generally start to spawn

5
1978

Figure 4. Mean reproductive condition of male and female blue mussels through the breeding

season, measured at times designated by solid circles, from seven sites on the east coast of the

United States. The reproductive condition varies between 1.0 for a fully ripe mussel and 0.0 for

one with no discernible gametes. ME = Damariscotta River, Maine; NH = Newcastle, New

Hampshire; MA = Cape Cod Canal, Massachusetts; RI = Narragansett Bay, Rhode Island; SB = Stony

Brook, New York; SHIN = Shinnecock, New York; DE = Broadkill Inlet, Delaware (from Newell et al.

1982).

first; the presence of sperm in the water

then stimulates the females to cease filtering

(Newell and Thompson 1984) and start

spawning. This synchronous spawning ensures

that the sperm and eggs are in the water

column concurrently.

At some localities, a particular set of

environmental conditions enables the blue

mussel to repeatedly spawn (Lowe et al. 1982;

Newell et al. 1982; Rodhouse et al. 1984).

Such spawnings may take the form of mass

spawnings in which an individual mussel

liberates most of its gametes over a short

period. Such spawning is followed by a

refractory period, during which further oocytes

and spermatocytes are developed for the next

spawning. In other situations, no large

numbers of gametes in any one mussel ripen

simultaneously; instead, gametes are continually

ripening and are liberated in a “dribble” spawn.

6
Fertilization requires dribble-spawning from a

number of individuals within the population.

Gametes and Fecundity

The eggs are spherical and 68-70 pm in

diameter; each possesses a vitelline coat OS-l.0

pm thick, and contains numerous lipid droplets

and yolk granules (for review see Bayne

1976b). Accurate measurements of fecundity

are difficult to obtain due to the experimental

difficulties of assessing an individual female’s

output over the entire breeding period.

Estimates obtained by inducing females to

spawn in the laboratory suggest that a large

adult mussel (4-5 cm long) weighing 1

(tissue dry weight) may liberate about 8 x 10g

eggs (Bayne et al. 1978; Thompson 1979).

More accurate fecundity estimates were

obtained by Thompson (1979) from the mantle

weight loss of mussels at three locations on

the east coast of North America, including

Stony Brook, Long Island, which indicate total

fecundities per gram dry tissue weight of 1 x

lo7 eggs for females and 1 .l x lo1 ’ sperm for

males.

Spermatozoa swimming freely in the water

column react on contact with the egg by

extruding an acrosome filament (Bayne 1976b)

that enables the sperm to penetrate the

vitelline coat and initiate meiosis. At 18 OC

the eggs hatch about 5 h after fertilization to

produce a ciliated embryo.

Renroductive Strateay

The large number and small size of eggs

produced by the blue mussel are typical of the

planktotrophic reproductive strategy in which

output is maximized but nutrient investment

per egg is small (for review see Bayne 1976b).

This strategy is generally considered to aid

dispersal as it allows mussels to produce the

maximum number of larvae which require a

prolonged pelagic development period.

However, such a strategy produces an egg with

the barest minimum of nutrient reserves to

enable the larva to develop sufficiently to

start feeding on plankton.

Laboratory experiments of Bayne et al.

(1975, 1978) demonstrated that the viability of

mussel larvae is compromised if the parent is

stressed (e.g., by high temperature, insufficient

food. or pollutants) during gametogenesis and

vitellogenesis. Such reduction in larval

viability is most likely due to less lipid

reserves being apportioned to each egg. If the

adult mussels are stressed during the

reproductively quiescent period or during the

early stages of gametogenesis, the normal

gametogenic cycle is not initiated (Bayne et al.

1982). Mussels that are stressed when ritae

gametes are present begin resorbing the

gametes (Bayne et al. 1982). Thus, a

perturbation of an environmental factor can

reduce the reproductive capacity of a blue

mussel population, even though it occurs

outside of the normal reproductive season and

does not appear to have any adverse effects

on the adult.

Larval Develooment and Behavior

The stages of larval development and

their durations are summarized in Table 1. It

must be emphasized that the larval stage may

last anywhere from 15 to 35 days and that the

duration is dependent on prevailing

environmental conditions. Larvae of blue

mussels from Connecticut developed normally

only within the temperature range of 15-20 OC;

at 15 OC they developed normally in salinities

ranging from 15 to 35 ppt, whereas at 20 oC

they could only develop normally between 20

and 35 ppt (Hrs-Brenko and Calabrese 1969).

Bayne (1965) reported that the trochophore

could develop successfully only in a salinity of

30-40 ppt and at temperatures of 8-18 OC, and

that within this temperature range, the

development rates were fastest at the highest

temperatures. Larvae from an oceanic blue

mussel population grew fastest at 30-32 ppt

and did ‘not grow well at salinities below 24

ppt (Bayne 1965). In contrast, larvae reared

from blue mussels collected from a more

estuarine population continued to develop in

salinities as low as 14 ppt. Innes and Haley

(1977) reported that in blue mussels, the

expression of population and family differences

in growth rate depended on the salinity at

which the larvae were reared. They

interpreted these results to indicate that there

was a significant genotype-environment

interaction during larval development.

These data on the influence of

temperature and salinity on larval growth

demonstrate that larvae are clearly influenced

7
Table 1. Life stages and characteristics of the blue mussel (Bayne 1976b).

Stage Size (length) Age and characteristics

Fertilized egg

Trochophore

Veliger

a) Prodissoconch I

b) Prodissoconch II

c) Eyed Larvae

d) Pediveliger

Plantigrade

Juvenile

Adult

68-70 pm

70-110 pm

1 lo-

-260 pm

220-260 pm

260 pm

0.26- 1.5 mm

Up to 100 mm

O-5 h Non motile.

5-24 h Ciliated and motile.

Up to 35 days; Feeds and

swims with ciliated velum.

Straight-hinged shell.

Umbo on shell.

Development of pigmented ‘eye spots’.

Development of foot.

Up to 6 months; temporarily attached

to filamentous substrates.

Up to 2 years; sexually immature.

Up to 20 years; sexually mature.

by the environmental regime of the parent.

There is some evidence to suggest that

environmental variables interact to affect

survival and growth (Bayne 1983). Also,

tolerance to environmental variation is lower

in the earlier than later larval stages, and

lower in the larvae than the adult. Bayne

(1976b) suggested that the environmental

requirements for embryonic development are a

limiting factor regulating the distribution of

estuarine blue mussel populations.

The first developmental stage is the

ciliated embryo which differentiates within

about 24 h of fertilization to form the

trochophore. Although the trochophore is

motile at this stage, it is non-feeding and thus

still relies on the yolk for nutrient. The

veliger stage is characterized by the

development of a functional mouth and

alimentary system, together with a group of

cilia at the anterior end that enlarge to form

the velum. The ciliated velum serves both to

propel the larva and to filter food particles,

especially nanoplankton. A shell gland

secretes a thin transparent shell, producing the

characteristic “straight hinge” of the

prodissoconch I shell. The veliger continues

to develop and eventually the cells of the

mantle assume their adult role in shell

formation with the initial production of the

prodissoconch II shell, characterized by the

development of a pronounced umbo on the

larval shell. The later stages of veliger

development are characterized by the formation

of a pair of photosensitive pigmented eye spots

and an elongated foot with a byssal gland.

Once the velum is fully developed, the

beating of the large marginal cilia on the

velum can pull the larva spirally upwards

through the water column. If the larva

withdraws the velum into the shell or reduces

the rate of ciliary beating, it sinks. The

veliger is carried passively with ocean and

estuarine currents because it has little ability

to swim horizontally. However, the larvae of

many bivalves (Mileikovsky 1973), including

those of Mvtilus edulis (Bayne 1963, 1964),

alter their swimming behavior in response to

certain key environmental stimuli such as

salinity, gravity, pressure, and light.

Generally, the responses by younger larvae to

environmental factors keeps them in surface

waters. Older larvae tend to sink to the

bottom in response to reduced salinity but

swim upward in response to increasing salinity.

Such behavioral responses have generally been

interpreted as indicating that larvae of

estuarine species respond to the reduction in

salinity that occurs in estuaries on the ebb

tide by dropping out of the net seawardmoving water mass. Once the tide turns, the

bottom salinity increases. Because there is a

net upstream flow in the bottom waters of

8
estuaries, any larvae entrained in this higher

salinity water mass are carried up the estuary

(Wood and Hargis 1971).

