Invasive species, such as the red lionfish, Pterois volitans, are damaging many ecosystems around the world by out-competing native species. However, little work has been done to determine if P. volitans have a direct influence on the feeding performance of native species with which they compete. This study examines the feeding performance in terms of suction pressure, kinematic timing, and excursion distances of spotted scorpionfish, Scorpaena plumieri. Through multiple trials it was examined how S. plumieri modulate their kinematic behavior in response to P. volitans and a conspecific. The creation of a smaller buccal cavity and a decrease in time of buccal expansion may allow individuals to create greater sub-ambient pressures to increase their prey-capture success. High-speed cinematography and pressure transducers were used to determine if S. plumieri modulate feeding performance in the presence of either P. volitans or a conspecific. The results of the study suggest that S. plumieri do not create larger subambient pressures or modulate their feeding kinematics in the presence of P. volitans or a conspecific.

Polypterus is an extant fish that is used as a model to understand the fin-to-limb evolutionary transition. Polypterus exhibits muscle phenotypes relevant to this transition. In particular, plastic changes in bone and muscle in Polypterus have been shown in response to spending time in a terrestrial environment. Muscle fiber changes are usually associated with changes in the performance demand placed on those muscles. We hypothesize that muscle fibers are recruited differently between aquatic and terrestrial environments to explain the change in fiber type. How pectoral fin muscle activity changes between swimming and walking is mostly unknown. Hence, this study utilizes electromyography (EMG) and high-speed videography to understand how the muscle activity pattern and function of all four pectoral fin muscle groups change during swimming and walking in aquatically raised fish. In this experiment, aquatically raised fish were placed in water and on land to observe changes in fin muscle function between behaviours. This study aims to understand how the instantaneous changes in the behaviour of the fish, particularly in the pectoral fin, could explain the muscle plasticity found in previous research. This study showed that fish adduct their pectoral fins much faster with increased muscle effort during walking compared to swimming. The adductor muscle also had the biggest change in function, activating for the majority of the fin-stroke cycle and therefore undergoing eccentric contraction. The increase in muscle effort seen in this study is consistent with the muscle fiber transition seen in fish that spend long periods on land, and the dramatic change of EMG magnitudes found in the adductor muscle may explain muscle damage previously found following acute walking.