COVID-19 lockdown highlights impact of recreational activities on the behaviour of coral reef fishes

Abstract

In 2020, the COVID-19 pandemic led to a reduction in human activities and restriction of all but essential movement for much of the world's population. A large, but temporary, increase in air and water quality followed, and there have been several reports of animal populations moving into new areas. Extending on long-term monitoring efforts, we examined how coral reef fish populations were affected by the government-mandated lockdown across a series of Marine Protected Area (MPA) and non-Marine Protected Area (nMPA) sites around Moorea, French Polynesia. During the first six-week lockdown that Moorea experienced between March and May 2020, increases (approx. two-fold) in both harvested and non-harvested fishes were observed across the MPA and nMPA inner barrier reef sites, while no differences were observed across the outer barrier sites. Interviews with local amateur and professional fishers indicated that while rules regarding MPA boundaries were generally followed, some subsistence fishing continued in spite of the lockdown, including within MPAs. As most recreational activities occur along the inner reef, our data suggest that the lockdown-induced reduction in recreational activities resulted in the recolonization of these areas by fishes, highlighting how fish behaviour and space use can rapidly change in our absence.

Effects of COVID-19 lockdown on the observed density of coral reef fish along coastal habitats of Moorea, French Polynesia

“…In addition, the period from May to August usually corresponds to the period of lowest sea surface temperatures in French Polynesia, when fishes are generally less abundant and larval recruitment is lower (Galzin 1987 ; Lo-Yat et al 2011 ). Therefore, the higher apparent density of fish observed in May, June and July 2020 compared to the overall 2019 average could be related to behavioural changes due to the lockdown period (similar to Feeney et al 2022 ).…”

“…However, despite the inability to statistically compare the relationship between fish density and nautical/fishing activities on the three coastline habitats, we can postulate that any change in the fish community would mainly depend on the degree of human activity existing at the location ordinarily and the intensity of the change after the lockdown, as this has been suggested by other recent studies (e.g. Edward et al 2021 ; Lecchini et al 2021 ; Feeney et al 2022 ). Furthermore, at Moorea, we are not aware of any particular variations or events (potentially related to weather, cyclone, coral bleaching or environmental conditions) that may have occurred during the same period that could explain the observed changes.…”

“…In a recent study, Lecchini et al ( 2021 ) showed that fish density at ecotourism sites in Bora-Bora (French Polynesia) increased significantly from March to May 2020 in the absence of humans and returned to pre-lockdown levels in August 2020 (12 weeks after the lockdown), after most human activities and tourism resumed. Another study performed on the inner and outer barrier reefs inside and outside marine protected areas of Moorea (Feeney et al, 2022 ) compared fish densities between 2011 and 2020, with densities observed in May and July 2020. The study recorded an increase in post-lockdown densities compared to this long-term average on sites where human activity decreased (inner barrier reefs) but not in areas where human activity was already lower (outer barrier reefs).…”

Coral reef fish resilience and recovery following major environmental disturbances caused by cyclones and coral bleaching: A case study at Lizard Island

“…Therefore, it is possible that the prolonged lockdown at Lizard Island led to a general increase in fish density due to the large reduction in human activities. Recent studies have shown a significant increase in coral reef fish densities during the lockdown period (Feeney et al, 2022; Bertucci et al, 2023). However, it is also possible that the lockdown affected the fish assemblage, which resulted in higher numbers during surveys, but this could lead to a decline in fish numbers once the lockdown is lifted and human activities resume (Lecchini et al, 2021).…”

Insights from the 2-year-long human confinement experiment in Grand Cayman reveal the resilience of coral reef fish communities

“…Pollution in the form of anthropogenic noise and chemical pollution from sea vessels negatively impacts fish behaviour 31 – 33 and physiology 31 , 33 , 34 thereby influencing community composition. During the short period when tourism and heavy water-based activities were reduced between March and May 2020, coral reef ecosystems in several regions that typically experience high anthropogenetic pressures showed immediate increases in fish species diversity and abundance 35 – 37 , linked to increased recruitment of juvenile fishes 38 . While marked increases immediately following a short respite is positive, studies examining how longer lockdown restrictions on water-based activities influenced the community composition are lacking.…”