First Record of a Cannonball Jellyfish Bloom (Stomolophus sp.) in Venezuelan Waters

Abstract

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.

1. Introduction

Jellyfish blooms are often associated with environmental changes, such as fluctuations in water temperature, salinity, nutrient levels, and ocean currents, and recent studies have set up a debate on whether or not climate change and anthropogenic activities are affecting the appearance and intensity of those blooms [1,2,3,4,5]. The classical approach hypothesized how different factors benefited jellyfish blooms [1,6]. Rising sea temperatures can accelerate jellyfish development and extend reproductive periods, while altered ocean circulation patterns influence larval dispersal and bloom formation [6,7]. Eutrophication-driven hypoxia, often caused by agricultural runoff and urban waste, creates low-oxygen conditions that many fish and invertebrates cannot tolerate, whereas jellyfish thrive in such environments due to their low metabolic requirements and ability to temporarily withstand anoxic conditions [8,9]. Additionally, overfishing reduces populations of jellyfish predators, such as sea turtles, birds, and certain fish species, while also decreasing competition for planktonic food sources, further favoring jellyfish proliferation [10,11]. These factors can influence the process of strobilation, which is the mechanism of asexual reproduction in jellyfish that leads to rapid population growth [12,13]. Moreover, coastal habitat modifications, such as artificial structures and offshore platforms, provide new surfaces for jellyfish polyps to settle and reproduce, enhancing the potential for bloom formation in anthropogenically impacted regions [10,14,15]. However, to prevent flawed citation practices [3], the analysis should be made species- and habitat-specific given the differential response across species to environmental stimuli, and other additional factors should be considered that might cause a collapse of particular jellyfish populations [5,16].

While jellyfish blooms can disrupt marine ecosystems, traditional fisheries, and aquaculture operations due to competition with fish for plankton, clogging of fishing gear, and interference with coastal industries [1,17,18], they also present valuable economic opportunities. In recent decades, jellyfish fisheries have expanded globally, driven by increasing demand in Asian markets and growing interest in alternative marine resources [19,20]. In Europe, although large-scale commercial jellyfish fisheries have yet to be established, there is growing interest in their exploitation. At least 15 species have been identified as candidates for harvesting, and research initiatives are exploring sustainable fishing techniques and the potential integration of jellyfish into European markets [21]. However, challenges remain, including the development of efficient fishing gear, proper processing techniques, and consumer acceptance, as jellyfish are not traditionally consumed in most European countries [21]. Sustainable management practices, such as seasonal harvesting regulations and size-selective fishing, have been explored to maintain jellyfish stocks while minimizing ecosystem impacts [22,23].

In the Americas, the cannonball jellyfish (Stomolophus meleagris Agassiz, 1860) represents one of the most commercially significant species, particularly in the southeastern United States, the Gulf of Mexico, and parts of Central and South America [20]. This species supports a well-established fishery, primarily targeting Asian export markets, where processed jellyfish products are considered a delicacy. The fishery employs various gear types, including dip nets and shrimp trawls, with annual landings fluctuating due to environmental variability and population dynamics [20]. Processing facilities specialize in drying and preserving jellyfish, ensuring product quality for export, whereas ongoing research explores ways to enhance the sustainability of this fishery through improved management strategies and monitoring efforts [20,23]. Additionally, jellyfish-derived compounds, particularly collagen, have garnered interest for use in biomedical, pharmaceutical, and cosmetic applications, further expanding their economic relevance [18,24]. Given the ecological and economic significance of jellyfish, a comprehensive understanding of bloom dynamics, environmental drivers, and population fluctuations is essential for both mitigating their potential negative impacts and optimizing fisheries management strategies that support sustainable exploitation [25].

