Northern (Pinto) Abalone - General Biology and Ecology
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Bamfield Community Huu-ay-aht Abalone Project (BCHAP)
The term "archaeo" means ancient, or primitive. Abalone
are the most primitive group of molluscs, and they have changed
little since their ancestors first originated during the Cambrian
period. Obviously, they got things right the first time!
Distribution and Habitat
pinto, or northern, abalone are found from the Aleutian Islands, Alaska
to Point Conception, California. They are the only naturally occurring
abalone in British Columbia. They like rocky, exposed shorelines - especially where there is lots of yummy algae around! High levels
of salinity and low temperatures are also habitat requirements. Abalone
are found in clumps, or aggregations, and one of their favourite places
to hang out is in Nereocystis kelp beds. Juveniles tend to
hang out around crustose red algae patches, and migrate much more
than adults. Adults prefer being near macroalgae (like kelp). In northern
reaches (Alaska to B.C.) the abalone are most common from 0-5m, but
in California they enjoy habitats as deep as 10m.
Structure and Function
Pinto abalone reach a maximum length
of 140mm, and a maximum age of 15 years. Age is more difficult to
determine than in some other molluscs, where growth rings correspond
to age. Their flat, broad shell provides great protection and also
is shaped to minimize resistance to water flow. The colour of the
outer shell may vary between individuals. The colour is from algae
pigments in the metabolic waste of the abalone (keep reading to
find out why their waste ends up on top of their shell!). Cool,
you may have noticed in the pictures, abalone have a series of 5
openings, followed by several bumps along the edge of their shell.
As the abalone grows these openings (perforations/foramina) fuse
and are replaced.
The diagram on the right shows the direction of water flow through the foramina. Oxygen rich water comes in, and waste, carbon
dioxide and sometimes gametes, go out. The anus and nephridial (kidney)
openings are found directly below one of the openings to allow for
an easy exit! Sometimes the abalone will stick its tentacles through
the openings, in order to keep them clear!
have three types of tentacles: 1. The cephalic tentacles (they have
primitive eyes) 2. The median tentacles, and 3. The pallial tentacles
around the margin (used to keep the foramina clear and are chemosensory)
You can check out the picture on the left for an internal
dorsal view of a pinto abalone.
Reproduction and Development
In general, this species is dioecious (separate male and female
sexes) but some hermaphrodites have also been collected. Gonad maturation
is affected by: day length, food availability, and water temperature.
On average, abalone reach sexually maturity at 50mm (after about
3 years). Abalone reproduce using a process called broadcast fertilization
or spawning. Broadcast spawning occurs when all the male and female
abalone in the area release their gametes into the water column.
This simultaneous release is probably triggered by hormones. Spawning
occurs from April to August, and requires temperatures between 10-14oC.
The female abalone can release up to 3 million eggs!
Twenty-four hours after fertilization, a trochophore larvae develops.
Archeogastropods are the only subclass with a trochophore larvae.
This stage is suppressed in all internally fertilizing gastropods.
This 0.2mm larvae only lasts about 24 hours before it metamorphoses
into a veliger larvae. Both larval stages are a form called "lecithotrophic".
This means that they feed on the remaining egg, rather than gathering
food from the surrounding environment.
After 11 days-3 weeks, the veliger larvae settles. This stage is
now called a "spat". Settlement is triggered by chemicals
produced by the encrusting red algae Lithothamnion, or by
an adult mucous trail. The presence of adults signals that this
might be a good abalone habitat! The chemical release by the algae
is called gamma-aminobutyric acid (or GABA for short). GABA is also
used to induce settlement in abalone aquaculture.
One to three months after settlement, the spat becomes a juvenile.
After about 2-3 years, the abalone finally reaches the adult stage!
For more on growth and development, click here!
Abalone are herbivores. They prefer eating pieces
of kelp, a large brown algae. However, they may also feed on phytoplankton
and diatoms if there is nothing else to eat. They use a radula,
an organ with many sharp teeth, in order to munch down their salty
meal. Abalone have to watch out for greedy sea urchins! The urchins
will compete for food and space against the abalone,
and usually the urchins win! Adult abalone also have to be wary
of predators such as octopus, crab, lobsters, seastars,
and otters. The muscular foot of the abalone makes a tasty and high-caloric
snack for these hungry animals! Abalone found in a sea otter range
are often smaller, on average, and more restricted to cracks and
crevices. Although their foot is good to eat, it unfortunately cannot
move quickly enough for a fast escape!
