(DRAFT) - Taxonomy
Species anchovy, bay
Species Id M010060
Date 27 AUG 96
TAXONOMY
NAME - anchovy, bay
OTHER COMMON NAMES - Common anchovy, Mitchill's anchovy, whitebait and little anchovy
ELEMENT CODE -
CATEGORY - Fish
PHYLUM AND SUBPHYLUM - Chordata, Vertebrata
CLASS AND SUBCLASS - Osteichthyes,
ORDER AND SUBORDER - Clupeiformes,
FAMILY AND SUBFAMILY - Engraulidae,
GENUS AND SUBGENUS - Anchoa,
SPECIES AND SSP - mitchilli,
SCIENTIFIC NAME - Anchoa mitchilli
AUTHORITY - Valenciennes
TAXONOMY REFERENCES - 80 and 252
Taxonomy - 1 (DRAFT) - Status
Species anchovy, bay
Species Id M010060
Date 27 AUG 96
STATUS
Coded Status
See Comments
REFERENCES FOR STATUS - 80
COMMENTS ON STATUS -
The bay anchovy is one of the most common fish inhabiting coastal areas.
Because of its abundance and its small size, it is an important prey
species. The bay anchovy is not currently used in North America as human
food and thus is not of direct commercial importance, but many of the fish
that feed on anchovies are important recreational and commercial species
*80*.
Status - 1 (DRAFT) - Distribution
Species anchovy, bay
Species Id M010060
Date 27 AUG 96
DISTRIBUTION
Distribution - 1 HABITAT ASSOCIATIONS
HABITAT - AQUATIC
REFERENCES FOR HABITAT - 136
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Estuarine UB2 4
Estuarine UB3 4
REFERENCES FOR NWI - 80
COMMENTS ON HABITAT ASSOCIATIONS -
Numerous trawling and seining surveys confirm that the bay anchovy is one
of the most abundant fish of estuarine waters in the northern Gulf of
Mexico. The bay anchovy typically spawns in water less than 20 m deep,
although, on the basis of egg collection, it is thought that they possibly
spawn to the edge of the Continental Shelf*80*.
Researchers collected bay anchovy in East Bay, Galveston, Texas, over a mud
to muddy sand substrate in water with a 50-cm to 70-cm turbidity value.
Researchers speculated that bay anchovies may be attracted to areas of high
turbidity. Researchers concluded that bay anchovy in Galveston Bay
preferred a sand and silt substrate with no water current to oyster reefs.
Bay anchovies are usually associated with the "shallows." Researchers
recorded that bay anchovy were taken from 11 m in their daytime trawls in
the Aransas Pass area *80*.
Bay anchovy primarily are primarily a shallow water estuarine and inshore
coastal water species. Studies show the bay anchovy is able to exploit a
wide variety of habitats such as: in bays and bayous; off sandy beaches; in
muddy coves; grassy areas along beaches; around mouths of rivers; and in
both shallow and deeper waters offshore, but prefers bays and estuaries to
shallow waters of the Gulf of Mexico. Population density appears to be
influenced by the mass of zooplankton present which probably accounts for
their preference for bays and, when found in the Gulf, bay water masses.
It is particularly common in primary and secondary bays, around shallow bay
margins, islands, spoil banks, and sheltered coves, but scarce in teritiary
bays.*252*
ANIMAL/PLANT SPECIES ASSOCIATIONS -
Alosid
REFERENCES FOR SPECIES ASSOCIATIONS - 136
COMMENTS ON SPECIES ASSOCIATIONS -
In overlapping ranges, Bay anchovy larvae are reported to compete with
alosid larvae for copepods *136*.