The genus Stomolophus Agassiz, 1860, commonly known as the cannonball jellyfish, is a cnidarian genus belonging to the family Stomolophidae Haeckel, 1880. It can be distinguished by the following diagnostic characteristics: a hemispherical to spherical bell with thick mesoglea; a central mouth surrounded by a prominent manubrium formed by the fusion of oral arms; eight pairs of scapulets (small, secondary mouth arms) arising from the pillars of the arm disc; oral arms with numerous club-shaped appendages; and a well-developed ring canal system with 16 radial canals [26,27,28]. Only two species within this genus are currently considered valid: Stomolophus meleagris Agassiz, 1860 and Stomolophus fritillarius Haeckel, 1880 [27]. However, despite its commercial importance, the taxonomic status of species within the genus Stomolophus is still under discussion [29,30], and integrative taxonomy is required to go beyond genus-level identification. Given the taxonomic uncertainties, López-Martínez et al. [31] suggested using Stomolophus c.f. meleagris for specimens that cannot be confidently assigned to a specific species. In this study, given our lack of genetic data, we opted for the most conservative approach, and we refer to the observed specimens as Stomolophus sp.

As for most of the scyphozoan species, the species within the genus Stomolophus shows a metagenic life cycle with the ephyra, medusa, and planula phases constituting the pelagic part of the cycle, and the polyp and strobila accounting for the benthic part [32]. The benthic part has rarely been found in the field for most of the species and ecosystems, and thus, it’s appropriate in situ monitoring remains a challenge. However, it is well known that they can give place to massive appearances in the most noticeable stage of the life cycle, the medusa phase, through the asexual reproduction of polyps and subsequent liberation of ephyrae through a process called strobilation [33,34]. The combined effect, under zero mortality conditions, can lead to a medusa population 2 to 150 times the original polyp population [5]. In Stomolophus species, the strobilation process typically releases two ephyrae per polyp and has been shown to occur 1–3 months before bloom events, driven by environmental fluctuations such as temperature shifts and increased food availability [32,35,36]. Understanding these pre-bloom conditions is essential for identifying the potential drivers of jellyfish proliferation.

The cannonball jellyfish feed primarily on mollusk and fish eggs, although within their diet composition are also crustaceans, cladocerans, tintinnids, larvaceans, and diatoms, with their dietary composition fluctuating according to seasonal prey availability [37,38,39]. Their feeding mechanism is influenced by their short oral arms, which interact with vortices in a way that may impact prey selection, though the ecological consequences of this remain uncertain [39]. Digestion times vary depending on prey type, ranging from 0.5 h for certain plankton organisms to over 23 h for larger prey items, highlighting their opportunistic feeding strategy [39]. During phytoplankton blooms, diatoms become more prevalent in their diet, whereas fish egg consumption peaks coincide with spawning events, potentially influencing fish recruitment [38]. As active consumers of both primary producers and zooplankton, Stomolophus sp. play significant roles in nutrient cycling and trophic interactions within coastal ecosystems [39].

The genus is widely distributed in the Atlantic Ocean and the Gulf of Mexico, with its range extending from the east coast of the United States to the Caribbean Sea and the Gulf of Mexico [27,32,40,41,42]. Its presence in the Pacific Ocean has been documented in various studies, including those that explore its species richness in the Tropical Eastern Pacific [43] and its ecological and fisheries significance in Mexican waters [44]. The cannonball jellyfish exhibits distinct seasonal abundance patterns, with blooms primarily occurring during the dry season (November–April) in the Gulf of Mexico and the Caribbean Sea [45]. In the Gulf of California, for example, ephyrae of Stomolophus sp. 2 are detected in winter and spring (November–May), preceding the adult blooms exploited by local fisheries [46]. The genus Stomolophus was first reported in Venezuela by Trinci [47] from the Gulf of Paria, who observed specimens with up to 16 lobes per octant arranged in eight pairs. Later, Stiasny [48] also documented specimens from the same region, noting individuals with white bell coloration. Historical records of Stomolophus sp. in Venezuela remain scarce since its first records in the early 20th century [47,48]. However, the scarcity of records may not necessarily reflect the species’ rarity, but rather the lack of dedicated studies on jellyfish in the region. The absence of specialized research on scyphozoans in Venezuela could explain the limited documentation of this species.

