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Gonionemus sp. Macromorphology of medusae and tentacles. Medusae in apical dorsal (A-C), lateral (D and E), and oral ventral view (F and G), showing gonads, radial canals, ring-canal, bell-rim flaps/lappets, statocysts, manubrium, tentacles with nematocyst batteries and adhesive pads, tentacle base tentacle with tentacle-canal and yellow streak, and velum. Abbreviations: arrows, point at adhesive pads; brf, bell-rim flap/lappet; gmd, developing male gonad; gf, female gonad; m, manubrium; rac, radial canal; ric, ring-canal; s, statocyst; sto, stomach; stoa, stomach attachment; tb, tentacle base; tc, tentacle-canal; v, velum; ys, yellow streak. Photo credits: Carina Östman (A-F), Ulf Jondelius (G). Full-size DOI: 10.7717/peerj.6883/fig-2
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The clinging jellyfish Gonionemus sp. is a small hydromedusa species known historically from the Swedish west coast but not reported in recent times. This species is thought to be native to the northwest Pacific where it is notorious for causing severe stings in humans and is considered invasive or cryptogenic elsewhere. This year, unlike in the pa...
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Temporal variation of the population dynamics of the medusae and ctenophores (gelatinous zooplankton) is described over an annual cycle in the Mar del Plata Harbor, Argentina. A total of 18 species were identified, 3 of which were ctenophores (2 of Class Tentaculata and 1 of Nuda) and 15 medusae (14 of Class Hydrozoa and 1 of Scyphozoa). A species...
Citations
... comm.). It has been suggested that the outbreak at the Swedish west coast is linked to the exceptionally warm summer of 2018 following either a climate-driven range shift or a direct introduction to the area via shipping activity (Govindarajan et al. 2019). An analysis of mitochondrial COI sequences demonstrated that the Swedish medusa belong to the same clade as highly toxic populations previously found in the Sea of Japan and the northwestern Atlantic (Govindarajan et al. 2019). ...
... It has been suggested that the outbreak at the Swedish west coast is linked to the exceptionally warm summer of 2018 following either a climate-driven range shift or a direct introduction to the area via shipping activity (Govindarajan et al. 2019). An analysis of mitochondrial COI sequences demonstrated that the Swedish medusa belong to the same clade as highly toxic populations previously found in the Sea of Japan and the northwestern Atlantic (Govindarajan et al. 2019). Govindarajan et al. (2019) speculated that the toxic clinging jellyfish belong to a species other than G. vertens and that there has been a cryptic invasion of this species (Gonionemus sp.). ...
... An analysis of mitochondrial COI sequences demonstrated that the Swedish medusa belong to the same clade as highly toxic populations previously found in the Sea of Japan and the northwestern Atlantic (Govindarajan et al. 2019). Govindarajan et al. (2019) speculated that the toxic clinging jellyfish belong to a species other than G. vertens and that there has been a cryptic invasion of this species (Gonionemus sp.). ...
... These organisms feed on other zooplankton, preying on and competing with a wide array of invertebrates and fish (Matsakis & Conover 1991, Purcell 1991, Nicholas & Frid 1999, Purcell & Arai 2001, Wintzer et al. 2011. Some species are of medical and economic importance, as they negatively impact aquaculture and tourism through their detrimental effects on animal and human health (Båm stedt et al. 1998, Baxter et al. 2011, Govindarajan et al. 2019. They have a highly seasonal presence in the ecosystem, sometimes forming massive, short-lived blooms and occasionally becoming the most abundant invertebrate predators (Purcell 1981, Lucas et al. 1995, Robi son et al. 1998, Gorsky et al. 2000, Hosia & Båmstedt 2007, Boero et al. 2008, Genzano et al. 2008. ...
