Pisciculture

Pisciculture, or Rearing of Fish, is a term now generally applied to the system of artificial hatching or rearing of fish, molluscs, or Crustacea. The treatment of eggs has been so worked out that eggs can be sent across the ocean without any appreciable loss; and young fry can be carried safely for long distances. The objects in view in pisciculture are (1) the saving of a greater percentage than would survive in a natural state, and (2) the protection of the fry from many dangers. The process of fertilising and hatching, applied to the salmon is somewhat thus: - The gravid salmon is held over a pan, into which she discharges the ova, and upon these the milt is squeezed from the male, and the pan is tilted to ensure fertilisation. Water is then added, and the pan allowed to rest for a time, after which the milt is poured off, and the eggs left to hatch. After hatching, the young remain for six weeks in water among gravel, and then are fed with yolk of eggs and beef until the time when they are fit to be turned out to find their own food in more or less protected water. Sir James Gibson Maitland at Howiestoun rears 98 per cent. of the eggs treated. Jacobi in the 18th century tried artificial hatching in Westphalia, and John Shaw applied it to salmon on the Nith in 1837, while Remy and Gehin applied it to trout in France in 1841. In 1848 the French Government established a hatching-station at Huningue near Basel. The United States Commission of 1871 did much to advance the knowledge of the subject.