Predation is a fundamental ecological process that shapes marine ecosystem dynamics. This study reveals a novel predator–prey interaction between the giant Caribbean sea anemone Condylactis gigantea and the two jellyfish species Cassiopea sp. and Aurelia sp., challenging traditional understanding of sea anemone feeding habits. Observations from citizen science platforms and field recordings documented C. gigantea successfully capturing and consuming these gelatinous marine organisms. The research highlights the trophic plasticity of C. gigantea, demonstrating its ability to prey on larger gelatinous organisms beyond its traditionally known diet. This predation event represents a possible benthic–pelagic coupling mechanism and underscores the value of citizen science in capturing rare ecological interactions.

Cassiopea, commonly known as “upside-down” jellyfish, is a globally distributed genus of Scyphozoa found in tropical and subtropical ecosystems. This review synthesizes existing knowledge on the distribution, habitat preferences, trophic interactions, and physiological adaptations of Cassiopea to evaluate the current literature on the field ecology of the upside-down jellyfish and provide a baseline of their ecological impacts in a rapidly changing environment. Cassiopea exhibits a unique life history alternating between a sexual medusa phase and a benthic, sessile polyp stage, characterized by a symbiotic relationship with dinoflagellates of the Symbiodiniaceae family, which is essential for this metamorphosis. This mutualistic symbiosis provides the jellyfish with a sheltered habitat and enables it to receive up to 70% of its basal energy needs from photosynthetic symbionts. As mixotrophs, Cassiopea efficiently captures a variety of food particles, including microorganisms and small zooplankton, through mucus and ciliary currents from the water column while also benefiting from photosynthetic nutrients. The relevance of this genus is heightened by the rising research of their potential role as both a bioindicator and an ecosystem engineer, particularly in human-impacted coastal systems. However, a significant knowledge gap remains, as the majority of research has concentrated on the Western Atlantic, leading to a limited understanding of the field ecology and behavior of Cassiopea in other ecosystems worldwide. This review highlights the necessity for further research beyond the Western Atlantic to fully comprehend the global ecology of Cassiopea and identifies critical knowledge gaps that warrant future research attention.

Jellyfish blooms are dynamic events driven by environmental and anthropogenic factors. This study reports the first documented bloom of the cannonball jellyfish (Stomolophus sp.) in Venezuelan waters, observed between March and April 2024 along approximately 120 km of coastline. Reports from anglers and divers confirmed high jellyfish abundances (~3 ind. m⁻³) across multiple sites. Environmental analyses suggest that fluctuations in sea surface temperature, increased chlorophyll a concentrations, and high precipitation in the preceding months may have triggered strobilation and subsequent bloom formation. However, the polyps have not yet been observed in the field, and advective movement from other locations cannot be ruled out. Given the commercial importance of Stomolophus spp. in neighboring regions, this record underscores the need for continued monitoring to assess potential range expansions and their ecological and socio-economic impacts. Additionally, the emergence of this bloom raises questions about the species’ distribution patterns, potential establishment in Venezuelan waters, and possible implications for local fisheries. Our findings contribute to the broader understanding of gelatinous zooplankton dynamics in the Caribbean Sea and provide baseline information for future ecological assessments and fisheries management strategies. Further studies, including genetic analyses, are needed to confirm species identity and investigate the drivers behind this unprecedented bloom.

Jellyfish play crucial roles in marine food webs as both predators and prey, but their trophic interactions remain poorly understood due to challenges in systematic observation and sampling. We document opportunistic predation by the foureye butterflyfish Chaetodon capristatus on hydromedusae of the genus Aequorea in Cuba's Cienaga de Zapata Marine Reserve. Two instances of active predation were observed, with butterflyfish selectively consuming portions of the jellyfish bells and subumbrellar regions. Simultaneously, we discovered a prevalent parasitic association between these jellyfish and the hyperiid amphipod Brachyscelus globiceps, with 100% of examined Aequorea (n = 6) hosting between 31 and 67 amphipods each. These observations suggest complex ecological roles for Aequorea in this ecosystem. Supplemental jellyfish consumption could nutritionally subsidize coral reef fish during periods of low prey abundance. However, intense overexploitation could deplete jellyfish populations, potentially disrupting plankton community structure and energy flow through the food web. Conversely, moderate predation on parasitized individuals may facilitate biomass recycling while removing weakened hosts. This study highlights the need for further research to elucidate jellyfish trophic dynamics in the face of environmental change, emphasizing their importance in marine ecosystem functioning and the value of long-term monitoring in marine reserves.