Barnacles are sessile creatures. Thus, they cannot go and find another member of their species farther away to reproduce with. This means, in order for them to reproduce, they must mate with a member closer to them, and have the characteristic of being hermaphroditic. Being hermaphroditic means the barnacles have both male and female sex organs (Ellis 2013). They can produce both male sperm cells and female egg cells (Ellis 2013). Thus, Chthamalus fragilis can either reproduce with itself or fertilize an adjacent neighbor. It may be convenient to reproduce with oneself; however, self-fertilization does not create much genetic diversity. When Chthamalus fragilis needs to fertilize a neighbor, it can use a retractable tube (UWT 2007). The tube can reach up to several inches and contains sperm. This is how the sperm are delivered to a neighboring barnacle. Once the tube is used, it is “thrown away”, and a new one is established for the next reproductive season (UWT 2007).

            Once the egg is fertilized, it grows into a larvae. This occurs for about a month inside of the adult barnacle. After a month, the larvae is expelled out of the mouth of the adult as a free-swimming larvae. This swimming and motility in the larval stage of development allows C. fragilis to settle new areas (WHOI n.d.). If the larval stage did not have the characteristic of motility, then the species would be confined to one area with high population density and intraspecie competition would be high too. The first larval stage is nauplius. At this time the young barnacles swim freely to eat and molt many times to increase their size. They then move on to the second larval stage which is the cypris stage. At this point, the larvae are strictly set on finding a suitable surface to settle on. Once the larvae finds a proper place, with the help of ocean currents, the larvae secretes a glue out of its antennae and secretes calcium carbonate to form a shell. It is now an adult barnacle. Its life span ranges from eight to twenty years (Whoi n.d.).


Works Cited for Reproduction

Ellis, Michael. 2013. <URL:        barnacles/>. Accessed 19 March 2014.

WHOI N.D. <URL:>. Accessed 19 March 2014.

UWT 2007. <URL:>. Accessed 19 March 2014.

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