QL

155

.S63

Biological Report 82(1 l-125) TR EL-82-4

December 1989

Species Profiles: Life Histories and

Environmental Requirements of Coastal Fishes

and Invertebrates (Pacific Southwest)

CRANGONID SHRIMP

no. 82-

11.125

Fish and Wildlife Service

U.S. Department of the Interior

Coastal Ecology Group

Waterways Experiment Station

U.S. Army Corps of Engineers

.

Biological Report 82(11.125)

TR EL-82-4

December 1989

Species Profiles: Life Histories and Environmental Requirements

of Coastal Fishes and Invertebrates (Pacific Southwest)

CRANGONID SHRIMP

bY

Clifford A Siegfried

Biological Survey

New York State Museum and Science Service

Albany, NY 12230

Project Officer

David Moran

U.S. Fish and Wildlife Service

National Wetlands Research Center

1010 Gause Boulevard

Slidell, LA 70458

Performed for

U.S. Army Corps of Engineers

Coastal Ecology Group

Waterways Experiment Station

Vicksburg, MS 39180

and

U.S. Department of the Interior

Fish and Wildlife Service

Research and Development

National Wetlands Research Center

Washington, DC 20240
DISCLAIMER

The mention of trade names does not constitute endorsement or recommendation for use by the

Federal Government.

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:

Siegfried, CA 1989. Species profiles: life histories and environmental requirements of coastal fishes

and invertebrates (Pacific Southwest)--crangonid shrimp. U.S. Fish Wildl. Serv. Biol. Rep.

82(11.125). U.S. Army Corps of Engineers, TR EL-82-4. 18 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 Gnanccd 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

U.S. Fish and Wildlife Service

National Wetlands Research Center

NASA-Slide11 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 39180

. . .

111
CONVERSION TABLE

Multiply BY To Obtain

millimeters (mm)

centimeters (cm)

meters (m)

meters

kilometers (km)

kilometers

square meters (m’)

square kilometers (km2)

hectares (ha)

0.03937 inches

0.3937 inches

3.281 feet

0.5468 fathoms

0.6214 statute miles

0.5396 nautical miles

10.76 square feet

0.3861 square miles

2.471 acres

liters (1) 0.2642

cubic meters (m3)

gallons

35.31 cubic feet

cubic meters 0.0008110 acre-feet

milligrams (mg) 0.00003527 ounces

grams (g) 0.03527 ounces

kilograms (kg) 2.205 pounds

metric tons (t) 2205.0 pounds

metric tons 1.102 short tons

kilocalories (kcal)

Celsius degrees (” C)

inches

inches

feet (ft)

fathoms

statute miles (mi)

nautical miles (nmi)

square feet (ft2)

square miles (mi2)

acres

3.968

1.8(“C)+32

U.S. Customary to Metric

25.40

2.54

0.3048

1.829

1.609

1.852

British thermal units

Fahrenheit degrees

millimeters

centimeters

meters

meters

kilometers

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 (oz) 28350.0 milligrams

ounces 28.35 grams

pounds (lb) 0.4536 kilograms

pounds 0.00045 metric tons

short tons (ton) 0.9072 metric tons

British thermal units (Btu) 0.2520 kilocalories

Fahrenheit degrees (” F) 0.5556 (” F - 32) Celsius degrees

Metric to U.S. Customary

iv
CONTENTS

Page

PREFACE ..........................................................111

CONVERSION TABLE ............................................. iv

ACKNOWLEDGMENTS ............................................ vi

NOMENCLATURE/TAXONOMY/RANGE ............................... 1

MORPHOLOGY/IDENTIFICATION AIDS ............................... 1

REASON FOR INCLUSION IN SERIES ................................. 4

LIFE HISTORY ................................................... 4

Spawning and Larvae .............................................. 4

Postlarvae and Juveniles ............................................ 5

Migrations ......................... 6

Adults ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . ......................... 6

GROWTH ....................................................... 7

Mortality ...................................................... 7

Disease and Parasites .............................................. 8

THE FISHERY

ECOLOGICAL R&b . : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : :

........... 8

........... 9

ENVIRONMENTAL REQUIREMENTS ................................. 10

Temperature .................................................... 10

Salinity ........................................................ 11

Temperature-Salinity Interactions ...................................... 11

Substrate ...................................................... 11

Freshwater Flow ................................................. 12

Other Environmental Requirements .................................... 13

LITERATURE CITED .............................................. 15

V
ACKNOWLEDGMENTS

.

I am grateful for the reviews by Richard Wahle of the University of Maine and Kathy Hieb of the

California Department of Fish and Game, Stockton, California, and helpful editorial comments by an

unidentified reviewer, which greatly improved the readability of this work.

vi
Figure 1. Representative crangonid shrimp (from Smith and Carlton 1975).

CRANGONID SHRIMP

NOMENCLATURE/TAXONOMY/RANGE

Three species of crangonid shrimp, commonly

called bay shrimp (Figure l), are important to

epifaunal decapod shrimp communities of the

Pacific Southwest.

Scientific name . . . . . . . Crangon franciscotum

(Stimpson)

Preferred common name . . . . . . . sand shrimp

Other common names . . . grass shrimp,

common shrimp.

