Research Article |
Corresponding author: Sergio N. Stampar ( sergiostampar@gmail.com ) Academic editor: Rosana Rocha
© 2020 Sergio N. Stampar, Edgar Gamero-Mora, Maximiliano M. Maronna, Juliano M. Fritscher, Bruno S. P. Oliveira, Cláudio L. S. Sampaio, André C. Morandini.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Stampar SN, Gamero-Mora E, Maronna MM, Fritscher JM, Oliveira BSP, Sampaio CLS, Morandini AC (2020) The puzzling occurrence of the upside-down jellyfish Cassiopea (Cnidaria: Scyphozoa) along the Brazilian coast: a result of several invasion events? Zoologia 37: 1-10. https://doi.org/10.3897/zoologia.37.e50834
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The massive occurrence of jellyfish in several areas of the world is reported annually, but most of the data come from the northern hemisphere and often refer to a restricted group of species that are not in the genus Cassiopea. This study records a massive, clonal and non-native population of Cassiopea and discusses the possible scenarios that resulted in the invasion of the Brazilian coast by these organisms. The results indicate that this jellyfish might have invaded the Brazilian coast multiple times.
Invasive species, jellyfish bloom, medusa, non-native species
Cassiopea Péron & Lesueur, 1810 is a unique genus of large jellyfishes that occur in several shallow water environments around the world (
Populations of upside-down jellyfish have been found in several parts of the world where they had never been found before, and several of these records have been regarded as the products of invasion events (
It is argued that the population found in most of the Brazilian coast was originated from an old invasion, probably during the Age of Discovery (Great Navigations) approximately 500 years ago (
Dozens of Cassiopea jellyfish (Figs
Specimens of Cassiopea from Meirim River estuary: (1) general view of the touristic area with dozens of specimens; (2, 3) details of some large specimens, around 17 cm; (4, 5) details of formalin preserved large specimens; (6–8) details of oral arms, marginal lappets and a rhopaliar niche, respectively. Scale bars: 4–7 = 1 cm, 8 = 1000 µm.
Observations on living specimens were mostly restricted to the color pattern and size and shape of the mouth-arms appendages. Preserved individuals were measured, checked for morphological features (mouth-arms ramification, number of rhopalia and lappets), and sexed (small piece of gonad tissue observed under the microscope).
Since the mouth of the Meirim River was inside a touristic area of a private beach resort, we questioned the managers about anecdotal effects of jellyfish on tourism.
Data sampling for jellyfish coverage was carried out in January 2017. We performed 11 underwater visual censuses (UVC) in two stretches of the Meirim River, in a region where the upside-down jellyfish had invaded (7 UVCs). Up that stretch (4 UVCs) there is a region where it is not present. In both stretches, the depth of the water ranged from 0.5 to 1.5. Each visual census was 40 m2 (20 x 2 m), totaling 280 m2 in the invaded region and 160 m2 in the region without Cassiopea. The occurrence of other organisms at censuses such as fish, crustaceans, mollusks, seagrass and algae was also registered. Additionally, we asked the fishermen and the tourists questions about recreational and fishing activities in the region, even in the presence of Cassiopea, at the same time we collected other data.
DNA was extracted using two alternative techniques: a Chelex-based (InstaGene Matrix/Bio-Rad #732-6030) and Salt-precipitation protocol (ammonium acetate). Total DNA extractions were checked with NanoDrop 2000c and 2% Agarose gels stained with GelRed (Biotium #41001 – 41003-T). The Cytochrome Oxidase I (COI) was the molecular/genetic marker of choice: a partial sequence of this gene was amplified using PCR for a total of four individuals (universal primers: LCO1490 and HCO2198; using the original PCR program) based on the protocol defined by
Terminal ID | Molecular species ID | Locality | GenBank accession number | Reference |
CandroHaw1 | C. andromeda | Hilton Lagoon, Waikiki Beach, Oahu, Hawaii, USA | AF231109.1 |
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CxamaUSAFl1 | C. andromeda | Key Largo, Florida Keys | AY319468.1 |
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CfrondUSAFl1 | C. andromeda | Key Largo, Florida Keys | AY319467.1 |
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CxamaBerm1 | C. andromeda | Walsingham Pond, Bermuda | AY319466.1 |
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CxamaBerm2 | C. andromeda | Richardson Bay, Bermuda | AY319465.1 |
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CxamaBerm3 | C. andromeda | Richardson Bay, Bermuda | AY319464.1 |
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CxamaBerm4 | C. andromeda | Walsingham Pond, Bermuda | AY319463.1 |
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CandroEgyRSea | C. andromeda | El Ghardaqa, Egypt, Red Sea | AY319458.1 |
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CandroHaw4 | C. andromeda | Kainaone fish pond, Moloka’i, Hawaii, USA | AY319454.1 |
