(DRAFT) - Taxonomy
Species anchovy, northern
Species Id M010013
Date 27 AUG 96
TAXONOMY
NAME - anchovy, northern
OTHER COMMON NAMES - northern anchovy and anchovy
ELEMENT CODE -
CATEGORY - Fish
PHYLUM AND SUBPHYLUM - Chordata,
CLASS AND SUBCLASS - Osteichthyes,
ORDER AND SUBORDER - Clupeiformes,
FAMILY AND SUBFAMILY - Engraulidae,
GENUS AND SUBGENUS - Engraulis,
SPECIES AND SSP - mordax,
SCIENTIFIC NAME - Engraulis mordax
AUTHORITY - Girard
TAXONOMY REFERENCES - 118 and 190
Taxonomy - 1 (DRAFT) - Status
Species anchovy, northern
Species Id M010013
Date 27 AUG 96
STATUS
Coded Status
Commercial
Commercial/consumption
Commercial/bait
Existing, FMP exists
Commercial/industrial
REFERENCES FOR STATUS - 118
COMMENTS ON STATUS -
The largest catches at present are taken by the commercial fleet which
fishes for reduction purposes. Reliable records of commercial landings of
northern anchovies, used for human consumption, dead bait, feeding in fish
hatcheries and mink farms, and reduction to oil and meal, date from 1916.
During the earlier years of the fishery, annual landings averaged only 458
tons. Most of the catch from 1916 through 1921 was for reduction to oil and
meal. In 1919 a law was passed prohibiting the reduction of whole fish
except under permit. By 1921, this law had reduced anchovy landings to an
average of 150 tons for the next 17 years. During the period 1939-1946,
landings averaged 1,319 tons.
Scarcity of the Pacific sardine, Sardinops sagax caeruleus, caused
processors to begin canning anchovies in quantity in 1946; and in 1947, the
catch increased to 8,591 tons with landings exceeding canning needs and the
excess deliveries being diverted to reduction plants. In order to lower the
quantity of anchovies being reduced, The California Game and Fish Commission
required each processor to place a large proportion of each ton of anchovies
in cans (40-60% depending on can size). Anchovy canning declined with the
temporary resurgence of the sardine population through 1951. With the
collapse of the sardine fishery in 1952, anchovy landings again increased to
38,935 tons in 1953. Due to economic conditions, presumably low consumer
acceptance of canned anchovies, and an upsurge of sardine in 1958, landings
declined to 18,392 tons in 1957 and 5,263 tons in 1958. Landings remained
below 4500 tons through 1965. In November 1965, the California Fish and
Game Commission authorized a 68,040 metric ton anchovy harvest for
reduction. The 1978-79 season was the first under management of the Pacific
Fishery Management Council (PFMC) Anchovy Plan.
The live-bait industry consists of the harvest, maintenance, and sale of
small, live marine fish to anglers for use as bait and/or chum. As the
sport fishing industry grew, the demand for live-bait also increased,
causing a greater degree of specialization in boats and nets, and in the
methods of locating and distributing the live-bait. Shortly after WWII, the
demands for live-bait became sufficient to support a fleet engaged solely to
supply bait. This fishery is important today because prized sport fishes
usually prefer live-bait to any other offering *118*.
Status - 1 (DRAFT) - Distribution
Species anchovy, northern
Species Id M010013
Date 27 AUG 96
DISTRIBUTION
Distribution - 1 HABITAT ASSOCIATIONS
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Marine OW0 V 1
Marine OW0 V 1
Estuarine FL. V 1
Estuarine FL. V 1
REFERENCES FOR NWI - 118
COMMENTS ON HABITAT ASSOCIATIONS -
The northern anchovy is an epipelagic species although it has been observed
at depths of 300 m. Adults tend to remain relatively offshore. Juveniles
are often found close inshore, in shallow waters, and in estuaries, as well
as offshore. Turbid waters with high densities of edible fine particulate
matter make harbor waters an excellent habitat for larvae and juveniles.
Favorable larval habitat consists of dense plankton blooms of edible and
nutritious organisms *118*.
Habitat Associations - 1 (DRAFT) - Food Habits
Species anchovy, northern
Species Id M010013
Date 27 AUG 96
FOOD HABITS
TROPHIC LEVEL -
OMNIVORE
REFERENCES FOR TROPHIC LEVEL - 118
LIFESTAGE FOOD FOOD PART
General Crustaceans Not Specified
General Microorganisms Not Specified
Important Copepods Not Specified
Important Microorganisms Not Specified
Adult Copepods Not Specified
Adult Crustaceans Not Specified
Adult Detritus - Organic Not Specified
Adult Clupeiformes Egg/Fetus stage
Larva Copepods Egg/Fetus stage
REFERENCES FOR GENERAL FOOD - 118
REFERENCES FOR IMPORTANT FOOD - 118
REFERENCES FOR ADULT FOOD - 118
REFERENCES FOR JUVENILE FOOD - 118
REFERENCES FOR LARVAE FOOD - 118
COMMENTS ON FOOD -
The percentage of food items by number from stomach samples has been
estimated as crustaceans, 50.78%; other zooplankters, 35.76%;
phytoplankton, 10.99%; and foriegn matter, 2.4%. It was concluded that the
northern anchovy is an omnivorous species feeding predominantly on
zooplankters and to a lesser extent on phytoplankton. The most important
food items of the adults are copepods and euphausiids. Anchovies may also
feed on amorphic organic material; the extent of this behavior may be
underestimated by usual stomach contents analyses. In relation to feeding
habits, the anchovy is diurnal, feeding mostly during the day. The northern
anchovy is primarily a filter feeder, but may also be a particulate or
selective feeder, depending on the size of the available food. Experiments
have shown that prey organisms less than 1 mm are consumed by filter feeding
and organisms a few millimeters in length are taken by particulate biting.
