Ex situ culture of colonial marine ornamental invertebrates: Concepts for domestication

The worldwide market for ornamental saltwater invertebrates supplies the needs of millions of aquarium hobbyists, as well as for public exhibition (zoos, aquaria), universities, and research institutions. The large-scale continuous collection of marine organisms is responsible, in many places, for the destruction of habitats, including coral reefs. The perceived expansion of the animal trade further threatens these fragile habitats. In the present paper, several concepts for the domestication of marine ornamental invertebrates (mainly colonial species) are discussed, offering an alternative commercial approach. The major rationale is based on future ex situ propagation, not field collections; a strategy aimed to circumvent the need for wild-harvested animals. This strategy is based on: (1) collection, settlement and metamorphosis of large numbers of larvae from marine organisms or of naturally shed germ cells under aquarium conditions, where survivorship exceeds several orders of magnitude than that in nature; (2) fragmentation of very small pieces (such as the size of a single polyp in colonial corals or blood vessel ampullae in tunicates) for the production of new colonies; (3) the development of replicates and inbred-lines from chosen ornamental species; (4) the use of cryopreservation of larvae and germ cells which will support the supply of material year-round; (5) several concepts for husbandry methods. Some benefits and deficiencies associated with the strategy for ex situ cultures are discussed, revealing its importance to the future of the trade.