Habitat Associations - 1 (DRAFT) - Food Habits
Species anchovy, bay
Species Id M010060
Date 27 AUG 96
FOOD HABITS
TROPHIC LEVEL -
CARNIVORE
DETRITIVORE
REFERENCES FOR TROPHIC LEVEL - 80 and 136
LIFESTAGE FOOD FOOD PART
Adult Zooplankton Not Specified
Juvenile Zooplankton Not Specified
Adult Tardigrades Not Specified
Juvenile Tardigrades Not Specified
Adult Detritus - Organic Not Applicable
Juvenile Detritus - Organic Not Applicable
Adult Crustaceans Larva stage
Juvenile Crustaceans Larva stage
Adult Insects: aquatic Larva stage
Juvenile Insects: aquatic Larva stage
Larva Copepods Larva stage
Larva Copepods Adult stage
General Clupeiformes See Comments
General Snails Not Specified
General Copepods See Comments
General Copepods Not Specified
General Branchiopods Not Specified
General Crustaceans Not Specified
General Detritus - Organic Not Specified
General Phytoplankton Not Specified
General Zooplankton Not Specified
REFERENCES FOR GENERAL FOOD - 80 and 136
REFERENCES FOR ADULT FOOD - 80
REFERENCES FOR JUVENILE FOOD - 80
REFERENCES FOR LARVAE FOOD - 80
COMMENTS ON FOOD -
Researchers examined the food habits of bay anchovy collected in
Apalachicola Bay, Florida, and found calanoid copepods were the major food.
With fish growth, copepod importance declined and was replaced by larger
zooplankters such as mysids. Diets were similar for fish collected at
different sites in the estuary, but mysids, insect larvae, and cladocerans
were major food items for fish collected near the mouth of the Apalachicola
River. Copepods were the dominant prey in all months, but were less
important in October, December, and February, when other crustaceans and
insect larvae became relatively more abundant *80*.
Minor food items of the bay anchovy were other anchovies, gastropods, and
isopods *80*.
Their relatively small size and large numbers make the anchovies one of the
Food Habits - 1 (DRAFT) - Food Habits
Species anchovy, bay
Species Id M010060
Date 27 AUG 96
most important groups of forage fish in the Gulf of Mexico. Sea birds also
feed heavily upon these fish *80*.
Anchovies feed primarily on mysids and copepods. In overlapping ranges, Bay
anchovy larvae are reported to compete with alosid larvae for copepods. The
anchovy is a year-round resident, and an important forage fish of the
Chesapeake. During the summer, in the mesohaline portion of Chesapeake
Bay, anchovies consume large quantities of phytoplankton, zooplankton, and
organic detritus *136*.
COMMENTS ON ADULT FOOD -
As anchovies grow in size their diet becomes increasingly selective,
shifting from copepods more and more to small shrimp, larval and juvenile
fish, mysids, insect larvae, crab zoeae, clams, cladocerans, schizopods,
gastropods, isopods, malacostracans, and supplemented by detritus from
occasional bottom feeding. Gut analysis of individuals 30-49 mm long showed
58% zooplankton, and 33% organic detritus. Benthic animals and sand are
most frequently encountered during winter suggesting more intensive feeding
in theis area at this time.*252*
COMMENTS ON JUVENILE FOOD -
Bay anchovies are primary consumers that feed predominantly on zooplankton
in nocturnal currents. Young individuals are plankton strainers, consuming
microzooplankton such as copepod nauplii and rotifers. When a body length
of approximately 7 mm is reached, they feed on copepodites and copepods.
Some detritus is consumed but phytoplankton is not, suggesting that food
straining occurs near the bottom.*252*
COMMENTS ON LARVAE FOOD -
Posthatch larvae (2 mm) of bay anchovy selected copepod nauplii,
copepodites, and adult copepods when potential food organisms were stocked
at a density of 1,600 to 1,800/l. Initial prey organisms were 50 to 75
micro meters in body width. After reaching 8 mm in length, the larvae did
not eat copepod nauplii. In another study, researchers stocked bay anchovy
eggs at densities from 0.5 to 32.0/l along with wild plankton stocked at a
range of 50 to 5,000 organisms/l. Survival exceeded 40% when prey was
1,000 organisms/l or greater. Growth and dry weight yields increased
significantly at the higher food concentrations. Researchers also showed
that 10% survival of the bay anchovy larvae could be predicted when prey
concentration equaled approximately 100/l and that the weight of the larvae
increased 13.4 times in 16 days at a prey density of 100/l. Compared to
larvae of sea bream (Archosargus rhomboidalis) and lined sole (Achirus
lineatus), bay anchovy larvae had the best predatory ability. When larval
growth rates, survival rates, and growth efficiencies were considered,
however, sea bream larvae were the most efficient predators and the least
likely of the three species to be limited by low prey concentrations *80*.
