Species dependent aggression in bicolor damselfish during reproductive and non-reproductive cycles

Bicolor damselfish, Stegastes partitus, are well known for their aggressive nature. They are known to attack almost any species threatening their food, territory or spawn, often regardless of the size of the intruder. Studies show that three spot damselfish are even able to identify certain species based on the threat they present by displaying different aggressive behaviors. However, little is known on how, and if, these aggressive displays are species dependent in bicolors. The purpose of this study was to test for species dependent aggression in bicolor damselfish during reproductive season to determine if this behavior relates to increased egg protection during reproductive season. Four damselfish individuals were analyzed over the course of five weeks during one reproductive and one non-reproductive cycle using underwater video camcorders. S. partitus was shown to increase frequency of aggression toward egg threatening intruders while guarding eggs. Conversely, they were shown to decrease in frequency of aggression towards intruders threatening their food resources. Lastly, the frequency of intrusion for eggeating intruders was not shown to significantly increase while bicolor damselfish eggs were present.

This student research was retrieved from Physis: Journal of Marine Science XV (Spring 2014)19: 9-14 from CIEE Bonaire.