Scientific name . . . . Crangon nigricauda

(Stimpson)

Preferred common name . . . . . . . black shrimp

Other common names . . . . deep-water shrimp,

black-tailed shrimp

Scientific name . . . . . Crangon nigromaculata

(Lockington)

Common name . . . . . . . . . blue-spotted shrimp

Class . . . . . . . . . . . . . . . . . . , . . . Crustacea

Order . . . . . . . . . . . . . . . . . . . Decapoda

Suborder Natantia

Tribe . . . : : : : : : . . . . : : . . .* . . .* .* . . .* . . Caridea

Family . . . . . . . . . . . . . . . . . . . Crangonidae

Geographic range: sand shrimp and black

shrimp are widely distributed along the Pacific

coast of North America--sand shrimp from

southeastern Alaska to San Diego, California,

and black shrimp from Alaska to Baja

California (Figure 2) (Rathbun 1904) and

possibly as far west as Japan (Schmitt 1921).

Both shrimp are abundant in bays on mud

and sand bottoms and offshore in deeper

waters (Carlton and Kuris 1975). The range

of blue-spotted shrimp is more restricted; it

occurs from the Gulf of Farallons to Baja

California (Rathbun 1904) (Figure 2). It is

rarely abundant in embayments, living more

commonly offshore on mud and sand bottoms.

MORPHOLOGY/IDENTIFICATION AIDS

The crangonid shrimp of the Pacific

Southwest are easily distinguished from other

members of the tribe Caridea by four features

(Figure 3); (1)-the rostrum is very short,

generally not extending beyond the eyestalks,

(2)-the body is dorsally flattened, (3)-the

chelipeds are not strongly developed, i.e., they

1
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SAN DIEGO

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PACIFIC OCEAN

Crangon franciscorum z::.*

and C. nigricauda t

. . . .

C. nigromaculata ezd

Figure 2. Distribution of crangonid shrimp in the Pacific Southwest.

2
b

-

rostrum

Q

Figure 3. Distinguishing characteristics of

crangonid shrimp (from Smith and Carlton

1975).

are subchelate in form, and (4)-the eyes are not

covered by the carapace (Carlton and Kuris

1975). Shrimp of the genus Crangon are

further distinguished by a single median spine in

the gastric region of the carapace.

The three species of Crangon are easily

distinguished by the structure of the cheliped or

the presence of distinctive markings. The

“hand” of the cheliped of sand shrimp is slender

and elongate (Figure 3) and the “finger,” when

closed, turns back almost longitudinally. The

hand of the cheliped of black shrimp is more

robust: the closed finger of the hand is

directed almost transversely. The hand of the

3

cheliped of blue-spotted shrimp is intermediate

in form--not as elongate as that of sand shrimp

and not as robust as that of black shrimp. The

differences in cheliped shape are not always

distinctive in small shrimp but sand shrimp have

a pair of spines on the fifth abdominal segment

that can be used to separate small sand shrimp

from small black shrimp. Blue-spotted shrimp

are easily recognized (in life) by a prominent

dark circular spot with a blue center surrounded

by a black and then a yellow ring on each side

of the 6th abdominal segment (Carlton and

Kuris 1975).

The sexes of mature crangonid shrimp are

easily distinguished. Sand shrimp sexes can be

distinguished at about 26-30 mm while bluespotted and black shrimp can be separated at

22-24 mm (Israel 1936; Krygier and Horton

1975; Siegfried 1980). The most distinguishing

characteristic separating the sexes is the

structure of the endopodite of the second

pleopod (Lloyd and Yonge 1947; Meredith

1952). Males have an appendix masculina

(Figure 4) on the endopodite of the second

pleopod, whereas females do not, i.e., the first,

second, and third pleopods look alike. The

structure of the endopodite of the first pleopod

is short and curved inward in males and long

and straight in females. The location of the

gonopore is still another distinguishing

characteristic, but it is often difficult to

recognize in preserved shrimp (Siegfried 1980).

The gonopore is at the base of the fifth pair of

walking legs in males and at the base of the

third pair of walking legs in females.

exopod

appendix

masculina

\

kl

lcm

endopod cf

Figure 4. Sexual dimorphism in Crangon

ji-anckorzun (from Smith and Carlton 1975).
REASONS FOR INCLUSION IN SERIES

The crangonid shrimp of the California coast

have been fished commercially since the 1800’s.

This commercial fishery was centered in San

Francisco Bay. Before the 1960’s, most of the

catch was dried and shipped to the Orient, but

part of it went to the fresh fish markets (Israel

1936). After the 1960’s, the fishery became

primarily a bait fishery, and annual harvests

were less than 200,000 pounds.

The importance of crangonid shrimp in the

food web of coastal estuaries is well

documented. These shrimp are often the

predominant food of the principal sport and

commercial fishes of the Pacific coast estuaries

(Johnson and Calhoun 1952; Ganssle 1966;

Haertel and Osterberg 1966; Boothe 1967).

Crangonids are opportunistic predators that feed

on the most abundant small epibenthic and

benthic fauna and thus serve as an important

step in the transfer of energy from the primary

consumers and detritivores to the top predators

of estuarine food webs.

The agitation of bottom sediments by

crangonids in search of food and protection may

be important in the cycling of nutrients in

coastal systems (Lloyd and Yonge 1947). Fecal

pellets of crangonids are important substrates

for bacterial colonization and may be important

in nutrient regeneration in shallow water

habitats (Knight 1978). Nitrogen excretion by

large populations of crangonids in shallow water

may have important influences on the nitrogen

budget of coastal systems (Nelson et al. 1979).

Crangonid shrimp have recently become the

subject of research on aquaculture potential of

native decapods (Knight 1978) and as a

standard bioassay test organism for west coast

estuaries (Dr. P. Sheehan, Aqua Terra

Technical; pers. comm.).

LIFE HISTORY

Spawning and Larvae

Crangonid shrimp carry their eggs under the

abdomen attached to and between the basal

joints and inner rami of the pleopods. The

distribution and abundance of ovigerous females

is a useful index of reproductive activity.

Several investigators have reported that the

spawning season of crangonid shrimp is long.