Settlement and Juvenile Develooment

When the pediveliger is fully developed, it

extends its foot, makes contact with the

substrate, and searches for a filamentous

material, such as algae and hydroids (Bayne

1976b). On contact with such a substrate the

larva first uses its foot to crawl over the

surface or attach loosely (Bayne 1976b). If

the substrate is suitable, the larva

metamorphoses into the juvenile form, termed

a plantigrade, and attaches with byssus threads

(primary settlement). The plantigrade remains

attached to filamentous substrates until it

reaches a length of about l-l.5 mm. It has

been suggested that this primary settlement

enables the young mussels to grow in an

environment free from the competition for

food and space that can occur in dense mussel

beds (Thorson 1957).

After growing to about 1.5 mm shell

length the plantigrades release themselves from

the filamentous substrate and reenter the

plankton. The extension of the foot and the

attached byssal threads causes the plantigrades

to be passively carried by currents in the

bottom waters (Bayne 1976b). When the

plantigrades contact adult mussels they are

stimulated to produce new byssus threads and

attach themselves to the substrate, or directly

onto the shells of other mussels (Bayne 1976b).

This primary settlement and growth

period of the plantigrades, followed by their

secondary recruitment into the adult

population, makes it difficult to predict exactly

when recruitment to any given mussel

population will occur (Seed 1976). When this

uncertainty is coupled with the wide variation

in the time of spawning in different blue

mussel populations in the North and MidAtlantic Regions, it becomes apparent that

recruitment can occur at almost any time of

the year.

Adults

The blue mussel lives in habitats that

range from flat intertidal shores that drain

slowly to vertical surfaces that are subject to

much wave splash (Seed 1976). In some

localities the penetration of the blue mussel

into the sub-littoral zone is limited by the

presence of various predators (see Predators

section). A primary requisite for the

establishment of a blue mussel population is a

surface for attachment of the byssus threads;

however, the substrate may vary from large

boulders to pebbles or, very frequently, other

mussel shells. In sheltered environments, large

aggregations of mussels sometimes form dense

beds that provide shelter and food (in the

form of copious amounts of biodeposits) for a

variety of other invertebrates. In both these

sheltered environments and exposed shores,

blue mussel clumps sometimes become so thick

that relatively few individuals are attached to

the firm substrate. In such situations, storms

occasionally wash away large sections of the

bed (for review see Seed 1976).

GROWTH CHARACTERISTICS

Blue mussel larvae produced from adults

collected from the North Sea and maintained

at 12 OC grew at an average daily rate of 7.5

pm which was reduced to 3.3 pm when the

amount of food was decreased by 80% (Sprung

1984). Rate of larval growth increased

progressively at temperatures above 5 OC to a

maximum at about 16 OC. Growth was not

reduced by temperatures of up to 20 OC (Bayne

1965); for larvae from parents collected from a

low temperature environment, increases in

temperature above 16 OC reduced growth rates

(Bayne 1965). However, as discussed in both

the Larval Development and the Environmental

Requirements sections, the influence of

temperature is not fixed but varies among

populations as a balance between genetic

composition and previous thermal history.

The size of an adult mussel at any year

during its life can be assessed from the annual

growth bands that are exposed when the shell

is sectioned along the antero-posterior axis

(Lutz 1976). These age-length data can be

used to construct growth curves to which an

exponential equation, such as the generally

accepted Von Bertalanffy growth model, can be

fitted. Such growth data are available for

natural mussel populations from Stony Brook,

Long Island, New York (Rodhouse et al. 1986)

and Bellevue, Newfoundland (Thompson 1984b).

These data (Figure 5) illustrate that the

9
Figure 5. Shell length as a function of age, with the Von Bertalanffy growth model fitted,

for blue mussels from New York (open circles; data from Rodhouse et al. 1986) and from

Newfoundland (solid circles; data from Thompson 1984b).

southern population has a much faster growth

rate for the first two years; however, the

maximum age and size attained by mussels is

only 4-5 years and 5.5 cm in the southern

population but at least 11-12 years and 9.5 cm

in the northern population. Such a dependence

of growth rate on latitude may possibly be a

consequence of the shorter feeding seasons for

northern populations; the increased longevity

of northern mussels may be a result of reduced

metabolism (Seed 1976). On the east coast of

the United States the highest recorded growth

rates of as much as 5 cm per year (or up to

25 times that in natural populations) were

measured in mussels growing continuously

submerged in areas of high food availability,

such as those in raft-based mariculture

operations (Incze and Lutz 1980).

Although shell growth rates are relatively

easy and convenient to measure, Thompson

(1984b) noted that they are biologically less

relevant than estimates of tissue production;

he reported that the maximum dry tissue

biomass (1.07 kg dry tissue weight * mm2) of a

population of blue mussels in Newfoundland

developed in June, before a large proportion of

the production was spawned as gametes. This

estimate is similar to the value of 1.5 - kg mm2

recorded by Nixon et al. (1971) for a mussel

population in Narragansett Bay, Rhode Island.

However, great care must be taken to ensure

that when shell growth rates of blue mussels

are used to estimate tissue growth that there

is no seasonal variation in the allometric

relationship between shell growth and tissue

growth (Hilbish 1986). Frequently in the blue

mussel, as well as in other species of molluscs,

the growth of new shell may be

disproportionately faster than that of tissue;

inaccuracies in production estimates may

result. Hilbish (1986) reported that shell

growth of small blue mussels (~2 cm shell

length) from Long Island Sound, New York,

was greatest from April to June, whereas

tissue growth was greatest in June and July.

10
Thompson (1984b) demonstrated that in

blue mussels from Newfoundland, the majority

of energy was initially partitioned into shell

and somatic growth. As the animal grew

older, progressively larger proportions of the

production was germinal; in the largest

mussels, 94% of the assimilated energy was

used for the production of gametes. Rodhouse

et al. (1986) demonstrated that fecundity was

higher in genetically heterozygous than in

homozygous blue mussels sharing the same

environment.

THE FISHERY

Commercial Shellfisheries

In the United States, the blue mussel has

historically not been considered to be as

delectable as oysters, scallops, or various

species of clams (Clifton 1980); however, due

to intensive marketing efforts over the last

decade it is becoming an increasingly popular

item on seafood restaurant menus throughout

the United States. In Canada and Europe the

blue mussel is considered to be a quality

seafood product and in Spain, France, Holland,

and Italy, it forms the basis of an extensive

commercial mariculture industry (for review see

Mason 1976).

The blue mussel has a number of

characteristics that make it ideal for intensive

commercial mariculture. The high fecundity

and recruitment of natural blue mussel

populations allow small mussels to be collected

from natural seed beds (Incze and Lutz 1980).

The larvae can also be collected directly, at

metamorphosis, on fibrous spat collectors that

provide the filamentous substrate needed for

primary settlement (Mason 1976). Both of

these attributes eliminate the need for

expensive hatchery production of seed, as

required in the oyster mariculture industry of

the west coast of the United States. The

‘ability of mussels to attach to surfaces, such

as ropes, makes it possible to cultivate them

easily ‘off-bottom’ and not in more complex

and expensive suspended racks or cages. This

trait is an important benefit to commercial

mariculture because it eliminates both selffouling from the biodeposits (feces and

pseudofeces) and the incidence of pearls, and

reduces mortality from benthic predators. A

detailed analysis of the technical and financial

aspects of blue mussel mariculture (Lutz 1980)

demonstrated that Mvtilus edulis is a good

candidate for successful shellfish culture in

New England. It grows faster than most

traditional shellfish species, yields a higher

ratio of meat to total weight, and is

nutritionally superior. However, because the

market is still relatively limited, intensive

mariculture of the blue mussel is only a

marginal economic proposition (Clifton 1980).

Currently the economics of the fishery

for wild stocks and part-managed bottom

culture are much better because per-unit

production costs are only about one third

those for off-bottom mariculture (Clifton 1980).

Although the fishery for wild stocks in New

England was thought to be approaching a

maximum sustainable yield (Clifton 1980), the

discovery of new inshore and offshore beds in

Maine and Massachusetts, as well as the

development of certain management practices,

such as thinning wild stocks and moving stocks

between areas to improve meat quality and

yields, has enabled annual harvests to increase

with demand (Table 2). Blue mussels are

generally gathered in the larger commercial

operations by dredging and sorting aboard ship

using a mechanical washer-grader; in smaller

operations they may be harvested in shallow

water by raking or pitchforking them into

small boats before they are transferred to a

larger vessel for mechanical cleaning and

sorting (Chalfant et al. 1980).

The blue mussel harvest on the east coast

of the United States increased gradually during

the decade before 1975 and then rapidly, to

more than 1,400 t of meats, in the late 1970’s

(Clifton 1980). This harvest was the first time

the high level of the early 1940’s was reached,

when the mussel was widely exploited during

World War II (Miller 1980). Currently, most of

the commercial landings of the blue mussel on

the east coast of the United States come from

Maine and Massachusetts, and smaller (annually

variable) amounts from New York, Rhode

Island, and New Jersey (Table 2). The 1986

total harvest of 3,909 t was more than twice

as large as that in 1982 and was worth nearly

$4 million. The lower average unit value of

mussels from Maine, compared with that in

other states, is partly due to the fact that a

substantial portion of Maine’s harvest comes

I1
Table 2. Annual blue mussel landings (metric tons of wet meat weight) and dockside value of the

landings (thousands of dollars) for mussel producing states on the east coast of the United States.

