(DRAFT) - Taxonomy
Species shrimp, black
Species Id M070013
Date 26 AUG 96
TAXONOMY
NAME - shrimp, black
OTHER COMMON NAMES - deep-water shrimp and black-tailed shrimp
ELEMENT CODE -
CATEGORY - Aquatic Crustaceans
PHYLUM AND SUBPHYLUM - ,
CLASS AND SUBCLASS - Crustacea,
ORDER AND SUBORDER - Decapoda, Natantia
FAMILY AND SUBFAMILY - Crangonidae,
GENUS AND SUBGENUS - Crangon,
SPECIES AND SSP - nigricauda,
SCIENTIFIC NAME - Crangon nigricauda
AUTHORITY - Stimpson
TAXONOMY REFERENCES - 257 and 231
COMMENTS ON TAXONOMY -
Tribe: Caridea.*257*
Taxonomy - 1 (DRAFT) - Status
Species shrimp, black
Species Id M070013
Date 26 AUG 96
STATUS
Coded Status
Sport Fish
Commercial
Commercial/consumption
Commercial/bait
REFERENCES FOR STATUS - 257
COMMENTS ON STATUS -
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. After the 1960's,
the fishery became primarily a bait fishery, and annual harvests were less
than 200,000 pounds.*257*
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.*257*
Status - 1 (DRAFT) - Distribution
Species shrimp, black
Species Id M070013
Date 26 AUG 96
DISTRIBUTION
Distribution - 1 HABITAT ASSOCIATIONS
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Marine FL2
Marine FL3
REFERENCES FOR NWI - 257
COMMENTS ON HABITAT ASSOCIATIONS -
Crangonid shrimp are abundant in bays on mud and sand bottoms and offshore
in deeper waters.*257*
Habitat Associations - 1 (DRAFT) - Food Habits
Species shrimp, black
Species Id M070013
Date 26 AUG 96
FOOD HABITS
TROPHIC LEVEL -
CARNIVORE
REFERENCES FOR TROPHIC LEVEL - 257
LIFESTAGE FOOD FOOD PART
Larva Copepods Not Specified
Adult Crustaceans Not Specified
Adult Polychaetes Not Specified
Adult Molluscs Not Specified
Adult Plants Not Specified
Adult Cirripeds Not Specified
Adult Fish Egg/Fetus stage
Adult Bryozoans Not Specified
Adult Hydrozoans Not Specified
Adult Arachnids Not Specified
Adult Ostracods Not Specified
Adult See Comments; Food
REFERENCES FOR ADULT FOOD - 257
REFERENCES FOR LARVAE FOOD - 257
COMMENTS ON FOOD -
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 Artemia
naulii.*257*
Juvenile and adult crangonids are predaceous, their dietary differences
being related to shrimp size and prey availability. Seasonal and
geographical dietary studies have indicated that crangonid prey in the diet
is generally proportional to their occurrence in an estuary. Researchers
who studied the feeding ecology of 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. Larger crangonids ate larger prey. Foraminiferans, copepods, and
ostracods were taken by small shrimp, while shrimp, polychaetes, and isopods
were taken by large shrimp.*257*
The distribution of N. mercedis does affect the distribution of crangonids
in the San Francisco Bay Delta. 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. The
delta region of San Francisco Bay has impoverished benthic communities 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.*257*
Food Habits - 1 (DRAFT) - Food Habits
Species shrimp, black
Species Id M070013
Date 26 AUG 96
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. Nitrogen excretion by large populations of crangonids can have
important effects on the nitrogen budget of estuarine systems.*257*
COMMENTS ON ADULT FOOD -
Juvenile and adult crangonids are predaceous, their dietary differences
being related to shrimp size and prey availability. Seasonal and
geographical dietary studies have indicated that crangonid prey in the diet
is generally proportional to their occurrence in an estuary. Researchers
who studied the feeding ecology of 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. Larger crangonids ate larger prey. Foraminiferans, copepods, and
ostracods were taken by small shrimp, while shrimp, polychaetes, and isopods
were taken by large shrimp.*257*
The distribution of N. mercedis does affect the distribution of crangonids
in the San Francisco Bay Delta. 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. The
delta region of San Francisco Bay has impoverished benthic communities 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.*257*
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. Nitrogen excretion by large populations of crangonids can have
important effects on the nitrogen budget of estuarine systems.*257*
COMMENTS ON LARVAE FOOD -
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 Artemia
naulii.*257*
Food Habits - 2 (DRAFT) - Environment Associations
Species shrimp, black
Species Id M070013
Date 26 AUG 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
A Water Temperature: Specified in Comments
A
A Dissolved Oxygen: Specified in Comments
A Bottom Type [Aquatic]: Mud or silt
A Bottom Type [Aquatic]: Sand
REFERENCES FOR ENVIRONMENTAL ASSOC_ - 257
REFERENCES FOR ADULT ENVIRONMENTAL ASSOC_ - 257
COMMENTS ON ENVIRONMENTAL ASSOCIATIONS -
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. 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.*257*
