Abstract

Many fish species employ a variety of behaviors when capturing different functional types of prey, especially among generalist feeders. These behavioral variations are known as modulation and are used to maximize success when feeding on different prey types and in different habitat locations. This analysis was aimed at determining the degree to which goliath groupers, Epinephelus itajara, modulate their feeding behaviors relative to different prey types and locations within the water column. As the largest species of bony fish in North American waters, goliaths are capable of consuming virtually any prey on the reef and thereby play a significant role in shaping reef communities. Goliaths maximized their performance on larger and faster prey striking fastest at live carangids and deep-bodied prey (e.g. Anisotremus surinamensis, Chaetodipterus faber). They accelerated through both the approach and attack phases of the feeding bout while maximizing cranial elevation, jaw gape, and suction generation. Dead prey in the water column elicited greatly reduced feeding kinematics and suction pressures. Interestingly, dead prey presented on the ocean floor were met with highly modified feeding behaviors including body deceleration, minimized gape, and highly focused suction flow patterns that were rarely encumbered with sediment. Goliath groupers have a tremendously broad diet consisting of spiny lobsters, fishes, and even juvenile sea turtles, and their success at capturing these highly variable prey types is certainly a result of their ability to modulate their feeding behaviors relative to the constraints imposed by each prey item.

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