Temperature. Bay anchovy have collected from in water ranging from 4.5 to
39.8 degrees C. Researchers investigated the relationship among growth,
survival, and starvation at temperatures of 22 to 32 degrees C for the bay
anchovy, the lined sole, and the sea bream. The rate at which the number
of hours after hatching until starvation decreased in relation to
temperature for unfed larvae did not differ significantly among the three
species, ranging from -5.4 to -6.3 hr per degree increase in temperature.
Food Habits - 2 (DRAFT) - Food Habits
Species anchovy, bay
Species Id M010060
Date 27 AUG 96
If the "critical period" is considered relative to time of hatching, lined
soles need not find food for 3 to 3.5 days after hatching, but bay anchovy
and sea bream must feed within 2.5 days of hatching *80*.
Food Habits - 3 (DRAFT) - Environment Associations
Species anchovy, bay
Species Id M010060
Date 27 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
G Water Temperature: Greater than 27 degrees C
G Water Temperature: Between 21-27 degrees C
G Water Temperature: Between 15-21 degrees C
G Water Temperature: Below 15 degrees C
G Water Temperature: Specified in Comments
G
G
G
G Dissolved Oxygen: Low [less than 5 mg/l] oxygen concentrations
G Dissolved Oxygen: Specified in Comments
G Turbidity: Murky water [High turbidity]
G Turbidity: Specified in Comments
G Bottom Type [Aquatic]: Mud or silt
G Bottom Type [Aquatic]: Sand
G Aquatic Habitat Zonation: Shallows with emergent vegetation [littoral zone]
L Aquatic Habitat Zonation: Open water [pelagic zone]
L Aquatic Habitat Zonation: Specified in Comments
L
L
L
BA Aquatic Habitat Zonation: Open water [pelagic zone]
BA Aquatic Habitat Zonation: Specified in Comments
BA
BA
BA
BA
BA
BA
BA
BA Water Temperature: Greater than 27 degrees C
BA Water Temperature: Between 21-27 degrees C
BA Water Temperature: Between 15-21 degrees C
BA Water Temperature: Specified in Comments
E
E
L Water Depth Preference: Specified in Comments
REFERENCES FOR ENVIRONMENTAL ASSOC_ - 80
Environment Associations - 1 (DRAFT) - Environment Associations
Species anchovy, bay
Species Id M010060
Date 27 AUG 96
REFERENCES FOR BREEDING ADULT ENVIRONMENTAL ASSOC_ - 136
REFERENCES FOR LARVAE ENVIRONMENTAL ASSOC_ - 136
REFERENCES FOR FEEDING LARVAE ENVIRONMENTAL ASSOC_ - 80
REFERENCES FOR EGG ENVIRONMENTAL ASSOC_ - 80 and 136
COMMENTS ON ENVIRONMENTAL ASSOCIATIONS -
Temperature: Bay anchovy have collected from in water ranging from 4.5 to
39.8 degrees C. Researchers investigated the relationship among growth,
survival, and starvation at temperatures of 22 to 32 degrees C for the bay
anchovy, the lined sole, and the sea bream. The rate at which the number
of hours after hatching until starvation decreased in relation to
temperature for unfed larvae did not differ significantly among the three
species, ranging from -5.4 to -6.3 hr per degree increase in temperature.