Years with no commercial harvest are designated by NH. Data provided by National Marine

Fisheries Service.

State and item 1979 1980 1981 1982 1983 1984 1985 1986

Maine

Metric tons 1,361 1,058 1,427 1,315 2,018 2,596

Thousands of dollars 716 546 851 835 I,408 1,998

Massachusetts

Metric tons

Thousands of dollars

Rhode Island

Metric tons

Thousands of dollars

New York

Metric tons

Thousands of dollars

New Jersey

Metric tons

Thousands of dollars

88 185 296 409

107 237 444 511

26 45 15 109

43 29 26 504

62 90 51 52

72 112 82 8 1

NH NH 0.14 0.05

0.02 0.08

334 328

510 443

NH NH

52 67

98 117

0.41 2.7

0.39 4.2

Totals

Metric tons 1,537 1,378 1,789.14 1,885.05 2,404.41 2,993.7

Thousands of dollars 938 924 1,403.02 1,931.08 2,016.39 2,562.2

2,762 2,831

2,079 2,307

872 993

1,296 1,441

58 73

258 175

70 1 2

118 27

NH NH

3,762 3,909

3,751 3,950

from unmanaged wild blue mussel beds. The

lower meat yield and the high incidence of

pearls makes these blue mussels generally

inferior to those produced in adjacent managed

bottom culture operations. Such differences in

quality are mainly due to differences in growth

rate, with mussels in natural beds taking over

7 years to attain market size, compared to 2-

5 years in managed bottom culture. The higher

average value of the wild mussels from

Massachusetts and Rhode Island reflects

differences in the environmental conditions in

these two states that leads to faster growth

rates and hence improved meat quality and

overall appearance.

There is recreational hand gathering of

blue mussels in all states north of New Jersey

(Miller 1980); however, little information is

available on the size of this fishery because it

is subject to much less control (by local

ordinances) than are other sport shellfisheries

(e.g., for softshell and hard clams). Perhaps

one reason the sport fishery is not more

important, apart from the lack of public

awareness of the blue mussel, is that large

numbers of blue mussel beds near population

centers are closed because of high coliform

counts (Chalfant et al. 1980). In addition,

there are public concerns about Paralytic

Shellfish Poisoning (PSP), which sometimes

results in neurotoxic symptoms and even death

in humans (Halstead 1965). This poisoning

results from the bioaccumulation by blue

mussels (in common with other suspension

feeding bivalves, such as scallops and clams) of

toxins produced by dinoflagellate algae,

especially of the genus Gonvaulax (for a

review see Yentsch and Incze 1980). These

phytoplankton species, though present

throughout the year, undergo periodic blooms

during the warmer months, when their numbers

increase rapidly. It is only in such situations

that the bivalves can accumulate enough toxins

to cause PSP. In Maine, New Hampshire, and

Massachusetts, state-operated PSP programs

use sensitive bioassays to monitor toxin levels

in the blue mussel at numerous designated

12
sampling stations. In this way the mussel beds

can be closed to harvest before toxin levels

become dangerous (Yentsch and Incze 1980).

Population Dvnamics

A large percentage of the eggs spawned

by the blue mussel may not get fertilized and

large percentages (up to 99) of the larvae that

develop may be eaten prior to metamorphosis

(Bayne 1976b). Despite this high attrition,

blue mussel larvae sometimes are the dominant

component of the zooplankton for short

periods. Fish and Johnson (1937) re orted

larval abundances of more than 25 x 1 0s mm3

during August in the Bay of Fundy.

The blue mussel has a complex

recruitment pattern of primary settlement away

from the adult population, followed by almost

continual gradual recruitment of the

plantigrades into the adult population (Seed

1976). This behavior makes it difficult to

assess the mortality patterns of the juvenile

stages in a population because it is

complicated by immigration and emigration.

Thus, the number of plantigrades in a

population is seasonally and annually variable

but can range from between 20 to 200 cm-2

(Seed 1976).

The mortality pattern of adult blue

mussels depends on site-specific envi:onmental

factors, such as storms, salinity, temperature,

and type of predators (Seed 1976). Thompson

(1984b) reported that in a Newfoundland mussel

population, mortality was highest during the

first 2 years after recruitment. Annual

mortality rate was low (5%-160/b) at

intermediate ages but increased to 91% in blue

mussels over 9 years old.

ECOLOGY

Feeding and Nutrition

The blue mussel, both as a planktotrophic

larva and as an adult, is an active suspension

feeder, deriving its nutrition by filtering

organic particles from the water column.

Phytoplankton cells are the dominant food

source for all life stages (Bayne 1983).

Evidence for the role of detritus in the

nutrition of the blue mussel is equivocal

(Williams 1981), but there is no reason to

suppose that non-refractory organic matter is

not digested in the same way as living cells

(Widdows et al. 1979a). The direct utilization

of refractory detritus varies among species of

bivalves, but is generally low (Newell and

Langdon 1986; Kreeger et al. 1988). Attached

bacteria are a major source of protein in

detritus (Crosby 1987), and there is evidence

that adult blue mussels can digest bacteria

(Birbeck and McHenery 1982).

Both larvae and adults use cilia to

remove food particles from suspension. The

cilia generate a pattern of water flow that

creates complex shear velocities which result

in small-scale regions of high and low

pressure. In the low pressure regions,

particles can be entrained in surface water

currents generated by other cilia, which then

move the particles to oral food grooves

(Jorgensen 1981; Jorgensen et al. 1984). The

particles, entrapped in mucus secreted within

these food groves, are then transported to the

mouth.

In larvae, the ciliated velum is used as

both a swimming and feeding organ (Bayne

1983). Phytoplankton cells ingested by bivalve

larvae must be small (Bayne 1983) because of

the physical constraints of the larval

esophagus, which is about 10 pm wide. In

rearing studies the fastest growth has usually

been recorded in larvae fed a mixture of naked

flagellates (Bayne 1976b), but little information

exists on the natural food of larval blue

mussels. Obviously adequate food of a suitable

size is essential for the survival and

development of larval blue mussels, which have

such sharply limited nutrient reserves. Indeed,

Sastry (1979) postulated that bivalves may time

their reproductive cycle to ensure synchrony

between larval development and a suitable

supply of food. However, larval mussels can

withstand starvation for periods of as long as

10 days (at 16 OC) without adverse side effects

on later development (Bayne 1965).

In adults the gills, which consist of four

demibranchs each comprising numerous ciliated

filaments, constitute the feeding organ as well

as the site for gas exchange. Water enters

the mantle cavity through the inhalant siphon

and is moved through the ostia (the spaces

between adjacent filaments) by the action of

lateral cilia. The water exits from the

13
suprabranchial chamber via the exhalent

siphon. The retention efficiency of the gill is

high for particles larger than 5 pm, but

declines sharply for smaller particles, such that

particles smaller than 2 pm are retained with

low efficiency (Mohlenberg and Riisgard 1978).

Food particles travel in the oral food

grooves to the two pairs of labial palps, which

are ridged sorting organs. The palps of

bivalve molluscs not only serve to control the

total amount of food ingested but also its

organic composition (Newell and Jordan 1983),

so that the ration ingested by the blue mussel

is enriched in organic particles, compared to

the particle composition in the water (Kiorboe

et al. 1980). The material rejected by the

palps, together with some large particles

rejected directly by the gills, form aggregates

loosely bound in mucus. These pseudofeces are

expelled through the inhalant siphon but are

close enough to the exhalent siphon to be

entrained in the current and carried away

(Foster-Smith 1975).

Ingested particles enter the stomach,

where they are subject to a combination of

enzymatic and mechanical attack from the

continuously revolving crystalline style.

Particles are also sorted in the stomach, with

some particles being channeled by ciliary

currents into the digestive diverticula and

others, of possibly lower nutritional value and

in excess of the capacity of the digestive

diverticula to process, constitute the intestinal

feces which are removed by ciliary tracts from

the stomach into the mid-gut. Particles

directed into the ducts of the digestive

diverticula are taken into digestive cells by

endocytosis and are subject to intracellular

digestion for periods of many hours (for

review see Bayne et al. 1976a). Assimilated

material diffuses into the blood system and the

undigested fragments (glandular feces) are

ejected into the duct and thence into the

stomach and mid-gut. At this point, intestinal

and glandular feces are joined into a single

mucus-coated fecal ribbon that passes through

the anus and is carried away in the exhalent

water current.

