Meeting Abstract
Despite the growing body of data on predatory interactions, we are still lacking information on the feeding ecology for many top predators that inhabit kelp forest ecosystems. The elusiveness of some large predators contributes to the paucity of information. For six years, we have been gathering data on the cryptic California moray eel (Gymnothorax mordax). Here, we present dietary breadth and bite force data for morays inhabiting Two Harbors, Santa Catalina Island, CA. Morphological data and dietary items were recovered from sedated morays using manual palpation. Dietary items were measured and classified to the lowest distinguishable taxonomic unit. In vivo bite force measurements were collected on 49 morays ranging from 567 – 1192 mm total length. Between 2012 and 2016, the main dietary items of morays consisted of kelp bass, octopus, and red rock shrimp, respectively. Kelp bass (80 – 297 mm total length) was the most consumed item across all sites and years, suggesting that morays may be imposing a significant source of predation pressure on juvenile and recruiting kelp bass. Bite forces ranged from 32 – 467 N; bite force exhibited positive allometry with moray head length and width. Our prey size data indicate that as morays grow larger, they are capable of consuming larger prey, but smaller items still remain in the diet. Additional analyses using prey availability and abundance data suggest that morays are generalist predators, consuming a wide range of prey. Our results indicate that morays may be highly influential piscivorous predators in the Southern California kelp forest ecosystem, frequently preying upon a kelp bass – a species also known to impact a wide range of vertebrate and invertebrate prey.