When presented with a mixture of large and small food items, anchovies tend
to adopt the feeding mode which results in the highest caloric intake.
A significant portion of eggs spawned by anchovies may be cannibalized.
Based on 31 samples of 10 or more fish, they concluded that 17.2% of the
daily egg production was consumed. Both the evidence from stomach contents
and from theoretical filter-feeding rates were examined, and it was
concluded that cannibalism is an important mechanism regulating the
reproduction of anchovies.
Food habits of anchovy larvae have been examined. Copepod eggs and nauplii
were the most abundantly consumed food items. Unarmored dinoflagellates
Food Habits - 1 (DRAFT) - Food Habits
Species anchovy, northern
Species Id M010013
Date 27 AUG 96
may also be an important food source, especially for first-feeding anchovy
larvae. It has been hypothesized that dense local concentrations of edible
food items are required for successful first-feeding, and that recruitment
strength may be strongly influenced by the formation and destruction of
these habitats *118*.
COMMENTS ON ADULT FOOD -
The percentage of food items by number from stomach samples has been
estimated as crustaceans, 50.78%; other zooplankters, 35.76%;
phytoplankton, 10.99%; and foriegn matter, 2.4%. It was concluded that the
northern anchovy is an omnivorous species feeding predominantly on
zooplankters and to a lesser extent on phytoplankton. The most important
food items of the adults are copepods and euphausiids. Anchovies may also
feed on amorphic organic material; the extent of this behavior may be
underestimated by usual stomach contents analyses. In relation to feeding
habits, the anchovy is diurnal, feeding mostly during the day. The northern
anchovy is primarily a filter feeder, but may also be a particulate or
selective feeder, depending on the size of the available food. Experiments
have shown that prey organisms less than 1 mm are consumed by filter feeding
and organisms a few millimeters in length are taken by particulate biting.
When presented with a mixture of large and small food items, anchovies tend
to adopt the feeding mode which results in the highest calotic intake.
A significant portion of eggs spawned by anchovies may be cannibalized.
Based on 31 samples of 10 or more fish, they concluded that 17.2% of the
daily egg production was consumed. Both the evidence from stomach contents
and from theoretical filter-feeding rates were examined, and it was
concluded that cannibalism is an important mechanism regulating the
reproduction of anchovies *118*.
COMMENTS ON LARVAE FOOD -
Food habits of anchovy larvae have been examined. Copepod eggs and nauplii
were the most abundantly consumed food items. Unarmored dinoflagelllates
may also be an important food source, especially for first-feeding anchovy
larvae. It has been hypothesized that dense local concentrations of edible
food items are required for successful first-feeding, and that recruitment
strength may be strongly influenced by the formation and destruction of
these habitats *118*.
Food Habits - 2 (DRAFT) - Environment Associations
Species anchovy, northern
Species Id M010013
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
A Water Temperature: Specified in Comments
LIM Water Temperature: Specified in Comments
L Water Temperature: Specified in Comments
G Dissolved Oxygen: Specified in Comments
G Turbidity: Specified in Comments
L Turbidity: Specified in Comments
J Turbidity: Specified in Comments
L Aquatic Features: Specified in Comments
E Estuarine habitat zone: specified in comments
L Estuarine habitat zone: specified in comments
J Estuarine habitat zone: specified in comments
G Water Depth Preference: Specified in Comments
G Relation to Substrate: Unattached - normally free living
REFERENCES FOR ENVIRONMENTAL ASSOC_ - 118
REFERENCES FOR LIMITING ENVIRONMENTAL ASSOC_ - 118
REFERENCES FOR FEEDING ADULT ENVIRONMENTAL ASSOC_ - 118
REFERENCES FOR RESTING ADULT ENVIRONMENTAL ASSOC_ - 118
REFERENCES FOR BREEDING ADULT ENVIRONMENTAL ASSOC_ - 118
REFERENCES FOR FEEDING JUVENILE ENVIRONMENTAL ASSOC_ - 118
REFERENCES FOR RESTING JUVENILE ENVIRONMENTAL ASSOC_ - 118
REFERENCES FOR FEEDING LARVAE ENVIRONMENTAL ASSOC_ - 118
REFERENCES FOR RESTING LARVAE ENVIRONMENTAL ASSOC_ - 118
REFERENCES FOR EGG ENVIRONMENTAL ASSOC_ - 118
COMMENTS ON ENVIRONMENTAL ASSOCIATIONS -
TEMPERATURE: Adult anchovies have been regularly observed in waters
ranging from 12 to 20 deg C surface temperature in southern California.