This study reports the unprecedented, or previously undocumented, first large-scale bloom of Stomolophus sp. in Venezuelan coastal waters, highlighting its potential ecological and socio-economic significance. Given the species’ commercial importance in neighboring countries and its role in regional food webs, understanding the environmental drivers of this event is crucial. We analyzed the environmental conditions (sea surface temperature, precipitation, salinity, and chlorophyll a concentration) in the pre-bloom phase (3 months prior) and during the bloom using open-source satellite-derived data to delineate the triggering causes.

2. Materials and Methods

2.1. Bloom Detection and Stomolophus’ Occurrence in the Western Atlantic

In March 2024, an unusual jellyfish appearance was detected off the northeastern coast of Venezuela during a recreational diving trip of H. Ramírez. The jellyfish were photographed for identification, and the specimens were observed at nine recreational diving locations across approximately 120 km of coastline (10.48° N to 10.88° N, 68.20° W to 67.24° W) (Figure 1). Local divers and fishermen were asked to provide any further information beyond our ‘by chance’ observation. The information they provided allowed us to identify the first record (5 March) and to delimitate the bloom geographically (10°45′–10°36′ N, 68°18′–67°03′ W) and temporarily (March–April 2024). Following these initial reports, we contacted several local stakeholders (divers and fishermen), who provided photographic records and spatiotemporal information (locations, timing) about the sightings. The bloom period (March–April 2024) was confirmed based on consistent observations of high jellyfish abundances across multiple sites and stakeholder-reported data. Species identification was conducted post hoc by the research team using diagnostic morphological features (hemispherical bell, fused oral arms, scapulets; Figure 1) evident in the submitted photographs. The last significant aggregations were documented in late April 2024, with only sporadic individual sightings thereafter. All reports were cross-validated through photographic verification by the research team to minimize misidentification risks.

To assess the historical occurrence of Stomolophus spp. in the region and provide context for the observed bloom, we compiled data from three open-access biodiversity repositories: the Global Biodiversity Information Facility (GBIF; 1884–2025; https://www.gbif.org (accessed on 21 February 2025)), the Ocean Biodiversity Information System (OBIS; 1884–2025; https://obis.org (accessed on 21 February 2025)), and iNaturalist^® (1975–2025; https://www.inaturalist.org (accessed on 21 February 2025)). These records include both stranded and swimming individuals, although most prior observations in Venezuela correspond to isolated specimens rather than large aggregations.

Records were retrieved before 20 February 2025 and constrained to the Western Atlantic region. Community science observations from iNaturalist^® were limited to a “Research Grade” status, ensuring community validation. Duplicate entries across platforms were removed, and records lacking coordinates, temporal metadata, or taxonomic certainty were excluded. Spatial outliers (e.g., inland or non-pelagic coordinates) were flagged using marine geospatial layers and manually verified. To provide a better picture of the distribution of the cannonball jellyfish in the surrounding area, occurrence records for Stomolophus spp. in the Western Atlantic were retrieved from GBIF (8332 records), OBIS (6319 records), and iNaturalist^® (6414 records). After rigorous quality control, 7562 duplicate entries were removed, along with records lacking spatial coordinates or earth coordinates validation (e.g., 5 iNaturalist^® records excluded). The final filtered datasets comprised 5680 records from GBIF (primarily preserved specimens and institutional observations), 3414 from OBIS (marine biodiversity-focused data), and 6231 from iNaturalist^® (research-grade community science contributions).

Also, a systematic literature review was conducted to identify occurrences of Stomolophus jellyfish in the Western Atlantic (Gulf of Mexico and Caribbean Sea). Databases, including the Web of Science, Scopus, and Google Scholar, were searched using keywords such as “Stomolophus meleagris”, “cannonball jellyfish”, “Western Atlantic distribution”, and “Gulf of Mexico jellyfish”. Additional records were sourced from gray literature, institutional reports, and historical publications. The inclusion criteria focused on studies reporting geographical coordinates, ecological observations, or fisheries data for Stomolophus spp. Duplicates and studies outside the target region or lacking spatial data were excluded. Screening, eligibility assessment, and data extraction were performed iteratively, with the extracted data including location names, coordinates, references, and citation details.