If the "critical period" is considered relative to time of hatching, lined
soles need not find food for 3 to 3.5 days after hatching, but bay anchovy
and sea bream must feed within 2.5 days of hatching *80*.
Salinity: The bay anchovy is often found at low salinities. The bay
anchovy has been taken from coastal freshwater to salinities of 45 part per
thousand (ppt) *80*.
Dissolved Oxygen: Bay anchovies have been taken from water containing no
more than 1.5 mg/l dissolved oxygen. The bay anchovy is certainly
susceptible to oxygen depletions, but researchers found that the bay
anchovy showed its tolerance by being the dominant fish in
pollution-stressed areas *80*.
Researchers collected bay anchovy in East Bay, Galveston, Texas, over a mud
to muddy sand substrate in water with a 50-cm to 70-cm turbidity value.
Researchers speculated that bay anchovies may be attracted to areas of high
turbidity. Researchers concluded that bay anchovy in Galveston Bay
preferred a sand and silt substrate with no water current to oyster reefs.
Bay anchovies are usually associated with the "shallows." Researchers
recorded that bay anchovy were taken from 11 m in their daytime trawls in
the Aransas Pass area *80*.
COMMENTS ON ADULT ENVIRONMENTAL ASSOC_ -
Eurythermal, reported from waters from 4.5 to 39.8 degrees C with adults
preferring 8.1 to 32.2 degrees C. Euryhaline, collected from waters
ranging from 0 to 80 ppt. Salinity appears to have no relationship with
distribution, but recorded preferences include 1 to 32 ppt for adults in
Matagorda Bay, TX; 5 ppt and less in Copano and Aransas Bays, TX; 11 to 30
ppt for adults.*252*
COMMENTS ON BREEDING ADULT ENVIRONMENTAL ASSOC_ -
Spawning is pelagic and occurs in the Chesapeake Bay at salinities ranging
from 1-22 ppt. Spawning also occurs at the Chesapeake Bay mouth where
salinities are typically 25-28 ppt. Spawning activity in the Delaware Bay
occurs between 15 degrees C and 30 degrees C with peak activity occurring
at 22-27 degrees C *136*.
COMMENTS ON LARVAE ENVIRONMENTAL ASSOC_ -
Eurythermal, reported from waters from 4.5 to 39.8 degrees C with larvae
Environment Associations - 2 (DRAFT) - Environment Associations
Species anchovy, bay
Species Id M010060
Date 27 AUG 96
preferring > 11 degrees C.*252*
Anchovy larvae are pelagic and are also found over a wide salinity range.
The larvae move upstream to low salinity regions after hatching, with the
highest concentrations of larvae observed at salinities of 0-7 ppt
salinity. Larvae were found 40 miiles above brackish water in Virginia and
in the Potomac River in freshwater near Bryans Point, about 12 miles below
Washington, D.C. *136*.
In the upper Chesapeake Bay, larvae are observed in shallow shore areas
where the salinities range between 3-7 ppt *136*.
The larval stage is considered the most sensitive life stage for the Bay
anchovy. The larvae have been observed to congregate at the surface waters
of the oligohaline areas of tributaries. Concentration of larvae in the
surface waters may cause localized overpopulation which possibly resulting
in a reduction in year class abundance *136*.
COMMENTS ON FEEDING LARVAE ENVIRONMENTAL ASSOC_ -
Temperature. Bay anchovy have collected from in water ranging from 4.5 to
39.8 degrees C. Researchers investigated the relationship among growth,
survival, and starvation at temperatures of 22 to 32 degrees C for the bay
anchovy, the lined sole, and the sea bream. The rate at which the number
of hours after hatching until starvation decreased in relation to
temperature for unfed larvae did not differ significantly among the three
species, ranging from -5.4 to -6.3 hr per degree increase in temperature.
If the "critical period" is considered relative to time of hatching, lined
soles need not find food for 3 to 3.5 days after hatching, but bay anchovy
and sea bream must feed within 2.5 days of hatching *80*.