There is some evidence that anchovies tend to avoid high surface
temperatures by remaining deeper in the water column, as demonstrated by
Environment Associations - 1 (DRAFT) - Environment Associations
Species anchovy, northern
Species Id M010013
Date 27 AUG 96
the anomalous conditions in November 1976. The lower lethal temperature
for adult northern anchovy was 7 deg C in laboratory acclimation tests.
DEPTH: The northern anchovy is an epipelagic species although it has been
observed at depths of 300 m.
HABITAT ZONE: Adult northern anchovies tend to remain relatively offshore.
DISSOLVED OXYGEN: Oxygen depletion has caused occasional fish kills at
Terminal Island, Los Angeles. In 1973-74, oxygen depletion due to dieoff
of massive dinoflagellate blooms caused fish kills in Fish Harbor, as well
as at other locations in coastal waters.
TURBIDITY: Anchovies have been attracted to harbor waters when the
Terminal Island Treatment Plant has malfunctioned and released high BOD
floc and wastes, and when dredging created high levels of turbidity and
resuspended edible particulates and microbiota *118*.
COMMENTS ON RESTING ADULT ENVIRONMENTAL ASSOC_ -
TEMPERATURE: Adult anchovies have been regularly observed in waters
ranging from 12 to 20 deg C surface temperature in southern California.
There is some evidence that anchovies tend to avoid high surface
temperatures by remaining deeper in the water column, as demonstrated by
the anomalous conditions in November 1976. The lower lethal temperature
for adult northern anchovy was 7 deg C in laboratory acclimation tests.
DEPTH: The northern anchovy is an epipelagic species although it has been
observed at depths of 300 m.
HABITAT ZONE: Adult northern anchovies tend to remain relatively offshore.
DISSOLVED OXYGEN: Oxygen depletion has caused occasional fish kills at
Terminal Island, Los Angeles. In 1973-74, oxygen depletion due to dieoff
of massive dinoflagellate blooms caused fish kills in Fish Harbor, as well
as at other locations in coastal waters.
TURBIDITY: Anchovies have been attracted to harbor waters when the
Terminal Island Treatment Plant has malfunctioned and released high BOD
floc and wastes, and when dredging created high levels of turbidity and
resuspended edible particulates and microbiota *118*.
COMMENTS ON FEEDING ADULT ENVIRONTAL ASSOC_ -
DISSOLVED OXYGEN: Prior to regulatory control, oxygen depletion due to
excessive dumping of high oxygen demand wastes into waters with reduced
circulation caused episodes of fish kills, but such areas provided
attractive food supplies preliminary to the oxygen depletion events.
TURBIDITY: Anchovies have been attracted to harbor waters when the
Terminal Island Treatment Plant has malfunctioned and released high BOD
floc and wastes, and when dredging created high levels of turbidity and
resuspended edible particulates and microbiota *118*.
COMMENTS ON BREEDING ADULT ENVIRONMENTAL ASSOC_ -
HABITAT ZONE: Heaviest concentrations of spawning fish occur inshore.
TEMPERATURE: Spawning usually occurs in temperatures between 12 and 15 deg
C, which are typical during late winter *118*.
Environment Associations - 2 (DRAFT) - Environment Associations
Species anchovy, northern
Species Id M010013
Date 27 AUG 96
COMMENTS ON RESTING JUVENILE ENVIRONMENTAL ASSOC_ -
DEPTH: Juvenile northern anchovies are often found in shallow waters, as
well as offshore.
TURBIDITY: Turbid waters with high densities of edible fine particulate
matter apparently made harbor waters an excellent habitat for juvenile
anchovies *118*.
COMMENTS ON RESTING LARVAE ENVIRONMENTAL ASSOC_ -
TEMPERATURE: Temperatures below 10 deg C were lethal to developing
northern anchovy larvae.
TURBIDITY: Turbid waters with high densities of edible fine particulate
matter apparently made harbor waters an excellent habitat for larval
fishes.
HABITAT FEATURES: Favorable larval habitat consists of dense plankton
blooms of edible and nutritious organisms *118*.
COMMENTS ON FEEDING LARVAE ENVIRONMENTAL ASSOC_ -
HABITAT FEATURES: Favorable larval habitat consists of dense plankton
blooms of edible and nutritious organisms. Some organisms of the proper
size, such as armored dinoflagellates, cannot be digested by the anchovy
larvae. These plankton blooms characteristically form as thin layers often
extending over large geographic areas *118*.
COMMENTS ON EGG ENVIRONMENTAL ASSOC_ -
HABITAT ZONE: Anchovy eggs are common out to 200 miles offshore and have
been taken out as far as 300 miles in some years *118*.
