Animals without backbones (or invertebrates) include over 2,000,000 described species, and comprise about 97% of the Animal Kingdom. The remaining 3% of animal species includes Homo sapiens, plus a fair smattering of other mammals, birds, reptiles, amphibians, fishes, and protochordates. By comparison, the Plant Kingdom boasts about 350,000 species, and whereas plant organisms don't exceed animals in numbers of species, they are at least one magnitude more dominant in numbers of individuals and biomass.

Contents
Invertebrate Biology
Pearl Culture
Nutrition in Invertebrates
Pearl Culture in Abalone
Prehistoric Use of Pearls by Man

Invertebrate Biology
Over the past 25 years, my research has addressed the question of how many diverse groups of invertebrates obtain their nutritional requirements. In this regard, I have studied feeding and/or digestive mechanisms within several phyla of marine invertebrates including the Cnidaria, Ctenophora, Annelida, Ectoprocta, Arthropoda, Mollusca, and Echinodermata.
____Looking back over time, it is evident that the seminal events leading to my current interests in marine invertebrates occurred over 50 years ago when I had the good fortune to be growing up at Piney Point, Maryland, a locale adjacent to both the brackish waters of the Potomac River and the shoreline of Chesapeake Bay. As a boy, I occupied my summers with foraging for the ubiquitous blue-claw, swimming crabs (especially the soft-shelled, post-molting individuals), Virginia oysters, glass shrimps, and experiencing chance encounters with sea nettles while swimming.

Pearl Culture
In 1945, Piney Point supported a U.S. Navy torpedo testing facility, and my father was stationed there as a Navy physician. One of the perks that came with being stationed in Piney Point was the use of a crewed schooner that lay moored several hundred feet off the banks of the Potomac River which fronted our quarters. Joe Paliwallo was the boatswain-mate in charge of the schooner, and he spent many of his off hours as a waterman, tonging oysters off the river bottom. He was a kind man, and every now and then he would take me along with him in his flat-bottomed skiff to "help" him. After collecting a bushel basket of oysters, Joe would sit on the river bank to shuck the oysters from their shells. Little boys have a great interest in such matters, and I never tired of watching Joe carry out this task.
____Joe was normally a stolid individual, so I got caught up in the excitement when suddenly he jumped up from his shucking and held aloft a pearl, about half the diameter of a marble, which he had just plucked from amongst the soft parts of the oyster he had been shucking. I believe that it was this early experience of sharing the discovery of a natural pearl found within an oyster, which blossomed (tardily) into my current preoccupation with pearls and pearl culture technology. It wasn't until many years later that I discovered edible oysters are not capable of producing gem quality pearls. Nonetheless, I remain grateful for Joe's sleight of hand and sense of humour.

Nutrition in Invertebrates My research on nutrition on marine Mollusca began in 1967 when I described the ciliary currents of feeding and digestion in a peapod-shaped mussel Adula (Botula) falcata,a rock-boring species common to mudstone and shale reefs along the coast of California. ____In the late 1960's, at Coconut Island, Kaneohe Bay, Hawaii, and later Eniwetok Atoll, Marshall Islands, I initiated a study on symbiosis and nutrition in tropical giant clams (Tridacnidae) which continues to this day. The Tridacnidae include two genera of coral reef dwelling bivalves, Tridacna and Hippopus. The true giant of this family is Tridacna gigas, a species which can reach 52" in length, and is recognized as the largest clam species known to have existed. ____One of the significant findings to arise from this early work concerned the nature of the symbiosis between Tridacna, and its endosymbiont (zooxanthellae). Results from the very careful light microscope work of Sir Maurice Yonge during The Great Barrier Reef Expedition in the 1920's had established that the nature of the relationship between the clam and its symbiontic zooxanthellae was similar to the relationship between a farmer and his cabbages. In the case of the giant clam (farmer), its amoeboid blood cells appeared to be harvesting zooxanthellae from the clam's blood spaces, much like a farmer taking cabbages from his garden. The results arising from my electron microscopical pictures suggested that while it was true that zooxanthellae could be seen in the blood cells of Tridacna in varying stages of digestion, the only harvested by the clams blood amoebocytes were a small minority of senescent individuals which were so degenerated that they had become the target of the clam's scavenging blood cells (see papers by Professors Tom Goreau and Leonard Muscatine for detailed accounts on zooxanthellae as a source of nutrition for giant clams and reef-forming corals). ____In addition, my electron microscopical histochemistry preparations revealed that lysosome enzymes were involved in the digestion of senescent zooxanthellae by tridacnid amoebocyte blood cells. Further electron microscopical evidence of uptake of dissolved and particulate food material through the hypertrophied siphons of Tridacna lead me into the research area of uptake of natural algal exudated materials (leaked by blades of the giant kelp Macrocystis) by other soft-bodied marine invertebrates.

