The foraging distribution of Cape gannets in relation to Addo Elephant National Park Marine Protected Area

Sammanfattning: Seabirds are considered to be the sentinels of the ocean, as they are able to locate their prey in spite of the great heterogeneity of the marine environment. During the breeding season, these central-place foragers not only need to find prey to maintain themselves but also to feed their young. The changes in the distribution of their prey due to environmental and human activity factors can affect their individual and population health. In order to protect the local biodiversity, the Addo Elephant National Park Marine Protected Area was proclaimed in 2019 in Algoa Bay, Eastern Cape, South Africa. Bird Island (Algoa Bay) hosts the largest Cape gannet (Morus capensis) colony in the world and lies within Addo Elephant Nation Park Marine Protected Area. This Marine Protected Area aims to offer refuge to a vast variety of species and promote fisheries sustainability. This study is focused on the foraging distribution of Cape gannets in relation to Addo Elephant National Park Marine Protected Area. The deployment of adult Cape gannets with GPS devices during the rearing season of 2021, enabled the analysis of their foraging range, behaviour, and the speculation on possible enhancements in their foraging effort as a result of the implementation of this Marine Protected Area. These top predators showed a variety of distributions, but the majority of the birds stayed in the vicinity of Algoa Bay. Their behaviour was classified and feeding grounds related to the Marine Protected Area were identified. Comparison to previous data from 2010 until 2020 indicated a fluctuating foraging range, but showed a possible reduction in the gannet distribution since the Marine Protected Area implementation. Last, an area of high activity was identified and paired with results from previous studies. In conclusion, this location could be proposed as an additional Marine Protected Area after further investigation. This research provides an assessment of the foraging distribution of Cape gannets that can be used for their management, but also for the monitoring of the Addo Elephant National Park Marine Protected Area.