The Roles of Acoustic and Visual Signals in the Reproductive Behavior of the Federally Threatened Pygmy Sculpin, Cottus paulus, (Cottidae)
Type of Degreethesis
DepartmentFisheries and Allied Aquacultures
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Animals use many modes of communication (i.e. tactile, visual, acoustic and chemical) for territory defense, resource defense, and/or courtship. These communication systems can be used singularly or combined together, such as visual courtship displays can be used to circulate pheromones secreted into the water by fishes. Animals may use modes depending on the context and content of the intended signal and the use of multiple signals can increase the chance of the complete signal reaching the intended receiver. The objectives of this thesis were to investigate two modes of communication, acoustic and visual, in the federally threatened pygmy sculpin, Cottus paulus. Acoustic v communication was documented in breeding male C. paulus during agonistic and courtship contexts. There are two distinct call types, a single knock and a knock train, and both were produced during courtship and agonistic behaviors. Acoustic parameters were significantly different between contexts. Calls are similar to those documented for the European sculpin, Cottus gobio, and the mottled sculpin, Cottus bairdi. Coloration is used in crypsis in most sculpin, with colors ranging from tan, rust, olive, brown to black, with some sculpin exhibit an orange margin on the 1st dorsal fin. Breeding male pygmy sculpin, C. paulus, exhibit a black and orange coloration on their fins as well as their body. The male body condition is positively correlated with orange hue as well as the average number of eggs and clutches. However, there is no correlation between coloration and eggs. This suggests that females are choosing males based on condition but are not using coloration as an indicator for condition but some other trait not tested in this thesis.