(DRAFT) - Taxonomy
Species squid, market
Species Id M060180
Date 26 AUG 96
TAXONOMY
NAME - squid, market
OTHER COMMON NAMES -
ELEMENT CODE -
CATEGORY - Aquatic Molluscs
PHYLUM AND SUBPHYLUM - Mollusca,
CLASS AND SUBCLASS - Cephalopoda, Coleoidea
ORDER AND SUBORDER - Decapoda, Teuthoidea
FAMILY AND SUBFAMILY - ,
GENUS AND SUBGENUS - Loligo,
SPECIES AND SSP - opalescens,
SCIENTIFIC NAME - Loligo opalescens
AUTHORITY -
TAXONOMY REFERENCES - 209 and 210
Taxonomy - 1 (DRAFT) - Status
Species squid, market
Species Id M060180
Date 26 AUG 96
STATUS
Coded Status
Commercial/bait
Commercial/consumption
REFERENCES FOR STATUS - 209
COMMENTS ON STATUS -
Loligo opalescens is generally thought to be an underutilized resource
along the extent of its range. However, in concentrated fishing areas, such
as Monterey Bay, both the abundance and size of the squid have been
decreasing. It is not known whether these significantly reduced catches are
due to overfishing or to natural changes in abundance. In the mid 1900s,
Monterey fishermen succeeded in banning the use of lights on the traditional
fishing grounds in an attempt to discourage land-based processors from
attracting the squid to the docks. In 1984, the Oregon Department of Fish
and Wildlife establisted a 9 mt per boast, per day, trip limit for L.
opalescens. This action was largely in response to the local processors'
concern over their ability to handle unpredictable fluctuations in squid
landings and still produce a top quality product.*209*
Status - 1 (DRAFT) - Distribution
Species squid, market
Species Id M060180
Date 26 AUG 96
DISTRIBUTION
Distribution - 1 HABITAT ASSOCIATIONS
Habitat Associations - 1 (DRAFT) - Food Habits
Species squid, market
Species Id M060180
Date 26 AUG 96
FOOD HABITS
TROPHIC LEVEL -
CARNIVORE
REFERENCES FOR TROPHIC LEVEL - 209
LIFESTAGE FOOD FOOD PART
Adult Crustaceans Larva stage
Adult Polychaetes Juvenile stage
Adult Microcrustaceans Not Specified
Larva Plankton Not Applicable
Larva Crustaceans Larva stage
Juvenile Crustaceans Not Specified
Juvenile Polychaetes Not Specified
Juvenile Fish Not Specified
Juvenile Squid, Octopus Not Specified
Juvenile Clupeiformes Not Specified
Juvenile See Comments; Food Not Applicable
REFERENCES FOR ADULT FOOD - 209
REFERENCES FOR JUVENILE FOOD - 209
REFERENCES FOR LARVAE FOOD - 209
COMMENTS ON ADULT FOOD -
Adult squid usually tend to feed in the water column but benthic organisms,
particularly on the spawning grounds, also play a part in their diet. Adult
squid mainly feed on crustaceans, the most important being euphausiids,
mysids and megalops larvae. Juvenile gastropods, nereid polychaetes, fish
and dead or dying squid play a lesser role. Egg-like spheres and sand
particles also have been found in stomach contents of squid. It was found
in field studies that males tended to ingest cephalopod parts more
frequently and to eat more megalops per meal than did females. Since L.