____During the mid-1970's, I established the in situ uptake of DOC and DOM in several marine invertebrates including oyster pediveliger larvae, bryozoans, solitary corals and sabellid worms. From the late 1970's through to the late 1980's I studied feeding mechanisms and the ecology of sea cucumbers. In the course of 40 month investigation, I established for the first time that the absence of visceral organs in sea cucumbers during the fall and winter months was due to seasonal visceral atrophy (see chart below), and not as had been claimed earlier by Professor Emory Swan and others, an example of spontaneous evisceration.

Pearl Culture in Abalone
In 1985, I came across a reference in the Japanese Journal of Applied Physics suggesting that it was possible to culture pearls in abalone. Correspondence with researchers at the Mikimoto
Pearl Company got me started in pearl culture, an area of research which I have always been intrigued by but didn't think would be possible to pursue in Canada's cool, temperate waters.
____Following several false starts at implanting pearl nuclei into local abalone, I made critical improvements upon the technology developed in the 1890's by the famous French Scientist Louis Boutan (the father of underwater photography), and Professor Kan Uno, who carried out his experiments during the mid-1950's. By so doing, in 1987 I successfully produced a 17mm blister pearl in the pinto abalone (=northern ear shell) Haliotis kamtschatkana. This pearl represented the first time a gem-quality, marine pearl had been cultured in North America.
____During the following year, an R & D company Pacific Pearl Culture Ltd was incorporated, and in 1994, U. S. patent No. 5,347,951 "Process for producing pearls in abalone and other shell-bearing molluska and nucleus used therewith" was issued describing half-a-dozen processes for producing blister and free pearls in abalones and other shell-bearing Mollusca.
____At present, I have ongoing pearl culture experiments on the largest species of abalone Haliotis rufescens (=red abalone) which I anticipate will substantially improve upon my current procedures for producing attached and free pearls in abalone. These experiments are being carried out on campus at Simon Fraser University, and at the Monterey Abalone Company in California. Using the red abalone within a central California locale, it has been possible to culture mabe pearls within a two year time frame using nucleus implants measuring greater than 1" in diameter.
____During the fall of 1995, blister pearls measuring 27mm x 30mm in diameter were produced by my laboratory. One of these pearls has just been submitted to the Guinness Book of Records for consideration as the largest cultured abalone pearl.

Prehistoric Use of Pearls by Man
The history of mans' use of pearls as gemstones is also of interest to me, and in this regard, I have been examining anthropological collections of Chumash Indian abalone artifacts curated in U.S. museums. For instance, collections of Chumash Indian burial artifacts at the Santa Barbara Museum of Natural History include pearls which evidence features clearly abalone in origin. These natural abalone pearls consisted of many typical tusk and baroque-shaped examples, which apparently been mistaken by anthropologists in past for polished, mother-or-pearl beads. Carbon-14 data accompanying these Chumash burial artifact collections suggests that it may be possible to pre-date man's first use of pearls to nearly 8000 B.P.

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