Answer:
Method of controlling the population of crabs.
Step-by-step explanation:
The method of controlling the crabs by parasitic barnacle species I suggest should be learn before its introduction because this method provides valuable knowledge about the method the parasitic barnacle species control the crabs population. This barnacle species is a parasite that feeds on the crabs, it controls the population of crab by not killing the crabs but attack on the reproductive part of the crabs that leads to infertility and as a result the population of the crabs are decreases and controlled.