Artificial production of the young of coastal crustacea

Claim 1

A method for producing the young of crabs of the ''''gazami'''' crab species, which comprises putting parent crabs holding eggs in a hatching and culturing tank filled with raw sea water or sea water similar thereto for maturing eggs, adding a small amount of nitrogen and phosphorus to the culture tank water for a period until hatched larvae develop to young crabs from the time the eggs change from light yellow to dark yellow, at least for a period said larvae metamorphose to the megalopa stage from the zoea stage for developing vegetable plankton such as diatoms in the culture water, thereby multiplying successively food organisms of animal plankton such as copepoda and bottom-living organisms in the culture water so as to meet the metamorphosis process of larvae which start taking said animal plankton and bottom-living organisms to meet a period during which larvae metamorphose from the zoea stage to the post larvae stage, and thereby carrying out both raising larvae of crabs and culturing food necessary therefor throughout the whole period from the initial raising stage simultaneously in the same body of water.

Claim 2

A method for producing the young of prawns of the ''''ise'''' prawn species which comprises putting parent prawns holding eggs in a hatching and raising tank filled with raw sea water or sea water similar thereto for maturing eggs, adding a small amount of nitrogen and phosphorous to the culture tank water starting from the time eggs change from yellow to red, thereby multiplying animal plankton such as copepoda in the culture water so as to meet the hatching of phyllosoma larvae, thereby establishing a stabilized food-chain of vegetable plankton such as diatoms, animal plankton such as copepoda and bottom-living organisms, and thereby carrying out both raising larvae of ''''ise'''' prawn and culturing foodstuffs necessary therefor throughout the whole period from the initial raising stage simultaneously in the same body of water.

Claim 3

A method for artificially producing the young of valuable coastal crustacea and raising the larvae for a period until they grow to the adult size and also culturing food required by the larvae for said period simultaneously and naturally in the same body of water, the steps comprising: filling sea water in a hatching and culturing tank as a culture water; putting crustacea containing culture water in said prefilled tank; adding a predetermined amount of organic matter containing organic nitrogen compounds and a predetermined amount of phosphorous compound in the culture water; carrying out the addition of said amounts at fixed rates and intervals, thereby successively multiplying various kinds of plankton and bottom-living animal larvae of the plankton-living type such as contained in said raw sea water, thus establishing in said culture water a stabilized food chain which comprises added nutrient matter, vegetable plankton such as free-floating diatoms, zooplankton such as copepoda, and bottom-living organisms, to cause a successive multiplication of live food organisms in accordance with the metamorphoses stages of larvae which start taking food represented by said organisms.