Evaluation of risks of oil contamination in endangered seabirds in Algoa Bay, South Africa, linked to ship-to-ship bunkering and anthropogenic maritime activities.

Maritime traffic trends around the southern tip of Africa – Did marine noise pollution contribute to the local penguins' collapse?

The African penguin population has declined precipitously in recent decades, and if current rates of decline persist, this species could become extinct in the wild by 2035. Resource extraction of small pelagic fish prey by the purse-seine fishery around African penguin breeding colonies has been identified as a demographically meaningful threat to African penguins. Consequently, long-term, effective no-take zones around breeding colonies have been endorsed by an expert panel of scientists constituted by the South African government. Here, we consider the six largest South African penguin colonies that currently hold 76% of the global population. We evaluate the adequacy of different no-take zone options using a trade-off mechanism recommended by the expert panel. For all six colonies except Bird Island, Algoa Bay, which is subject to the least fishing pressure, the current no-take zone delineations are assessed as having little benefit to the African penguin and little to no cost to the purse-seine fishery. Four of the six current no-take zones include ≤50% of the African penguins’ core foraging areas. Alternative no-take zones that approximate a more balanced trade-off offer more impactful alternatives to the current fisheries restrictions. Given the urgent need to implement evidence-based conservation interventions for the endangered African penguin, we recommend the substitution of the current no-take zones with those proposed herein.

Biased offspring sex ratio is relatively rare in birds and sex allocation can vary with environmental conditions, with the larger and more costly sex, which can be either the male or female depending on species, favoured during high food availability. Sex‐specific parental investment may lead to biased mortality and, coupled with unequal production of one sex, may result in biased adult sex ratio, with potential grave consequences on population stability. The African Penguin Spheniscus demersus, endemic to southern Africa, is an endangered monogamous seabird with bi‐parental care. Female adult African Penguins are smaller, have a higher foraging effort when breeding and higher mortality compared with adult males. In 2015, a year in which environmental conditions were favourable for breeding, African Penguin chick production on Bird Island, Algoa Bay, South Africa, was skewed towards males (1.5 males to 1 female). Males also had higher growth rates and fledging mass than females, with potentially higher post‐fledging survival. Female, but not male, parents had higher foraging effort and lower body condition with increasing number of male chicks in their brood, thereby revealing flexibility in their parental strategy, but also the costs of their investment in their current brood. The combination of male‐biased chick production and higher female mortality, possibly at the juvenile stage as a result of lower parental investment in female chicks, and/or at the adult stage as a result of higher parental investment, may contribute to a biased adult sex ratio (ASR) in this species. While further research during years of contrasting food availability is needed to confirm this trend, populations with male‐skewed ASRs have higher extinction risks and conservation strategies aiming to benefit female African Penguin might need to be developed.

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 608:279-289 (2019) - DOI: https://doi.org/10.3354/meps12827 Success comes with consistency in hard times: foraging repeatability relates to sex and breeding output in African penguins Gwendoline Traisnel*, Lorien Pichegru DST-NRF Centre of Excellence at the Percy FitzPatrick Institute of African Ornithology, Institute for Coastal and Marine Research and Department of Zoology, Nelson Mandela University, Port Elizabeth 6031, South Africa *Corresponding author: traisnel.gwendoline@gmail.com ABSTRACT: The concept of individual behavioural consistency has received a great deal of attention in the past 2 decades. However, the fitness benefits of being consistent in varying environmental conditions remain poorly explored. Such information is strongly relevant to our understanding of ecological processes, but also for predicting how some individuals and populations cope with environmental changes. We investigated short-term consistency in foraging behaviours of African penguins Spheniscus demersus at population and individual levels on Bird Island (Algoa Bay, South Africa) between 2015 and 2017, and related individual levels of consistency to reproductive outputs. Short-term overall consistency in foraging behaviour across individuals of the same population (population level) was generally moderate, although it was high for bearing (i.e. direction) towards the furthest point of the foraging trip. At the individual level, foraging consistency differed between years and was higher when environmental conditions were less profitable. Females were more flexible in their foraging behaviours than males. Overall, these results suggest that both intrinsic and extrinsic factors are responsible for inter-individual differences in foraging consistency in African penguins. Chicks of parents that were consistent in their foraging trip duration had higher growth rates than those of more flexible individuals when conditions were poor. It is not clear whether penguins adapt their level of short-term consistency at sea to the changing conditions or maintain their strategy across years. However, our results have revealed a reproductive advantage of individual foraging consistency during a year when resources were poor. For the first time, we have identified a potential mechanism to explain why some African penguins may cope better than others during poor environmental conditions. KEY WORDS: Flexibility · Chick growth · Trip duration · Seabirds Full text in pdf format Supplementary material PreviousNextCite this article as: Traisnel G, Pichegru L (2019) Success comes with consistency in hard times: foraging repeatability relates to sex and breeding output in African penguins. Mar Ecol Prog Ser 608:279-289. https://doi.org/10.3354/meps12827 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 608. Online publication date: January 03, 2019 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2019 Inter-Research.

