Asexual reproduction strategies and blooming potential in Scyphozoa

Abstract

Scyphistomae show different modes of propagation, occasionally allowing the sudden release of great numbers of medusae through strobilation leading to so-called jellyfish blooms. Accordingly, factors regulating asexual reproduction strategies will control scyphistoma density, which, in turn, may influence blooming potential. We studied 11 scyphistoma species in 6 combinations of temperature and food supply to test the effects of these factors on asexual reproduction strategies and reproduction rates. Temperature and food availability increased reproduction rates for all species and observed reproduction modes. In all cases, starvation was the most important factor constraining the asexual reproduction of scyphistomae. Differences in scyphistoma density were found according to the reproductive strategy adopted by each species. Different Aurelia lineages and Sanderia malayensis presented a multi-mode strategy, developing up to 5 propagation modes. These species reached the highest densities, mostly through lateral budding and stolons. Cassiopea sp., Cephea cephea, Mastigias papua and Phyllorhiza punctata adopted a mono-mode reproductive strategy, developing only free-swimming buds. Lychnorhiza lucerna, Rhizostoma pulmo and Rhopilema esculentum also presented a mono-mode strategy, but they only developed podocysts. These 3 species had the lowest reproduction rates and polyp densities; not only their reproduction rates but also the need for a 2-fold set of environmental stimuli to produce new polyps (one for encystment, another for excystment) made this reproduction mode the slowest of those observed to be utilized for propagation. We conclude that blooms may be defined phylogenetically by the specific asexual modes each species develops, which, in turn, is regulated by environmental conditions.

Growth, Duplication and Lateral Mutual Compressive Deformation of Akouemma hemisphaeria on the Seafloor of Okondja Basin at 2.2 Ga (Gabon)

“…These processes demonstrate some ductility of these organisms in unconso- The growth process by budding, recalls that of unicellular organisms like yeast [17] [18] or that of basic metazoan organisms like Cnidarian polyps, Jelly fish [19], Scyphozoa [20] and Hydra [21]. Similarly, the fission process recalls the cell division of microorganisms such as algae [22], protozoa [23] and Archean micro-organism [24], or the duplication of primitive metazoans as enigmatic macrofossils of late Ediacaran [25], Echinoderm Holothuria (sea cucumbers) [ …”

Wind Pattern Change Along a Period of Coastal Occurrence Variation of a Stinging Medusa on a SW Atlantic Beach

“…On the other hand, as it is widely known, sea temperatures is one of the main environmental factors influencing the distribution and abundance of medusae communities (Arai, 1992;Purcell, 2005;Primo et al, 2012;Schiariti et al, 2014). Although different medusae species may respond differently to changing environmental conditions and same species may also differ by region (Lucas et al, 2012), the general trend for temperate gelatinous species is that warm temperatures lead to greater and more rapid production (Purcell, 2005).…”

“…This is particularly important in tourist coastal areas where environmental information for the prediction of stinging species is employed to prevent harmful encounters (Kaneshiro-Pineiro & Kimmel, 2015;Keesing et al, 2015). Temperature is another factor that influences blooming potential in medusae (Arai, 1992;Purcell, 2005;Schiariti et al, 2014), so it should be considered to understand variations in the dynamic of their populations.…”

Jellyfish fisheries in the Americas: origin, state of the art, and perspectives on new fishing grounds

“…Exactly how such changes will affect edible jellyfish species remains to be seen, but developing a better understanding of polyp populations should be a priority for jellyfish fisheries researchers and managers. Polyps may asexually produce more polyps through several different modes, or may form dormant cysts under a variety of conditions (Adler and Jarms 2009;Arai 2009;Lucas et al 2012;Schiariti et al 2014). Ephyrae are released asexually through strobilation and subsequently join the pelagic realm, growing rapidly into medusae (Arai 1997;Palomares and Pauly 2009), after which they may be targeted by the fishery.…”