R. Michael Laurs and Ronald C. Dotson. 1992. Albacore. In California’s
Living Marine Resources and Their Utilization. W. S. Leet, C. M. Dewees,
and C. W. Haugen (Eds.), 136-138. Sea Grant Extension Program, Department of
Wildlife and Fisheries Biology, University of California, Davis, CA 95616.
History of the Fishery
The albacore (Thunnus alalunga) is a highly migratory species
valuable to commercial and sport fisheries in California. Commercial
albacore fishing began off southern California near the turn of this
century. In 1903, an experimental pack of 700 cases of albacore led to the
development of the U.S. tuna canning industry. The fishery expanded quickly
in response to the almost instantaneous high demand for canned tuna, which
quickly outpaced the supply of albacore. By the 1920's, bluefin, yellowfin,
and skipjack tuna were also being canned. However, albacore is the only tuna
species, which may be marketed as "white meat tuna," and it brings a premium
price at the dock and in the can.
The geographic range of the U.S. north Pacific albacore fishery has expanded
during the past eight decades. Early commercial fishermen made one-day trips
within coastal waters off southern California. The fishery extended
northward and seaward, and by the late 1930's it reached to waters off the
Pacific Northwest and several hundred miles offshore. There was a major
offshore extension in the mid-1970's across the central Pacific to about the
Dateline. However, beginning in the mid-1980's, there has been a general
shrinking of the breadth of the fishery to within about 500-600 miles of the
Pacific west coast
Since the early 1980's, about 90 percent of the annual albacore catch has
been made by trolling jigs and 10 percent by live-bait pole-and-line
fishing. In earlier years, live-bait fishing sometimes accounted for up to
40 percent of the annual catch. In some years, up to a few hundred tons of
albacore maybe caught by purse seine vessels, usually incidental to bluefin
tuna fishing. California-based drift gillnet vessels also catch small
quantities of albacore incidental to shark and swordfish fishing. Generally,
two fishermen conduct fishing operations from troll vessels and three to
five fishermen from live-bait vessels. Many vessels, which fish for
albacore, also take part in other fisheries. Their participation in the
albacore fishery depends on the price and availability of albacore, the
success of other fisheries, and weather conditions during the albacore
season. In the 1940's, there were about 500 vessels in the albacore fleet. A
high of 3,000 boats was reached in 1950; the number dropped to about 1,000
vessels by 1960, climbed to 2,100 vessels during the 1970's, and dropped to
fewer than 500 boats in the late 1980's. The average size of albacore jig
boats is about 45-50 feet, with a sea-keeping capability of about one to two
weeks. In recent years, there has been a steady increase in vessels of 60-80
feet, which are capable of fishing at sea for six to eight weeks. The larger
vessels may participate in a virtual year-round albacore fishery by fishing
in mid-North Pacific waters, the North American coastal fishery, and in the
recently established South Pacific albacore fishery.
The North Pacific albacore stock is also harvested by Asian fisheries,
including a Japanese pole-and-line fishery in the spring, which targets two
to five year old fish off the Japanese coast eastward to near the Emperor
Seamount chain. There are also Japanese, Taiwanese and South Korean longline
fisheries, which target five to seven plus year old albacore in subtropical
and temperate waters across much of the Pacific during winter. Beginning in
the early 1980's, Asian high-seas drift gillnet fisheries have targeted two
to four year old albacore across much of the Pacific. In addition, there is
a relatively small Canadian troll fishery for albacore during years when
they are distributed in waters off British Columbia.
In the late 1890's and early 1900's, sport fishermen on Private boats would
fish for large bluefin tuna inside the Channel Islands. The 10-20 pound
albacore, which would strike the bait intended for a 100-pound bluefin, were
considered a nuisance and were usually tossed over the side after landing.
Gradually, some boats began to carry spoils anglers as paying passengers,
who quickly came to appreciate the fighting and eating qualities of the
albacore, or "longfin tuna," as they are often called. The fishing for hire
party boats gained in popularity in southern California, and by the 1950's,
about 100-150 fished for albacore in near shore waters.
In the 1960's, the albacore runs began to shift outside the Channel Islands
and to waters off upper Baja California, over 50 miles from southern
California ports. In response to this, larger commercial passenger fishing
vessels with a greater range were built. Today, there are about 40 large
commercial passenger fishing vessels, mostly in southern California and some
in the Morro Bay and San Francisco area, that are capable of carrying 20 to
60 sport fishermen on one to three-day fishing trips. In addition to the
large vessels, there are about 50 to 60 smaller vessels that typically are
chartered to smaller fishing parties of around six.
As the result of increased numbers of private boats, the ready availability
of modem commercial passenger-carrying fishing vessels (CPFV), and
improvements in sport fishing gear, albacore sport fishing has become
increasingly attractive to California anglers. In fact the first albacore of
the season caught in southern California waters sets off "albacore fever"
among recreational fishermen. No other sport fish in southern California
elicits the excitement exhibited each year by the thousands of fishermen
pursuing albacore. Over 120,000 anglers go out on southern California CPFVs
in search of albacore during the course of a season. Albacore sport fishing
in southern California contributes about $23 million to the local economy
through the purchase of the boat ticket tackle, food, gas, licenses, and
Status of Biological Knowledge
The albacore is a highly advanced teleost with many specialized adaptations.
It is capable of thermoregulation, has a high metabolic rate, an advanced
cardiovascular system, specializations in the circulatory system and
blood/gas exchange systems, distinctive enzyme and complement systems, and
high energetic costs for migration which maybe partly met by utilization of
The distribution of albacore is cosmopolitan in subtropical and temperate
waters of all oceans. Off the coast of North America, the distribution
during summer and fall months may range from lower Baja California,
northward to the Queen Charlotte Islands, Canada, and occasionally into the
Gulf of Alaska.