African penguins are among the most threatened seabird species globally and an African Penguin Biodiversity Management Plan (BMP) published in 2013 guides conservation strategies to prevent their extinction. To counter the impact of past guano exploitation which reduced the nesting habitat of these burrowing seabirds, rendering them vulnerable to predators and extreme weather events, a suite of artificial nests was deployed in various colonies over the past decades with varying success. The BMP called for new nest designs to maximise breeding output. This study assesses African penguin breeding success over the past 14 years in four types of artificial nests and in natural nests at all major colonies in South Africa. Overall, artificial nests outperformed natural nests and successfully increased breeding output of African penguins by 16.5% (95% CI: 6.7–26.2). No design was, however, consistently most effective across locations. For example, fibreglass nests had the poorest hatching success of all nest types at one colony (Bird Island), but outperformed cement nests at another (Boulders Beach). The latest design of double‐layered ceramic nests tended to perform better than other artificial nests, although not consistently at all colonies and occupancy rates were low in some areas. Practical implication. The deployment of artificial nests proved to be a successful conservation measure for African penguins although the variety of habitats in the different colonies seems to have prevented a one solution‐fits‐all approach. The consistent poor breeding output in some areas in all nest types (<30% at the mainland colony in Simons' Town and the islands in Algoa Bay) further calls for colony‐specific conservation strategies beyond artificial nests, while the continuous decline in African penguin numbers globally calls for broader measures urgently, primarily increasing access to their forage fish prey.

The likelihood of success of a marine protected area (MPA) is strongly dependent on stakeholders’ support. A concern often raised by local fishers is their lack of involvement in the design or management of a MPA and their loss of income owing to lost fishing grounds. We used Algoa Bay, South Africa, as a case study to analyse fisher’s and fish-processing factory managers’ concerns and perceived economic losses from fishing closures using structured interviews. Since 2009, a 20 km-radius purse-seine fishing-exclusion zone has been tested in Algoa Bay to assess the benefit to population recovery of the endangered African penguin Spheniscus demersus. Costs to the industry were estimated in terms of loss of catches and additional travel time to fishing grounds with and without closures. Fisher responses to interviews revealed general support for conservation and MPAs, but individuals interviewed did not feel that the 20 km fishing exclusion zones in Algoa Bay would aid African penguin conservation. While they systematically raised concerns about potential economic costs to their industry from closures, neither their catch sizes nor travel times varied significantly with fishing exclusion measures. Acknowledgement and assessment of the economic concerns may aid in initiating an informed dialogue amongst the various stakeholders in Algoa Bay, which may increase compliance and success of the newly proclaimed Addo elephant National Park MPA. Continued dialogue may also act as a catalyst for more integrated ocean management of biodiversity and human uses in the bay.

Throughout the animal kingdom, individual variation in reproductive success is commonly observed, even under similar environmental conditions. However, the mechanisms behind such differences remain unclear. The notion of behavioural consistency in animals has developed rapidly since the early 21st century partly as an approach to understand among‐individual differences. In this context, a number of studies have highlighted the influence of pair assortment in personality on breeding success. In this study, we related breeding success to individual behaviour, specifically a risk‐taking behaviour, and pair assortment per behaviour in African penguins (Spheniscus demersus) over two breeding seasons of contrasting food availability. On Bird Island, Algoa Bay, South Africa, we used indices of boldness and overall mobility in penguins’ nest defence behaviour as a response to a standard pedestrian approach during chick‐rearing. These behaviours were consistent over the trials and indicated these traits may be related to personality in African penguins. Individuals were categorized as risk‐prone (“bold,” “mobile”) or risk‐averse (“shy,” “non‐mobile”). We then assessed their breeding success through chick growth and survival over 4 weeks in 2015 and 2016. There was weak positive assortment of pairs in relation to nest defence behaviour. However, pair assortment did not significantly influence birds’ breeding success. Shy penguins were generally the most successful (had the highest chick growth rates), which was especially apparent during a food shortage in 2016, possibly reflecting a higher energy investment when foraging. In contrast, chicks from bold parents grew significantly slower, especially in 2016. Bold parents may defend their nest successfully against predation or intra‐specific aggression when food is abundant, but when predation risks are limited and food availability is low, this strategy may not be beneficial. In the context of climate change, where food shortage events may become more frequent, risk‐averse individuals may be favoured and genetic diversity may be reduced in African penguins.

