Meeting Abstract
Moray eels (Anguilliformes: Muraenidae) comprise a large radiation of snake-like marine predators. Morays have a reduced capacity to use suction during prey capture; instead they apprehend prey by biting and use their pharyngeal jaws to transport and swallow prey. The pharyngeal jaws enable morays to maintain at least one set of jaws on their large struggling prey at all times. While morays are known to swallow prey whole, they have also been observed using a diversity of strategies, including shaking, body rotation, knotting, and ramming prey against other objects to manipulate prey into more manageable pieces and assist in feeding. There is little diet data informing us of how large of prey morays can consume and whether manipulation strategy differs between prey items. In this present study, we supplemented field dietary data of the California moray (Gymnothorax mordax) with feeding performance trials in a controlled laboratory environment. Both ingestion ratio (IR) and relative prey mass (RPM) were calculated from various cephalopod and fish prey varying in size. Each trial was recorded for further analysis to determine behavioral differences in feeding strategy. We find that while morays can consume prey with IRs and RPMs as high as 1.18 and 0.28, the material properties strongly affect the maximum size of prey morays can consume whole. Morays had greater success tearing apart fish prey with behaviors such as knotting, while cephalopods were either swallowed whole or only their tentacles were consumed. Tentacles were removed mostly by rotational feeding. Shaking most frequently occurred at the beginning of feeding trials, while other behaviors were more randomly dispersed. Knotting seemed to be induced when IRs surpassed 0.4. We find a strong positive relationship between both IR and RPM and duration of prey manipulation behaviors in cephalopod prey (r2 = 0.47, r2 = 0.94).