2.2. Environmental Data Acquisition and Visualization

To provide a better picture of the reigning environmental conditions before, during, and after the massive appearance of Stomolophus sp. in the northeastern coast of Venezuela, we retrieved sea surface temperature (SST), sea surface chlorophyll a (SSC), and precipitation (here used as a proxy for land nutrient input and salinity fluctuations) data from the NASA Earth Observation (NEO) server (https://neo.gsfc.nasa.gov/, accessed on 18 October 2024). Data were retrieved from September 2023 to August 2024 with a 0.1-degree resolution, and the monthly averages for the study area were calculated. Sea surface salinity (SSS) data were extracted from the Tropical Atmosphere Ocean project (TAO; https://tao.ndbc.noaa.gov/ (accessed on 21 January 2025)) using the “rerddap” package (1.0.2, rerddap: General Purpose Client for ‘ERDDAP’ Servers_ https://CRAN.R-project.org/package=rerddap (accessed on 21 January 2025)) [49]. The main data extraction was performed using the ‘pmelTao5daySss’ dataset, which provides 5-day averaged SSS measurements. A custom function (obtener_sss_media) was developed to query the dataset for each location and period, extracting the SSS values (variable: S_41) and calculating both the mean salinity and standard deviation for each site.

Environmental data were visualized using R version 4.4.2 [50], and Geographic Information System software QGIS 3.28 [51] was used to create the maps. In the resulting figure, we have highlighted two periods: the bloom detection (March–April 2024) and the period in which most likely strobilation occurred (November 2023–January 2024).

The timing of jellyfish blooms is closely linked to the strobilation process, during which sessile polyps undergo transverse fission to produce free-swimming ephyrae. In Stomolophus spp., this process is strongly influenced by environmental factors, particularly temperature fluctuations, food availability, and salinity changes [35,36]. Laboratory studies indicate that strobilation in Stomolophus meleagris is triggered by a decline in temperature followed by a subsequent warming phase, a pattern that aligns with seasonal transitions [52]. Additionally, increased nutrient input and phytoplankton blooms (proxied by chlorophyll a concentration) provide a food-rich environment that supports ephyrae development and enhances medusa survival [38].

Based on this knowledge, we hypothesized that the strobilation process for the observed bloom occurred between November 2023 and January 2024, approximately 1–3 months before the bloom event (March–April 2024). To test this, we analyzed four key environmental variables—the sea surface temperature (SST), precipitation (as a proxy for the land nutrient input and salinity fluctuations), chlorophyll a concentration, and sea surface salinity (SSS)—in both the pre-bloom phase (November 2023–January 2024) and the bloom phase (March–April 2024). The period from November 2023 to January 2024 had all the environmental conditions known to trigger the strobilation in Stomolophus sp., including a gradual temperature decline, high primary productivity, and increased freshwater input from precipitation, which can influence salinity and nutrient availability. These factors have been linked to polyp strobilation and subsequent medusa formation in rhizostome jellyfish.

3. Results

3.1. Bloom Detection and Stomolophus’ Occurrence in the Western Atlantic

In March and April 2024, an unprecedented bloom of the rhizostome jellyfish Stomolophus sp. was observed along the coastal waters of Venezuela (Figure 1; Videos S1 and S2). This bloom was characterized by a jellyfish abundance of approximately three individuals m⁻³, with the specimens having an estimated umbrella diameter between 15 and 20 cm. Multiple sightings were reported, particularly near popular fishing and recreational areas (Figure 2a). The identification of Stomolophus sp., commonly known as the jellyball or cannonball jellyfish, was facilitated by its distinctive morphological features: a hemispherical umbrella, gelatinous translucent body with varied yellow and blue coloration, dichotomous oral arms fused to form a pseudo-manubrium without filaments, a central primary mouth, and the presence of scapulas (Figure 1). Given that we could not collect material for genetic analysis, we only refer to the specimens as Stomolophus sp. While no juveniles (sub-adults) were observed during the bloom, it is worth noting that the polyp stage of Stomolophus has never been found in nature. Therefore, we must assume that the measured sub-surface parameters in this study (see below) are also applicable to the currently unknown depths where polyps reside.

