Quantifying movement of the tropical Australian cubozoan Chironex fleckeri using acoustic telemetry

Abstract

Cubomedusae are considered to have superior swimming abilities compared to other pelagic cnidarians, yet many of the theories describing such behaviours are based on anecdotal evidence, sting records or opportunistic sightings, rather than quantitative data. Acoustic telemetry was used to document the movements of adult Chironex fleckeri medusae within both coastal and estuarine habitats. The rate at which tagged medusae moved was influenced by an interaction between time period (day or night) and habitat (coastal or estuarine), with rates of travel being relatively similar during the day and night within the coastal habitat, but significantly greater at night than during the day within the estuarine habitat. Medusae in coastal habitats travelled at similar rates throughout all tidal states while estuarine medusae travelled at significantly faster rates towards the middle of the tide than at the low and high ebbs. Such movements occurred with, and independent of, tidally generated currents, but at increased current speeds, medusae tended to travel with the current. Data are also presented that show that large medusae may move from coastal to estuarine habitats.

Jelly-falls historic and recent observations: a review to drive future research directions

“…Seymour et al, 2004;Gordon & Seymour, 2008;Hays et al, 2008) on individuals found in blooms to discover their fate (Table 2). Tags can be mechanically secured in cnidarians in the bell area and peduncle, or using setting glue.…”

Sources and movements of Chironex fleckeri medusae using statolith elemental chemistry

“…The Sr:Ca ratios of statolith edge zones of medusae caught then varied only 5.7% from the mean, suggesting a relatively consistent exposure to water among individuals. Acoustic telemetry tracking of C. fleckeri medusae showed that six out of seven medusae tagged in coastal habitats remained in coastal habitats (Gordon & Seymour, 2009); the two medusae they tagged in Wooldrum Point remained there for the duration of the tracking period (up to 38 h). Although it is possible that the medusae caught in our study travelled out of the 1.5 km sampling area along Wooldrum Point during 3 days, the tracking experiment results plus the fact that exposure of medusae to estuarine influence would require a round trip of more than 10 km, gives us confidence that the Sr:Ca ratios in the outer *2.4 growth increments of statoliths from this time reflected the salinity measured at Wooldrum Point.…”

“…Adult medusae tracked with acoustic telemetry within coastal and estuarine habitats showed variable movements over short periods of time (Gordon & Seymour, 2009). Of twelve large medusae tagged, eleven remained in their respective coastal or estuarine habitats, while only one individual (IPD = 180 mm) travelled *10 km over 26 h up and down a beachfront and in and out of an estuary (Gordon & Seymour, 2009).…”

“…C. fleckeri medusae are considered to be littoral (sensu Tibballs, 2006) and are found mostly in shallow water mangrove channels, creek mouths and along sandy beaches (Hamner et al, 1995;Coates, 2003). Knowledge of cubomedusan distribution and movements is limited (but see Gordon & Seymour, 2009;Kingsford et al, 2012).…”

Abundance patterns of cubozoans on and near the Great Barrier Reef

“…Despite their low species diversity (40-50 species, Bentlage et al, 2010), they are morphologically diverse and have fast growth rates (Gordon et al, 2004), interesting life histories (Hartwick, 1991a;Straehler-Pohl & Jarms, 2005), strong swimming abilities (Gordon & Seymour, 2009), complex eyes that are used to hunt (Coates & Theobald, 2003;Nilsson et al, 2005), and powerful venom (e.g., Kintner et al, 2005). The nematocysts of ''Stingers'' (Chironex fleckeri Southcott) cause life threatening stings and have been responsible for many deaths in Australia alone (Gershwin et al, 2010).…”