COVID-related anthropause highlights the impact of marine traffic on breeding little penguins

The COVID-19 pandemic and its lock-down measures have resulted in periods of reduced human activity, known as anthropause. While this period was expected to be favorable for the marine ecosystem, due to a probable reduction of pollution, shipping traffic, industrial activity and fishing pressure, negative counterparts such as the increased use of disposable plastic and reduced fisheries surveillance and enforcement could counterbalance these positive effects. Simultaneously, on-land pressure due to human disturbance and tourism should have drastically decreased, potentially benefiting land-based marine breeders such as seabirds. Thus, long-term datasets became crucial to differentiate between historical trends and any evident changes resulting from the anthropause. We analyzed 11 years of data on several biological parameters of little penguins (Eudyptula minor) from the Penguin Parade (R), a popular tourist attraction at Phillip Island, Australia. We investigated the impact of anthropogenic activities on penguin behavior during the breeding season measured by (1) distribution at sea, (2) colony attendance, (3) isotopic niche (4) chick meal mass, and (5) offspring investment against shipping traffic and number of tourists. The 2020 lock-downs resulted in a near absence of tourists visiting the Penguin Parade (R), which was otherwise visited by 800,000+ visitors on average per year. However, our long-term analysis showed no effect of the presence of visitors on little penguins activities. Surprisingly, the anthropause did not triggered any changes in maritime traffic intensity and distribution in the region. While we found significant inter- and intra-annual variations for most parameters, we detected a negative effect of marine traffic on the foraging efficiency. Our results suggest that environmental variations have a greater influence on the breeding behavior of little penguins compared to short-term anthropause events. Our long-term dataset was key to test whether changes in anthropogenic activities affected the wildlife during the COVID-19 pandemic. Impact statementWe found that marine traffic, but not tourist presence, negatively impact the foraging and provisioning behavior of little penguins.