Related FAQs: Abalones, Abalone Identification, Abalone Behavior, Abalone Compatibility, Abalone Selection, Abalone Systems, Abalone Feeding, Abalone Disease, Abalone Reproduction, Gastropods in General: Marine Snails 1, Marine Snails 2, Marine Snails 3,  Marine Snails 4,  Snail ID 1, Snail ID 2, Snail ID 3,  Related Articles: Gastropods, Mollusks,  /The Conscientious Marine Aquarist Abalone For Aquaria... Maybe

By Bob Fenner

A Green Abalone in captivity

Aba what? Isn't that the foreign rock group from yesteryear?

Yeah those guys could really sing. No silly, the shellfish abalone. A more and more common organism for saltwater systems.

So What The Heck Are They Anyway?

You know, they're Mollusks, from the Greek meaning "soft bodied". The group includes snails, clams, squids, octopi, Chitons and more. More species than any other invertebrate group other than the arthropods (jointed legged critters like insects, crabs and shrimps). The Phylum (from the Latin meaning branch) Mollusca is further subdivided into several Classes; some of which should be very familiar: The Bivalvia includes the clams, oysters and mussels. The Polyplacophora the Chitons. The Class Cephalopoda comprises the octopi, squids and nautiloids.

The Family of abalones, Haliotidae are subsumed by the Class Gastropoda, "the stomach-footed" Mollusks, along with the many freshwater, marine and terrestrial snails. Even more specifically, abalones are members of the Order Archaeogastropoda (just like the word archaeology), the "old stomach-footed" Mollusks.

Interest/Use:

Abalone are really nifty marine invertebrate, tropical and cold-water reef organisms. Thanks to the aquaculture industry and years of efforts to produce "abs" for human consumption at least one species, the California black abalone, Haliotis carcherodii. Other species are available seasonally and geographically . These have proven to be sturdy aquarium specimens with broad chemical and physical condition tolerance, accepting prepared foods readily; and they're apparently quite disease free/resistant.

 Selection:

Cultured and wild abalone are usually offered in two formats; alive and healthy, & outright dead. It's relatively simple to determine which you're dealing with. A viable individual will be "bright": out and about with epipodium (body girdle) and eyes (around the perimeter) extended. The organism may not appear to be very active, but probably is moving and/or feeding. Dead specimens are not adhered to anything, are off-color and turgid.

 

Haliotis fulgens Philippi 1845, the Green Abalone of California coasts... To about eight inches in diameter... Coldwater species. Here at the SIO Birch Aquarium in 09. https://en.wikipedia.org/wiki/Haliotis_fulgens

Haliotis rufescens, the Red Abalone of California coasts... To more than a foot in diameter... Coldwater species. Here at the SIO Birch Aquarium in 09

Environment:

Abalone are distributed along the coastal waters of every major continent with the exception of South America and the east coast of North America. They are also found along many islands in the Atlantic, Pacific and Indian Oceans. The greatest number of species of species and densities are located off of Australia, Japan and western North America.

The Black abalone's depth distribution extends from high tide to approximately twenty feet, with a maximum in the intertidal zone (the area covered and uncovered by the usual tides). In the wild they adhere to rocky surfaces. If removed they can right themselves and crawl on sandy, gravel surfaces to firmer ground.

By and large abalone are secretive, "shy" creatures that prefer subdued lighting. They will move around a bit and do display interesting, albeit slow motion behavior after becoming established.

Like most "reef" species abalone enjoy "high" water quality; specific gravities of 1.023-25, low to no ammonia, nitrite, ... The species (naturally shallow water) in use is better suited than deeper dwelling ones as far as environmental tolerance goes. I do not endorse any special quarantine or preventative dipping procedures with abalones. They should be carefully placed and removed. Use a stiff card (credit) slid slowly and deliberately underneath to peel them off the side of their tank, buy the rock they are on or gingerly pries off with your wetted thumb; but do not cut into their body. As with anemones this almost always spells disaster. Hold them near their new home until they move out and begin attaching themselves.

The few parasitic and symbiotic organisms associated with Haliotids don't seem to affect other species negatively. Hitch-hiking creatures on the wild specimens shells might be a cause for concern however. I would avoid any with barnacles if stocking fish in the same system. Many barnacles have larval life's as fish parasites.

Feeding:

Very young abalone feed on benthic diatoms (those brownish scums and stains on your coral, substrate and sides). Larger (bigger than a dime) individuals are "macrophagous herbivores" meaning they eat larger algae. This they grate with a specialized rasp-like organ, like their relatives the snails. The structure of this "radula" is quite remarkable and constantly replaces itself as it is worn down.

Ideally, you might have an ocean full of various fresh kelps to select new "drift" from daily for your ab(s). In actual practice some algae-growing "live-rock" and algae-based frozen and dried foods do the trick. I'd like to plug the oriental food markets here as a good, inexpensive source for the latter. Check them out; kombu and Nori is cheap!

Depending on temperature, size, type of food, daily to twice weekly feeding is warranted. Place the food near the abalone. Their sense of smell is excellent; the specimen should move over and trap the food item under the front of it's foot.

Other Tank-Mates:

Territoriality is not a problem amongst abalones, however other species, notably spiny urchins and stinging animals (corals, anemones) may be. Provide plenty of sharing space and be observant. Crustacean, worm, mollusk munchers like triggers, some wrasses, marauding crabs et al. are not to be trusted.

Breeding:

Abalones are dioecious (from the Greek meaning "two houses") creatures, little boys and girls (separate sexes). Females can be distinguished from males by the presence of a green colored gonad (ovary) under the food and mantle of the right side of the shell. In males the gonad is cream or beige colored. They release gametes into the water through temperature lighting and chemical cues and can be (and are) induced to spawn all year long. The planktonic young pass through eleven bizarre larval stages before settling down to a sessile (bottom) life.

Growing Your Own:

Don't count on it, one year olds are about an inch in diameter. Legal size (5" minimum for blacks) takes somewhere between five and ten years in the wild. In California the fishing season is limited and the newest fishing (diving) limit is one per person per day. They are scarce and getting scarcer.

The cultured ones and occasional wild-caught tropical ones are better aquarium fare anyway. Have your supplier check around for you.

Bibliography/Further Reading:

Barnes, Robert D., 1974. Invertebrate Zoology, 3rd ed.. W. B. Saunders.

Brown, Joseph E. 1971. New hope for the sirloin of the sea; two nations join in a unique abalone transplanting project. Oceans Magazine 4(1):71.

Dybas, Cheryl Lyn. The critters; tough but tender abalone stage a comeback. Sea Frontiers 5-6/94.

Hahn, Kirk O., 1990. Annotated Bibliography of the Genus Haliotis. S.I.O. Reference.

Howarth, Peter, 1978. The Abalone Book. Nature Graph. Morse, D. 1977. Hydrogen peroxide induces spawning in mollusks, with activation of prostaglandin endoperoxide synthetase. Science 196(4287):298-230.