Digestive Enzyme Activity and Energy Reserves in Mesenterial Filaments of Intertidal Sea Anemones (Actiniaria)

Rocky intertidal zones are characterized by strong environmental variability and fluctuating food availability, conditions that impose significant constraints on digestive performance and energy management in benthic organisms. Sea anemones are abundant cnidarians in these habitats and exhibit flexible feeding strategies, yet comparative information on their digestive physiology remains scarce. In this study, we compared digestive enzyme activities and energy reserves in the mesenterial filaments of three intertidal sea anemones from the southwestern Atlantic: Bunodosoma zamponii, Aulactinia marplatensis, and Anthopleura correae. Activities of carbohydrases, lipolytic and proteolytic enzymes, aminopeptidase-N, and carbonic anhydrase were quantified, together with biochemical energy reserves. All three species exhibited a broadly similar enzymatic repertoire, consistent with opportunistic feeding strategies. However, significant interspecific differences were detected in digestive enzyme activities and in the accumulation of energy reserves. These differences suggest contrasting physiological investments in digestive processing and energy storage among species that coexist within the same intertidal environment. The observed patterns are consistent with previously reported differences in feeding habits and microhabitat use and highlight digestive physiology as a relevant dimension of functional variability in actinarian assemblages. Overall, our results provide a comparative description of digestive physiology in intertidal sea anemones and contribute to a better understanding of physiological diversity among sympatric cnidarians inhabiting highly variable coastal environments.