Ovigerous females have been reported to occur

during 9 to 12 months of the year in various

populations (Israel 1936; Lloyd and Yonge

1947; Meredith 1952; Price 1962; Krygier and

Horton 1975).

Ovigerous females of the three species

reviewed in this report can be found year-round

along the California coast. Ovigerous sand

shrimp are usually most abundant in the spring

and summer in coastal embayments but are

abundant offshore in winter (California

Department of Fish and Game 1987). The

abundance of ovigerous black shrimp is

generally bimodal, peaking in winter-spring and

summer-fall. They are usually found in

embayments; few are collected in nearshore

areas. Ovigerous blue-spotted shrimp are

usually most abundant in nearshore coastal

areas, peaking in winter (California Department

of Fish and Game 1987).

Israel (1936) reported that both male and

female sand shrimp live for about one year.

More recent investigations suggest that females

may live 1.5 to 2.5 years and males 1.5 years

(Hatfield 1985; Kinnetic Laboratories 1987).

Repeated spawning has been demonstrated by

the presence of females bearing ovarian stages

5-7, early in the spawning season, as well as

eggs on their egg pad (Israel 1936; Krygier and

Horton 1975).

Ovigerous black shrimp females usually

remain partly buried in the sediment during the

day. The eggs usually hatch at night. Females

emerge from the sediment and beat their

pleopods, generating currents that release the

newly hatched larvae. The females are usually

free of eggs by dawn (Villamar and Brusca

1988).

The brood sizes of crangonid shrimp are

related to shrimp size and species. Siegfried

(1980) determined the best fit relationship

between brood size of sand shrimp from San

Francisco Bay and total length to be:

Log N = -3.66 + 4.09 Log TL,

d

4

Juvenile (and adult) black shrimp are rare in

waters of <lo ppt salinity (California

Department of Fish and Game 1987).

Mgmtions

Both sand shrimp and black shrimp migrate

to deeper, more saline water as they mature

(Krygier and Horton 1975; Siegfried 1980,

Hatfield 1985). This out-migration from lowsalinity water appears to be related to

reproduction, as it coincides with the

development of sexual characteristics. The

migration is particularly pronounced in sand

shrimp. Juveniles are often found in the upper

reaches of estuaries, in nearly fresh water. As

the shrimp mature, they move to water of

higher salinity, which may result in size

gradients in sand shrimp populations. The

mean length of sand shrimp collected in

midsummer in the San Francisco Bay Estuary

ranged from 31 mm near the upstream limit of

their distribution (1 ppt) to >50 mm in the

central bay (Siegfried et al. 1978; Siegfried

1980).

Further evidence for an outward migration

related to reproductive state is provided by

information on mean salinity of occurrence of

females bearing eggs of various stages

(California Department of Fish and Game

1987). The range of salinity for the three

crangonid species is more restricted for

ovigerous females than for other life stages.

Females bearing stage-l eggs are found at

salinities of 0.1 to 33.8 ppt (mean 20 ppt).

Gvigerous sand shrimp are generally found only

at salinities greater than 14.6 ppt (Hatfield

1985; Krygier and Horton 1975). The average

salinity appears to increase with egg stage (up

to 24.6 ppt for those with stage-4 eggs;

California Department of Fish and Game 1987).

Females bearing stage-4 eggs were not collected

from waters of salinity less than 3.7 ppt.

Ovigerous black shrimp apparently prefer

somewhat higher salinities of about 25 ppt

(California Department of Fish and Game

1987); their outward migration is less extensive

because they do not penetrate as Ear inland as

sand shrimp. Blue spotted shrimp prefer even

higher salinities; ovigerous females are scarce in

embayments but abundant offshore (>30 ppt;

California Department of Fish and Game 1987).

The outward migration of crangonid shrimp is

believed to be related to temperature-salinity

interactions. Ovigerous females are found in

coastal embayments in summer but are

uncommon in them in winter; they seemingly

migrate offshore in winter, possibly in response

to water temperature fluctuation (Hatfield

1985). This offshore population then

contributes larvae and postlarvae for the spring

abundance peaks.

Sand shrimp also undergo die1 vertical

migrations. Siegfried et al. (1978) first reported

a die1 pattern in which the shrimp enters the

water column and disperses through the water

column at night but remains on or near the

bottom during daylight. The ecological

significance of this behavior remains unknown,

but the habit may serve to allow feeding near

the surface while protected by darkness from

visual feeding predators (fish). Migration into

the water column may also be a response to the

movement of their primary food, Neomysis

mercedis, into the water column (Welch 1970;

Siegfried et al. 1979). Additional studies

substantiated the die1 activity patterns of sand

shrimp and N. mercedis (Sitts 1978). There is

no comparable information on the die1 activity

patterns of the other crangonids of the

California coast.

A&h

Male black shrimp in Yaquina Bay, Oregon,

have been reported to be mature--i.e., to

contain ripe sperm--at lengths of 26-28 mm;

male sand shrimp matured at 34 mm (Krygier

and Horton 1975). Gvigerous females as short

as 36.2 mm for black shrimp and 43.6 mm for

sand shrimp were reported by Krygier and

Horton (1975) in Oregon waters. These lengths

at maturity agree well with findings in California

(Israel 1936; Siegfried 1980).

Israel (1936) reported a seasonal variation in

the sex ratio of sand shrimp from San Francisco

Bay: males predominated before the breeding

season and females predominated during the

peak of the breeding season. This variation can

Y

6
be attributed to the short life span of males,

which are believed to die soon after copulation,

and the longer life span of at least some of the

breeding females. In general the sex ratios of

crangonid populations of the Pacific Southwest

appear to be about 1:l. This ratio is expected

in nonsynchronously spawning populations in

which a portion of the population has more

than one brood (Krygier and Horton 1975).