The volume of water swept completely

clear of particles per unit time is termed the

filtration or clearance rate. The filtration

rate is not constant for any particular weight

of mussel, but is infinitely adjustable between

zero and a size-dependent upper limit. The

actual filtration rate of a mussel at any

particular time is the result of a complex

balance between endogenous factors (e.g.,

energy demands and degree of acclimation to

environmental variables) and exogenous factors.

The only exogenous factor discussed here is

the influence of particle concentration; other

key environmental determinants of filtration

activity (e.g., temperature, salinity, oxygen

tension) are discussed later.

The blue mussel is capable of adjusting

its filtration rate to maintain a complex

balance between the amount of material

filtered, the amount rejected as pseudofeces,

and the amount ingested (for a detailed review

see Bayne and Newell 1983; Bayne et al. 1987).

The animal is not stimulated to feed at

extremely low particle concentrations (ca. <l

mg . 1-l) but filtration increases rapidly with

increasing particle concentration. The

filtration rate reaches a plateau at particle

concentrations of l-5 mg * 1-l and declines to

zero only at particle concentrations over ca.

200 mg * 1-l (Widdows et al. 1979a). Even

though the mussel is capable of filtering large

amounts of material from suspension, the

amount ingested is finite and depends on gut

size (which is a function of body size) and gut

residence time. Increasing proportions of the

filtered material are rejected as pseudofeces at

concentrations above 5 mg . 1-l; the ingestion

rate is highest at concentrations between 5

and 10 mg . 1-l at which point all further

material filtered is rejected as pseudofeces.

The large amounts of material ingested are

first sorted on the palps, ensuring that even in

environments with a low ratio of organic food

to inorganic particles, the animals ingests

predominately organic particles (Kiorboe et al.

1980). Thus, the maintenance of a high

filtration rate, followed by efficient particle

sorting, is not a wasteful strategy because the

energetic costs of filtration are relatively

small, whereas those of digesting the food are

high (Bayne and Newell 1983). Mussels can

compensate for dietary changes by increasing

their ingestion rate, absorption efficiency, and

the efficiency of the digestive process to help

offset decreases in the organic content of the

food (Bayne et al. 1987). However, as with

physiological adaptations to other

environmental perturbations (e.g., temperature)

14
.

‘b

an acclimation period of about 2 weeks is

necessary for the compensation mechanisms to

be fully invoked. Thus, such mechanisms are

likely to be more important in mediating the

mussel’s response to seasonal changes in food

quality, rather than short-term variations

associated with diurnal fluctuations in

phytoplankton populations or resuspension of

sediment by changes in tidal current velocity.

Predators

Predation pressure on the blue mussel is

highest during the 3 weeks when it is a

planktonic larva, for it is then subject to

grazing from a wide variety of species, ranging

from jellyfish to larval and adult fishes. After

metamorphosis, predation can limit the distance

the blue mussel penetrates into the sublittoral zone (Paine 1971, 1974). Generally

predation is highest on the smallest individuals

that have the weakest shells. Once a mussel

has attained a relatively large and thick shell

(4-5 cm) it is vulnerable to attack by only the

strongest predators (e.g., large starfish, large

crustaceans, and some birds).

In some localities, birds are the most

voracious predators of the blue mussel: up to

70% of the net annual production of some

mussel populations in Scotland is eaten by

birds (Milne and Dunnet 1972). On the east

coast of the United States, common avian

predators include some species of diving duck

(e.g., the common eider Somateria mollissima),

various species of gulls, and the American

oystercatcher Haematopus palliatus. The

aquatic predators are decapod crustaceans,

including the American lobster (Homarus

americanus), crabs (e.g., Cancer irroratus,

--, Cancer borealis and Carcinus maenas), starfish

(Asterias sp.), whelks (e.g., Thais lanillus and

Buccinum undatum), and various fish species

(e.g., Tautoaa & and Tautonolabrus

adspersus [Olla et al. 19751). Because most

aquatic predators of the mussel are marine,

low salinity estuarine environments provide a

refuge from predation for adult blue mussels.

Parasites and Diseases

The blue mussel, in common with other

bivalve species, is host to numerous parasites

of many species (Lauckner 1983). In only

isolated instances have extensive blue mussel

mortalities been ascribed to infestation by a

parasite. However, off Prince Edward Island,

Canada, a haplosporidian tentatively identified

as Labvrinthomvxa sp. (Li and Clyburne 1979)

did cause extremely high mortalities.

Generally the host-parasite relation has

evolved to avoid host mortality (Lauckner

1983), although sublethal effects often occur.

For example, the trematode Bucephalus sp.,

which lives in the gonad of the blue mussel,

can castrate both sexes. Although castration

does not affect the host’s survival, it

ultimately can compromise the survival of the

population by reducing fecundity.

The blue mussel is host to a pea crab

macroparasite (Pinnotheres maculatus being

more commonly found than P. ostreum [Schmitt

et al. 19731) which lives firmly attached by its

rear legs to the gill of the bivalve. In this

position, the crab feeds on food particles

traveling in the food grooves and can cause

severe gill damage, resulting in both a

reduction in filtration (Pregenzer 1979) and

metabolic rate (Bierbaum and Shumway 1988).

Pea crabs are generally confined to sublittoral

blue mussel populations south of Cape Cod

where, in some populations, infestation rates

may be as high as 70% (Schmitt et al. 1973;

Bierbaum and Shumway 1988). The spionid

polychaete Polvdora sp. bores its way into the

shell of blue mussel and other molluscs as a

refuge. If the polychaete’s tube penetrates

the inner surface of the shell, the bivalve

seals the perforation with a new layer of

conchyolin and nacre shell, thus forming a

distinct blister (Kent 1979). Blue mussels with

heavy infestations of Polvdora sp. may have

significantly lower tissue weights than those

with lighter infestations (Kent 1979).

Competitors

The adult blue mussel on the east coast

of the United States is a “competitive

dominant,” although the juveniles can be in

competition for settlement space with barnacles

(Seed 1976). Generally, space occupied by blue

mussels becomes available for other species

only as a result of the removal of entire

sections of mussel beds by storms or the

elimination of large numbers of animals by

predators (Seed 1976). Intraspecific competition is high for the blue mussel due to its

1 5
gregarious settling behavior which leads to

extremely high population densities (Thorson

1957). Animals within these dense clumps

consequently must filter water in which food

concentration has been reduced by the feeding

activity of neighboring mussels (Wildish and

Kristmanson 1984; Frechette and Bourget 1985).

Such animals generally do not die, but their

growth rate is reduced until they either

migrate to the outer edge of the clump

(Harger 1968) or the surrounding mussels are

removed by other factors (e.g., wave action or

predators).

ENVIRONMENTAL REQUIREMENTS

The blue mussel typically inhabits littoral

to shallow sublittoral areas in oceanic and

polyhaline to mesohaline estuarine environments. Littoral estuarine environments are the

most variable of all marine systems in such

environmental factors as temperature, salinity,

duration of exposure to air, and concentration

of suspended particles (Newell 1979). The blue

mussel has thus evolved a suite of

sophisticated behavioral, physiological, and

biochemical adaptations that enable it to

survive in such a rigorous environment. These

adaptations make it impossible to define for

the blue mussel a narrow range of

environmental criteria that uniquely describe

its habitat. Moreover, the blue mussel is

subjected to simultaneous fluctuations in a

variety of environmental factors, and its

response is to the total resulting stimulus,

rather than to single environmental variables.

An example of the consequences of such

synergistic interactions is that individuals may

be able to survive either elevated temperatures

or lowered salinities, but cannot survive both

perturbations concurrently.

Temverature

The blue mussel along the east coast of

the United States cannot establish permanent

inshore populations farther south than Cape

Hatteras because the adults are incapable of

surviving in these waters, where summer water

temperatures exceed 27 OC (Wells and Gray

1960). This temperature closely corresponds

with a laboratory estimate of an upper lethal

temperature of 27-29 OC made by Bayne at al.

(1977), who also demonstrated that the upper

lethal temperature response of the blue mussels

depends on the animal’s previous thermal

history. In mussels acclimated to an

intermediate temperature (20 OC) and

transferred to water at 27.5 OC, the “time to

50% mortality” was 350 h, which was about 8

times as long as that of mussels acclimated to

10 OC. Tolerance of elevated temperature was

also affected by reproductive condition; it was

lower in ripe than reproductively quiescent

blue mussels. Bayne et al. (1977) also reported

that a temperature of 30 OC was tolerated by

small mussels (1-2 cm) twice as long as larger

ones (>5 cm).