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 fall-winter offshore movement of mature shrimp may
be a migration to cooler waters.*257*
Crangonids of the Pacific Southwest have been collected over a wide range
of temperatures. Black shrimp have been collected from 6.7 to 22.1 degrees
C. Black shrimp are abundant at <18 degrees C.*257*
Crangonids are euryhaline, occurring at salinities from nearly fresh water
to seawater. Black shrimp have been collected from San Francisco Bay at
salinities of 0.1 - 34.3 ppt.*257*
Little information is available relating crangonid distribution to
substrate type. Crangonids are found on substrates ranging from mud to
peat to sand. They appear to be particularly 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.*257*
Environment Associations - 1 (DRAFT) - Environment Associations
Species shrimp, black
Species Id M070013
Date 26 AUG 96
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.*257*
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.*257*
COMMENTS ON ADULT ENVIRONMENTAL ASSOC_ -
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. 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.*257*
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 fall-winter offshore movement of mature shrimp may
be a migration to cooler waters.*257*
Crangonids of the Pacific Southwest have been collected over a wide range
of temperatures. Black shrimp have been collected from 6.7 to 22.1 degrees
C. Black shrimp are abundant at <18 degrees C.*257*
Crangonids are euryhaline, occurring at salinities from nearly fresh water
to seawater. Black shrimp have been collected from San Francisco Bay at
salinities of 0.1 - 34.3 ppt.*257*
Little information is available relating crangonid distribution to
substrate type. Crangonids are found on substrates ranging from mud to
peat to sand. They appear to be particularly 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.*257*
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.*257*
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.*257*
Environment Associations - 2 (DRAFT) - Life History
Species shrimp, black
Species Id M070013
Date 26 AUG 96
LIFE HISTORY
MORPHOLOGY/IDENTIFICATION AIDS: The crangonid shrimp of the Pacific
Southwest are easily distinguished form other members of the tribe Caridea
by four features; (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 are subchelate in form, and (4)-the
eyes are not covered by the carapace. Shrimp of the genus Crangon are
further distinguished by a single median spine in the gastric region of the
carapace.*257* 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 black shrimp is robust: the closed finger of the hand is
directed almost transversely. The differences in cheliped shape are not
always distinctive in small shrimp.*257* The sexes of mature crangonid
shrimp are easiy distinguished. Black shrimp can be separated at 22-24 mm.
The most distinguishing characteristic separating the sexes is the structure
of the endopodite of the second pleopod. Males have an appendix masculina 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. 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.*257*
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.*257* Ovigerous females of the black shrimp can be found
year-round along the California coast. 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. *257*
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.*257* Eggs
hatch directly into late zoea-stage larvae, which swim dorsal sides up and
with abdomens hanging vertically. The larvae of black shrimp molt to a
megalops 24-30 days after hatching.*257* Early stage larvae are generally
found in near-surface waters and late stage larvae near the bottom. Early
larvae would be expected to occur in the nearshore zone, transported there
by offshore surface currents or released from reproductive females.
Late-stage larvae are more likely to be transported onshore or upstream in
the shoreward moving lower layer of the water column. Abundance of crangonid
larvae generally corresponds to this expected pattern. Seasonal abundance of
larvae is generally bimodal, with a large spring peak and a smaller fall
peak.*257*
POSTLARVAE AND JUVENILES: Postlarvae, the smallest juvenile
Life History - 1 (DRAFT) - Life History
Species shrimp, black
Species Id M070013
Date 26 AUG 96
stages of crangonid shrimp, are 5-10 mm long and cannot be distinguished to
species. Postlarvae occur over a wide range of salinity, from seawater to
nearly fresh water, but are concentrated in more saline water. The
preference of crangonid postlarvae for bottom waters places them in
favorable currents for onshore and upstream transport. Postlarvae are
abundant in San Francisco Bay in spring to early summer.*257* Crangonids
longer than 10 mm can be identified to species and are considered juveniles.
