A pearl is a hard, glistening object produced within the soft tissue of a living shelled mollusk or another animal, such as fossil conulariids. Just like the shell of a mollusk, a pearl is composed of calcium carbonate in minute crystalline form, which has deposited in concentric layers. The ideal pearl is perfectly round and smooth, but many other shapes, known as baroque pearls, can occur. The finest quality of natural pearls have been highly valued as gemstones and objects of beauty for many centuries. Because of this, pearl has become a metaphor for something rare, fine, admirable and valuable.
Kokichi Mikimoto was a Japanese entrepreneur who is credited with creating the first cultured pearl and subsequently starting the cultured pearl industry with the establishment of his luxury pearl company Mikimoto.
Oyster is the common name for a number of different families of salt-water bivalve molluscs that live in marine or brackish habitats. In some species, the valves are highly calcified, and many are somewhat irregular in shape. Many, but not all oysters, are in the superfamily Ostreoidea.
Mussel is the common name used for members of several families of bivalve molluscs, from saltwater and freshwater habitats. These groups have in common a shell whose outline is elongated and asymmetrical compared with other edible clams, which are often more or less rounded or oval.
Bivalvia or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of aquatic molluscs that have laterally compressed soft bodies enclosed by a calcified exoskeleton consisting of a hinged pair of half-shells known as valves. As a group, bivalves have no head and lack some typical molluscan organs such as the radula and the odontophore. Their gills have evolved into ctenidia, specialised organs for feeding and breathing.
Pinctada is a genus of saltwater oysters, marine bivalve mollusks in the family Pteriidae. These pearl oysters have a strong inner shell layer composed of nacre, also known as "mother of pearl".
Baroque pearls are pearls with an irregular, non-spherical shape. Shapes can range from minor aberrations to distinctly ovoid, curved, pinched, or lumpy shapes. Most cultured freshwater pearls are baroque because freshwater pearls are mantle-tissue nucleated instead of bead nucleated. Cultured saltwater pearls can also be baroque, but tend to be more teardrop-shaped due to the use of a spherical nucleation bead.
Cultured pearls are pearls which are formed within a cultured pearl sac with human intervention in the interior of productive living molluscs in a variety of conditions depending upon the mollusc and the goals. Having the same material as natural pearls, cultured pearls can be cultivated in seawater or freshwater bodies. Over 95% of the pearls available on the market are cultured pearls.
Unionida is a monophyletic order of freshwater mussels, aquatic bivalve molluscs. The order includes most of the larger freshwater mussels, including the freshwater pearl mussels. The most common families are the Unionidae and the Margaritiferidae. All have in common a larval stage that is temporarily parasitic on fish, nacreous shells, high in organic matter, that may crack upon drying out, and siphons too short to permit the animal to live deeply buried in sediment.
Freshwater bivalves are molluscs of the order Bivalvia that inhabit freshwater ecosystems. They are one of the two main groups of freshwater molluscs, along with freshwater snails.
Aquaculture started to take off in New Zealand in the 1980s. It is dominated by mussels, oysters and salmon. In 2007, aquaculture generated about NZ$360 million in sales on an area of 7,700 hectares. $240 million was earned in exports.
Aquaculture in Australia is the country's fastest-growing primary industry, accounting for 34% of the total gross value of production of seafood. 10 species of fish are farmed in Australia, and production is dominated by southern bluefin tuna, Atlantic salmon and barramundi. Mud crabs have also been cultivated in Australia for many years, sometimes leading to over-exploitation. Traditionally, this aquaculture was limited to table oysters and pearls, but since the early 1970s, there has been significant research and commercial development of other forms of aquaculture, including finfish, crustaceans, and molluscs.
Keshi pearls are small non-nucleated pearls typically formed as by-products of pearl cultivation. A Japanese word also meaning "poppy", it is used in Japanese for all pearls that grew without a nucleus. Originally, keshi pearls referred to those pearls formed when a bead nucleus was rejected. More recently, keshi has been used to refer to second harvest pearls and even to freshwater non-nucleated pearls. However the later usage referring to freshwater pearls is considered erroneous by many leading gem trade associations. Because they have no nucleus, keshi pearls are composed entirely of nacre.
Aquaculture is the farming of fish, shellfish or aquatic plants in either fresh or saltwater, or both. The farmed animals or plants are cared for under a controlled environment to ensure optimum growth, success and profit. When they have reached an appropriate size, they are harvested, processed, and shipped to markets to be sold. Aquaculture is practiced all over the world and is extremely popular in countries such as China, where population is high and fish is a staple part of their everyday diet.
Sea sponge aquaculture is the process of farming sea sponges under controlled conditions. It has been conducted in the world's oceans for centuries using a number of aquaculture techniques. There are many factors such as light, salinity, pH, dissolved oxygen and the accumulation of waste products that influence the growth rate of sponges. The benefits of sea sponge aquaculture are realised as a result of its ease of establishment, minimum infrastructure requirements and the potential to be used as a source of income for populations living in developing countries. Sea sponges are produced on a commercial scale to be used as bath sponges or to extract biologically active compounds which are found in certain sponge species. Techniques such as the rope and mesh bag method are used to culture sponges independently or within an integrated multi-trophic aquaculture system setting. One of the only true sustainable sea sponges cultivated in the world occur in the region of Micronesia, with a number of growing and production methods used to ensure and maintain the continued sustainability of these farmed species.
South Korea is a major center of aquaculture production, and the world's third largest producer of farmed algae as of 2020.
Saltwater aquaponics is a combination of plant cultivation and fish rearing, systems with similarities to standard aquaponics, except that it uses saltwater instead of the more commonly used freshwater. In some instances, this may be diluted saltwater. The concept is being researched as a sustainable way to eliminate the stresses that are put on local environments by conventional fish farming practices who expel wastewater into the coastal zones, all while creating complementary crops.
Pteria sterna, or commonly known as the rainbow-lipped pearl oyster or the Pacific wing-oyster, is a species of marine bivalve mollusk in the family Pteriidae, the pearl oysters. This oyster can be found in shallow water along the tropical and subtropical Pacific coast of America, its range including Baja California, Mexico and northern Peru.
Pinctada margaritifera, commonly known as the black-lip pearl oyster, is a species of pearl oyster, a saltwater mollusk, a marine bivalve mollusk in the family Pteriidae. This species is common in the Indo-Pacific within tropical coral reefs.
Aquaculture in the United Kingdom is dominated by salmon farming, then by mussel production with trout being the third most important enterprise. Aquaculture in the United Kingdom represents a significant business for the UK, producing over 200,000 tonnes of fish whilst earning over £700 million in 2012 (€793 million).