Environment Associations - 3 (DRAFT) - Life History
Species anchovy, northern
Species Id M010013
Date 27 AUG 96
LIFE HISTORY
See C. Life.Hist for detailed life history account
LIFE HISTORY CODES -
Breeding/Spawning Season: January
Breeding/Spawning Season: February
Breeding/Spawning Season: March
Breeding Spawning Season: April
Breeding/Spawning Season: May
Spawning Site: Standing Water
Periodicity: Active in day
COMMENTS ON LIFE HISTORY -
DISTRIBUTION AND MOVEMENT PATTERNS: The population of northern anchovy is
distributed from the Queen Charlotte Islands, British Columbia to Magdalena
Bay, Baja California. The central subpopulation ranges from approximately
San Francisco, California, 38 deg N, to Pt. Baja, Baja California 30 deg N.
The eggs and larvae are common out to 200 miles offshore and have been taken
out as far as 300 miles some years. Based on the relative abundance of
anchovy larvae, the greatest density of anchovies is in the inshore regions.
The seasonal movement patterns of the northern anchovy in northern Baja
California and southern California are not well defined. The information is
based on CF&G acoustic transect-midwater trawl surveys (frequently referred
to as the sea surveys) for the period June 1966 to February 1973. Anchovies
in this area are widely distributed from shore to 157 km seaward. The
greatest concentrations were generally within 37 km of shore and deep water
basins.
The more distant deep water basins lying 37 km to 111 km offshore
collectively contained the largest portion of the anchovy population in this
region with small but very numerous schools distributed over large areas.
Relatively small amounts of fish were found in the shallow banks and inshore
waters. School groups or concentrations rarely exceeded or equaled those of
deeper water. However, these areas may be more important than results
indicated since acoustic equipment, particularly sonar, is less efficient in
detecting schools in shallow water. In addition, a common scattered
schooling behavior in shallow water often made school enumeration difficult
or impossible.
Anchovy distribution within the Southern California Bight varied
considerably both seasonally and annually. During the fall months, a large
portion of the population was located inshore and in the more northern part
of the Bight. Schools were generally larger in size but fewer in number
than in any other season.
Commencing in late winter, an offshore and southeasterly movement occurred
coinciding with the onset of major spawning activity. At this time the
population was widely spread over large areas offshore and south of San
Pedro. Schools became extremely numerous and small, reaching peak numbers
usually in April or May. A return northward also occurred at this time with
part of the population forming large daytime surface schools during some
years. Time of formation of these schools varied from the middle of March
to late June.
Seasonal distribution in northern Baja California was less varied and
Life History - 1 (DRAFT) - Life History
Species anchovy, northern
Species Id M010013
Date 27 AUG 96
different than in southern California. During a large portion of the year,
anchovies were found in concentrations in deep water close to shore similar
to the southern California fall distribution. In contrast to southern
California, however, very few schools were detected during spring months,
and few or no fish were found more than 27.8 km offshore except near the
offshore border area between the two localities.
By far the most prevalent and common schooling behavior observed in the
Southern California Bight was the formation of small, very low density near
surface schools during daylight hours. After dark, anchovy school
invariably dispersed into a thin surface scattering layer and remained so
until the following dawn. Small low density schools near the surface were
always found over bottom depths of more than 183 m and were widely
distributed over thousands of square miles of sea surface area. Although
they were found over deep water everywhere, they were the only type schools
distributed in the more offshore areas. Schools of this type comprised an
estimated 90% of all detected by sea surveys. They were dominant type
during all seasons but were most numerous and prevalent during the late
winter and spring. At this time, schools are very small (probably 0.5 to
6.0 tons) and vary. All the actively spawning anchovies collected during
the sea survey were from this type of school.
The rapidity of vertical migration and the large differential temperatures
encountered indicate a eurythermal tolerance for anchovies.
Tagging conducted in the late 1960's demonstrated that anchovies move
alongshore between central California (San Francisco Bay to Morro Bay), and
southern California in both a northerly and southerly direction. There is
some evidence that anchovies in southern California move from offshore areas
to inshore and vice versa. Anchovies tagged off Catalina and San Clemente
Islands were later recovered in the Los Angeles-Long Beach Harbor. Tagged
fish released in the Harbor area were caught in southern California fishing
grounds and off Baja California. One tagged anchovy that was released off
San Diego was recovered at Monterey 129 days later. The fish travel at
least 370 miles at a rate of nearly 3 miles per day. Unfortunately, the
overall tag recovery rate was low.
The swimming speed of a small school of 90-100 mm SL anchovies was measured
in the laboratory at 3 body lengths per second. If a school of 130 mm SL
anchovies maintained an average speed of 3 body lengths per second, they
could travel a distance of approximately 34 km in 24 hours. This is greater
than the average velocity in the tagging study mentioned above, but it is
unlikely that a school travels in a straight line for a distance of 34 km.
Analysis of CFG anchovy sea survey data indicates that fish length at age
increases at higher latitudes. Anchovies inhabiting offshore waters within
the Southern California Bight are generally larger and older than anchovies
in the nearshore regions. In addition, preliminary studies show anchovies
of the same age are larger offshore. This indicates that mixing is limited
or systematic, creating this heterogeneity within the central subpopulation.
