The commercial catch in Almejas Bay, Mexico, was monitored from August 1990 through December. Sizes in male and female M. califomica were 37-86 and 30-128 cm DW, respectively; in M. longirostris they respectively were 31-59 and 31-88 cm. M. californica give birth, ovulate and mate during spring-summer. In both species, males begin rnaturity around 50 cm DW.The commercial catch in Almejas Bay, Mexico, was monitored from August 1990 through December. Sizes in male and female M. califomica were 37-86 and 30-128 cm DW, respectively; in M. longirostris they respectively were 31-59 and 31-88 cm. M. californica give birth, ovulate and mate during spring-summer. In both species, males begin rnaturity around 50 cm DW