Blue mussels tolerate low temperatures

for extended periods, even to the extent of

being frozen in ice for up to 8 months each

year in Labrador (Seed 1976). Williams (1970)

demonstrated that the animal could not recover

if its tissue temperature dropped below -10 to

-15 OC. At lower temperatures more than 65%

of the body water freezes, causing irreversible

tissue damage. The northward sublittoral

distributional limit of the species is not

determined by its tolerance of low temperature

because sea water never gets colder than about

-1.5 OC. Instead, it becomes limited by the

requirement for water temperatures above

approximately 5 OC that last long enough to

allow somatic and germinal growth to occur.

This fact emphasizes the necessity for

understanding how a species responds to

typical daily and seasonal temperature

fluctuations within its habitat, in addition to

understanding its tolerance of environmental

extremes in temperature.

Blue mussels are ectothermic organisms, in

which tissue temperatures are determined by

ambient water or air temperatures. Metabolic

processes of the blue mussel are not passively

regulated by environmental temperature

however, as some rate functions can be

adjusted to render them relatively independent

of variations in environmental temperature (see

review by Bayne et al. 1976a; Newell 1979).

The metabolic responses of the blue

mussel to a non-lethal change in temperature

have been separated on the basis of the time

course of the response (Bayne et al. 1976a).

An acute response occurs within the first few

hours after an abrupt change in temperature.

The response is characterized by an alteration

1 6
in rates of oxygen consumption, filtration, etc.,

which are totally dependent on the magnitude

and direction of the temperature fluctuation.

If the change in temperature is maintained the

acute response is superseded, over an

approximately 14-day acclimation period, by a

suite of physiological and biochemical

adaptations that enable the metabolism to

return to near the level prevailing before the

temperature changed (reviewed by Bayne et al.

1976a). If the temperature change represents

a permanent shift in the environment (e.g., the

thermal effluent plume from a power station),

the blue mussel population may have to evolve

genetically. Such genetic adaptations govern

the upper and lower temperature limits.

Widdows (1976) showed that the blue

mussel adjusted its filtration rate completely,

and metabolic rate partly, to a sinusoidal

temperature cycle that varied between 11 and

19 OC every 24 h. The time course of

adaptation was about 14 days, which was

similar to the time required for blue mussels

to adjust to constant changes in temperature.

The final level to which the metabolic rate

and filtration were adjusted was similar to

these levels in animals acclimated to a

constant 15 OC, and intermediate between the

levels recorded for the animals maintained at a

constant 11 OC or 19 OC.

Thompson and Newell (1985) demonstrated

a difference in response to temperature

between latitudinally separated blue mussel

populations. Animals from Long Island Sound,

NY, acclimated their feeding rate to

temperatures within the range of 5-25 OC,

though their metabolic rate did not acclimate

to temperatures above 20 OC. These southern

mussels sustained a positive energy balance,

and only 10% died after 26 days, even at the

near-lethal temperature of 25 OC. Mussels

from near the northern limits of distribution in

Newfoundland acclimated neither their feeding

rate nor their metabolic rate to temperatures

outside the experimental range of 5-20 OC.

They were so severely stressed at 25 OC that

they did not sustain a positive energy balance

and consequently catabolized nutrient reserves;

as a consequence, nearly 50% died within 26

days. Thompson and Newell (1985) explained

these differences as being due to the

differences in exposure to summer water

temperatures, which ranged up to 26 OC in the

south but only from 14 to 17 OC in the north.

Thompson and Newell (1985) suggested

that “it is unsatisfactory to define rigidly a

particular suite of physiological responses to

temperature as characteristic” of a species as

widely distributed as the blue mussel. Instead,

the response of different populations of the

blue mussel to a change in temperature must

be viewed as a complex balance between each

population’s thermal history, food availability,

reproductive condition (Widdows 1978), and

genetic composition.

Salinity

The blue mussel is a euryhaline species

that occurs in environments ranging from full

oceanic salinities (34 ppt) to mesohaline (5-18

ppt) estuarine conditions (Bayne et al. 1976a).

As discussed in the life history section, the

range of salinities that allows normal larval

development may be more restricted than the

range tolerated by adults. Blue mussels are

osmoconforming, i.e., the osmotic pressure of

the intracellular fluids is kept isosmotic with

the medium by the adjustment of the

concentration of free amino acids (Bayne et al.

1976b).

Many estuarine habitats are characterized

by fluctuations in salinity associated with the

normal ebb of low salinity waters from the

estuary and the flood of higher salinity waters

back into the estuary. If the tidal variation

in salinity is small (< 10 ppt), the blue mussel

remains active throughout the salinity

fluctuation (Widdows 1985). In response to a

rapid drop in ambient salinity, such as may

occur with the ebb tide in estuaries with a

large input of fresh water, the blue mussel

first closes its exhalent siphon to stop the

ventilation of the mantle cavity, and then

closes its shell if the salinity change is large

enough (reviewed by Davenport 1982). It can

thus effectively isolate its tissue from up to

half the change in ambient osmotic

concentration (Shumway 1977). Shell closure

cannot be maintained longer than about 96 h

(Gilles 1972) because the animal must rely on

stored nutrient reserves and anaerobic

metabolism to sustain energy demands. If the

change in ambient salinity is not a transient

event, but represents a longer term change in

1 7
environmental conditions, the animal opens its

shell and adjusts osmotically to the ambient

conditions (Bayne et al. 1976b; Widdows 1985)

The genetic basis of some aspects of the

response to salinity change of the blue mussel

from populations in the North and MidAtlantic Regions have been elucidated

(reviewed by Koehn 1983; Koehn and Hilbish

1987). The enzyme aminopeptidase- 1 is

involved in producing some of the free amino

acids that the blue mussel uses to regulate its

intracellular osmotic pressure. There are six

common allozymes of aminopeptidase-1, all of

which have different specific activities. In

oceanic blue mussel populations a

preponderance of individuals produce the

allozyme with the highest specific activity; in

low salinity populations most individuals

produce the allozyme with the lowest specific

activity. Thus, oceanic mussels can more

rapidly produce greater quantities of some of

the amino acids used in mediating their

response to a salinity change. Although larvae

from the high salinity populations can settle in

estuaries, they die within a few months after

settlement (Koehn et al. 1980).

Substrate and Current

The mussel is an epibenthic species that

as an adult lives in areas with substrates

ranging from rock to coarse gravel; even areas

with mud and sand substrates can be colonized

provided that there is a firm surface, such as

a stone or another mussel shell, to which the

byssus threads can be attached. In areas

sheltered from fast currents and high energy

waves, mussels can build dense beds as a

result of their gregarious settlement behavior.

Such beds can become unstable as the

attachment of the lower mussels to firm

surfaces is strained by a large mass of mussels

above them. Eventually such dense beds are

dislodged by wave action during storms and

any mussels that survive have to reattach to

available substrate (Seed 1976).

The blue mussel requires sufficient water

flow to ensure larval dispersal and carry

suspended food particles. It tends to attain a

larger size in sheltered environments than in

more exposed open coast conditions (Seed

1976). This differential size is probably due to

differences in food availability between

habitats and the stunting effect of the

extensive disturbance of feeding and exposure

to air in open coastal populations (Seed 1976).

In addition, predation may be so severe in the

exposed sea coast populations that few mussels

survive into their third year (Seed 1969).

Oxvnen

Oxygen diffuses into the blue mussel

across the gill, where there is close contact

between the water and the hemolymph pumped

through the gill filaments by the heart. There

are no oxygen-carrying pigments in the blood

(Newell 1979). During exposure to air the

blue mussel has only a limited capacity to

utilize atmospheric oxygen because the valves

must be tightly closed to avoid desiccation

(Widdows et al. 1979b). During periods of

shell closure the oxygen in the water retained

in the mantle cavity is used first; thereafter

the animal’s tissues are subject to hypoxic

conditions, and energy requirements are

supplied by anaerobic metabolic pathways

(Gabbott 1976).

Under certain environmental conditions

dissolved oxygen concentrations are reduced in

estuarine and coastal waters with restricted

circulation, due to the high biological oxygen

demand of decomposing organic matter. If the

waters become anoxic, the concentration of

hydrogen sulfide produced is toxic to many

animal species, including the blue mussel.

Theede et al. (1969) reported that under

laboratory conditions the blue mussel survived

35 days in water at 10 OC containing only 0.15

ml 02 . l- ‘, but survival was reduced to 25

days when hydrogen sulfide was present.

In response to a gradual decline in

oxygen content, the blue mussel can increase

its extraction efficiency for oxygen. Oxygen

consumption is thus regulated to be

independent of the availability of

environmental oxygen (Bayne et al. 1976b).

When oxygen availability declines below 60% of

saturation, the mussel is unable to compensate

by further increases in extraction efficiency.