opalescens spawn mostly in sheltered bays, local industrial discharges could
alter the local community structures. Other factors include competition
with crustacea-eating fishes, productivity, temperature and circulation of
the water body. Squid are voracious predators until the time of spawning,
when both sexes, especially the female, tend to eat less.*209*
COMMENTS ON JUVENILE FOOD -
Juvenile squid are both demersal and pelagic feeders. Feeding occurs mostly
during daylight hours in 20-50 m of water. Juvenile squid are carnivores
that feed heavily on crustaceans, fish, polychaetes and cephalopods,
including L. opalescens. Noncrustaceans also play a role in the diet of
juvenile squid. Gastropods, cumaceans, megalops larvae, the anchovy,
Engraulis mordax, and bottom debris are also ingested. When feeding on
fishes or shrimps in the laboratory, the squids ate only the flesh,
discarding the fish heads and bones or, in the case of crustaceans, the
entire exoskeleton.*209*
Food Habits - 1 (DRAFT) - Food Habits
Species squid, market
Species Id M060180
Date 26 AUG 96
COMMENTS ON LARVAE FOOD -
Being weak swimmers, hatchlings feed on organisms that drift by them on the
surface or mid-level in the water column. Squid hatchlings feed on small
planktonic crustaceans: crab larvae, copepods, penaeid shrimp myses, post
larvae and in the laboratory, brine shrimp. No data for prey density
requirements for hatchlings in the wild are available. For rearing in the
laboratory, it was calculated that a 1-day-old hatchling would require 23
Artemia sp. nauplii per day to meet normal metabolic needs. A 7-10 mm,
approximately 2-month-old, hatchling would require 225 nauplii or 20 anchovy
larvae per day.*209*
Food Habits - 2 (DRAFT) - Environment Associations
Species squid, market
Species Id M060180
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
BA Water Temperature: Specified in Comments
BA Biodegradable Organics: Specified in Comments
J Currents: upwelling
BA Currents: upwelling
E Water Temperature: Specified in Comments
REFERENCES FOR BREEDING ADULT ENVIRONMENTAL ASSOC_ - 209
REFERENCES FOR RESTING JUVENILE ENVIRONMENTAL ASSOC_ - 209
REFERENCES FOR EGG ENVIRONMENTAL ASSOC_ - 209
COMMENTS ON ENVIRONMENTAL ASSOCIATIONS -
The warming trend associated with El Nino was followed by greatly reduced
abundances, possibly due to delay in upwelling resulting in food for L.
opalescens hatchlings being unavailable.*209*
COMMENTS ON BREEDING ADULT ENVIRONMENTAL ASSOC_ -
The temperature of the water appears to have a significant effect on the
timing and duration of spawning. The presence of squid in high
concentrations on the spawning grounds seems to be tied to the warming of
the water that follows by several months the cessation of upwelling. It is
thought that a warming trend may trigger spawning by stimulating the optic
gland that regulates the maturation of male squid gondads and sperm
production. The optic gland also may be affected by day length.*209*
COMMENTS ON RESTING JUVENILE ENVIRONMENTAL ASSOC_ -
Juvenile squid are believed to generally occur in the perlagic environment
offshore. However, trawl samples have indicated that some young squid (<40
mm) remain in or return to sheltered bays near the spawning grounds. In
addition, spawning schools may include a high proportion of immature
individuals. However, juvenile L. opalescens only occasionally are
collected in bottom and mid-water trawls, and their occurrences are so few
and sporadic that their distributional patterns, migrations or interannual
variability cannot be assessed.*209*
COMMENTS ON FEEDING JUVENILE ENVIRONMENTAL ASSOC_ -
Timing and intensity of upwelling and current regimes may have a
significant impact on the abundances and availability of prey for squid
Environment Associations - 1 (DRAFT) - Environment Associations
Species squid, market
Species Id M060180
Date 26 AUG 96
juveniles. These factors also may be important in determining the squid's
exposure to predators and their ability to be transported to more favorable
environments.*209*
COMMENTS ON FEEDING LARVAE ENVIRONMENTAL ASSOC_ -
Large-scale patterns for squid are poorly understood. It is theorized that
young squid, upon hatching, swim toward light, thus reaching the surface
where they become dispersed by currents. Few hatchlings have been found in
surface, mid- or bottom water near the spawning grounds. This finding led
researchers to suggest that L. opalescens hatchlings may be quickly
dispersed to deeper water offshore by bottom currents. L. opalescens
hatchlings are present year-round but their peak abundances follow peak
spawning events by several weeks. The exact timing is dependent on the
temperature of the water.*209*
COMMENTS ON EGG ENVIRONMENTAL ASSOC_ -
The rate of embryonic development is dependent on water temperature. The
approximate number of days for eggs to hatch at various temperatures was 90
at 8 degrees C., 60 at 10 degrees C., 30 at 13.6 degrees C., and 15-23 days
at 16 degrees C. In laboratory experiments, eggs developed in 30 days at 15
degrees C. The distribution of eggs is dependent upon suitable conditions
for spawning and for the incubation of eggs. The body of water needs to be
somewhat protected and well oxygenated, with a sand or mud substrate.