AGE AND GROWTH: The age of northern anchovies has been determined by annual
rings on scales and otoliths. The use of otoliths for aging was verified
and it was concluded that the age composition obtained from otoliths did not
significantly differ from that for scales. Because 40% of the anchovies
sampled from the fishery did not have readable scales, California Fish and
Game now uses otoliths for aging. It was found that scale annuli formed
during early winter and spring months. A complete annual ring for otoliths
was defined as the interface between an inner hyaline and an outer opaque
Life History - 2 (DRAFT) - Life History
Species anchovy, northern
Species Id M010013
Date 27 AUG 96
zone. The peak time of ring formation in otoliths is late spring and nearly
all new rings are completed by June 1st.
Length-at-age varies considerably with geographic locality. Anchovies
sampled by CDF&G midwater trawls show a clinal variation in length-at-age,
with progressively smaller mean lengths at more southerly latitudes.
Importantly, there are not only differences between subpopulations, but
within the central subpopulation itself. Furthermore, there is an
inshore-offshore cline in length-at-age in the Southern California Bight.
These differences suggest that the central subpopulation may not be as
homogeneous as genetic studies and tag recapture patterns indicate.
The von Bertalanffy growth curve was fitted to backcalculated lengths for
age groups 1 through 6 using otoliths. The equation is:
l(t) = L(infin.) (1-exp(-k(t-t(o))
with parameter estimates L(infin)=165.5 mm SL, K=0.2987 and t(o)=-1.714.
Total length (TL) of the anchovy in millimeters can be estimated by
multiplying standard length in millimeters by 1.17111. A 5-inch anchovy is
approximately 108 mm SL.
The length-weight relationship has been found to vary significantly within
seasons and between seasons. The following allometric relationship was
given for southern California anchovies from the 1966-67 fishery:
female: W = 1.0933 x 10^-5 L^2.98408
male: W = 8.056 x 10^-6 L^3.04859
where weight, W, is in grams and length, L, is in mm SL. For these
estimates the isometric relationship
W = 1.015 x 10^-5 L^3
appears to be approximately equivalent for the two sexes.
SIZE AND AGE AT RECRUITMENT: Recruitment is the addition of young fish from
recent year classes to the catchable portion of a fish stock. Fish recruit
to the vulnerable portion of the stock as a result of growth, behavior, and
changes in location. In the management of northern anchovies, it is
important to know the age at recruitment, location where recruitment takes
place, and the magnitude of the biomass of the incoming recruits.
Age at recruitment for anchovies is different for the live-bait and
commercial reduction fisheries. From a live-bait sampling program in the
summer of 1968, it was found that age I fish accounted for 62% of the catch
by weight. Age groups O and II contributed 15% and 19% of the catch by
weight, respectively. Age groups III and older made up 4% of the catch
(these percentages were adjusted to account for the 4% of sampled fish that
could not be aged). These data suggest that recruitment to the live-bait
fishery occurs over a 6 to 12 month age interval beginning with age O fish
in the middle of their first year of life (anchovies of this small size are
commonly referred to as "pinheads").
Age of recruitment to the California commercial reduction fishery is older
than for the live-bait fishery. Recruitment for the San Pedro reduction
fishery begins with age O fish in the winter months near the end of their
first year of life. Age I fish approach full recruitment in the following
winter near the end of their second year of life. During the late 1970's,
under conditions of lower biomass and an age composition emphasizing young
fish, age I fish recruited earlier. Age II fish are fully recruited. Most
of the southern California reduction catch is composed of reproductively
mature fish (i.e., spawning biomass). The extent of pre-spawners in the
catch is most easily measured by the incidence of fish with gonads
insufficiently developed to distinguish their sex. These fish have
Life History - 3 (DRAFT) - Life History
Species anchovy, northern
Species Id M010013
Date 27 AUG 96
comprised from 1.0% to 8.5% of the San Pedro catch, with a long term average
of 5%. The incidence of pre-spawners has risen in recent years, and is
associated with an overall decrease in average age of the catch.
The reduction fishery historically has been subject to a 5-inch total length
(108 mm SL) minimum size limit and a 3-mile nearshore area closure. These
restrictions have influenced the size and age at recruitment. A comparison
of mean length of anchovies sampled by the reduction fishery and by CDF&G
midwater trawls in the same area was made. The mean lengths at age are
similar for ages greater than about 1.5, but differ for younger, smaller
fish. The difference in small fish mean lengths suggests that the fishery
selects for the larger fish in the cohort. Importantly, this selection
appears to happen only in the size range below the historic legal size
limit. Most of the smaller younger fish are associated with nearshore areas
which were sampled by the CDF&G trawl, but are closed to the reduction
fishery. It is not clear to what extent the 5-inch minimum size limit has
influenced the lengths at age.
Recruitment to the reduction fishery is delayed because small fish typically
inhabit nearshore areas; historically the fishery has been prohibited from
operating in nearshore areas in southern California. There is a definite
onshore-offshore gradient in the size distribution of the anchovies sampled
by midwater trawls on CF&G sea surveys. Anchovies in nearshore stations
were generally smaller than those taken in the offshore areas while the
larger and older fish exhibited a greater offshore distribution. Results of
a nearshore survey indicate that age O anchovies occurred in the nearshore
zone with a higher frequency relative to offshore surveys of previous years.
