When beginning research into the cultivation of marine shrimps and prawns, it is usually the most worth while of the local species that is chosen for study. From this it follows that in tropical regions the penaeids tend to be favoured, especially following the pioneering work of Hudinaga (1942) with Penaeus japonicus (Bate), whereas in the temperate regions of Europe and Canada it is the carideans that are receiving most attention, particularly the palaemonids. One notable exception is the advanced study of the Asiatic Giant Prawn Macrobrachium rosenbergii (de Man), which was initiated in Malaysia and subsequently taken up in Hawaii and Great Britain (Ling, 1962).

Doubtless each chosen species has its merits, but overriding importance must be attached to ease of mating, for this imposes an immediate limit on the reliability of the whole process and holds the key to the selective breeding of improved strains. Indeed, it has been pointed out that reliance on wild-spawned animals is a major obstacle to commercial development (Tabb et al., 1969) and such vagaries in the supply of young shrimps has already limited some research (Cook & Murphy, 1969).

Under captive conditions it has proved a great deal easier to mate carideans than penaeids, but the continuing part played by caridean females in incubating the eggs over a contracted period is a disadvantage. Relieving the ovigerous females of this task would allow the eggs to be incubated at greatly increased densities in conditions no longer dictated by the females. Further, it would lead to the more effective use of the female during the period she would otherwise be incubating.