As a consequence, the mussel’s oxygen uptake

declines rapidly, in direct proportion to the

decline in environmental oxygen concentration

(Bayne et al. 1976b). Such a decrease in

oxygen consumption does not necessitate a

reduction in energy production, since anaerobic

1 8
‘k

b

pathways are proportionally induced as

environmental oxygen levels drop below 90% of

saturation (Famme et al. 1981). This use of

anaerobic pathways enables the metabolic rate,

as measured by heat output, to be sustained

near the aerobic rate during brief periods of

shell closure or hypoxia.

Anthroponenic Contaminants

The blue mussel has been the subject of

innumerable studies of its response to

anthropogenic pollutants. Its widespread use

for such studies reflects the broad

geographical distribution of the species and the

fact that it is sessile and intimately exposed

to large volumes of water as a result of its

suspension feeding activities. The animal is

also relatively easy to collect and maintain in

the laboratory. The monitoring of

physiological and biochemical changes in blue

mussels subject to pollution, or the monitoring

of chemicals in the tissue, provides a

biologically relevant method for quantifying

the bioavailability of contaminants in the

environment. The use of the blue mussel for

this purpose was the objective of the

International Mussel Watch Program and

Workshop (National Academy of Sciences 1980)

which is being continued by the U.S. Environmental Protection Agency. An excellent

review of the extensive literature on, and

methods for assessing, the effects of stress

and pollution on marine invertebrates was

compiled by Bayne et al. (1985).

One general conclusion from these studies

must be emphasized. Much of the original

pollution research was designed to determine

the time or concentration of contaminants

required to cause a 50% mortality in a test

population. Such studies generally involved

concentrations that greatly exceeded those

commonly found in the environment. Recent

studies, pioneered with the blue mussel as a

test species, have emphasized the sublethal

effects of pollutants. That is, adults might

not die, or even be obviously affected, as a

result of exposure to a contaminant, but

certain aspects of their physiology might be

disrupted. If this disruption is prolonged, it

can (for example) reduce the energy that

individuals have available to partition into

somatic and germinal growth. As reviewed in

the reproductive strategy section above, any

reduction in the nutrient reserves of the egg

can reduce larval viability. Thus the stress on

the adult is likely to ultimately affect the

viability of the population by reducing

recruitment.

1 9

LITERATURE CITED

‘

‘it.

Abbott, R.T. 1975. American Seashells, 2nd ed.

Van Nostrand Reinhold, New York. 568 pp.

Bayne, B.L. 1963. Responses of Mvtilus edulis

larvae to increases in hydrostatic pressure.

Nature (Lond.) 198:406-407.

Bayne, B.L. 1964. The responses of the larvae

of Mvtilus edulis L. to light and gravity.

Oikos 15:162-174.

Bayne, B.L. 1965. Growth and the delay of

metamorphosis of the larvae of Mvtilus

edulis L. Ophelia 2: l-47.

Bayne, B.L. ed., 1976a. Marine mussels: their

ecology and physiology. Cambridge University

Press, New York. 506 pp.

Bayne, B.L. 1976b. The biology of mussel

larvae. Pages 81-120 ti B.L. Bayne, ed.

Marine mussels: their ecology and physiology.

Cambridge University Press, New York.

Bayne, B.L. 1983. Physiological ecology of

marine molluscan larvae. Pages 299-342 ti

N.H. Verdonk, J.A.M. van den Biggelar, and

A.S. Tompa, eds. The Mollusca. Volume 3.

Development. Academic Press, New York.

Bayne, B.L., and R.C. Newell. 1983.

Physiological energetics of marine molluscs.

Pages 407-515 h A.S.M. Saleuddin and K.M.

Wilbur, eds. The Mollusca. Vol. 4. Physiology,

Part 1. Academic Press, New York.

Bayne, B.L., P.A. Gabbott, and J. Widdows.

1975. Some effects of stress in the adult on

the eggs and larvae of Mvtilus edulis L. J.

Mar. Biol. Assoc. U.K. 55:675-689.

Bayne, B.L., R.J. Thompson, and J. Widdows.

1976a. Physiology I. Pages 121-206 b B.L.

Bayne, ed. Marine mussels: their ecology and

physiology. Cambridge University Press, NY.

Bayne, B.L., J. Widdows, and R.J. Thompson.

1976b. Physiological integrations. Pages 261-

291 b B.L. Bayne, ed. Marine mussels: their

ecology and physiology. Cambridge University

Press, New York.

Bayne, B.L., J. Widdows, and C. Worrall. 1977.

Some temperature relationships in the

physiology of two ecologically distinct

bivalve populations. Pages 379-400 ti F.J.

Vernberg, A. Calabrese, F. Thurnberg and W.

Vernberg, eds. Physiological responses of

marine biota to pollutants. Academic Press,

New York.

Bayne, B.L., D.L. Holland, M.N. Moore, D.M.

Lowe, and J. Widdows. 1978. Further studies

on the effects of stress in the adult on the

eggs of Mvtilus edulis. J. Mar. Biol. Assoc.

U.K. 58:825-841.

Bayne, B.L., A. Bubel, P.A. Gabbott, D.R.

Livingstone, D.M. Lowe, and M.N. Moore.

1982. Glycogen utilisation and gametogenesis

in Mvtilus edulis L. Mar. Biol. Lett. 3:89-105.

Bayne, B.L., D.A. Brown, K. Burns, D.R. Dixon,

A. Ivanovici, D.R. Livingstone, D.M. Lowe,

M.N. Moore, A.R.D. Stebbing, and J.

Widdows. 1985. The effects of stress and

pollution on marine animals. Praeger Press,

New York. 384 pp.

Bayne, B.L., A.J.S. Hawkins, and E. Navarro.

1987. Feeding and digestion by the mussel

Mvtilus edulis L. (Bivalvia: Mollusca) in

mixtures of silt and algal cells at low

concentrations. J. Exp. Mar. Biol. Ecol.

lll:l-22.

Bierbaum, R., and S.E. Shumway. 1988.

Feeding and oxygen consumption in mussels,

Mvtilus edulis with and without pea crabs,

Pinnotheresmaculatus. Estuaries. 11:264-271.
Birbeck, T.H., and J.G. McHenery. 1982.

Degradation of bacteria by Mvtilus edulis -*

Mar. Biol. 72:7-15.

Carter, G.A. 1980. Selected mineralogical data

for the Bivalvia. Pages 627-643 b D.A.

Rhoads and R.A. Lutz, eds. Skeletal growth

of aquatic organisms. Plenum Press, New

York.

Chalfant, J.S., T. Archambault, and A.E. West.

1980. Natural stocks of mussels: growth,

recruitment and harvest potential. Pages 38-

68 ti R.A. Lutz, ed. Mussel culture and

harvest: a North American perspective.

Elsevier Scientific Publishing, Amsterdam,

Holland.

Clifton, J.A. 1980. Some economics of mussel

culture and harvest. Pages 312-338 b R.A.

Lutz, ed. Mussel culture and harvest: a

North American perspective. Elsevier

Scientific Publishing, Amsterdam, Holland.

Crosby, M.P. 1987. Utilization of detrital

complexes by the oyster Crassostrea virninica

(Gmelin). Ph.D. Thesis. University of

Maryland, College Park. 175 pp.

Davenport, J. 1982. Environmental simulation

experiments upon marine and estuarine

animals. Adv. Mar. Biol. 19:133-256.

Famme, P., J. Knudsen, and E.S. Hansen. 198 1.

The effect of oxygen on the aerobicanaerobic metabolism of the marine bivalve,

Mvtilus edulis Mar. Biol. Lett. -* 2:345-351.

Fish, C.J., and M.W. Johnson. 1937. The

biology of the zooplankton in the Bay of

Fundy and Gulf of Maine with special

reference to production and distribution. J.

Biol. Board Can. 3:189-322.

Foster-Smith, R.L. 1975. The effect of

concentration of suspension on the filtration

rates and pseudofaecal production for

Mvtilus edulis L., Cerastoderma m(L.) and

Venerupis pullastra (Montagu). J. Exp. Mar.

Biol. Ecol. 17: l-22.

Frechette, M., and E. Bourget. 1985. Energy

flow between the pelagic and benthic zones:

factors controlling particulate organic matter

available to an intertidal mussel bed. Can. J.

Fish. Aquat. Sci. 42:1158-l 165.

Gabbott, P.A. 1976. Energy metabolism. Pages

293-355 h B.L. Bayne, ed. Marine mussels:

their ecology and physiology. Cambridge

University Press, New York.

