Non-breeding movements of endangered Benguela seabirds: the missing link in effective at-sea conservation measures

The Endangered African penguin, Cape gannet and Cape cormorant populations along the southern coast of Africa have faced drastic declines over the past 50 years. These declines have largely been driven by the declining availability of their prey: anchovy and sardine. These fish species are targeted by the largest fishery, by volume, in South Africa, and have undergone distributional shifts in recent years. To increase the availability of these fish for the birds, conservation strategies, to date, have principally been in the form of Marine Protected Areas and experimental no-take zones for fisheries. Only the African penguin has been tracked outside of the breeding season and consequently, there are currently no conservation strategies focused on this crucial life-history stage for the Cape cormorant nor the Cape gannet.

The foraging range of breeding seabirds is constrained, as they must return regularly to care for young. These constraints are relaxed outside of the breeding season, when seabirds often extend their distribution to target distant, profitable habitats. Research into the links between breeding Cape gannet movements and their diet revealed that low prey availability, which is being exacerbated by resource-competition with fisheries, is a major driver of the declining Cape gannet population. However, little is known about the threats non-breeding gannets face especially considering that their expanded distributions increases their potential of being exposed to threatening anthropogenic activities.

For the first time, we aim to track the Cape Gannet outside of the breeding season. Using these data we will identify important areas for this endangered species during this understudied life-history stage and incorporate this spatial information into South African government-led Marine Spatial Planning initiatives, including the expansion of Marine Protected Areas, and an Ecosystem-based Approached to Fisheries Management.

This research has been made possible partly due to a donation made by Ko de Korte. He awarded us his donation due his own involvement in seabird research, particularly on closely related siblings of the Cape gannet, the boobies found in the tropics. We are extremely grateful to Ko de Korte and the van Tienhoven Foundation. We are looking forward to the conservation strategies and research that will be the fruits of the research they have funded.