Journal Article
Evidence for successive breaching events by basking sharks Cetorhinus maximus (Lamniformes: Cetorhinidae)
Simon David Berrow; Michiel De Boeck; Ryan Andrew Davies; Fintan Ryan; Richard Collins
Environmental Biology of Fishes · Vol. 108, Issue 11 · pp. 1621-1628 · 2025
Abstract
Basking sharks were recorded breaching frequently off the coast of Co Clare, Ireland. The frequency and time between breaching events were analysed to determine any patterns in this behaviour. A total of 93 breaches of basking sharks were recorded over a 3-day period in September 2020. The mean number of breaches per hour, during a total observation period of 515 min, ranged from 6.0 to 15.3 with a mean ± SD of 9.2 ± 4.3 breaches per hour. Inter-Breach-Intervals (IBI) ranged from less than 1 min to a maximum of 34 min with a mean value of 5.4 min (median 2.0 min) across all observations. A total of 39.8% of all breaches were recorded within 1 min of the previous breach, whilst 65.6% were made within 5 min. Results suggest one breaching event may act as a trigger for other breaching events.