Marron Spawning and Supply of Juveniles

The life cycle of marron in captivity was closed in 1972, at the Department of Fisheries South West Freshwater Research and Aquaculture Centre at Pemberton.

Light, temperature and diet are the key factors which influence maturation and spawning in marron.

Farmed broodstock marron should be at least two, and usually three, years of age as reproductive output depends on size.

Marron mate in early spring and the females incubate 200 - 300 eggs for 12 to 16 weeks on pleopods under the tail, from which 150-250 prejuveniles will be released in early summer.

In late July, broodstock are transferred to 150 m 2 nursery (stock) ponds (Figure 3). A male deposits a spermatophore between a female's fifth pair of walking legs.

About 75 per cent of 2.5 year-old females become berried, after which the males and non-berried females should be separated from the berried females.

Artificial weed should be supplied to provide shelter for released juveniles and, to prevent cannibalism, the adult females should be removed immediately after the juveniles are released (Morrissy 1992a).

A number of licensed pond-based hatcheries in Western Australia sell juveniles between one and six months old for stocking purposes although many farms produce their own juveniles.

In general, the supply of juveniles is no longer a major limiting factor for the industry, although the survival of juveniles in growout systems is variable and depends largely on providing a grow-out system that meets the environmental requirements of marron.