Knowledge of the spatio-temporal dynamics of hydromedusae and siphonophores is scarce despite their key role as predators. In the temperate inlet of Oslofjorden, studies dealing with these organisms are limited to a few reports from the 1960s on the relationship between selected species and environmental conditions of the inner fjord, but comprehensive assessments of the horizontal, vertical and seasonal variation of the pelagic hydrozoan community are lacking. In this contribution, the quantitative composition of pelagic hydrozoans in Oslofjorden was surveyed using 2 separate sampling designs: one providing a snapshot of the horizontal variation along the inner-outer fjord axis and the other assessing horizontal, seasonal and vertical changes over a yearly cycle. In total, 27 hydrozoan taxa were recorded. Hydrozoan assemblages were structured horizontally, vertically and seasonally, but patterns in the inner-outer axis were evident only when depth and seasonal variation were excluded from the analysis. A distinct assemblage of holoplanktonic hydromedusae inhabited deep (>100 m) waters regardless of season and position in the fjord. Seasonal shifts in species composition and abundance occurred sequentially, with meroplanktonic hydromedusae increasing in numbers from spring to summer and resulting in large aggregations of the medusa-budding species Rathkea octopunctata , Stauridiosarsia gemmifera and Lizzia blondina in late summer and early autumn. No support was found for previous claims stating that the abundance of the common species Aglantha digitale , Lensia conoidea and R. octopunctata increases towards the inner-fjord. This work provides the first baseline data set against which potential changes in gelatinous zooplankton in the region can be contrasted.
... It is hoped that highlighting some of these unusual jellyfish will encourage beachcombers and naturalists to look out for such interesting visitors to our shores. Rare or unusual species could appear almost anywhere and even species previously unknown in Scottish waters could turn up (see Govindarajan et al., 2019). A similar jellyfish invasion caused the death of thousands of caged salmon in North Uist in the Outer Hebrides during November 2014 (BBC News, 2014). ...
Bacteria communities in cnidarian jellyfish can be harmful to many important aquaculture species, as they can be key vectors of bacterial pathogens. However, our knowledge of bacterial communities associated with jellyfish in culture ponds and their potential roles in the regulation of aquaculture species remains unclear. In this study, sequencing based on the bacterial 16S rRNA gene was used to investigate the composition and variation of the bacterial communities associated with hydromedusa Gonionemus vertens in sea cucumber culture ponds and natural marine environment. The associated bacterial communities of G. vertens from the culture ponds in the Yellow Sea and Bohai Sea had significantly different compositions, when compared with those from ambient seawater environment. Furthermore, bacterial communities associated with G. vertens had similar diversity and composition in culture ponds and natural marine environment in the Yellow Sea. There were 31 unique bacterial biomarkers identified in three locations. The major communities were highly abundant in Kiloniellales, Octadecabacter, Polynucleobacter, and Polaribacter, and are related to the environmental information processing. Pathogen candidates such as Vibrionales and Chlamydiales had notably low relative abundances (<1%). The venom of the jellyfish was considered responsible for damage to the aquaculture. This study provides important data to help assess the impact of cnidarians-associated bacterial communities on pond aquaculture and the influences on material cycling and energy flow in marine ecosystems.
Abstract In recent years, the cryptogenic and often highly toxic hydrozoan Gonionemus sp. has appeared in new locations around the globe and has become increasingly abundant in the Northwest Atlantic where it is now associated with severe stings. Several such stings have been documented from the island of Martha’s Vineyard, located approximately 8 km south of the Cape Cod, Massachusetts coast. It appears that Gonionemus sp. may be expanding its range in this region. Here we surveyed for medusae in the major coastal ponds along the perimeter of Martha’s Vineyard, refined our knowledge of Gonionemus sp. habitat by recording salinity, water depth, and bottom type from surveyed areas, and obtained a basic population life history assessment by measuring the sizes and sex ratios of medusae collected in the surveys. We found Gonionemus sp. present in five ponds: Farm Pond, Sengekontacket Pond, Lake Tashmoo, Stonewall Pond, and Edgartown Great Pond. Medusae were associated with eelgrass meadows in all cases. Salinities for medusa populations ranged from 18 ppt in Edgartown Great Pond to 29 ppt in the other ponds. The Farm Pond and Stonewall Pond medusae were significantly smaller than those from other ponds and were comprised of primarily immature individuals despite sampling relatively later in the season, suggesting factors other than temperature may be affecting medusa growth. For mature medusae, sex ratios were highly biased, suggesting a strong clonal component to population growth. Edgartown Great Pond contained only males and thus may represent an entirely clonal population. These medusae are the first record of Gonionemus sp. in Edgartown Great Pond, despite a long history of study. Medusae were most abundant in the portion of the pond near the town landing, which suggests that the medusae could have originated by clonal polyps, frustules, or cysts associated with a boat hull. Given the presence of male and female medusae in other parts of Martha’s Vineyard, it seems likely that additional genetic individuals will arrive in the near future, potentially establishing a sexually reproductive population.