This and the age composition of the live-bait catch strongly suggest that
the younger anchovies (ages O and I) predominate in the nearshore zone, the
area of the bait fishery. These younger fish make only a small contribution
to the spawning biomass because many are probably sexually immature.
Recruitment to the Mexican fishery occurs at a smaller size and younger age.
Anchovies in northern Baja California are smaller at age than in southern
California. Moreover, the Mexican fishery is not subject to the size or
area restrictions that affect the California fishery. The young of the year
are recruited to the Mexican fishery in the fall, at 6 months of age and a
length of 80 to 90 mm SL. An estmated 18% of the Mexican landings were fish
smaller than 100 mm SL. The Mexican fishery uses a smaller mesh size than
does the California purse seine fishery.
MATURITY AND REPRODUCTION: Anchovy spawning occurs in all nomths of the
year, but is most intense from January to May. Spawning takes place in open
waters throughout the range. The geographic distribution of larvae expands
and contracts with changes in population size. Spawning occurs from sunset
to midnight, and adults appear to spawn about once per week during the peak
season.
Size at sexual maturity may vary with geographic location and population
size, but information is insufficient to accurately define the pattern. In
the early 1950's, central California anchovies were found to mature at a
relatively large size, ca. 120 mm SL. During the peak abundances of the
mid-1970's, CDF&G found nearly all anchovies to be mature at two years of
age. Recent histological analysis shows anchovies to mature at small sizes,
corresponding to ages of less than one year. In 1978 all fish sampled were
mature (length 70 mm SL and above). In 1979, length at 50% maturity was 96
mm SL. Inclusion of more recent unpublished data indicates that about 90%
of the age O-I fish are sexually mature. Age at onset of reproductive
Life History - 4 (DRAFT) - Life History
Species anchovy, northern
Species Id M010013
Date 27 AUG 96
maturity is density dependent in many species, and it appears likely that
the early maturation seen in recent years is related to decreased population
sizes. Small fish that have attained maturity typically have a slightly
lower weight-specific fecundity, slightly lower spawning frequency during
the peak spawning season, and a shorter spawning season.
SEX COMPOSITION: Male and female anchovies appear to occur in the
population in equal numbers. The overall female to male ratio in CDF&G
midwater trawl samples from 1966 to 1975 was 1.09:1, only slightly greater
than the expected 1:1 ratio. Still, there were an inordinate number of
samples with a large proportion of either males or females, particularly
during the peak spawning months of February to June. Sex composition
sampled by midwater trawl has been shown to vary with time of night. The
largest discrepancies from 1:1 occur during the hours of peak spawning. All
evidence points to a tendancy for male and female fish to segregate in
association with spawning behavior.
The California purse seine fishery takes a disproportionate fraction of
females, and a similar tendancy has been shown for the Baja California
fishery. A clear trend for the imbalance to increase with age of the fish
has been shown, with the two sexes of young fish being captured in
approximately equal numbers. Recently, fishery sex ratios have declined
toward equal catches of males and females. The decline in percentage female
is probably related to the overall decline in average age of the catches
since 1975, although the relationship is not precise.
The previous FMP voiced concern that the disproportionate harvest of females
could result in decreased productivity. If the reproductive potential of
the population resides in the female portion of the biomass, the unbalanced
harvest has a greater impact on productivity than indicated by models
assuming balanced harvests. However, if the recent tendancy toward a
balanced sex ratio is a natural consequence of age composition changes due
to exploitation, the problem may be largely self-correcting.
MORTALITY: The age composition of anchovy from CDF&G midwater trawl catches
has been used to estimate the total mortality rate (Z) of adults age 2+.
Long-term fluctuations in apparent adult mortality have been shown, and it
has been noted that the decreased life span of recent year-classes is
suggestive of increased mortality.
The age composition data has been reanalylized using a technique that
accounts for variable recruitment, changes in biomass, and the commercial
harvest. It was noted that anchovy are incompletely available to the trawl
through their second birthday, therefore mortality at ages 1 and 2 must be
assumed to be the same as mortality at age 3. Age-specific natural
mortality rate (M=Z-F) during the period from 1968-1981 has averaged 0.50
for aged 1-3, 0.97 for age 4, and 1.19 for age 5. The long-term trend
identified previously was evident in this analysis; minimum mortality
occurred during 1971-74.
Fishing mortality (F) increased about ten fold during the period from 1974
to 1978 and currently is similar in magnitude to natural mortality. The
average relative availability of age classes to the fisheries is as follows:
Age 1 2 3 4 5
F(i)/F(total) .66 1.74 2.26 1.80 1.01
The following hypothetical stable population was constructed with the
fishery parameters observed during 1977-1982. The recruitment level (i.e.,
initial biomass) was selected to yield a result similar to that observed
during recent years. Biomass here refers to total biomass, not spawning
Life History - 5 (DRAFT) - Life History
Species anchovy, northern
Species Id M010013
Date 27 AUG 96
biomass.