GROWTH

In all crangonids, males and females grow at

different rates (Lloyd and Yonge 1947;

Meredith 1952; Allen 1960; Price 1%2; Krygier

and Horton 1975; Siegfried 1980). The length

of male sand shrimp from San Francisco Bay

rarely exceeded 50 mm although some

individuals as long as 71 mm long have been

collected (California Department of Fish and

Game 1987). Female sand shrimp longer than

70 mm were commonly collected (Israel 1936;

Siegfried 1980). In the somewhat smaller black

shrimp, males generally reached 40 mm and

females 60 mm (Israel 1936). The longest black

shrimp reported from San Francisco Bay were

59 mm (male) and 64 mm (female) long. The

maximum size of blue-spotted shrimp is believed

to be similar to that of black shrimp. The

length of crangonids in San Francisco Bay are

somewhat greater than in Oregon, where

Krygier and Horton (1975) reported maximum

lengths of ~40 mm for male and ~55 mm for

female black shrimp and 50 mm (males) and

~62 mm (females) for sand shrimp. The

shrimp may grow larger in San Francisco Bay

because water temperatures are higher there

than in Oregon, presumably leading to faster

growth or longer growing seasons.

Offshore populations of crangonids may reach

much larger lengths. Collections of sand shrimp

off the mouth of the Columbia River indicate a

population with a mean length >80 mm and

maximum lengths of 110 mm (Durkin and

Lipovsky 1977). Estuarine populations of the

European species, C. crangon, attained smaller

body sizes than nearby populations of the same

species in marine habitats (Maucher l%l).

Remane and Schlieper (1971) suggested that

reduction in size of marine animals, although

generally slight in higher Crustacea living in

brackish water, is comparable to Bergmann’s

Law: size is related to features of the physical

environment. The reduction may be attributable

to the physiological effects of salinity, reduced

food availability, or a combination of these and

other factors. Studies of osmotic regulation

indicated that smaller sand shrimp are capable

of better hyper-regulation but larger ones are

capable of better hypo-regulation (Shaner 1978).

Thus, the migration of larger shrimp to high

salinity waters would be energetically

advantageous and may lead to faster growth.

Growth rates are extremely difficult to

estimate from size-frequency histograms derived

from field collections of crangonid shrimp.

Immigration, emigration, temperature and

salinity effects, and differential mortality

combine to obscure growth patterns. Krygier

and Horton (1975) estimated that the growth

of juveniles ranged from 0.76 to 1.37 mm per

week in Oregon. Growth rates of crangonids

in California are somewhat higher. Kinnetics

Laboratories (1984) estimated male and female

sand shrimp >30 mm long to grow 1.7 to

2.4 mm per month.

Length-weight relationships for juvenile, male,

and female sand shrimp were given by Siegfried

(1980). The regression equations describing

these relationships follow:

juveniles: Log W = -5.41 + 2.58 LogTL

males: Log W = -6.12 + 3.27 LogTL

females: Log W = -6.62 + 3.57 LogTL

where W = dry weight in grams and TL =

length in mm. Analysis of covariance revealed

significant differences in slopes between the

length-weight regressions of juvenile and mature

shrimp. The difference is at least partly

attributable to gonadal development.

Mortality

Annual abundance of crangonid shrimp varies

widely (Siegfried 1980; California Department of

Fish and Game 1987). Annual abundance

indices for sand shrimp in San Francisco Bay

were several orders of magnitude higher in

some years than in others from 1980 to 1985,

c

7
and that of blue-spotted and black shrimp

varied by more than tenfold (California

Department of Fish and Game 1987). Annual

abundance of crangonid shrimp appears to be

determined mostly by mortality of larvae and

postlarvae. Mortality due to predation is

undoubtedly high and may explain geographic

patterns of abundance within embayments

(Kinnetic Laboratories 1983; Kuipers and

Dapper 1984). Recruitment to bay populations

in any one year, however, appears to depend on

environmental conditions.

Recruitment of crangonid shrimp to San

Francisco Bay is independent of the abundance

of ovigerous females, i.e., the parent stock.

Correlations between annual abundance of

crangonid larvae and postlarvae and of

ovigerous females are non-significant (California

Department of Fish and Game 1987), suggesting

that environmental conditions play a major role

in determining annual abundance. Thus,

management to maintain crangonid populations

should be aimed at maximizing recruitment

(Christmas and Etzold 1977).

Annual abundance of crangonid shrimp has

been linked to the volume of freshwater flow to

San Francisco Bay (California Department of

Fish and Game 1987). The volume of

freshwater inflow determines the magnitude of

seaward and landward currents, the salinity

regime, temperature, and the distribution and

abundance of other organisms including

crangonid predators and prey (Siegfried et al.

1979; Armor and Herrgesell 1985). All of these

factors play major roles in determining

crangonid recruitment and mortality.

&ease and Parasites

Crustaceans are subject to infection by

bacteria, fungi, protozoans, platyhelminths, and

nematodes which can cause disease (Green

1968; Couch 1978; Overstreet 1978). Although

infestation of crangonids by these groups has

been observed (C.A. Siegfried, pers. obs.), there

is little information on the incidence of

infection or the effects on crangonid

populations. In crangonids of San Francisco

Bay, the incidence of infection by

microsporidian protozoans is often high (C.A.

Siegfried, pets. obs.).

