Abalone
Description:
Abalone are members of a large class (Gastropoda) of molluscs
having one-piece shells. They belong to the family Haliotidae
and the genus Haliotis, which means sea ear, referring
to the flattened shape of the shell. Abalone shells are
rounded or oval with a large dome towards one end. The
shell has a row of respiratory pores. The muscular foot
has strong suction power permitting the abalone to clamp
tightly
to rocky surfaces. An epipodium, a sensory structure and
extension of the foot that bears tentacles, circles the
foot and projects beyond the shell edge in the living
abalone.
Nine species of abalone occur in North America:
black (H. cracherodii)
flat (H. walallensis)
green (H. fulgens)
pink (H. corrugata)
pinto (H. kamtschatkana)
red (H. rufescens)
threaded (H. assimilis)
Western Atlantic (H. pourtalesii)
white (H. sorenseni)
Black abalone (H. cracherodii) have black and smooth
epipodium and tentacles. The shell surface is black or
dark blue, and smooth. There are 5 to 9 open pores, and
the pores are flush with the shell surface. Black abalone
range from Mendocino County, California to southern Baja
California. They are found in intertidal and shallow subtidal
zones down to a depth of about 20 feet.Black
abalone reach 7.75 inches in length, but are commonly
5 to 6 inches long.
Flat
abalone (H. walallensis) have a mottled yellowish
and brown epipodium, with a pebbly appearing surface and
lacy edge. The tentacles are greenish and slender. The
shell is flattened, narrow, and marked with low ribs.
There are 5 to 6 open pores, and the pore edges are moderately
elevated above the shell surface. Flat abalone range from
British Columbia, Canada to San Diego, California. They
are found in the subtidal zone from 20 feet down to at
least 70 feet. Flat abalone reach 7 inches in length,
but are commonly under 5 inches.
Green
abalone (H. fulgens) have a mottled cream and brown
epipodium, with tubercles scattered on the surface and
a frilly edge. The tentacles are olive green. The shell
is usually brown, and its surface marked with many low,
flat-topped ribs that run parallel to the pores. There
are 5 to 7 open pores, and the pore edges are elevated
above the shell surface. A groove often parallels the
outer edge of the line of pores. Green abalone range from
Point Conception, California to Bahia Magdalena, Baja
California. They are found in the intertidal and subtidal
zones down to at least 30 feet. Green abalone are often
found in crevices where surfgrass and algal cover is dense.
They reach 10 inches in length, but are generally smaller.
Pink abalone (H. corrugata) have a mottled black
and white epipodium with many tubercles on the surface
and a lacy edge. The foot is yellow to light orange. The
tentacles are black. The shell is thick and its surface
is marked with wavy corrugations. There are 2 to 4 open
pores, and pore edges are strongly elevated above the
surface. Pink abalone range from Point Conception, California
to Santa Maria Bay, Baja California. They are found in
the subtidal zone from 20 feet down to at least 120 feet,
commonly in beds of giant kelp. Pink abalone reach 10
inches in length, but individuals over 7 inches long are
now rare.
Pinto
abalone (H. kamtschatkana) have a mottled pale yellow
to dark brown epipodium, with a pebbly appearing surface
and lacy edge. Tentacles are yellowish brown, or occasionally
green, and thin. The shell is irregularly mottled and
narrow. There are 3 to 6 open pores, and the pore edges
are elevated above the shell surface. A groove often parallels
the line of pores. Pinto abalone range from Sitka, Alaska
to Monterey, California. They are found in the intertidal
and subtidal zones down to at least 70 feet. Pinto abalone
reach 6.49 inches in length, but are commonly 4 inches
long. Pinto abalone are also known regionally as northern
abalone.
Red
abalone (H. rufescens) usually have a black epipodium,
but some specimens have a barred black and cream pattern
on their epipodium. The surface of the epipodium is smooth
and broadly scalloped along the edge. The area around
the foot is black and the sole is tan to grey. The tentacles
are black. The shell surface is generally brick red and
the inside edge is often red. There are 3 to 4 open pores,
and the pores are moderately elevated above the shell
surface. Red abalone range from Sunset Bay, Oregon to
Tortugas, Baja California. North of Point Conception,
they are found in the intertidal and subtidal zones down
to at least 60 feet. South of Point Conception, they are
found in the subtidal zone down to over 100 feet. Red
abalone reach 12.3 inches in length, but are commonly
7 to 9 inches long.
Threaded
abalone (H. assimilis) have a mottled pale yellow
to dark brown epipodium with a pebbly appearing surface
and frilly edge. The tentacles are yellowish brown, short
and thin. The shell is oval and the surface is marked
with prominent ribs interspersed with narrow ones. There
are 4 to 6 open pores, and the pores are moderately elevated
above the shell surface. Threaded abalone range from San
Luis Obispo County, California to Bahia Tortugas, Baja
California. They are found in the subtidal zone from 20
feet down to at least 80 feet, commonly on rock surfaces.