Age 1 2 3 4 5 6 sum
wt(g) 12.2 17.2 20.5 23.4 26.9 30.4
M .50 .50 .50 .97 1.19 1.19
F .28 .69 .96 .81 .81 .81
initial
biomass
(10^3mtons) 610 396 145 39 8 1 1198
catch
(10^3mtons) 121 159 73 15 3 0 371
The average natural mortality rate (M) of all ages combined is 0.55, while
the average natural mortality rate of biomass (M-G) of this population is
0.36. The equilibrium biomass with no fishery is 1939 thousand m tons.
PREDATION: The anchovy is a prey species throughout all its life stages:
egg, larvae, juvenile, and adult. The list of predators is long and
includes almost every predator species of fish, birds and mammals in the
California Current region. Anchovy eggs and larvae, as part of the
zooplankton complex, fall prey to the assortment of invertebrate and
vertebrae planktivores including adult anchovies. Because of the rapid
larval growth rates, the duration of this life stanza is about 2 to 4
months, but the mortality is high. As juveniles in the nearshore zone,
anchovies are vulnerable to game fish of recreational and commercial
importance although these species must compete with a variety of other
predators of less recreational value. Important recreational species in
southern California are Pacific bonito (Sarda chiliensis), yellowtail
(Seriola dorsalis), California barracuda (Sphyraena argentea), and in
northern California salmon (Oncorhynchus sp.), and striped bass (Roccus
saxatilis). Less valued species such as Pacific electric ray (Torpedo
californica) and the abundant white croaker (Genyonemus lineatus) have been
observed feeding on anchovy schools.
As adults offshore, anchovies are fed upon by numerous predators that
include recreationally and commercially important fish (i.e., albacore,
bonito, Pacific mackerel), marine mammals, and marine birds. Many of these
predators are opportunistic feeders preying on whichever species is
available. Unfortunately, very little is known about the actual quantities
of anchovy consumed or the percentage of anchovies in the predator diets in
relation to other forage species. The annual fraction of adult anchovies
that succumb to predation can be calculated from the equation:
P/B = M(1-e^-(Z-G))/ (Z-G)
where P/B is the ratio of predator consumption to initial biomass; M,Z, and
G are instantaneous rates of natural mortality, total mortality and body
growth, respectively. Predators comsume 46% of the initial spawning biomass
of anchovies in an average year. This percentage will decrease, as will the
average biomass, as fishing pressure increases. The biomass of pre-recruit
anchovies which is available to predators cannot be measured directly, but
analysis shows that a year class achieves maximum biomass before first
spawning.
FOOD HABITS:
The percentage of food items by number from stomach samples has been
estimated as crustaceans, 50.78%; other zooplankters, 35.76%;
phytoplankton, 10.99%; and foriegn matter, 2.4%. It was concluded that the
northern anchovy is an omnivorous species feeding predominantly on
zooplankters and to a lesser extent on phytoplankton. The most important
Life History - 6 (DRAFT) - Life History
Species anchovy, northern
Species Id M010013
Date 27 AUG 96
food items of the adults are copepods and euphausiids. Anchovies may also
feed on amorphic organic material; the extent of this behavior may be
underestimated by usual stomach contents analyses. In relation to feeding
habits, the anchovy is diurnal, feeding mostly during the day. The northern
anchovy is primarily a filter feeder, but may also be a particulate or
selective feeder, depending on the size of the available food. Experiments
have shown that prey organisms less than 1 mm are consumed by filter feeding
and organisms a few millimeters in length are taken by particulate biting.
When presented with a mixture of large and small food items, anchovies tend
to adopt the feeding mode which results in the highest calotic intake.
A significant portion of eggs spawned by anchovies may be cannibalized.
Based on 31 samples of 10 or more fish, they concluded that 17.2% of the
daily egg production was consumed. Both the evidence from stomach contents
and from theoretical filter-feeding rates were examined, and it was
concluded that cannibalism is an important mechanism regulating the
reproduction of anchovies.
Food habits of anchovy larvae have been examined. Copepod eggs and nauplii
were the most abundantly consumed food items. Unarmored dinoflagelllates
may also be an important food source, especially for first-feeding anchovy
larvae. It has been hypothesized that dense local concentrations of edible
food items are required for successful first-feeding, and that recruitment
strength may be strongly influenced by the formation and destruction of
these habitats.
HABITAT:
The northern anchovy is an epipelagic species although it has been observed
at depths of 300 m. Adults tend to remain relatively offshore. Juveniles
are often found close inshore, in shallow waters, and in estuaries, as well
as offshore. Turbid waters with high densities of edible fine particulate
matter make harbor waters an excellent habitat for larvae and juveniles.
Favorable larval habitat consists of dense plankton blooms of edible and
nutritious organisms.
TEMPERATURE: Adult anchovies have been regularly observed in waters
ranging from 12 to 20 deg C surface temperature in southern California.