Gabbott, P.A. 1983. Developmental and

seasonal metabolic activities in marine

molluscs. Pages 165-217 b P.W. Hochachka,

ed. The Mollusca. Volume 2. Environmental

biochemistry and physiology. Academic Press,

New York.

Gales, R. 1972. Osmoregulation in three

molluscs: Acanthochitona discreoans (Brown),

Glvcvmeris nlvcvmeris (L.) and Mvtilus edulis

L. Biol. Bull. (Woods Hole) 142:25-35.

Halstead, B.W. 1965. Poisonous and venomous

animals of the world, Volume I.

Invertebrates. U.S. Government Printing

Office, Washington, DC 994 pp.

Harger, J.R.E. 1968. The role of behavioral

traits in influencing the distribution of two

species of sea mussel, Mvtilus edulis and M.

californianus. Veliger 11:45-49.

Hilbish, T.J. 1986. Growth trajectories of shell

and soft tissue in bivalves: seasonal variation

in Mytilus edulis L. J. Exp. Mar. Biol. Ecol.

96:103-113.

Hrs-Brenko, M., and A. Calabrese. 1969. The

combined effects of salinity and temperature

on larvae of the mussel Mvtilus edulis Mar. -.

Biol. (Berl.). 4:224-226.

Incze, L.S., and R.A. Lutz. 1980. Mussel

culture: an East Coast perspective. Pages 99-

140 h R.A. Lutz, ed. Mussel culture and

harvest: a North American perspective.

Elsevier Scientific Publishing, Amsterdam,

Holland.

Innes, D.J., and L.E. Haley. 1977. Genetic

aspects of larval growth under reduced

salinity in Mvtilus edulis. Biol. Bull. (Woods

Hole). 153:312-321.

Jorgensen, C.B. 198 1. A hydromechanical

principle for particle retention in Mvtilus

33
edulis and other ciliary feeders. Mar. Biol.

61:277-282.

Jorgensen, C.B., T. Kiorboe, F. Mohlenberg,

and H.U. Riisgard. 1984. Ciliary and mucusnet filter feeding, with special reference to

fluid mechanical characteristics. Mar. Ecol.

Prog. Ser. 15283-292.

Kent, R.M.L. 1979. The influence of heavy

infestations of Polvdora Filiata on the flesh

content of Mvtilus edulig. J. Mar. Biol.

Assoc. U.K. 59289-297.

Kiorboe, T., F. Mohlenberg, and 0. Nohr. 1980.

Feeding, particle selection and carbon

absorption in Mvtilus edulis in different

mixtures of algae and resuspended bottom

material. Ophelia 19193-205.

Koehn, R.K. 1983. Biochemical genetics and

adaptation in molluscs. Pages 305-330 b P.W.

Hochachka, ed. The Mollusca. Volume 2.

Environmental biochemistry and physiology.

Academic Press, New York.

Koehn, R.K., and T.J. Hilbish. 1987. The

biochemical genetics and physiological

adaptations of an enzyme polymorphism. Am.

Sci. 75:134-141.

Koehn, R.K., R.I.E. Newell, and F.W.

Immermann. 1980. Maintenance of an

aminopeptidase allele frequency cline by

natural selection. Proc. Natl. Acad. Sci.

U.S.A. 77:5385-5389.

Kreeger, D., C.J. Langdon, and R.I.E. Newell.

1988. Utilization of refractory cellulosic

carbon derived from Soartina alterniflora by

the ribbed mussel, Geukensia demissa. Mar.

Ecol. Prog. Ser. 42:171- 179.

Lauckner, G. 1983. Diseases of Mollusca:

Bivalvia. Pages 477-961 h 0. Kinne, ed.

Diseases of marine animals. Volume II.

Biologische Anstalt Helgoland, Hamburg, West

Germany.

Li, M.F., and S. Clyburne. 1979. Mortalities of

blue mussels (Mvtilus edulis) in Prince

Edward Island. J. Invert. Pathol. 33:108-l 10.

Lowe, D.M., M.N. Moore, and B.L. Bayne. 1982.

Aspects of gametogenesis in the marine

mussel Mvtilus &,l!& L. J. Mar. Biol. Assoc.

U.K. 62:133-145.

Lutz, R.A. 1976. Annual growth patterns in

the inner shell layer of Mvtilus edulis L. J.

Mar. Biol. Assoc. U.K. 56:723-731.

Lutz, R.A., ed. 1980. Mussel culture and

harvest: a North American perspective.

Elsevier Scientific Publishing, Amsterdam,

Holland. 350 pp.

Lutz, R.A., and H. Hidu. 1979. Hinge

morphogenesis in the shells of larval and

early post-larval mussels (Mvtilus edulis L.

and Modiolus modiolus (L.)). J. Mar. Biol.

Assoc. U.K. 59111-121.

Mason, J. 1976. Cultivation. Pages 385-410 jg

B.L. Bayne, ed. Marine mussels: their ecology

and physiology. Cambridge University Press,

New York.

Mileikovsky, S.A. 1973. Speed of active

movement of pelagic larvae of marine bottom

invertebrates and their ability to regulate

their vertical position. Mar. Biol. 23:11-17.

Miller, B.A. 1980. Historical review of U.S.

mussel culture and harvest. Pages 18-37 ti

R.A. Lutz, ed. Mussel culture and harvest: a

North American perspective. Elsevier

Scientific Publishing, Amsterdam, Holland.

Milne, H.A., and G.M. Dunnet. 1972. Standing

crop, productivity and trophic relations of

the fauna of the Ythan estuary. Pages 86-

106 in R.S.K. Barnes and J. Green, eds. The

estua?rne environment. Associated Scientific

Publishers, Amsterdam.

Mohlenberg, F. and H.U. Riisgard. 1978.

Efficiency of particle retention in 13 species

of suspension feeding bivalves. Ophelia

17:239-246.

National Academy of Sciences. 1980. The

International Mussel Watch. National

Academy of Sciences, Washington, D.C. 248

PP.

National Marine Fisheries Service, Office of

Data and Information Management,

Washington, DC.

23
Newell, R.C. 1979. Biology of intertidal animals.

Marine Ecological Surveys Ltd., Faversham,

U.K. 781 pp.

Newell, R.I.E., and S.J. Jordan. 1983.

Preferential ingestion of organic material by

the American oyster, Crassostrea virninica.

Mar. Ecol. Prog. Ser. 13:47-53.

Newell, R.I.E., and C.J. Langdon. 1986.

Digestion and absorption of refractory

carbon from the plant Spartina alterniflora

by the oyster Crassostrea virninica. Mar.

Ecol. Prog. Ser. 34105-115.

Newell, R.I.E. and R.J. Thompson. 1984.

Reduced clearance rates associated with

spawning in the mussel, Mvtilus edulis (L.)

(Bivalvia, Mytilidae). Mar. Biol. Lett. 521-33.

Newell, R.I.E., T.J. Hilbish, R.K. Koehn, and

C.J. Newell. 1982. Temporal variation in the

reproductive cycle of Mvtilus edulis

(Bivalvia, Mytilidae) from localities on the

east coast of the United States. Biol. Bull.

(Woods Hole) 162299-310.

Nixon, SW., C.A. Oviatt, C. Rogers, and K.

Taylor. 197 1. Mass and metabolism of a

mussel bed. Oecologia (Berl.) 8:21-30.

Olla, B.L., A.J. Bejda, and A.D. Martin. 1975.

Activity, movements, and feeding behavior of

the Cunner, Tautoaolabrus adspersus, and

comparison with young Tautog, Tautoea

onitis off Long Island, New York. Fish.

Bull.,‘U.S. 73:895-900.

Paine, R.T. 1971. A short term experimental

investigation of resource partitioning in a

New Zealand rocky intertidal habitat.

Ecology 521096-l 106.

Paine, R.T. 1974. Intertidal community

structure. Experimental studies on the

relationship between a dominant competitor

and its principal predator. Gecologia (Berl.)

15:93-120.

Pregenzer, C. 1979. Effect of Pinnotheres

hickmani on neutral red clearance by Mvtilus

edulis. Aust. J. Mar. Freshwater Res. 30:547-

550.

Rodhouse, P.G., C.M. Roden, M.P. Hensey, T.

McMahon, B. Ottway, and T.H. Ryan. 1984.

Food resource, gametogenesis and growth of

Mvtilus edulis on the shore and in suspended

culture: Killary Harbour, Ireland. J. Mar.

Biol. Assoc. U.K. 64:513-529.

Rodhouse, P.G., J.H. McDonald, R.I.E. Newell,

and R.K. Koehn. 1986. Gamete production,

somatic growth and multiple-locus enzyme

heterozygosity in Mvtilus edulis. Mar. Biol.

(Berl.) 90:209-214.