Threaded abalone reach 6 inches in length, but are commonly
smaller. Threaded abalone are considered a subspecies
of the pinto abalone by some scientists.
Western
Atlantic abalone (H. pourtalesii) have a yellowish
epipodium with large and small sensory tentacles. The
sole of the foot is tan. The shell is reddish-orange.
Western Atlantic abalone range from North Carolina through
the Gulf of Mexico to Brazil. They are found from 187
feet down to at least 1,200 feet on hard substrates. The
largest recorded shell had a length of about 1.2 inches.
White
abalone (H. sorenseni) have a tan and pebbly epipodium.
The sole of the foot is orange. The shell is deep, thin
and oval. There are 3 to 5 open pores, and the edges of
the pores are elevated above the shell surface. White
abalone range from Point Conception to Bahia Tortugas,
Baja California. Most white abalone are found in the Channel
Islands in California. White abalone are found in the
subtidal zone down to at least 200 feet. They are commonly
found in open, exposed areas. White abalone reach 10 inches
in length, but are commonly 5 to 8 inches long.
Juvenile abalones feed on rock-encrusting coralline algae
and on diatom and bacterial films. Adult abalones feed
primarily on loose pieces of marine algae drifting with
the surge or current. Large brown algae such as giant
kelp, bull kelp, feather boa kelp and elk kelp are preferred,
although other species of algae may be eaten at various
times. Abalone eggs and larvae are consumed by filter-feeding
fish and shellfish. Predators of juvenile abalones include
crabs, lobsters, gastropods, octopuses, seastars, and
fishes.The
bat ray in southern California and the sea otter in central
California prey selectively on larger abalones.
In June, 1994, the California Department of Fish and Game
proposed and the Fish and Game Commission adopted effective
January 1, 1995 a two-year closure on sport and commercial
harvesting of pink, green and white abalone. Prices to
fishermen for red abalone were around $500 to $600 per
dozen in 1993-94. The California commercial abalone harvest
reached a record 5.4 million pounds in 1957. Since then,
commercial harvests have declined dramatically to about
461,376 pounds in 1993. Current stocks of most abalone
species in central and southern California are over utilized.
This is the combined result of commercial harvest efficiency,
increased market demand, sport fishery expansion, an expanding
population of sea otters, pollution of mainland habitat,
unexplained mortalities of black abalone due to a condition
known as "withering syndrome," and loss of kelp populations
associated with El Niņo events.
Management
efforts through size limits and limits on commercial harvesting
permits have been ineffective. Reseeding experiments have
not been successful. Commercial abalone harvesting in
California may be eliminated if the sea otter range is
not contained. Studies in a California fishery reserve
have shown that even protected populations cannot support
a fishery within the sea otter range in central California.
New laws pending in the 1997 Legislature would establish
a multi-year moratorium on the commercial and recreational
harvest of all species of abalone south of the entrance
to San Francisco Bay until stocks have demonstrated some
level of recovery and a new management plan is in effect.
In
1991, the commercial abalone fishery was closed to allow
abalone stocks to rebuild. After a 5-year period, the
commercial fishery may reopen if surveys indicate that
abalone stocks have recovered. Products During the early
years of the abalone fishery, abalones were dried and
smoked, or canned for export, and sold fresh for local
markets. Currently, most abalones are exported to Japan,
either fresh or frozen whole. The U.S. market is primarily
in California for live abalone for the sashimi market,
and for some fresh and frozen steaks for restaurants.
A major change occurred in marketing U.S. abalones in
1993. Prior to 1993, black abalones were the primary export
product. After the 1993 moratorium on black abalone harvesting,
due to the "withering syndrome" that reduced black abalone
stocks, red abalones took over the export market. Prices
to the fishermen of $500 to $600 per dozen for red abalone
made production of abalone steaks uneconomical for most
markets. High prices for abalone may have also intensified
illegal abalone fishing operations in closed areas.
Abalone
steaks are prepared by removing the abalone from the shell,
cutting off the head and viscera, and hand trimming the
foot. Red and some green abalone are allowed to relax
for 24 hours before the final trimming of the foot. This
resting period weakens muscle contractions that can damage
the flesh during tenderizing. The foot is then sliced
horizontally across the grain of the meat. The steaks
are tenderized by pounding, usually with wooden mallets,
to break the tough fibers in the meat. The yield of steaks
from a live abalone is about 15 percent. The entire flesh
of the abalone is edible. Traditional U.S. consumption
has been primarily the muscle portion. The gonad, however,
is considered a delicacy by the Japanese when it can be
removed and eaten immediately from a live abalone. The
trimmed muscles remaining after trimming for steak production
were historically used for abalone burger production.
As the price of abalone meat increased, these trimmings
were canned. Today, they are used fresh or frozen in Asian
restaurants for soups and other dishes.
The
primary use for abalone shells is in making mother-of-pearl
inlays on furniture, produced principally in Korea. Abalone
shells are also sold to shell collectors and as souvenirs,
and are used in making jewelry
The
above material can be further researched at http://www.dfg.ca.gov/mrd/status/