There is some evidence that anchovies tend to avoid high surface
temperatures by remaining deeper in the water column, as demonstrated by
the anomalous conditions in November 1976. The lower lethal temperature
for adult northern anchovy was 7 deg C in laboratory acclimation tests.
DEPTH: The northern anchovy is an epipelagic species although it has been
observed at depths of 300 m.
HABITAT ZONE: Adult northern anchovies tend to remain relatively offshore.
DISSOLVED OXYGEN: Oxygen depletion has caused occasional fish kills at
Terminal Island, Los Angeles. In 1973-74, oxygen depletion due to dieoff
of massive dinoflagellate blooms caused fish kills in Fish Harbor, as well
as at other locations in coastal waters.
TURBIDITY: Anchovies have been attracted to harbor waters when the
Terminal Island Treatment Plant has malfunctioned and released high BOD
floc and wastes, and when dredging created high levels of turbidity and
resuspended edible particulates and microbiota *118*.
REFERENCES FOR LIFE HISTORY- 118
Life History - 7 (DRAFT) - Management Practices
Species anchovy, northern
Species Id M010013
Date 27 AUG 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Existing Regulating commercial harvest levels
Existing Regulating harvest - setting bag/creel limits
Existing Regulating harvest - setting seasons
Existing Regulating harvest - setting size limits
Existing Regulating commercial harvest gear types
REFERENCES FOR EXISTING MANAGEMENT PRACTICES - 118
COMMENTS ON MANAGEMENT PRACTICES -
The Pacific Fishery Management Council initiated the development of an FMP
for northern anchovy in January of 1977 and, after reviewing and revising
several drafts, approved and submitted a final draft to the Secretary of
Commerce in June of 1978. Regulations implementing the FMP were published
in the Federal Register on September 13, 1978. A brief summary of the main
management provisions of the 1978 FMP are as follows:
1) Optimum yield (OY) from the central stock of northern anchovies is equal
to (a) zero, if estimated spawning biomass is less than 100 thousand short
tons, (b) 18 thousand short tons, if spawning biomass is between 100
thousand and 1 million short tons, or (c) 18 thousand short tons or one
third of the biomass in excess of 1 million, whichever is greater, when
spawning biomass exceeds 1 million short tons.
2) The overall harvest quota in the United States' Fishery Conservation
Zone (FCZ) is equal to 70% of the optimum yield.
3) Twelve thousand six hundred short tons of the U.S. quota is reserved for
the non-reduction fishery.
4) A portion of the reduction fishery quota equal to the smaller of 10,000
short tons or 10% of the total reduction quota is reserved for the fishery
north of Pt. Buchon.
5) No reduction fishery is allowed from July 1 through June 30 north of Pt.
Buchon, July 1 through September 14 south of Pt. Buchon, and February 1
through March 30 both north and south of Pt. Buchon. Non-reduction fishing
is permitted all year.
6) A size limit of 5 inches is imposed upon the reduction fishery but not
upon the non-reduction fishery. Incidental catch of short fish is allowable
in quantities of less than 15% by weight in any load.
7) Certain portions of the FCZ are closed to anchovy reduction fishing.
In November 1982 the PFMC has considered four amendments to the original FMP
prior to the present revision: three of these amendments were approved and
submitted to the Secretary of Commerce and have been implemented. The first
amendment changed the method of specifying the domestic annual harvest and
added an estimate of domestic processing capacity and expected annual level
of domestic processing as required by P.L. 95-354 which amends the FCMA.
The purpose of the second amendment was to increase the domestic fishing
fleet's opportunity to harvest the entire optimum yield from the FCZ by
re-allocating all or a portion of the northern area's reserve of northern
anchovy reduction quota to both the northern and southern areas if the
northern fishery had not harvested or demonstrated an intent to harvest the
full reserve by the end of the fishing season. The third amendment was
Management Practices - 1 (DRAFT) - Management Practices
Species anchovy, northern
Species Id M010013
Date 27 AUG 96
intended primarily as a safeguard during the interim period when egg
production estimates of spawning biomass were converted to larva census
equivalent biomass estimates for calculation of the annual quota. An
amendment that replaces the 5 inch size limit with a minimum mesh size
requirement was sent to the Secretary of Commerce by the PFMC in 1982, and
was implemented in 1983 *118*.
Management Practices - 2 (DRAFT) - References
Species anchovy, northern
Species Id M010013
Date 27 AUG 96
References
118* Frey, H., J. Ginter, D. Huppert, A. MacCall, R. Methot, G. Stauffer, C.
Thomson. 1983. Northern anchovy: fishery management plan incorporating
the final environmental impact statement and draft regulatory inpact
review/initial regulatory flexibility analysis. Pacific Fishery Management
Council and National Marine Fisheries Service, Fishery Management Plan
Amendment #5, 156 pp.
190 * Robins, C.R., R.M. Bailey, C.E. Bond, J.R. Brooker, E.A.
Lachner, R.N. Lea, and W.B. Scott. 1980. A list of common and
scientific names of fishes from the United States and Canada.
American Fisheries Society, Special Publ. No. 12, 4th edition
References - 1