Using Time Lagged Input Data to Improve Prediction of Stinging Jellyfish Occurrence at New Zealand Beaches by Multi-Layer Perceptrons

Abstract

Abstract. Environmental changes in oceanic conditions have the potential to cause jellyfish populations to rapidly expand leading to ecosystem level repercussions. To predict potential changes it is necessary to understand how such populations are influenced by oceanographic conditions. Data recording the presence or absence of jellyfish of the genus Physalia at beaches in the West Auckland region of New Zealand were modelled using Multi-Layer Perceptrons (MLP) with time lagged oceanographic data as input data. Results showed that MLP models were able to generalise well based on Kappa statistics and gave good predictions of the presence or absence of Physalia. Moreover, an analysis of the network contributions indicated an interaction between wave and wind variables at different time intervals can promote or inhibit the occurrence of Physalia.

Role of winds and tides in timing of beach strandings, occurrence, and significance of swarms of the jellyfish Crambione mastigophora Mass 1903 (Scyphozoa: Rhizostomeae: Catostylidae) in north-western Australia

“…The time lags account for the period between when physical processes are enacted and when their consequences (jellyfish on beach) are observed. The use of time lags in wind data has previously been shown (Pontin et al, 2009) to be important in predicting jellyfish distribution in Physalia (which have ''sails''). Our study shows that the use of time lags in tide range may be a useful predictor of rhizostome jellyfish distribution, at least, in areas where large tide ranges exist, such as in the north-west of Australia (Short, 2011).…”

“…The different manifestations of high densities of jellyfish and how they are formed have been reviewed previously (Graham et al, 2001;Hamner & Dawson, 2009). However, there has been recent interest in using and understanding oceanographic processes to develop predictive capacity to forecast when jellyfish might swarm near the shore bring them into contact with swimmers (Pontin et al, 2009;Gershwin et al, 2014). The extent to which jellyfish biology and behaviour can affect swarming and beach stranding (Fossette et al, 2015) has also gained recent attention.…”