Wtry, A.N. 1979. Pelecypoda (excluding

Gstreidae). Pages 113-292 h A.C. Giese and

J.S. Pearse, eds. Reproduction of marine

invertebrates. Volume V. Academic Press,

New York.

Schmitt, W.L., J.C. McCain and E.S. Davidson.

1973. Decapoda I., Brachura I, Family

Pinnotheridae. h H.-E.Gruner and L.B.

Holthuis, eds. Crustaceorum Catalogus. Part

3. Dr. W. Junk bv Publishers, the Hague.

160 pp.

Seed, R. 1969. The ecology of Mvtilus edulis

L. (Lamellibranchiata) on exposed rocky

shores. 2. Growth and Mortality. Oecologia

(Berl.) 3:317-350.

Seed, R. 1976. Ecology. Pages 13-65 ti B.L.

Bayne, ed. Marine mussels: their ecology and

physiology. Cambridge University Press, New

York.

Shumway, S.E. 1977. Effect of salinity

fluctuation on the osmotic pressure and Na+,

Ca2+ and Mg2+ ion concentrations in the

haemolymph of bivalve molluscs. Mar. Biol.

(Berl.) 41:153-177.

Sprung, M. 1984. Physiological energetics of

mussel larvae (Mvtilus eduliq). I. Shell

growth and biomass. Mar. Ecol. Prog Ser.

17:283-293.

Theede, H., A. Ponat, K. Hiroki, and C.

Schlieper. 1969. Studies on the resistance of

marine bottom invertebrates to oxygendeficiency and hydrogen sulphide. Mar. Biol.

(Berl.) 2325-337.

Theroux, R.B., and R.L. Wigley. 1983.

Distribution and abundance of east coast

24
bivalve molluscs based on specimens in the

National Marine Fisheries Service Woods

Hole collection. NOAA technical report

NMFS SSRF-768. US Government Printing

Office, Washington, D.C.

Thompson, R.J. 1979. Fecundity and

reproductive effort in the blue mussel

(Mvtilus edulis), the sea urchin

(Stronpvlocentrotus droebachiensis), and the

snow crab (Chionoecetes opilio) from

populations in Nova Scotia and

Newfoundland. J. Fish. Res. Board Canada.

36955-964.

Thompson, R.J. 1984a. The reproductive cycle

and physiological ecology of the mussel

Mvtilus edulis in a subarctic, non-estuarine

environment. Mar. Biol. (Berl.) 79:277-288.

Thompson, R.J. 1984b. Production, reproductive

effort, reproductive value and reproductive

cost in a population of the blue mussel

Mvtilus edulis from a subartic environment.

Mar. Ecol. Prog. Ser. 16249-257.

Thompson, R.J., and R.I.E. Newell. 1985.

Physiological responses to temperature in

two latitudinally separated populations of the

mussel, Mvtilus edulis. Pages 48 l-495 h P.E.

Gibbs, ed. Proceedings nineteenth European

Marine Biology Symposium. Cambridge

University Press, Cambridge, U.K.

Thorson, G. 1957. Bottom communities

(sublittoral or shallow shelf). Mem. Geol.

Sot. Am. 67:461-534.

Wells, H.W., and I.E. Gray. 1960. The seasonal

occurrences of Mvtilus edulis on the Carolina

coast as a result of transport around Cape

Hatteras. Biol. Bull. (Woods Hole) 119:550-

559.

Widdows, J. 1976. Physiological adaptations of

Mvtilus edulis L. to fluctuating temperatures.

J. Comp. Physiol. 105:115-128.

Widdows, J. 1978. Combined effects of body

size, food concentrations and season on the

physiology of Mvtilus edulis. J. Mar. Biol.

Assoc. U.K. 58:109-124.

Widdows, J. 1985. The effect of fluctuating

and abrupt changes in salinity on the

performance of Mvtilus edulis L. Pages 555-

566 h J.S. Gray and M.E. Christiansen, eds.

Marine biology of polar regions and effects

of stress on marine organisms. John Wiley,

London.

Widdows, J., P. Fieth, and C.M. Worrall. 1979a.

Relationship between seston, available food

and feeding activity in the common mussel

Mvtilus edulis. Mar. Biol. (Berl.) 50~195-207.

Widdows, J., B.L. Bayne, D.R. Livingstone,

R.I.E. Newell, and P. Donkin. 1979b.

Physiological and biochemical responses of

bivalve molluscs to exposure to air. Comp.

Biochem. Physiol. A. 62301-308.

Wilbur, K.M., and A.S.M. Saleuddin. 1983. Shell

formation. Pages 235-287 h A.S.M. Saleuddin

and K.M. Wilbur, eds. The Mollusca Volume

4. Physiology, Part 1. Academic Press, New

York, N.Y.

Wildish, D.J., and D.D. Kristmanson. 1984.

Importance to mussels of the benthic

boundary layer. Can. J. Fish. Aquat.

11:1618-1625.

Williams. P. 1981. Detritus utilization

Estuarine Coastal Shelf Mvtilus edulis.

12:739-746.

Sci.

by

Sci.

Williams, R.J. 1970. Freezing tolerance in

Mvtilus edulis. Comp. Biochem. Physiol.

35:145-161.

Wood, L., and W.J. Hargis. 1971. Transport of

bivalve larvae in a tidal estuary. Pages 29-44

in D.J. Crisp, ed. Fourth European Marine

Biology Symposium. Cambridge University

Press, London.

Yentsch, C.M., and L.S. Incze. 1980.

Accumulation of algal biotoxins in mussels.

Pages 223-246 ti R.A. Lutz, ed. Mussel

culture and harvest: a North American

perspective. Elsevier Scientific Publishing,

Amsterdam, Holland.

Yonge, C.M. 1976. The ‘mussel’ form and

habit. Pages 1-12 ti B.L. Bayne, ed. Marine

Mussels: their ecology and physiology.

Cambridge University Press, New York.

25
171-101

!EpoRl GOCUYENTATION 1. “Emm No. 2 3. R.clg(wt’s Accession No.

PAGE Biological Report 82(11.102)

ritl. and subtltl* 5. R*moon oat.

Species Profiles: Life Histories and Environmental Requirements of June 1989

Coastal Fishes and Invertebrates (Mid and North Atlantic)-blue mussel 6.

Author(*) a P*r(orminS orz~niz*tion Reti. NO

Roger I. E. Newell

hrfownln# OrSanlzation Name and Address 10. Pmiwt/lask/Work Unit No.

Horn Point Environmental Laboratories

University of Maryland 11. t&tract(C) or Crwat(G) No.

Box 775 (0

Cambridge, Maryland 2 163 1 (G) ?.. smroriry OrSanlratlon Name and Addnss

F

13. Typa d Ropoort 6 Period C-red

U.S. Dept. of the Interior U.S. Army Corps of Engineers

Fish and Wildlife Service P. 0 Box 631

National Wetlands Research Center Vicksburg, MS 39180 14.

Washington, D.C. 20240

5. tupplamentwy Notes

5. Abstract (Limit: 200 words)

The blue mussel, Mvtilus g&& L. is a widely distributed and locally abundant bivalve mollusc in the

North and Mid-Atlantic Regions. It is a valuable commercial species; regional landings in 1986 were

worth nearly $4 million. It is a semi-sessile species, anchored by byssus threads to firm surfaces in

littoral and sub-littoral environments at salinities ranging from 5 to 35 ppt. It is a suspension feeder,

ingesting phytoplankton and detrital particles in the size range of 3-30 pm. The geographical range of

the species is limited by lethal water temperatures above 27 OC in the south and by temperatures too low

for growth and reproduction in the north. Animals from the northern end of the range are stressed by

temperatures above 20 OC, whereas those near the southern distributional limit are not severely stressed

by temperatures as high as 25 OC. The blue mussel is diecious and oviparous. The planktotrophic larvae

take about 3 weeks to develop and metamorphose. The environmental tolerances of larvae are more

restricted than those of adults. The juveniles grow to approximately 1.5 mm while attached to

filamentous algae before being carried by water currents to reattach to a firm substrate, often close to

adult mussels. Larval and adult blue mussels are important prey items for many animals, including crabs,

fishes, and birds.

7. Docununt Analysis l . D8sctiptorr

Mussels

Estuaries

Life cycles

b. IdwMien/Open.End~d Terms

Blue Mussel

Mvtilus &&

e. COSATl FieldlGmup

L AvailabIlity Statement 19. Security Class CThis Rcpwt) 21. No. o( Paa.9

Unclassified 25

Unlimited - -

se. %curity Class CThis Pace) 22. Price

Unclassified

” ANSl-239.11)) OPTtONAL FORM 272 (671

(Fomwrty NTIS-35)

00partnnnt 0( Commwxe
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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 the environmental and cultural values of our

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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.

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