How to Breed a South California Rock Crab

The brown rock crab is abundant in southern Californian waters. These interesting little crustaceans tend not to move too far from the shore, where they scavenge for and hunt other crustaceans, star fish, clams and snails. The brown California rock crab possesses powerful crusher claws, which helps it feed on barnacles and thick-shelled snail species. These crabs are highly sensitive to the scent of food items in their rock pool habitat. Although Californian rock crabs pass through many growth stages, they can be successfully culture in captivity.

Things You'll Need

  • Adult male and female California rock crabs
  • Commercial crab habitat (including one pond for salt water and a section of beach with soft sea sand)
  • Aquarium heater
  • Rotifers
  • Newly hatched brine shrimp
  • Fresh or frozen sea food items (i.e. prawn and calamari)
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Instructions

    • 1

      Set the thermostat on an aquarium heater to 64 degrees F and place it into the water in a crab habitat.

    • 2

      Wait for the female California rock crab to molt. This typically occurs during spring and fall, although it can be at any time in the year, particularly as the crabs are under captive conditions. The female will release pheromone in her urine, which attracts the male and stimulates him to mate. Males will latch onto the female and wait for her shell to harden, at which time they mate.

    • 3

      Observe the mating, through which the male inserts his gonopod into the spermatheca of the female crab. The male deposits a spermatophore, which remains viable for 12 months after being deposited.

    • 4

      Confirm that the female has been mated by looking for the presence of the hardened spermatophore in the female's spermatheca. This plug prevents loss of sperm and presumably prevents other males from mating the same female.

    • 5

      Wait for approximately 11 weeks after mating occurred. The female will extrude her eggs and carry them beneath her abdominal flap, which will be slightly raised. The eggs will look like an orange colored spongy mass.

    • 6

      Carefully observe the color of the egg mass, which will change from the bright orange to a dark brown color, as the embryos use their yolk.

    • 7

      Wait for seven to eight weeks for embryo development and hatching.

    • 8

      Look for the tiny hatchlings, which are called prezoeae and molt into zoeae during the first hour after hatching.

    • 9

      Feed the developing youngsters rotifers and brine shrimp for the next 45 days. The tiny crabs pass through six zoeal stages and one megalopal stage during this time. Pour rotifers and day-old brine shrimps into the water twice a day. Add sufficient living food that the developing crabs can continue to feed on throughout the day.

    • 10

      Wait for the megalopal stage to metamorphose into juvenile crabs and feed thin pieces of fresh or frozen seafood items, such as shrimp or calamari. Feed each juvenile crab a small quantity of food every day.