Abstract

Feeding ecology studies have provided valuable insight into the impacts of lionfish on the native reef fish communities of the Western Atlantic and Caribbean. The lionfish are known to consume over 70 fish species and many inverte-brates, and relative prey abundance is strongly site specific. However, the majority of these studies have been based on morphological identification, usually of partially digested specimens. Morphological identification can be biased and prone to human error, depending on the digestive level of the prey item. Additionally, lionfish feed during crepus-cular hours, while many lionfish collections occur at opportune times for researchers and scientists, which usually do not correlate with feeding. The aforementioned points support the need for quantifying digestion rates for more accurate feeding ecology studies or for understanding existing biases. This study analyzed the digestion rate of known teleost and invertebrate prey items in lionfish stomachs, over a given period of time, to provide an estimate of digestion rate at basal metabolism. Two size classes of lionfish were examined and time intervals of 30 minutes to an hour were used to identify digestion rate. Approximately 5+ hours are required before a known fish prey item is deemed unrecog-nizable, and 9+ hours for shrimp. Temperature was observed to correlate with digestion rate. Given these results, a detailed prey digestion scale was developed to assist future morphological gut content analyses. Studies utilizing morphological identification should structure their experimental design to incorporate this information to obtain a higher percentage of undigested prey items for analysis.

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