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CandroHaw5 | C. andromeda | Kainaone fish pond, Moloka’i, Hawaii, USA | AY319453.1 |
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CandroHaw7 | C. andromeda | Hilton leeward, Oahu, Hawaii, USA | AY319451.1 |
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CandroHaw8 | C. andromeda | Hilton leeward, Oahu, Hawaii, USA | AY319450.1 |
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CandroHaw9 | C. andromeda | Hilton leeward, Oahu, Hawaii, USA | AY319449.1 |
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CandroHaw10 | C. andromeda | Hilton leeward, Oahu, Hawaii, USA | AY319448.1 |
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CandroBra1 | C. andromeda | Cabo Frio, Rio de Janeiro, Brazil | KC464458.1 |
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Cassiopea_Alagoas_4 | C. andromeda | Pratagy, Maceió, Alagoas, Brazil | MT806178 | This study |
Cassiopea_Alagoas_3 | C. andromeda | Pratagy, Maceió, Alagoas, Brazil | MT806179 | This study |
Cassiopea_Alagoas_2 | C. andromeda | Pratagy, Maceió, Alagoas, Brazil | MT806180 | This study |
Cassiopea_Alagoas_1 | C. andromeda | Pratagy, Maceió, Alagoas, Brazil | MT806181 | This study |
CfrondPan1 | C. frondosa | San Blas Islands, Panama | AY319470.1 |
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CfrondPan2 | C. frondosa | San Blas Islands, Panama | AY319469.1 |
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CandroInd1 | C. ornata | Kakaban, Kalimantan, Indonesia | AY319473.1 |
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CandroInd2 | C. ornata | Kakaban, Kalimantan, Indonesia | AY319472.1 |
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CandroFiji | C. ornata | Dravuni, Fiji | AY319457.1 |
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CandroPal1 | C. ornata | Short Drop Off, Palau | AY319456.1 |
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CandroPal2 | C. ornata | Short Drop Off, Palau | AY319455.1 |
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CxamaPan1 | C. xamachana | Bocas del Toro, Panama | JN700936.1 |
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CxamaBra1 | C. xamachana | São Sebastião, São Paulo, Brazil | MN539722.1 | This study |
CxamaBra2 | C. xamachana | Imbé, Rio Grande do Sul, Brazil | MN602311.1 |
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CandroAus | Cassiopea sp. 1 | Port Douglas, Queensland, Australia | AY319471.1 |
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CandroPNG1 | Cassiopea sp. 2 | Observation Point, Papua New Guinea | AY319459.2 |
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CandroPNG4 | Cassiopea sp. 2 | Observation Point, Papua New Guinea | AY319460.1 |
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CandroPNG2 | Cassiopea sp. 3 | Emona, Papua New Guinea | AY319461.1 |
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CandroHaw6 | Cassiopea sp. 3 | Wedding Chapel, windward O’ahu, Hawaii, USA | AY331594.1 |
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CandroHaw11 | Cassiopea sp. 3 | Mid Pacific Golf Course pond, windward O’ahu, Hawaii, USA | AY331593.1 |
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CandroJap1 | Cassiopea sp. 5 | Unknown | AB563740.1 |
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CandroJap2 | Cassiopea sp. 5 | Unknown | AB563739.1 |
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Catostylus_mosaicus | Catostylus mosaicus | Lake Illawara, New South Wales, Australia | AY319476.1 |
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Uncorrected pairwise distances were retrieved from the software Geneious™ 9 (
The 26 specimens collected resemble those previously identified as C. andromeda from Cabo Frio, SE Brazil (
The oral appendages display two patterns: specimens with broadly large ovate green appendages; and animals with elliptic elongated brownish appendages. In both morphotypes, there are no more than eight appendages on each mouth arm. The appendages vary in size according to the diameter of the specimen (namely, the bigger the jellyfish, the bigger the appendage). Usually, the longest appendage is at the center of the mouth-arm disk (either elliptic elongated or broadly ovate). It can be isolated or surrounded by smaller appendages. Throughout the mouth arms there are many small club-shaped beige-white appendages. In general, both morphotypes resemble one from Cabo Frio with large appendages because of the color (brownish-greenish), distribution (at the center, at the base of each pair of oral arms, and at the axil of the terminal bifurcation of oral arms) and shape (oval-elliptic elongated) of the appendages; however, there are difference in the number of appendages at the center of the disc, which is associated to sexual dimorphism.
From the 26 examined jellyfish, 13 had gonads and are females; but no clusters of eggs were found among the oral arms – which suggests no sexual reproduction is taking place in the area. Regardless of the morphotype, abnormalities were observed. Two specimens presented an abnormal number of gonads (3 and 5 instead of 4). Also, an abnormal number of oral arms was observed in 1/3 of the inspected organisms: 7, 9 or 10 instead of 8.