The bopyroidean branchial isopod, Argeia - -

pugettensis, an ectoparasite in the branchial

chamber, often infects crangonids in San

& W

Francisco Bay (Nelson and Simmons 1978) and

in Yaquina Bay, Oregon (Krygier and Horton

1975). It attacks shrimp in San Francisco Bay

only in higher-salinity waters. Krygier and

Horton (1975) reported only female parasitized

sand shrimp in Yaquina Bay, Oregon; however,

no parasitized ovigerous females were found.

In San Francisco Bay almost all parasitized

shrimp appeared to be females (Nelson and

Simmons 1978). Since it is unlikely that the

isopod would attack only females, and since

castration by parasites is reported for other

crustacean species, it is likely that the

attachment of A. pugettensis results in castration

in sand shrimp (Nelson and Simmons 1978).

Castration would inhibit gonadogenesis and

castrated male shrimp would take on feminizing

characteristics, including larger size. A larger

host would presumably make more energy

available to the parasitic isopod. Since host and

parasite weights are positively correlated, early

attachment of the parasite and growth with the

host is indicated (Nelson and Simmons 1978;

Kinnetics Laboratories 1987; Jay 1989). i ’

Whether female or castrated male, parasitized

crangonid shrimp are still significantly smaller

than nonparasitized shrimp, as shown in a field

study conducted in Humboldt Bay. The study

suggests that there are slower growth rates in

the parasitized shrimp (Jay 1980). Preliminary

laboratory investigation reveals that parasitism

by A. pugettensis depresses metabolic rates

(oxygen consumption) in sand shrimp but does

not affect excretion rates (Nelson and Simmons

1978).

THE FISHERY

The earliest commercial fishing for crangonid

shrimp along the California coast is believed to

have been done in San Francisco Bay in the

late 1860’s by Italian fishermen (Scofield 1919;

Bonnot 1932; Israel 1936). The shrimp were

taken in bag seines 18.3 m long by 2.4 m deep.

The catch of crangonid shrimp greatly increased

when Chinese fishing camps appeared in 1871.

The Chinese introduced the use of the Chinese

8
Ii

A\

t

shrimp net, a funnel-shaped net 12.1 m long

with a mouth 9.1 m wide. These nets were

held stationary by a system of lines and anchors,

and shrimp were captured as they were carried

into the net by the tide. Chinese nets were set

during a single ebb or flood tide and then lifted

just before the tide turned. By 1897, 26

Chinese fishing camps operated 20 to 50 nets

each in San Francisco Bay, landing 400 to 8,000

pounds of shrimp per camp per day. In the

early 1890’s, crangonid shrimp were also caught

in Tomales Bay, north of San Francisco, but the

fishery was abandoned by about 1895 (Bonnot

1932).

The local market for crangonid shrimp was

saturated soon after the Chinese began shrimp

fishing. However, a profitable export trade

soon developed, based on the shipment of dried

shrimp to the Orient. The use of Chinese

shrimp nets was investigated by the California

Fish and Game Commission in 1897 and again

in 1910, largely to assess the loss of young fish

(particularly striped bass, Morone saxatiZk) in

the Chinese nets. In 1901 the California State

Legislature established a closed season to

shrimp fishing from May to August. By 1911

the Chinese shrimp nets were prohibited, but in

1915 a law was passed to allow limited use of

the nets in parts of San Francisco Bay (Scofield

1919).

Trawl shrimp fishermen began operating in

San Francisco Bay in about 1910. Trawl

fishermen used trawls with beams of 5.5 to

6.1 m and an 18.3-m funnel-shaped net. The

trawl was dragged over the bottom in the

direction of the tide. A single haul lasted from

40 min to 2 h, and a day’s work consisted of

making 2-4 hauls and catching a total of 100 to

1,000 pounds of shrimp (Fry 1933).

The annual shrimp catch in San Francisco

Bay exceeded 720 t for much of the 1920’s and

1930’s; the peak catch of more than 1,591 t was

made in 1935 (California Department of Fish

and Game 1987). The annual catch did not

exceed 455 t during the 1940’s and 1950’s, and

had declined to less than 45 t by the late

1950’s, it did not exceed 114 t except in 1978

when 216 t were landed (California Department

of Fish and Game 1987).

The catch of crangonid shrimp continued to

be used for fresh or dried food until the 1960’s.

However, the demand declined steadily after the

1930’s and the fishery became a bait fishery,

supplying sport fishermen. Crangonid shrimp

are too small to shell and market economically.

The bait fishery relies entirely on trawls to

capture shrimp.

The sport fishermen of the region will

probably continue to support a bait fishery

landing 68-91 t of crangonid shrimp annually.

The prospect of expansion of the fishery is

poor.

ECOLOGICAL ROLE

Little is known about the ecology of larval

and postlarval crangonids. The larvae are

presumably predators on small zooplankters,

such as copepods. Larvae have been

maintained in the laboratory on a diet of

Arlemiu nauplii (Shaner 1978).

Juvenile and adult crangonids are predaceous,

their dietary differences being related to shrimp

size and prey availability (Siegfried 1982; Wahle

1985). Seasonal and geographical dietary

studies have indicated that crangonid prey in

the diet is generally proportional to their

occurrence in an estuary (Siegfried 1982; Wahle

1985). Wahle (1985) who studied the feeding

ecology of sand shrimp and black shrimp in San

Francisco Bay, found that these species feed on

a similar array of benthic prey made up of

crustaceans, polychaetes, mollusks,

foraminiferans, and plant material. Amphipods

were the most frequently ingested; barnacle

exuvia, fish eggs, bryozoans, hydrozoans, and

mites were occasionally ingested. Black shrimp

ate significantly more amphipods than did sand

shrimp. Larger crangonids ate larger prey.