Abalone are slow growers and long-lived. In addition, their recruitment
rates are often very unpredictable. Unfortunately, these characteristics
make abalone very susceptible to over-harvesting. The next section
describes the rapid demise of the pinto abalone population, and
of populations of abalone around the world.
Abalone has been harvested for hundreds
of years. The first record is of harvesting occurring in Japan in
30 A.D. The northern abalone has been used by the First Nations
of the northwest coast for food, and the nacre used for jewelry
and decoration. The muscular foot is marketed as food in America,
Europe and Asia. All seemed well for the abalone
introduction of SCUBA equipment in the 1960's. Instead of skin diving,
the abalone could now be collected in greater numbers, and from
greater depths, by divers using SCUBA gear. Adult abalone tend to
climb to the highest reaches of their habitat in order to spawn,
and so this makes mature, reproductive individuals easy to collect.
As a result, abalone fishing causes a decrease in recruitment; combined
with an increase in juvenile mortality and decrease in juvenile
settlement, the abalone were in for a bumpy ride.
Throughout the 1960's
and 1970's, abalone stocks around the world started to show a general
trend of decline. In 1976, a market for Canadian abalone sent to
Japan opened up. Abalone fishing in British Columbia peaked in 1978,
at an amazing 425 tonnes! This alarming harvesting rate triggered
DFO (Fisheries and Oceans Canada) to introduce catch quotas in order
to reduce the harvest rate. By 1990, the last year abalone harvesting
was legal in B.C., the annual harvest was only 43 tonnes.
This steep decline stimulated DFO to place a complete ban on abalone
harvesting. Unfortunately, the scarcity of abalone has driven market
prices as high as $74/kg. The high level of demand, and the accessibility
of abalone, has made poaching a major problem. Poachers even harvest
juvenile abalone, further dehabilitating the populations chance
of regenerating themselves. Pollution, predation, and poaching all
contribute to the continuing decrease of wild abalone stocks.
However, there may
still be a future for the northern abalone! The first abalone culture
began in Japan in 1956. There have been some attempts, and many
suggestions, at starting northern abalone cultures in British Columbia.
Recently, the small community of Bamfield, B.C. (located on the
Midwest coast of Vancouver Island and home to OceanLink) has come
together with the Bamfield Marine Station and the Huu-ay-aht First
Nation to develop a plan for a northern abalone culturing plant
in Bamfield. This project would not only provide income for the
community, through providing jobs and selling abalone, but could
also be used to raise juvenile abalone to repopulate wild stocks.
What can you do?
If you see someone illegally
poaching abalone in British Columbia, immediately report these actions
to the Department of Fisheries and Oceans, Canada, by calling toll-free
to the Observe, Record, Report Line: 1-800-465-4336.
For more information:
Call the Fisheries and Oceans Canada Regional
Abalone Coordinator: (250) 756-7230
DFO's Abalone Web site, check it out!
Anon. 1990. Abalone study: Haliotis kamtschatkana. Marine Biology for Teachers. Bamfield
Marine Station Publications.
Heleine, J-Y.,R.M. 1981.
The biology and culture possibilities of the abalone from Thesis for Doctorate in Veterinary Science. Department of Fisheries
and Oceans, Pacific Biological Station.
Meglitsch, P.A. Invertebrate
Zoology 2nd Edition. Oxford University Press. Toronto. 1972.
Lepore, C. 1993. Feasibility
of abalone culture in British Columbia. Principles of Aquaculture.
Bamfield Marine Station Publications.
Winther, I. 1985. Abalone
population characteristics and substrate utilization at Aguilar
Point. Marine Ecology. Bamfield Marine Station Publications.
Marriot, J.M. 1993. A study of the use of aquaculture technology
for stock enhancement of the Northern abalone, Haliotis kamtschatkana.
Principles of Aquaculture. Bamfield Marine Station Publications.
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