Haliotis kamtschatkana


Northern (Pinto) Abalone - General Biology and Ecology

 

Click here for information on the
Bamfield Community Huu-ay-aht Abalone Project (BCHAP)

 

  Classification

      Kindom: Animalia
      Phylum: Mollusca
      Class: Gastropoda
      SubClass: Archaeogastropoda
      SuperFamily: Pleuromariaceae
      Family: Haliotidae
      Genus: Haliotis
      Species: kamtschatkana

 

 

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

The 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, eh?

As 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!

Abalone 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!

Ecology

Abalone interactionsHerbivory

Competition

Predation

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.

 


The History

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…until the 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.

The Decline

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.

The Future

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!


References

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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