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The tourism activities linked to artificial provisioning of blacktip reef sharks (Carcharhinus melanopterus) and pink whiprays (Pateobatis fai) on a specific site in French Polynesia were suddenly and completely stopped due to a COVID-19 lockdown that lasted 6 weeks from March 20 until April 30, 2020. Using both drone footage and underwater counting, we were able to track the abundance of those two species before, during, and after reopening and thus investigate the impact of provisioning on wild shark populations. The absence of any stimulus during this long period resulted in almost total desertion of the site by the elasmobranchs. However, 1 day prior to reopening, some individuals of both species positively reacted to the single acoustic stimulus of an engine boat, showing the resilience of conditioning, and some elasmobranchs reacted to acoustic and olfactive stimuli linked to the provisioning practice from the first day after reopening. During the first 2 weeks after reopening, the abundance of both species remained at reduced levels comparable to those observed between 2008 and 2010 for sharks;i.e., around 9 animals in the presence of local tourists. Pre-lockdown abundance levels, reaching approximatively 15 individuals for sharks and 10 for rays, were considered restored 1 and 2 months after reopening for blacktip reef sharks and pink whiprays, respectively. These findings improve our capacity to better understand the potential effects of artificial provisioning tourism on the abundance of elasmobranchs by showing that conditioning is resilient for several weeks, suggesting that intermittent interruption of elasmobranchs feeding would not really help to decrease its impact on animal welfare.

Hibernation is a physiological adaptation that allows animals to survive adverse environmental conditions. A commonly assumed cost of hibernation is impaired memory retention. So far, however, the effects of hibernation on memory retention have been assessed on only a few behavioral tasks, and exclusively under laboratory conditions. Taking advantage of the longevity and strict colony fidelity of female Bechstein's bats, we were able to evaluate memory retention in the same individuals over two consecutive summers in the field. We used a pairwise roost choice experiment with automatic monitoring of RFID‐tagged bats. Roosts’ suitability as day roost was associated with a distinctive external echo‐acoustic cue. Experiments were separated by a natural hibernation period of eight months. We determined associative learning and memory retention by comparing the bats’ proportion of visits to suitable roosts within and between breeding seasons, respectively. During the first breeding season, bats quickly learned to associate the suitable roosts with their external cue. After hibernating, we found no evidence that individuals remembered the association between the roosts’ suitability and their respective external cue, suggesting a lack of memory retention. Nevertheless, bats quickly re‐learned the same association during the second breeding season, emphasizing the high behavioral flexibility of Bechstein's bats.

Memory is essential to enhance future survival and reproduction as it helps in storing and retrieving useful information to solve particular environmental problems. However, we lack quantitative evidence on how far animals in the wild can maintain given information for extended periods without reinforcement. Here, we document correlative evidence of cleaner fish Labroides dimidiatus remembering being caught in a barrier net for up to 11 months. In 2015, about 60% of cleaners from one large isolated reef had been used for laboratory experiments and then returned to their site of capture. Eleven months later, 50% of cleaners at the same site showed an unusual hiding response to the placement of the barrier net, in contrast to three control sites where no cleaners had been caught during the last 2 years. The results suggest that a single highly aversive event (i.e., being caught in a barrier net) resulted in cleaners storing long‐term crucial information that allowed them to avoid being caught again. Our results further our knowledge of fish cognitive capacities and long‐term memory retention.