SEA URCHIN REPRODUCTION
Sea urchins have 5 gonads that are located in the interambulacral region of the urchin. Each gonad has a duct rising out of it and out of the gonopore which lies in the anal region of the urchin. The urchin's gonads are surrounded my muscles and allows the urchin to squeeze gametes out of its body. The sea urchin starts to release gametes from its body during breeding season in the spring. The male ejaculates sperm while the female ejaculates eggs. Therefore, the eggs are fertilized in the open ocean when they come in contact with sperm.
The urchin larvae hatches from its eggs with 4 arms. In the weeks to follow he grows more arms until he has 8 arms (the rate of speed in which its arms grow depends on how much plankton is consumed by the urchin). By the time the urchin has 8 arms, it begins to show mature features. Shortly after the growth of the 8th leg, spines and tubefeet protrude out of the urchin.
The urchin larvae hatches from its eggs with 4 arms. In the weeks to follow he grows more arms until he has 8 arms (the rate of speed in which its arms grow depends on how much plankton is consumed by the urchin). By the time the urchin has 8 arms, it begins to show mature features. Shortly after the growth of the 8th leg, spines and tubefeet protrude out of the urchin.