Foraminiferans, copepods, and ostracods were

taken by small shrimp, while shrimp,

polychaetes, and isopods were taken by large

shrimp.

In the less saline regions of the San Francisco

Bay Estuary--the delta region--the most

important food of sand shrimp is the opossum

shrimp, Neomy.sh mercedis, which occurred in

9
62%&l% of all sand shrimp gastric mills

containing prey (Siegfried 1982). Larger

crangonids ate larger mysids. Sitts and Knight

(1979) suggested that predation by sand shrimp

affected the population structure and abundance

of mysids in the delta.

The distribution of N. mercedis does affect

the distribution of sand shrimp in the San

Francisco Bay Delta (Siegfried 1980). Not only

is crangonid density much greater in locations

where mysids are abundant, but crangonids in

areas of high mysid density take more prey than

those in areas of low prey density (Siegfried

1982). The delta region of San Francisco Bay

has impoverished benthic communities (Nichols

1979) and thus the region has few potential

prey organisms. This may be an important

factor linking the distributions of crangonids and

mysids in the delta region of San Francisco Bay.

Crangonid shrimp are important food for

many estuarine fish. They have been reported

to be important in the diets of striped bass

(Johnson and Calhoun 1952; Huebach et al.

1%3; Ganssle 1966; Kinnetic Laboratories

1983); white sturgeon, Acipenser trunsmonfunus

and green sturgeon, A. medirostris (Ganssle

1966; McKechnie and Fenner 1971); and

staghorn sculpin, Leptocottus armatus, (Ganssle

1966; Boothe 1967; Kinnetic Laboratories 1983).

They are also an important food of American

shad, Alosu supidissimu; brown smoothhound,

Mustelus henlei; Pacific tomcod, Microgudus

proximus; and white catfish, Ictulurus cutus

(Ganssle 1966).

Crangonid shrimp recycle nutrients during

their feeding activities. Agitation of bottom

sediments by crangonids searching for food and

shelter has been suggested as an important

mechanism of nutrient recycling in estuaries

(Lloyd and Yonge 1947). Nitrogen excretion

by large populations of crangonids can have

important effects on the nitrogen budget of

estuarine systems (Nelson et al. 1979).

ENVIRONMENTAL REQUIREMENTS

TempemW

Water temperature is a critical factor not only

in survival but in the regulation of most life

functions of cold-blooded organisms such as

crangonid shrimp. Water temperature affects + .

metabolic, growth, and feeding rates,

osmoregulation, movement, habitat selection,

and survival (Prosser 1950). The discharge of

heated effluents may restrict the distribution of

crangonids or other cold-blooded organisms in

estuarine systems, and sudden temperature

changes may be lethal.

The seasonal migrations of crangonids have

been linked to changing water temperatures.

The spring onshore migration of juveniles may

be a migration to warmer waters and the fallwinter offshore movement of mature shrimp

may be a migration to cooler waters (Israel

1936; Ktygier and Horton 1975; Siegfried 1980;

Hatfield 1985). Decreasing water temperature

resulted in the movement of C. septzknspinosu

from shallow to deeper areas of Chesapeake

Bay (Haefner 1976). Havinga (1930) suggests

that the seasonal migrations of C. crungon can

be explained as a search for the warmest water

mass.

Crangonids of the Pacific Southwest have

been collected over a wide range of

temperatures; sand shrimp, 6.3 to 23.9 “C, black

shrimp, 6.7 to 22.1 “C; and blue-spotted shrimp,

7.8 to 20.2 “C (California Department of Fish

and Game 1987). Sand shrimp are abundant at

> 15 “C, black shrimp at <18 “C, and bluespotted shrimp at 14-18 “C.

Temperature tolerance in adult sand shrimp

under laboratory conditions was reported by

Khorram and Knight (1977a). The research

indicated a significant interaction between

temperature and salinity on survival: water

temperature affected survival at different

salinities and salinity affected survival at

different temperatures. In general, survival of

adult sand shrimp was poor at water

temperatures below 10 “C or above 20 “C, and

decreased with decreasing salinity. The

optimum ranges of temperature and salinity for

adult sand shrimp, as determined by response

surface analysis (a statistical technique that

determines optimum response to more than one

variable), was 14.5-17.0 “C and 18-20 ppt. The

authors concluded that temperature was slightly

more important than salinity in determining

adult survival (Khorram and Knight 1977a).

10
Salinity

Crangonids are euryhaline, occurring at

salinities from nearly fresh water to seawater

(Siegfried 1980, Hatfield 1985). Sand and black

shrimp have been collected from San Francisco

Bay at salinities of O-1-34.3 ppt and blue-spotted

shrimp at the somewhat narrower range of 4.5

34.3 ppt (California Department of Fish and

Game 1987). Blue-spotted shrimp are generally

abundant only in water with salinity >23 ppt.

Black shrimp are generally more abundant in

water with salinity >23 ppt. Black shrimp are

generally most abundant in waters of salinity

>lO ppt and sand shrimp at salinities ~19 ppt

(California Department of Fish and Game

1987). These salinity ranges are based on the

abundance of juvenile and adult stages. Adult

crangonids, and particularly ovigerous females,

prefer the higher end of the salinity range.

The seasonal distribution of crangonids,

particularly sand shrimp, along the California

coast is closely related to salinity. Although the

sand shrimp inhabits brackish water during much

of its life cycle, it requires relatively high

salinities for reproduction. Ovigerous females

are rarely collected where salinity is low.