COMMENTS ON EGG ENVIRONMENTAL ASSOC_ -
The bay anchovy egg hatches in about 24 hr at room temperature *80*.
Spawning and egg development have been recorded from 22 to 32 degrees C.
Preferred temperature range is 27.2 to 27.8 degrees C.*252*
They also reported peak egg densities occur at salinities of 12-13 ppt in
Chesapeake Bay *136*.
Environment Associations - 3 (DRAFT) - Life History
Species anchovy, bay
Species Id M010060
Date 27 AUG 96
LIFE HISTORY
PHYSICAL DESCRIPTION
The bay anchovy is rather cylindrical in cross-section with adults attaining
lengths of 10 cm. It has a large subteminal mouth and large eyes. The bay
anchovy has a somewhat indistinct silvery lateral stripe. The anal fin
originates under or slightly posterior to the dorsal fin origin (under fifth
or sixth dorsal ray). Live bay anchovy are greenish with bluish reflections
above, pale lower parts, and translucent abdominal walls *80*.
REPRODUCTION
The bay anchovy typically spawns in water less than 20 m deep, although, on
the basis of egg collection, it is thought that they possibly spawn to the
edge of the Continental Shelf. Researchers reported bay anchovy larvae 20
mm or smaller collected during most months and concluded that spawning
probably occurs throughout most of the year. Tampa Bay bay anchovies spawn
during the spring and early summer with peak egg densities from April
through July. Spawning began after surface water temperatures reached 20
degrees C and ceased by November. Spawning off the North Carolina coast
occurred from June through August and peaked in July. Early
young-of-the-year bay anchovy become sexually mature during their first
summer. Specimens 49 to 60 mm long, taken in late July and during August at
Beaufort, North Carolina, contained well-developed roe. Spawning usually
occurs in the early evening *80*.
Eggs: The eggs of the bay anchovy are slightly oblong with the major axis
about 0.75 mm and the minor axis about 0.62 mm. The average size of the
eggs of the bay anchovy decreases as water salinity increases. The eggs
have no oil globule and are transparent. The yolk is composed of separate
masses. It hatches in about 24 hr at room temperature *80*.
Larvae: Researchers observed that newly hatched yolk-sac larvae of the bay
anchovy are 1.8 to 2.0 mm in length. The yolk sac is greatly elongated and
tapers to a point posteriorly. The larvae are transparent and show no
pigmentation. The yolk sac is completely absorbed 15 to 18 hr after
hatching. The mouth is apparently functional about 36 hr after hatching.
Larvae 7 to 8 mm in length have definite dorsal and anal fins and some
pigmentation in the thoracic region and at the base of the anal fin. At 12
mm in length, the dorsal and anal ray counts are 15 to 16 and 23 to 31,
respectively. Although the bay anchovy has been described from laboratory
work, larvae are too similar to separate early stages from the other five
engraulids occurring in the northern Gulf of Mexico (A. hepsetus, A. cubana,
A. lyolepis, Anchoviella perfasciata, and Engraulis eurostyle). Engraulid
larvae are usually identified as Engraulidae sp. or Anchoa sp. at best *80*.
Juveniles: The projecting snout of the bay anchovy is not developed until
the fish reaches 20 to 25 mm in length. The body of the bay anchovy becomes
deeper with age. Body depth is about one-twelfth of body length in 16-mm
fish, and about one-fifth of body length in 25-mm fish. Juveniles differ
from adults in having a terminal mouth and a short rounded maxillary, which
does not reach the margin of the opercle. Juveniles lack the silvery
lateral band. The fish acquire all adult characteristics by the time they
are 60 mm in length *80*.
Life History - 1 (DRAFT) - Life History
Species anchovy, bay
Species Id M010060
Date 27 AUG 96
Adults: They attain maturity at approximately 2.5 months and 34-40 mm TL.