The synthesis of filtered data reveals pronounced heterogeneity in the Stomolophus distribution (Figure 2, Supplementary Material S1). The highest densities occurred in temperate coastal ecosystems, particularly the northern Gulf of Mexico (Texas–Louisiana shelf, Mississippi Sound, and Florida Panhandle) and the United States East Coast (central Florida to North Carolina, including hotspots near Cape Canaveral and Pamlico Sound). These regions showed strong concordance across all platforms, with the GBIF contributing 72% of records (5680), reflecting systematic monitoring in shallow estuaries and shelf habitats. In contrast, low-record areas dominated the southern Caribbean Sea, including the Colombian Caribbean coast (Cartagena Bay, Güajira Peninsula) and Venezuelan coastal waters (Gulf of Venezuela, Paria Peninsula). The southern Gulf of Mexico (Yucatán Shelf, Bay of Campeche) also exhibited sparse records despite its proximity to suitable environments. The iNaturalist^® data highlighted patchy distributions in nearshore zones (e.g., tourist-accessible coasts), whereas OBIS showed minimal coverage in these regions. Notably, the GBIF records declined sharply in the southern latitudes (e.g., southern Gulf of Mexico and Caribbean Sea), aligning with the biogeographic boundaries or institutional research prioritization of northern temperate areas.

The literature review identified 55 records spanning from 1880 to 2023, documenting Stomolophus occurrences across 12 countries and regions, with hotspots in the U.S. Gulf Coast (e.g., Mississippi Sound, Georgia, North Carolina), Mexican lagoons (e.g., the Carmen-Machona-Redonda system), and Colombian coastal zones (e.g., Cispatá Bay). Notably, recent studies by Faulk et al. [42] provided high-resolution spatial data along the U.S. South Atlantic Bight, while historical works [53,54] highlighted long-term presence in estuarine systems. Repeated records in Mississippi Sound and overlapping citations emphasized regions of ecological or fisheries significance (Figure 3, Supplementary Material S1).

3.2. Environmental Conditions

Environmental variables monitored during the study period (September 2023–August 2024) showed distinct temporal patterns that align with the life cycle of Stomolophus sp. (Supplementary Material S2). The sea surface temperature (SST) exhibited a clear seasonal trend, with peak values in October 2023 (29.9 °C) followed by a cooling period from November to January. During this period, temperatures decreased from 29.0 to 27.5 °C, creating the type of thermal fluctuation known to trigger strobilation in this species. The cooling trend continued until it reached a minimum in March 2024 (27.0 °C), after which gradual warming occurred through August 2024 (29.3 °C; Figure 4a). Sea surface chlorophyll a (SSC) concentrations showed patterns particularly favorable for jellyfish development during the presumed strobilation period. A pronounced peak occurred in November 2023 (0.48 mg m⁻³), with sustained elevated levels through December 2023 and January 2024 (0.31 and 0.33 mg m⁻³, respectively), indicating high food availability for developing ephyrae. Concentrations subsequently declined, reaching a minimum in May 2024 (0.11 mg m⁻³; Figure 4b). The precipitation patterns provided additional evidence for conditions conducive to successful strobilation, with maximum rainfall in October and November 2023 (183.4 and 185.5 mm, respectively). This increased precipitation likely enhanced nutrient input into the coastal waters, contributing to the elevated SSC concentrations observed during this period. Precipitation then decreased sharply, with January 2024 receiving only 7.0 mm, followed by the driest conditions in March 2024 (5.7 mm; Figure 4c). The sea surface salinity (SSS) measurements during the study period (September 2023–August 2024) revealed a distinct seasonal pattern in the coastal waters. The SSS values remained relatively stable during the autumn months, with measurements around 35.1 in September 2023, showing a marginal increase to 35.2 in October, followed by consistent values around 35.1 through February 2024. A notable increasing trend began in March 2024 (35.2; Figure 4d), continuing through spring and reaching peak values in June 2024 (35.7). The salinity then showed a gradual decline through the summer months, decreasing to 35.6 in July and 35.3 in August 2024.