Most investigators have considered them to be juvenile or immature until
they develop sexual characteritstics, at lengths of 22-30 mm, although
shrimp larger than this can still be immature. The abundance of juvenile
crangonid shrimp commonly peaks in spring and summer; a smaller peak may
develop in late summer and fall.*257* Juvenile black shrimp generally have
abundance peaks in spring but live in higher-salinity regions. *257*
MIGRATIONS: Black shrimp migrate to deeper, more saline water as they
mature. This out-migration from low-salinity water appears to be related to
reproduction, as it coincides with the development of sexual
characteristics.*257* 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. Females bearing stage-1 eggs are
found at salinities of 1.0 to 33.8 ppt (mean 20 ppt). Ovigerous sand shrimp
are generally found only at salinities greater than 14.6 ppt. The average
salinity appears to increase with egg stage (up to 24.6 ppt for those with
stage-4 eggs. Females bearing stage-4 eggs were not collected from waters of
salinity less than 3.7 ppt.*257* Ovigerous black shrimp apparently prefer
salinities of about 25 ppt.*257* 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. This offshore population then contributes
larvae and postlarvae for the spring abundance peaks.*257*
ADULTS: 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. Ovigerous
females as short as 36.2 mm for black shrimp were reported in Oregon waters.
These lengths at maturity agree well with findings in California.*257* In
general the sex ratios of crangonid populations of the Pacific Southwest
appear to be about 1:1. This ratio is expected in nonsynchronously spawning
populations in which a portion of the population has more than one brood.
*257*
GROWTH: Males and females grow at different rates. Male black shrimp
generally reached 40 mm and females 60 mm. The longest black shrimp reported
from San Francisco Bay were 59 mm (male) and 64 mm (female) long. The length
of crangonids in San Francisco Bay are somewhat greater than in Oregon,
where studies reported maximum lengths of <40 mm for male and <55 mm for
female black shrimp. The shrimp may grow larger in San Franciso Bay because
water temperatures are higher there than in Oregon, presumably leading to
faster growth or longer growing seasons.*257* Offshore populations of
crangonids may reach much larger lengths. Researchers suggest 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.*257* Growth rates are extremely
Life History - 2 (DRAFT) - Life History
Species shrimp, black
Species Id M070013
Date 26 AUG 96
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. Researchers estimated that the growth of juveniles ranged form
0.76 to 1.37 mm per week in Oregon. Growth rates of crangonids in California
are somewhat higher.*257*
MORTALITY: Annual abundance of crangonid shrimp varies
widely. Black shrimp abundance varied by more than tenfold during the
years 1980 through 1985. 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. Recruitment to bay populations in any one year,
however, appears to depend on environmental conditions.*257* 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, suggesting that environmental conditions play a major role
in determining annual abundance. Thus, management to maintain crangonid
populations should be aimed at maximizing recruitment.*257* Annual abundance
of crangonid shrimp has been linked to the volume of freshwater flow to San
Francisco Bay. 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. All of these factors play major roles in determining crangonid
recruitment and mortality.*257*
DISEASE AND PARASITES: Crustaceans are
subject to infection by bacteria, fungi, protozoans, platyhelminths, and
nematodes which can cause disease. Although infestation of crangonids by
these groups has been observed, 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.*257* The bopyroidean branchial isopod, Argeia pugettensis, an
extoparasite in the branchial chamber, often infects crangonids in San
Francisco Bay and in Yaquina Bay, Oregon. It attacks shrimp in San Francisco
Bay only in higher-salinity waters.*257*
REFERENCES FOR LIFE HISTORY- 257
Life History - 3 (DRAFT) - Management Practices
Species shrimp, black
Species Id M070013
Date 26 AUG 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial Regulating harvest - restricting weapons/gear use
Beneficial Regulating harvest - setting seasons
REFERENCES FOR BENEFICIAL MANAGEMENT PRACTICES - 257
COMMENTS ON MANAGEMENT PRACTICES -
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 Commision in
1897 and again in 1910, largely to assess the loss of young fish
(particularly striped bass, Morone saxatilis) in the Chinese nets. In 1901
the Califonia 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.*257*
Management Practices - 1 (DRAFT) - References
Species shrimp, black
Species Id M070013
Date 26 AUG 96
References
References - 1