Reported size range for adults in study area is 34-93 TL with a recorded
mean of 56.3 mm TL for males and 60.0 mm TL for females. Two possibly three
size classes have been indistinguishable due to year round spawning.*252*
SPECIES INTERACTIONS
Compared to larvae of sea bream (Archosargus rhomboidalis) and lined sole
(Archosargus lineatus), bay anchovy larvae had the best predatory ability.
When larval growth rates, survival rates, and growth efficiencies were
considered, however, sea bream larvae were the most efficient predators and
the least likely of the three species to be limited by low prey
concentrations *80*.
Movement and Migrations: Moves into deeper waters during winter and back
inshore during summer. Larvae are reported to migrate to lower salinity
nursery areas while developing toward adulthood, and then migrate back to
more saline areas.
Bay anchovy has been observed in virtually all open waters throughout the
Chesapeake Bay from the tidal fresh to the polyhaline zone; the C&D Canal
and Havre de Grace down to Lynnhaven Roads, Virginia. Anchovy larvae are
pelagic and are also found over a wide salinity range. The larvae move
upstream to low salinity regions after hatching, with the highest
concentrations of larvae observed at salinities of 0-7 ppt salinity. Larvae
were found 40 miiles above brackish water in Virginia and in the Potomac
River in freshwater near Bryans Point, about 12 miles below Washington, D.C.
Anchovy larvae also occur in larger numbers throughout the lower Chesapeake
Bay *136*.
Spawning and Range: The Bay anchovy spawning season occurs from May to
September in the Chesapeake Bay. Spawning is pelagic and occurs in the
Chesapeake Bay at salinities ranging from 1-22 ppt. Spawning also occurs at
the Chesapeake Bay mouth where salinities are typically 25-28 ppt. Spawning
actiity in the Delaware Bay occurs between 15 degrees C and 30 degrees C
with peak activity occurring at 22-27 degrees C. They also reported peak
egg densities occur at salinities of 12-13 ppt in Chesapeake Bay. In the
upper Chesapeake Bay, larvae are observed in shallow shore areas where the
salinities range between 3-7 ppt *136*.
The larval stage is considered the most sensitive life stage for the Bay
anchovy. The larvae have been observed to congregate at the surface waters
of the oligohaline areas of tributaries. Concentration of larvae in the
surface waters may cause localized overpopulation which possibly resulting
in a reduction in year class abundance *136*.
LIFE HISTORY CODES -
Breeding Spawning Season: April
Breeding/Spawning Season: May
Breeding/Spawning Season: June
Breeding/Spawning Season: July
Breeding/Spawning Season: August
Life History - 2 (DRAFT) - Life History
Species anchovy, bay
Species Id M010060
Date 27 AUG 96
LIFE HISTORY CODES -
Reintroduced Native
Stocked
Breeding/Spawning Season: May
Breeding/Spawning Season: June
Breeding/Spawning Season: July
Breeding/Spawning Season: August
Breeding/Spawning Season: September
REFERENCES FOR LIFE HISTORY- 80, 252 and 136
Life History - 3 (DRAFT) - Management Practices
Species anchovy, bay
Species Id M010060
Date 27 AUG 96
MANAGEMENT PRACTICES
Management Practices - 1 (DRAFT) - References
Species anchovy, bay
Species Id M010060
Date 27 AUG 96
References
80* Robinette, H.R. 1983. Species Profiles: Life Histories and
Environmental Requirements of Coastal Fishes and Invertebrates
(Gulf of Mexico) -- Bay Anchovy and Striped Anchovy. U.S. Fish
and Wildlife Service Biol. Rep. 82(11.14) pp 15.
136 * Chesapeake Bay Program. 1988. Habitat Requirements for
Chesapeake Bay Living Resources. Chesapeake Executive
Council pp 86.
252 * Monaco, M.E., T.E.Czapla, D.M.Nelson, M.E. Pattillo. 1989.
Distribution and Abundance of Fishes and Invertebrates in Texas
Estuaries. NOAA's Estuarine Living Marine Resources Project
(ed.). U.S. Department of Commerce, Rockville, MD:107.
References - 1