4. Discussion and Conclusions

The taxonomic status of Stomolophus has been debated for over a century, with Mayer [53] and Bigelow [78] differing on whether S. fritillarius is distinct from S. meleagris. Stiasny [48,79,80] later found considerable variations in diagnostic traits, further complicating species delimitation. Moreover, population genetic studies on Stomolophus in the Gulf of California have revealed significant genetic differentiation, suggesting the presence of multiple cryptic lineages [29,43]. Using mitochondrial COI sequences and microsatellites, Getino-Mamet et al. [29] identified two distinct genetic lineages: Stomolophus sp.1 in the Golfo de Santa Clara and Stomolophus sp.2 in the southern Gulf of California and Baja California Pacific coast, with divergence estimated at 1.17 million years ago. These findings align with broader patterns of high genetic differentiation and restricted gene flow in scyphozoan jellyfishes, as reported by Gómez-Daglio and Dawson [43] in their comprehensive analysis of jellyfish species in the Tropical Eastern Pacific. The morphology of our analyzed specimens closely resembles S. meleagris from neighboring regions [32], but given the difficulties in morphologically delimitating the species and the lack of genetic material in our study, we conservatively identify our specimens as Stomolophus sp.

Despite certain taxonomic uncertainty, our study represents the first documented bloom of the cannonball jellyfish Stomolophus sp. in Venezuelan waters. This event occurred following a distinct sequence of environmental changes that align with known triggers for this species’ reproductive cycle, particularly between November 2023 and January 2024. This period appears crucial for understanding the subsequent bloom, as it combined several favorable conditions for Stomolophus’ strobilation as follows: (1) a steady temperature decline, likely triggering strobilation (29.0–27.5 °C); (2) peak chlorophyll a concentrations (0.48–0.31 mg m⁻³) as a proxy for primary productivity, indicating abundant food (primary consumer: zooplankton) resources; and (3) high precipitation (up to 185.5 mm per month), potentially enriching coastal waters with nutrients and maintaining low salinity (Figure 4). These environmental factors align with previous studies, demonstrating that temperature fluctuations are a primary trigger of strobilation in Stomolophus spp. [35,52]. Furthermore, elevated chlorophyll a levels indicate increased primary production, which enhances food availability for ephyrae and juvenile medusae, supporting their survival and growth [38]. Additionally, high precipitation rates can introduce terrestrial nutrients into the coastal system, promoting phytoplankton growth and indirectly benefiting jellyfish populations [1,3]. Although direct evidence of local polyps is lacking, the environmental patterns observed in this study are consistent with conditions that have preceded Stomolophus blooms in other regions. The environmental conditions observed in Venezuela align with those reported for Stomolophus meleagris in the South Atlantic Bight, where adult medusae occur in temperatures of 24–32 °C and salinities of 15–37 [42]. Seasonal shifts in temperature and productivity influence bloom formation, with populations migrating offshore in spring for spawning and returning inshore for reproduction as conditions become favorable [42]. In other regions, Stomolophus blooms have also been associated with periods of increased primary productivity and temperature fluctuations [40]. While these factors appear to be common bloom drivers, regional differences in hydrography, productivity cycles, and genetic variations may influence bloom dynamics. Further studies are needed to determine whether similar processes regulate the blooms in Venezuelan waters and assess Stomolophus population connectivity in the region.

The timing between the favorable strobilation conditions (November–January) and the observed jellyfish bloom (March–April) corresponds with the known development period of 1–3 months required for ephyrae to reach the medusa stage [32,81]. Similar temporal patterns have been documented on the east coast of the United States, where Stomolophus sp. populations show strong seasonality tied to environmental cues [42]. The presence of adult jellyfish during periods of lower temperature, reduced precipitation, and increasing salinity (from 35.09 in February to 35.20 in March 2024) suggests that the species may optimize its reproductive timing to ensure the ephyra release coincides with peak food availability, as indicated by the elevated chlorophyll a concentration. This pattern aligns with the observations by Calder [32], who noted that Stomolophus populations often thrive in slightly elevated salinity conditions during their adult phase. However, the lack of polyp-stage observations in Venezuelan waters raises questions about whether this bloom originated from local polyp beds or advected ephyrae from distant regions [2].