Ovigerous females are found year-round in San

Francisco Bay, but almost never in the less

saline portions of the bay (Israel 1936; Siegfried

1980; Hatfield 1985). Energetic demands of

osmoregulation at low salinities may preclude

egg development and thus reproduction in low

salinity waters. Broekema (1941) showed that

low salinities retard egg development in

crangonids. Salinity is thus important in larval

survival; preliminary investigations suggested that

survival of larval sand shrimp declined at

salinities below 12 ppt (S.W. Shaner, Univ.

Calif., Davis, unpubl.)

Salinity tolerance was significantly affected by

water temperature. At 5 ppt salinity, the 96-h

survival was zero at 5 “C and 25 “C, but ranged

from 30% to 42% at intermediate temperatures;

in waters of 25 ppt salinity, survival after % h

was >80% at 10 “C and 15 “C but 60% at 5 “C

(Khorram and Knight 1977a). More recent

salinity tolerance investigations indicated that

juvenile sand shrimp were more tolerant of low

salinity; survival was 100% in water of 2 ppt

salinity (S.W. Shaner, unpubl.) Sand shrimp

from high salinity waters (20-30 ppt) acclimated

to low salinity (2.2-5.5 ppt) in the laboratory

within 5-6 weeks. At this time, they

physiologically resembled sand shrimp from low

salinity (l-7 ppt) waters (Shaner et al. 1985).

The upstream distribution of sand shrimp in

the San Francisco Bay Estuary is limited by low

salinity. In extensive collections from this

system between 1976 and 1985, almost no

crangonids were taken in water of <l ppt

salinity (Siegfried 1980, California Department

of Fish and Game 1987).

The response of crangonids to changes in

temperature and salinity are highly

interdependent (Khorram and Knight 1977a).

Researchers disagree about the relative

importance of each of these factors in crangonid

distribution. Havinga (1930) and Haefner

(1976) suggsted that temperature is the most

important factor. Krygier and Horton (1975),

Siegfried (1980), and Hatfield (1985), indicated

that salinity was the most important factor

determining sand shrimp distribution. Both

factors are important in determining black

shrimp distribution; temperature is most

important in summer and salinity in the winter

(Krygier and Horton 1975).

Laboratory investigations of the interactive

effect of temperature and salinity on the

survival of adult sand shrimp indicated optimum

temperature and salinity ranges of 14.5-17.0 “C

and 18-20 ppt (Khorram and Knight 1977a).

The range of temperature and salinity optima

decreased with increasing exposure times. The

optimum ranges of temperature and salinity

were 8.0-22.5 “C and 13-25 ppt for a 24 h

exposure; 9.5-21.0 “C and 14.0-24.5 ppt after

48 h; and 12-19 “C and 15.5-22.0 ppt after 72 h.

Sub&ate

Little information is available relating

crangonid distribution to substrate type.

Crangonids are found on substrates ranging

from mud to peat to sand (Israel 1936; Carlton

and Kuris 1975). They appear to be particularly

11
suited to sand-mud substrates by being able to

nestle and bury themselves into the substratum

using their pleopods and walking legs. Some

crangonid species are reported from the rocky

intertidal zone (Carlton and Km-is 1975).

The dorsally flattened crangonids usually

spend days in shallow depressions in the

substrate with just the eyes above the substrate.

In laboratory aquaria this behavior occurs on

sand as well as on softer substrates. Substrate

selection by crangonids is undoubtedly

influenced by prey availability as well as habitat

considerations. Benthic prey is generally not

abundant on coarse sediments in San Francisco

Bay but is abundant and diverse on softer, more

organic sediments (Nichols 1979). These richer

sediments are often the preferred substrates of

crangonids.

Freshwater Flow

Freshwater flow to estuarine systems affects

water temperature, salinity, substrates, seaward

and landward currents, and the distribution of

potential prey and predators. During periods

of high freshwater flows, seaward and residual

landward currents are high and salinity intrusion

is low. During periods of low freshwater flows,

currents are reduced, high salinity waters intrude

higher into the estuary, and water temperatures

tend to be higher. These differences in current

patterns and temperature-salinity regimes lead

to important differences in recruitment and

habitat availability for crangonids and their prey

and predators.

The recruitment of crangonids to the San

Francisco Bay Estuary appears to be linked to

variations in current patterns related to

freshwater flow. Ovigerous females occur in

high salinity portions of the estuary and in the

offshore region (California Department of Fish

and Game 1987). Larvae are released in these

regions, and since they are generally in the

water column they can bc entrained by surface

currents moving seaward. Crangonid postlarvae

congregate near bottom and are thus more

likely to be transported upstream or landward in

the landward flowing lower layer of water

(Siegfried et al. 1978). The interaction of

currents flowing seaward and landward thus

determines recruitment of crangonids to the

estuary. & .

Correlation analysis of annual abundance of

sand shrimp in relation to freshwater flow to

San Francisco Bay indicates some highly positive

relations (California Department of Fish and

Game 1987). The annual abundances of

postlarvae, juveniles, and all sand shrimp stages

combined were positively correlated with

freshwater flows during the period from 1980 to

1985. The abundances of early and mid-stage

crangonid larvae in San Francisco Bay were

negatively correlated with freshwater flow. This

is consistent with a life history pattern in which

larvae are planktonic in the upper layers of the

water column and are carried offshore during

high freshwater flows. In years of high

freshwater outflow, a larger proportion of the

reproductive population moves from

embayments to the neat-shore coastal area,

resulting in more larvae hatched outside the

embayments (K Hieb, California Department of

Fish and Game, Stockton, CA; pets. comm.).

The annual abundance of black shrimp is also

correlated with freshwater inflow, but the

relation is not as strong as that of sand shrimp c

+

(California Department of Fish and Game

1987). The annual abundance of blue-spotted

shrimp, which does not show the extensive

migration associated with development of sexual

characteristics, is not correlated with freshwater

outflows.