Environment Associations - 2 (DRAFT) - Life History
Species squid, market
Species Id M060180
Date 26 AUG 96
LIFE HISTORY
Spawning Adults
Females are considered to be sexually mature when eggs are present in the
oviduct and males are mature when spermatophores are present in the
spermatophoric sac. The size at maturity is variable for both sexes. The
smallest mature male and female L. opalescens were reported to have a dorsal
mantle length (DML) of 72 mm and 81 mm, respectively. Generally, DML of
mature males ranges from 110 mm to 190 mm and of females from 100 mm to 180
mm. Weight of L. opalescens under 120 mm is about the same for both sexes,
whereas weight of larger males exceeds that of females of the same length.
In the commercial catch, average weights for males and females of average
DML of 150 mm and 140 mm were 70 g and 50 g, respectively.
After a single annual spawning event, both male and female L. opalescens
die. There are two peak spawning seasons, although eggs have been observed
year-round. L. opalescens is a demersal spawner. The females anchor egg
capsules, by means of a thin stalk, to previously laid egg capsules or to
the substrate. The preferred substrate is generally mud, and or gravel.
Large clusters of egg capsules may be formed; some are up to 12 m in
diameter and 1.3 m in height. An egg capsule may contain up to 300 eggs and
a female may extrude up to 20-30 capsules during a spawning event. Spawning
occurs throughout the year, but the population exhibits biannual spawning
peaks. Such events generally are progressive and occur early in the year
in the southernmost parts of the range. Spawning aggregations of L.
opalescens migrate seasonally to shallow inshore spawning grounds to mate
and lay their eggs. Spawning grounds are located in sheltered bays or
coves, often near submarine canyons. Egg capsules have been observed in
depths ranging from 3 to 180 m. Major spawning grounds are Monterey Bay,
waters around Santa Rosa, Santa Cruz, and Santa Catalina islands and several
coastal localities in southern California.
Parasites
Two types of parasites have been reported to infest L. opalescens. They
were found in the eye, stomach, digestive caeca, mantle cavity and the
mesenteries. An infection rate of 77% was found in one study, but no
mention was made of the effect or impact. It was noted that occasionally
pleuroceroid larvae of tetraphyllidean cestodes are found in the caecum or
elsewhere.
Eggs
The rate of embryonic development is dependent on water temperature. The
approximate number of days for eggs to hatch at various temperatures was 90
at 8 degrees C., 60 at 10 degrees C., 30 at 13.6 degrees C., and 15-23 days
at 16 degrees C. In laboratory experiments, eggs developed in 30 days at 15
degrees C. The distribution of eggs is dependent upon suitable conditions
for spawning and for the incubation of eggs. The body of water needs to be
somewhat protected and well oxygenated, with a sand or mud substrate.
Predation
Predation apparently is infrequent while eggs are in the egg capsules.
Predators include various species of starfish, a Lytechinus urchin and
possibly a worm, Capitella ovincola, which is found in the egg capsules. As
the abundance, selectivity or rates of predation are unknown, the effect of
Life History - 1 (DRAFT) - Life History
Species squid, market
Species Id M060180
Date 26 AUG 96
predation on the survival of eggs has not been determined.