This bloom’s occurrence in previously unreported waters raises important questions about the species’ distribution patterns and potential range expansion in the Caribbean region. While Stomolophus has been well-documented in neighboring Colombia [40], its emergence in Venezuelan waters may indicate the changing environmental conditions that are favorable to the species’ establishment. Similar range expansions have been observed for other jellyfish species in response to environmental changes [1], though care must be taken in attributing such events to climate change without long-term monitoring data [3]. However, it should be noticed that the Caribbean Sea has experienced a 0.5 °C warming per decade since the 1980s [82], which could facilitate the tropicalization of gelatinous zooplankton assemblages, and, for instance, Leoni et al. [83] documented new records of the cubozoan jellyfish Tamoya haplonema F. Müller, 1859 in Uruguayan coastal waters, associating these occurrences with positive sea surface temperature anomalies and the intrusion of warm oceanic waters. Localized eutrophication from agricultural runoff may further synergize with warming to create favorable conditions for the cannonball jellyfish. The possibility of Stomolophus populations expanding their distribution due to oceanographic changes, such as shifts in current systems or increased transport of pelagic larvae, should be further investigated. In this line, the absence of genetic data limits our ability to assess connectivity between the Venezuelan populations and established stocks in the Gulf of Mexico, a critical gap in establishing whether the bloom was locally produced or if the medusae were brought by advective movement, given the potential for range shifts under climate change [84]. The inclusion of genetic analysis could also bring to the debate whether Stomolophus populations in the Caribbean and Venezuelan waters represent genetically distinct units or share connectivity with populations in the Gulf of Mexico. Future research incorporating molecular tools will be essential to clarify the genetic structure of Stomolophus in the region and evaluate the potential dispersal pathways influenced by ocean currents, thus facilitating management measures implementation.

The apparent increasing frequency of jellyfish blooms worldwide highlights the need for continuous monitoring efforts to differentiate between natural fluctuations and shifts driven by environmental change. 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. Jellyfish blooms are known to influence marine food webs by preying on zooplankton and competing with fish larvae for resources [37]. Such shifts can have cascading effects on commercial fish stocks and local fisheries, potentially altering ecosystem dynamics and economic activities in the region. Future research should focus on quantifying these impacts and evaluating appropriate management responses.

Local media coverage of this unprecedented event [85,86,87] highlighted public interest and concern about the ecological implications of such blooms. Moreover, Venezuela’s government exported (after this recorded bloom) 156 tons of Stomolophus jellyfish to South Korea on 12 October 2024 [87]. The government presents this initiative as a step toward economic diversification, leveraging marine resources to reduce reliance on hydrocarbons. The lack of transparency regarding the sustainability of jellyfish harvesting calls into question potential long-term ecological consequences. The government claims that Stomolophus jellyfish represent a valuable and underutilized resource, yet no publicly available studies assess the population dynamics of this species in Venezuelan waters or the potential effects of large-scale extraction on an ecosystem’s stability [87]. Despite this opportunity, Venezuela faces unique challenges in establishing a sustainable jellyfish fishery. The country currently lacks the necessary processing infrastructure, while cultural acceptance of jellyfish as food remains low compared to the Asian markets [19], making domestic commercialization difficult. The fishery is primarily export-driven, with dried jellyfish being processed in coastal facilities before shipment overseas. However, interannual variability in jellyfish abundance poses challenges for long-term sustainability and economic reliability [23]. Developing adequate processing infrastructure, including cleaning, drying, and packaging facilities that meet international market standards, would be essential [21]. Additionally, a sustainable management framework must be established before large-scale commercial exploitation begins. In the Gulf of California, for example, the cannonball jellyfish fishery has provided alternative livelihoods for fishing communities during the off-seasons of traditional fisheries [88]. However, as demonstrated by the varying success of jellyfish fisheries worldwide, effective management strategies are crucial to ensuring long-term sustainability [23]. Without a well-regulated approach, Venezuela risks overexploitation, ecosystem disruption, and economic instability in this emerging fishery sector.