The phylogenetic relationship based on sequences of COI using Maximum Likelihood analysis (Fig.
Molecular reconstruction inferred under Maximum Likelihood (score: -lnL 3124) based on COI with
An 80% coverage of Cassiopea specimens was estimated on the invaded shallow and sheltered part of the Meirim River estuary, Maceió, Alagoas. In this area macroalgae and seagrass were not registered. Besides that, fish species typical of the region, such as mullet, mojarra and snapper, were seldom seen. Demersal fish, like flounder and gobies, besides sea slugs were not registered. In the upper stretch of the Meirim River Cassiopea was not recorded, with seagrass and algae covering 40% of the bottom.
During October 2016 sampling, the managers of the beach resort (final part of Meirim River) noted on the impact noticed on touristic activities. People were avoiding the riverine waters for recreation because they were concerned about the presence of jellyfish in the water. The few people who had the courage to entered the water complained about stings. On January 2017 only two fishermen and six tourists were present at the study area at the time of sampling.
Invasive species populations usually derive from a small number of founders, which may face a different environment from where they occur naturally. To survive in the new environment, morphological plasticity is often important (
The main morphological variation seen in the collected specimens was the shape and colour of the oral appendages, resulting in two distinct sympatric morphotypes that are genetically identical (see molecular section). Larger appendages may provide more light to the zooxanthellae housed in their oral appendages. Also, it improves feeding ability by helping to capture the meiofauna that is flushed to the oral appendages (
Specimens of Cassiopea andromeda from Cabo Frio, Rio de Janeiro, Brazil: (11) general view of the area with dozens of specimens, largest one ~25 cm; (12) oral view of a preserved specimen in formalin; (13) details of oral appendages of a formalin fixed specimen. Scale bars: 12, 13 = 1 cm.
Such morphological variation in color and appendage shape in clonal jellyfish individuals has not been discussed in the literature. There are records of morphological abnormalities in medusae (aquarium conditions) because of abnormalities found in polyp symmetry (
In the invaded area of the Meirim River, macroalgae and seagrass seem to be affected by physical contact and/or shading caused by large jellyfish.
Another impact noticed was the absence of artisanal fishermen and tourists. They sought other fishing and recreational areas, fearing the jellyfish stings. According to the resort manager, tourists, and artisanal fishermen, the jellyfish bloom is a reason to avoid the area. The stinging ability of several jellyfish species is widely known (
This is a different situation from the Cassiopea bloom recorded in the Araruama lagoon (Cabo Frio, Rio de Janeiro, SE Brazil), where no ecological or economic consequences were observed or reported (
Data retrieved from molecular phylogenetic reconstruction indicates that there are two different C. andromeda populations on the coast of Brazil. As both populations are composed of clonal individuals, probably originating from a single initial polyp in each case, the assumption that they are not from the same introduction event is reasonable. There are two possible hypotheses explaining those two populations. In the first scenario there was a unique invasion followed by broad dispersal, and a subsequent process of genetical isolation between two populations. This scenario is possible if we accept the proposal of
Current knowledge of the genetic variation at inter and intra specific levels in C. andromeda is the result of molecular data on polymorphisms at a single locus (
This work was partly supported by Fundação ao Apoio à Pesquisa do Estado de São Paulo (FAPESP 2015/24408-4, 2016/50389-0, 2019/03552-0), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, PROTAX 440539/2015-3) and CNPq (Research Productivity Scholarship 301293/2019-8) to SNS; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior,(Finance Code 001, grant number 238.273.628-30) to EGM; São Paulo Research Foundation (FAPESP 2016/04560-9) to MMM; São Paulo Research Foundation (FAPESP 2011/50242-5, 2015/21007-9) and CNPq 309440/2019-0 to ACM. We are deeply indebted to Victor Cedro by the update about Cassiopea population.
Figure S1. Map showing the collection localities of Cassiopea sequences used in the phylogenetic analysis. The green square refers to the site of collection of the population of C. andromeda from Alagoas, Brazil. Each color indicates a species. Cassiopea sp. 5 does not appear because of its unknown locality.
Data type: species data.
Table S1. Genetic distance matrix over sequence pairs within Cassiopea andromeda. Values shown below diagonal are uncorrected pairwise distances. Above the diagonal are the number of bases that are not identical. 1. Cassiopea_Alagoas_1; 2. Cassiopea_Alagoas_2; 3. Cassiopea_Alagoas_3; 4. Cassiopea_Alagoas_4; 5. CandroHaw8; 6. CandroHaw10; 7. CandroHaw7; 8. CandroHaw9; 9. CandroHaw1; 10. CandroEgyRSea; 11. Cbrazil; 12. CxamaBerm3 13. CxamaBerm4 14. CandroHaw4 15. CxamaBerm1 16. CandroHaw5 17. CxamaBerm2 18. CxamaUSAFl1.
Data type: species data.