Larvae
L. opalescens does not have a true larval stage; eggs hatch as miniature
adults with diproportionate small fins, which are called hatchlings. The
mean hatching size is 2.7 mm mantle length. Shortly after hatching, the
mantle is firm, cylindrical and 1.5 to 2 times as long as wide. Hatchlings
can live up to several days on the yolk sac. As squids do not go through
metamorphic changes as do other mollusks, stages from hatchlings to
juveniles are not delineated. However, there do seem to be subtle
physiological and behavioral changes at about 15 mm DML, or at approximately
50 days of age. Squid less than 15 mm DML are not able to maintain a
stationary position against a current and generally do not school. A change
in swimming posture during the positioning phase of attack also occurs with
squid larger than 15 mm DML. Large-scale patterns for L. opalescens are
poorly understood. It is theorized that young aquid, upon hatching, swim
toward light, thus reaching the surface where they become dispersed by
currents. Few hatchlings have been found in surface, mid- or bottom water
near the spawning grounds. L opalescens hatchlings may be quickly dispersed
to deeper water offshore by bottom currents. L. opalescens hatchlings are
present year-round but their peak abundances follow peak spawning events by
several weeks. The exact timing is dependent on the temperature of the
water.
Juveniles
Laboratory studies have shown that at 15 mm DML L. opalescens become more
powerful and maneuverable swimmers, begin to school, accept different types
of prey and are found deeper in the water column than smaller squid. At
this stage they are approximately 70-80 days old. L. opalescens are
believed to generally occur in the pelagic environmentl offshore. However,
trawl samples have indicated that some young squid (<40 mm) remain in or
return to sheltered bays near the spawning grounds. Juvenile squid are only
occasionally collected in bottom and mid-water trawls, and their
distributional patterns, migrations or interannual variability cannot be
assessed. Laboratory studies of captured squid indicate that juvenile squid
are obligate schoolers, exhibit parallel orientation of individuals and
strong cohesiveness and maintain school structure primarily by visual cues.
Field observations show that juveniles are usually gound in school made up
of animals of about the same size. It was suggested that the main function
of schooling behavior is defense against predation.*209*
LIFE HISTORY CODES -
Breeding Spawning Season: April
Breeding/Spawning Season: May
Breeding/Spawning Season: June
Average Number of Offspring/Reproductive Effort: 101-
Periodicity: Cyclic day/night activity rhythms
REFERENCES FOR LIFE HISTORY- 209
Life History - 2 (DRAFT) - Management Practices
Species squid, market
Species Id M060180
Date 26 AUG 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Adverse Applying other toxicants
Existing Regulating harvest - setting bag/creel limits
Existing Other management practices [specified in comments]
REFERENCES FOR ADVERSE MANAGEMENT PRACTICES - 209
REFERENCES FOR EXISTING MANAGEMENT PRACTICES - 209
COMMENTS ON MANAGEMENT PRACTICES -
Loligo opalescens is generally thought to be an underutilized resource
along the extent of its range. However, in concentrated fishing areas, such
as Monterey Bay, both the abundance and size of the squid have been
decreasing. It is not known whether these significantly reduced catches are
due to overfishing or to natural changes in abundance. In the mid 1900s,
Monterey fishermen succeeded in banning the use of lights on the traditional
fishing grounds in an attempt to discourage land-based processors from
attracting the squid to the docks. In 1984, the Oregon Department of Fish
and Wildlife establisted a 9 mt per boast, per day, trip limit for L.
opalescens. This action was largely in response to the local processors'
concern over their ability to handle unpredictable fluctuations in squid
landings and still produce a top quality product.*209*
Management Practices - 1 (DRAFT) - References
Species squid, market
Species Id M060180
Date 26 AUG 96
References
209 * Maupin, Sara. 1988. Species Synopses: Life Histories of
Selected Fish and Shellfish of the Northeast Pacific and Bering
Sea. Wilimovsky, N. J., L. S. Incze, S. J. Westrheim (eds.).
University of Washington:8311.
References - 1