There is a growing body of evidence that the North Pacific albacore
population is not as homogeneous as is usually assumed. Results from
albacore tagging studies suggest that at least two proposed subgroups offish
constitute the North Pacific albacore population and that these subgroups
have different migratory patterns, modal sizes in the U.S. fishery, growth
rates, and peak spawning periods. While the subgroups are geographically
separated and are differentiated by dissimilarities in biological or fishery
statistic criteria, they are not believed to be genetically distinct.
Albacore make extensive movements during their lifetime. The degree of
migration is geographically most extensive in the pre-adult ages between
about two and five years. Fish of these ages may conduct trans-oceanic
migrations in temperate and subtropical waters, following well-defined
routes between the eastern and western or central Pacific. However, the
spawning adults, above about six years, undertake relatively limited
movements, mostly within the subtropical and tropical regions of either the
western, central or eastern Pacific.
Results from extensive albacore tagging indicate that the northern subgroup
of albacore is fished by the U. S. fishery north of about 40º N, the
Japanese pole-and-line fishery in the western Pacific, and the Asian
longline fishery. The southern subgroup appears to be fished by the U.S.
fishery south of about 40ºN, and the Asian longline fishery, but only to a
limited extent by the Japanese pole-and-line fishery.
Based on physiological research findings, the normal habitat of albacore is
within a temperature range of 50º-64ºF, with dissolved oxygen saturation
greater than about 60 percent. While individuals may temporarily move into
waters outside of these values, thermoregulation and respiration functions
will be adversely affected and operate marginally. The acoustic tracking of
free-swimming albacore has demonstrated that albacore customarily live
within the depths of the thermocline, rather than the upper mixed layer as
has been generally presumed.
The migration, distribution availability, and vulnerability of albacore are
strongly influenced by oceanographic conditions in the Pacific Ocean,
notably oceanic fronts. The seasonal migration of albacore into North
American coastal waters is associated with the North Pacific Transition Zone
water and its frontal boundaries. In addition, oceanographic conditions also
play an important role in the local concentrations and movements of albacore
in coastal waters off Worth America. Albacore tend to aggregate on the warm
side of upwelling fronts and move away from the fronts upon their
disintegration in response to wind shifts unfavorable for upwelling.
Satellite images of ocean color and sea surface temperature and concurrent
albacore catch data clearly show that the distribution and availability of
albacore off California are related to coastal upwelling fronts and that
albacore are most abundant in warm, clear, blue oceanic waters near
temperature and color fronts at the seaward edge of coastal water masses.
It is presumed that albacore aggregate in the vicinity of upwelling fronts
to feed on small fishes, squids, and crustaceans that are plentiful in these
areas. Yet it remains unclear what physical factors prevent albacore from
crossing to the cooler side of these fronts in order to reach the highest
potential forage biomass. Past beliefs have stressed confinement to a
physiological optimum temperature range; however, explanations for
environmental preferences of albacore are changing as new knowledge is
acquired. The finding that albacore can regulate their body temperatures
suggests that temperatures on the cool side of an upwelling front should not
be limiting. Studies of free-swimming albacore in relation to ocean thermal
structure, using acoustic telemetry and coincident oceanographic sampling,
have shown that, while albacore would not cross from the warm side to the
cool side of an upwelling front which had a horizontal sea surface
temperature gradient of about a 4ºF over a few miles, the fish would
routinely swim through vertical temperature gradients up to about 180 F. The
fish made extensive vertical excursions up to several hundred yards and
crossed the thermocline in waters adjacent to the upwelling front Recent
research involving acoustic telemetry of free swimming albacore, satellite
measurements of ocean color and temperature, and oceanographic sampling of
water optical and other characteristics, and potential forage abundance,
indicates that water clarity as it affects the ability of albacore to detect
prey is an important mechanism underlying the aggregation of albacore on the
worth clear sides of upwelling fronts.
Status of Population
Fishing effort and catch of albacore in the Japanese pole-and-line and the
U. S. surface fisheries have declined, beginning in the early 1980's. In
contrast recent landings in the Japanese longline fishery have been
relatively constant and there has been a rapid development of Asian gillnet
fisheries that harvest large numbers of albacore in the North Pacific.
Several factors are associated with the decline in the traditional surface
fisheries, but their relative importance is unknown. It appears that no
single factor is responsible, but that the decline in catches is a result of
complex interactions among factors, including (1) a reduction in overall
fishing effort for albacore, (2) lack of fishing in areas of traditional
high catch, (3) indications of population decline and (4) major anomaly
patterns in oceanographic conditions across much of the North Pacific in the
niid-1980's and early 1990's.
Clemens, H. B. 1961. The migration, age, and growth of Pacific albacore (Thunnus
alalunga), 1951-1958. Calif. Dept Fish and Game, Fish Bull., 11 5, 128p.
Dotson, R. C. 1980. Fishing methods and equipment of the U.S. west coast
albacore fleet. U.S. Dep. Commer., NOAA Tech. Memo., NOAA-TM-NWS-SWFC-8, 126
Laurs, R. M., P. C. Fiedler, and D. R. Montgomery. 1984.Albacore tuna catch
distribution relative to environmental features observed from satellites.
Deep-Sea Res., 31(9):1085-1099.
Laurs, R. M. and R. J. Lynn. 1977. Seasonal migration of north Pacific
albacore, (Thunnus alalunga) into North American coastal waters:
Distribution, relative abundance, and association with transition Zone
waters. Fish. Bull., U.S. 75(4):795-822.
Laurs, R. M. and J. A- Wetherall. 1981. Growth rates of North Pacific
albacore, (Thunnus alalmga), based on tag returns. Fish. Bull., U.S.