Tracing beach litter sources: Drink lids tell a different story from their bottles.

Water and soft drink bottles made from polyethylene terephthalate (PET) sink at sea unless they contain trapped air, whereas their lids are made from polymers that float and can drift long distances. We sampled loose lids and bottles at 21 South African beaches to compare their origins. The proportions of foreign-made bottles and lids were correlated, and increased away from urban centres, indicating that much land-based litter strands close to source areas.

Seabird morphology determines operational wind speeds, tolerable maxima, and responses to extremes.

Storms can cause widespread seabird stranding and wrecking, yet little is known about the maximum wind speeds that birds are able to tolerate or the conditions they avoid. We analyzed >300,000 h of tracking data from 18 seabird species, including flapping and soaring fliers, to assess how flight morphology affects wind selectivity, both at fine scales (hourly movement steps) and across the breeding season. We found no general preference or avoidance of particular wind speeds within foraging tracks.

Important marine areas for endangered African penguins before and after the crucial stage of moulting.

The population of the Endangered African penguin Spheniscus demersus has decreased by > 65% in the last 20 years. A major driver of this decrease has been the reduced availability of their principal prey, sardine Sardinops sagax and anchovy Engraulis encrasicolus. To date, conservation efforts to improve prey availability have focused on spatial management strategies to reduce resource competition with purse-seine fisheries during the breeding season.

Seascapes of fear and competition shape regional seabird movement ecology.

Fear effects of predators on prey distributions are seldom considered in marine environments, especially over large spatial scales and in conservation contexts. To fill these major gaps, we tested the Seascape of Fear Hypothesis in the Benguela marine ecosystem off South Africa. Using electronic tracking data, we showed that Cape gannets and their predator, the Cape fur seal, co-occurred in daytime and competed with fisheries within coastal areas.

Urofaecal glucocorticoid metabolite concentrations in African penguin () chick populations experiencing different levels of human disturbance.

Despite the importance of ecotourism in species conservation, little is known about the industry's effects on wildlife. In South Africa, some African penguin () colonies have become tourist attractions. The species is globally endangered, with population sizes decreasing over the past 40 years.

The first baseline estimation of marine litter in Port Elizabeth, South Africa.

Data on marine litter is crucial to guide waste management but is scarce in third-world countries such as South Africa. We established the first baseline measurement of litter accumulation on two beaches differing in public access in Port Elizabeth, Eastern Cape, the poorest province in South Africa. Four 10-day surveys were conducted on each beach between June 2019 and June 2020.

Foraging movements of breeding Kelp Gulls in South Africa.

Background: Kelp Gulls are one of the most abundant gulls in the Southern Hemisphere and can play an important role in their ecosystem. Understanding their foraging ecology is therefore important, especially in the context of anthropogenic changes of the environment. Over 35,000 Kelp Gulls breed in South Africa but little is known about their habitat use.

The conservation status and population decline of the African penguin deconstructed in space and time.

Understanding changes in abundance is crucial for conservation, but population growth rates often vary over space and time. We use 40 years of count data (1979-2019) and Bayesian state-space models to assess the African penguin population under IUCN Red List Criterion A. We deconstruct the overall decline in time and space to identify where urgent conservation action is needed.

Multi-predator assemblages, dive type, bathymetry and sex influence foraging success and efficiency in African penguins.

Marine predators adapt their hunting techniques to locate and capture prey in response to their surrounding environment. However, little is known about how certain strategies influence foraging success and efficiency. Due to the miniaturisation of animal tracking technologies, a single individual can be equipped with multiple data loggers to obtain multi-scale tracking information.

Radar detectors carried by Cape gannets reveal surprisingly few fishing vessel encounters.

Fisheries compete with seabirds for vanishing marine resources, but also produce fishery waste consumed by seabirds. Marine birds may therefore avoid or seek fishing vessels, and have evolved complex, plastic behavioural responses to vessel presence. Understanding these responses is essential to the conservation of a globally declining seabird community.

Bayesian inference reveals positive but subtle effects of experimental fishery closures on marine predator demographics.

Global forage-fish landings are increasing, with potentially grave consequences for marine ecosystems. Predators of forage fish may be influenced by this harvest, but the nature of these effects is contentious. Experimental fishery manipulations offer the best solution to quantify population-level impacts, but are rare.

Avoidance of seismic survey activities by penguins.

Seismic surveys in search for oil or gas under the seabed, produce the most intense man-made ocean noise with known impacts on invertebrates, fish and marine mammals. No evidence to date exists, however, about potential impacts on seabirds. Penguins may be expected to be particularly affected by loud underwater sounds, due to their largely aquatic existence.

Group foraging increases foraging efficiency in a piscivorous diver, the African penguin.

Marine piscivores have evolved a variety of morphological and behavioural adaptations, including group foraging, to optimize foraging efficiency when targeting shoaling fish. For penguins that are known to associate at sea and feed on these prey resources, there is nonetheless a lack of empirical evidence to support improved foraging efficiency when foraging with conspecifics. We examined the hunting strategies and foraging performance of breeding African penguins equipped with animal-borne video recorders.

Recreational Fish-Finders--An Inexpensive Alternative to Scientific Echo-Sounders for Unravelling the Links between Marine Top Predators and Their Prey.

Studies investigating how mobile marine predators respond to their prey are limited due to the challenging nature of the environment. While marine top predators are increasingly easy to study thanks to developments in bio-logging technology, typically there is scant information on the distribution and abundance of their prey, largely due to the specialised nature of acquiring this information. We explore the potential of using single-beam recreational fish-finders (RFF) to quantify relative forage fish abundance and draw inferences of the prey distribution at a fine spatial scale.

Penguins are attracted to dimethyl sulphide at sea.

Breeding Spheniscus penguins are central place foragers that feed primarily on schooling pelagic fish. They are visual hunters, but it is unclear how they locate prey patches on a coarse scale. Many petrels and storm petrels (Procellariiformes), the penguins' closest relatives, use olfactory cues to locate prey concentrations at sea, but this has not been demonstrated for penguins.

A junk-food hypothesis for gannets feeding on fishery waste.

Worldwide fisheries generate large volumes of fishery waste and it is often assumed that this additional food is beneficial to populations of marine top-predators. We challenge this concept via a detailed study of foraging Cape gannets Morus capensis and of their feeding environment in the Benguela upwelling zone. The natural prey of Cape gannets (pelagic fishes) is depleted and birds now feed extensively on fishery wastes.