Abstract

Lionfish (Pterois volitans and P. miles) have become invasive throughout the tropical western Atlantic, with P. volitans widely distributed across the region. Most lionfish research has focused on their consumptive effects on reef fish and so little is known about their non-consumptive effects and their effects on invertebrates. Lionfish often shelter around biotic and abiotic structures on the reef, thus there is potential for competition between lionfish and other shelter using organisms. I will summarise the results of research carried out in Tela bay, Honduras, from June – August 2019. The aim of this research was to test whether the presence of invasive lionfish alters shelter-use behaviour of native spiny lobster, or vice versa. Shelter use was assessed ex-situ in a large tank with a single shelter, using infrared cameras to film for 60 seconds every hour over a 24 hour period. A subsidiary aim was to investigate what factors influence individual sheltering behaviour. Our preliminary results suggest that lionfish reduce their shelter use in the presence of lobster. Lionfish spent 421 ± 87 s (mean ± standard error) in shelter when alone, compared to only 142 ± 53 s when lobster were present. However, the same trend was not seen in lobsters, which spent similar lengths of time in shelter when alone (182 ± 69 s) and when lionfish were present (169 ± 75 s). Lionfish and lobsters rarely shared the shelter. Our results are positive for lobster populations because lionfish did not influence lobster shelter use. However, lionfish may impact lobster fisheries because once a lionfish entered a shelter, the lobster rarely co-habited the shelter. The exclusion of lionfish from their preferred habitat may reduce survival or feeding success, resulting in lionfish being less successful invaders on reefs with limited shelter.

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