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Induction of ovarian maturation in Penaeus vannamei, by implantation of ganglion prepared from female lobster, Homarus americanus, with developing ovaries was investigated under tank culture conditions. Four of six females with thoracic ganglion implants were maturing while only two of thirteen females of the control groups with abdominal ganglion or no implant matured. Two ripe stage V were found 18 days after implantation of lobster's thoracic ganglion. This indicates that ovarian maturation of P. vannumei in tanks can be induced and accelerated by implantation of thoracic ganglion prepared from maturing females of another species. Ovarian maturation may be induced by a gonad‐stimulating hormone, secreted by the thoracic ganglion of maturing females. This gonnd‐stimdating hormone is not species specific in activity in the shrimp and lobster.

First discovered in San Francisco Bay in 1992, the Chinese mitten crab, Eriocheir sinensis, has become established over hundreds of km 2 of the San Francisco Estuary. Ecological and economic impacts of this invasive species motivated our search for a greater understanding of the crab's life history as an important step in better management and control. Data for this life history model comes from the authors' research and scientific literature. Juvenile crabs migrate from the Estuary into fresh water where they develop into adults. Environmental signals may stimulate gonad development that is followed by a downstream migration beginning at the end of summer. Mating occurs after the crabs reach saline water. Embryos are carried until hatching, and the larvae undergo five zoeal stages before settlement. Our model projects rates of development at various temperatures and growth increments, supports a minimum of 2 years in low salinity or freshwater habitat, and predicts that most California mitten crabs are at least 3 years old before becoming sexually mature. Environmental factors strongly influence the timing and duration of the crab's life stages, and are discussed in the context of a gradient of development times for worldwide populations of this important invasive species.

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