The occurrence of this bloom indicates potential economic opportunities through jellyfish fisheries development, particularly given the growing global market for edible jellyfish products. Stomolophus jellyfish have become an increasingly important commercial species throughout the Americas, with established fisheries generating significant revenue through export to Asian markets [20]. This expansion reflects a broader trend in marine resource utilization, as jellyfish fisheries have emerged globally as adaptive responses to both increasing bloom frequency and declining traditional fish stocks [89]. In Europe, jellyfish fisheries are gaining traction as sustainable ventures, particularly targeting Mediterranean species such as Rhizostoma pulmo (Macri, 1778) and Aurelia coerulea von Lendenfeld, 1884. Recent studies highlight their potential for food and biotechnological uses, with processing innovations like thermal treatment (100 °C) and calcium-based dehydration improving safety and texture for Western markets [90,91]. Initiatives aim to diversify applications beyond traditional Asian consumption, including nutraceuticals (e.g., collagen extracts with antioxidant properties) and cosmetic ingredients [90,91]. Challenges persist in balancing the ecological impacts, as jellyfish are critical prey for endangered species like leatherback turtles, necessitating harvest limits (e.g., <4.3 tons/year for R. octopus (Gmelin, 1791) in UK waters) [92]. Collaborative frameworks are emerging to align economic opportunities with ecosystem-based management [90,91,92]. In Mexico, for example, the fishery for S. meleagris is a seasonal activity that employs artisanal fishers during the off-season of other target species [88]. Globally, jellyfish fisheries have emerged as adaptive responses to blooms. For instance, in Japan, Nemopilema nomurai Kishinouye, 1922 blooms spurred industrial processing for food exports [93], demonstrating how communities can adapt to and potentially benefit from changing marine ecosystems [94].

Predicting jellyfish blooms is challenging [5], but the delimitation of the environmental frame in which the blooms develop could facilitate the establishment of management strategies for eventual jellyfish fisheries in Venezuelan waters. The experience from well-managed jellyfish fisheries, such as those in the southeastern United States, provides a model for balancing ecological and economic interests. In this region, seasonal closures and bycatch mitigation measures have been implemented to reduce the impact of jellyfish harvests on other marine organisms [42]. Community-based monitoring programs, leveraging local fishers’ ecological knowledge, could enhance bloom predictability, while fostering stakeholder engagement. Similar to successful management approaches on the east coast of the United States [42], monitoring of key environmental parameters—particularly temperature fluctuations and chlorophyll a concentrations—could help predict bloom timing and its extent. However, the establishment of such a fishery would require careful consideration of the ecosystem impacts, as Stomolophus jellyfish play important roles in marine food webs and nutrient cycling [95].

Our findings highlight a need for the continued monitoring of jellyfish populations along the Venezuelan coast, particularly given the species’ potential commercial value and ecological significance. Future research should focus on understanding the frequency and cyclicity of these blooms, their relationship with regional oceanographic conditions, and their potential impacts on local marine ecosystems and fisheries. Integrating environmental DNA (eDNA) techniques could improve the detection of polyps and early-stage ephyrae, addressing a critical knowledge gap in Stomolophus’ life history [96]. Developing an early warning system for jellyfish blooms, based on remote sensing and environmental modeling, could significantly aid in resource management and impact mitigation efforts [25]. Long-term monitoring programs, similar to those established in other regions where Stomolophus sp. is commercially harvested [20], would be valuable for sustainable resource management and conservation planning. Additionally, further taxonomic work, including genetic analysis, is needed to definitively determine the species identity of Venezuelan Stomolophus populations and their relationship to other populations in the Caribbean region.