Standard Presentation (15 mins) Australian Marine Sciences Association 2022

Environmental drivers of the occurrence and abundance of the Irukandji jellyfish (Carukia barnesi) (#158)

jamie seymour 1 , Olivia C Rowley 1 , Robert Courtney 1 , Tobin Northfield 2
  1. James Cook University, Cairns, QLD, Australia
  2. Tree Fruit Research and Extension Center Washington State University, Wenatchee, Washington, USA

The ‘Irukandji’ jellyfish (Carukia barnesi) is well known for its small size, cryptic nature, and highly venomous sting. In this study, we use six years of direct C. barnesi capture data to explore patterns pertaining to the annual occurrence and abundance of this species in the nearshore waters of the Cairns coast. Using a two-part hurdle model, eight environmental parameters were investigated over four time periods for associations with records of medusa presence and abundance. Final models showed a small amount of variation in medusa presence and abundance patterns could be accounted for by long-term trends pertaining to rainfall and wind direction. However, the assessed environmental parameters could not explain high annual variation or site location effects. Ultimately best-fit models had very low statistical inference power explaining between 16 and 20% of the variance in the data, leaving approximately 80% of all variation in medusa presence and abundance unexplained.  These data destroy the myth that north east breezes are associated with the presence and increased numbers of this species of Irukandji jellyfish.