Assessing the adequacy of a novel fisheries no-take zone around a major African penguin (Spheniscus demersus) colony, Dyer Island, South Africa

Abstract

The African penguin is the most threatened penguin species globally and could become extinct in the wild by 2035. One of the main threats facing this species is a lack of prey: mostly anchovy and sardine. The causes of the reduced availability of prey are complex but competition with the purse-seine fishery is partly responsible as this fishery targets the same species as the penguins. To mitigate resource competition, the South African government implemented no-take zones around six of the largest African penguin colonies in 2022, forbidding catches of small pelagic fish (sardine, anchovy and round herring) in these zones, although the extent of the majority of these closures was assessed as not being representative of important penguin foraging areas. After a court order in March 2025, improved no-take zones were implemented around four of the six colonies. However, the zone around the colony at Dyer Island remained unchanged. This thesis focuses on the specific case of the no-take zone around Dyer Island, which, unlike other no-take zones that involve a total fishing ban, includes a fully restricted zone inside of a broader vessel-size restricted zone, prohibiting vessels equal to or greater than 26 meters long to enter the zone – a design aiming to allow local vessels to continue fishing, while excluding the larger vessels from more distant ports. Hence, this work aims to assess the adequacy of this novel no-take zone configuration around the Dyer Island colony through a comparative study of different penguin path metric parameters before and after the closure was implemented in 2022. This work also assesses how the general trend of fishing catches changed after the implementation of this zone, and assesses whether the current no-take zone configuration has the potential to alleviate competition between local vessels and those from elsewhere. There was no evidence of significant differences in the maximum distance penguins travelled from the colony, total distance travelled per trip and trip duration between the period preceding and following the implementation of the no-take zone. Fishing trends within the no-take zone perimeter appeared to be driven primarily by imposed fishing quotas rather than the no-take zone itself. Specifically, fishing trends and fishing effort from vessels frequently operating in the area remained similar within the closure area after its implementation, suggesting the no-take zone did not have an impact on the local fishing vessels. Overall, results of this assessment suggest that the current configuration of the no-take zones around Dyer Island is likely insufficient to reduce resource competition on African penguins and highlights the need to explore alternative fishing closure regimes for this important colony.