The volume of freshwater outflow, and thus

the location of the sediment entrapment zone

associated with the salinity gradient in the San

Francisco Bay Estuary, has been linked to

variations in the annual abundance and

distribution of N. merce&, the principal food

of sand shrimp in the upper estuary (Siegfried

et al. 1979). The distribution of sand shrimp

in the upper estuary has in turn been related

to the distribution of N. mercedis (Siegfried

1980). Thus, the distribution of crangonids can

also be affected indirectly as well as directly by

freshwater flow. The distributions and

abundances of many species of fshes in the San

Francisco Bay system are also influenced by

freshwater flows (Armor and Herrgesell 1985).

Abundance of fishes appears to be higher

during years of high freshwater flows. Potential

1 3
predators as well as the prey of crangonid

shrimp are thus affected by freshwater flow to

the San Francisco Bay system.

OtherEnvironmentalRequirements

Other environmental factors, such as dissolved

oxygen concentration, metals concentrations,

pesticides, and other agricultural, municipal, and

industrial pollutants may affect the distribution

and abundance of crangonids. Khorram and

Knight (1977b) reported the toxicity to sand

shrimp of Kelthane, an organochlorine miticide

once commonly used on vegetable, fruit, and

grain crops in regions tributary to San Francisco

Bay. The lethal threshold was estimated to be

about 100 ppb. Kelthane and its breakdown

products bioaccumulate in body tissue (Khorram

and Knight 1977b). Shrimp exposed to this

pesticide showed a characteristic sublethal

response, including increased physical activity,

and decreased feeding and molting rates.

Low dissolved oxygen concentrations, in

combination with high water temperatures, are

believed to limit the occurrence of crangonids

in several streams tributary to San Francisco

Bay (Israel 1936; Nichols 1979; Kinnetic

Laboratories 1983). Sand shrimp were abundant

upstream from San Francisco Bay, into the

Sacramento River, during years of low

freshwater flows (Siegfried 1980). Crangonid

shrimp were not collected from the San Joaquin

River in Siegfried’s study (1980) even though

the temperature and salinity regimes in each

river are similar. The San Joaquin River

receives more industrial and agricultural effluent

than the Sacramento River, relative to its

discharge. This increased effluent may create

water quality differences between the two rivers

that limit shrimp distribution.

e

13

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Wahle, R.A. 1985. The feeding ecology of

Crangon fiancbxtum and Crangon nigricauda

in San Francisco Bay, California. J. Crust.

Biol. 5311-326. &

Welch, B.L. 1970. Some aspects of the vertical

migration and predatory behavior of the sand

shrimp, Crangon septimspinosa. MS. Thesis,

University of Maryland, Baltimore. 69 pp.

18
REPORT E;MENTATION j l. REPoR: No.

1 Btologtcal Report 82( 11.125)*

,. Title and Subt*tls

Species Profiles: Life Histories and Environmental Requirements

of Coastal Fishes and Invertebrates (Pacific Southwest)--Crangonid Shrimp

i December 1989

i6.

7. Author(a)

Clifford A. Siegfried

I

6. Performing Or6rmzation Rept. Nt

9. Per(ormnng Organtzatlon Name and Address

Biological Survey

NYS Museum and Science Service

Albany, NY 12230

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

____ __.

12. Sponsonng Or6aniration Name and Address

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

Fish and Wildlife Service Coastal Ecology Group

Research and Development Waterways Experiment Station

Washington, DC 20240 Vicksburg, MS 39180

13. TYIX Of Report 6 Period Coveret

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

16. Abstract (Limht: 200 words)

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

environmental requirements of coastal aquatic species. They are prepared to assist in environmental

impact assessments. Crangonid shrimp once were important in an export fishery but are now the basis

of a bait fishery in San Francisco Bay. The shrimp are important components of the estuarine system,

serving as an important food of almost all sport and commercial fshes of west coast estuaries.

Spawning occurs in waters of ~15 ppt salinity. Gvigerous females are found year-round; abundance

peaks in spring and summer in embayments and in winter offshore. Eggs hatch directly into planktonic

zoea which require 30-40 days to develop into postlarvae. Larvae prefer surface waters, while

postlarvae prefer bottom waters. Larvae are exposed to predominantly seaward currents and postlarvae

to landward moving bottom currents. Juvenile crangonids are generally found in brackish to nearly

fresh water but move to more saline waters as they mature. Crangonids are opportunistic predators

of epibenthic and benthic forms. Annual abundance of crangonids in San Francisco Bay has been

linked to the volume of freshwater flow to the estuary. Maintaining adequate freshwater flows to the

estuary to ensure successful recruitment is vital to maintaining populations of this important component

of the estuarine system.

17. Document Analysis a. Descriptors

Estuaries

Shrimp

Fisheries

b. Idsntlfisn/Opcn.Endcd Terms

Crangonid shrimp

Crangon nigricauda

Crangon franciscorum

Crangon nigromaculata

c. COSATI Field/Group

16. Avrolability Statement

Unlimited Distribution

j 19. Security Class (This Report) 21. No. of Pales

18

__-

22. Price

:See ANSI-239.16) OPTIONAL FORM 272 (4-7

(Formerly NTIS-35)

Departm*nt Of commcrc.
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 the environmental 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 lo 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.

U.S. DEPARTMENT OF THE INTERIOR

FISH AND WILDLIFE SERVICE

TAKE PRIDE

in America

UN ITED STATES

DEPARTMENT OF THE INTERIOR

FISH AND WILDLIFE SERVICE

National Wetlands Research Center

NASA-Slide11 Computer Complex

1010 Gause Boulevard

Slidell, LA 70458