This account presents the first known observations of Cape Gannet Morus capensis fledgling mortalities as a result of aggressive nest defence behaviour by African Penguins Spheniscus demersus. Observations were conducted in 2013 on Bird Island, Algoa Bay, South Africa – the world's largest breeding colony of Cape Gannets. Twentyeight attacks were witnessed between 21 March and 18 May 2013 of which 16 resulted in mortality. The absence of previous observations of this phenomenon may be due to an unusually high proportion of African Penguin chicks being present relatively early on in the breeding season, associated with a potential for increased nest defence at this stage, and a larger number of gannet fledglings that year compared to previous years over the same period.

An analysis of cephalopod remains collected from jackass penguin Spheniscus demersus regurgitations and stomachs at St Croix Island, Algoa Bay, in 1976 and 1977 revealed the presence of three cephalopod species. Most common was Loligo reynaudi, with Heterotuthus sp. and Argonauta argo constituting trace items. Beak measurements were used to estimate dorsal mantle lengths and wet masses of cephalopods taken by penguins. The dominant cephalopod taken by penguins was the same species as that harvested by commercial fisheries. Despite an overlap in the size range of squid taken by penguins and trawlers, penguins tended to take smaller squid and did not take the larger squid landed by trawlers. The seasonal occurrence of squid in the penguin diet in 1976 and 1977 was the opposite of the abundance of squid in the area as reflected by trawler landings. This is explained in terms of the abundance and preference for other prey items. It is suggested that penguins take fish in preference to squid because of the rel...

The diet of jackass penguins Spheniscus demersus in Algoa Bay, South Africa, and its bearing on population declines elsewhere

In coastal waters, nutrient supplies originate principally from allochthonous sources, such as inputs from rivers, estuaries or oceanic waters. Recently, it has been suggested that marine life contributes to the nutrient load, with penguin colonies being the largest contributor worldwide. This study aimed to quantify the nitrogen (N) and phosphorus (P) produced by the largest colony of African penguins Spheniscus demersus, which is located in South Africa, using a bioenergetics model (GUANO). We modelled the fate of N excreted and measured potential effects on the physicochemical parameters of the waters surrounding St Croix Island, Algoa Bay, as well as on local primary and secondary productivity. A total of 58.66 (SD 14.99) tonnes (t) of N and 4.35 (SD 1.20) t of P were estimated to be produced by penguins annually, a magnitude comparable to that exported by permanently open estuaries in Algoa Bay. However, only 8% of penguin-produced N washed into the ocean (after moderate to heavy precipitation) as total ammoniacal N, while 58% of N was excreted as volatilised ammonia. Consequently, penguin excreta appeared to have limited influence on productivity in the waters surrounding St Croix Island, at both proximate (200 m) and distant (2 km) locations. Additional experiments should confirm whether the input of N excretion in coastal waters was too ephemeral to be detected at the monthly scale, or whether the effects were restricted to intertidal communities. Regardless, sources of nutrients other than penguins, such as coastal upwelling and runoff, are likely to have a greater influence on the physicochemical dynamics and productivity of Algoa Bay nearshore waters.

The jackass penguin, endemic to southern Africa, is the only member of the Sphenisciformes now breeding in Africa. Its breeding distribution extends from Sylvia Hill, South West Africa (Namibia), to Bird Island, Algoa Bay, South Africa. The non-breeding range extends from Sette Cama, Gabon, to Inhaca Island, Moçambique. Jackass penguins do not usually occur far off shore. The minimum total breeding population in 1978/79 was estimated to be approximately 134 000 birds. Numbers halved between 1956 and 1978 alone as a result of collapses in the South and South West African pilchard populations. Numerical decreases at Possession and Dassen Islands were particularly severe. Prior to 1956 numbers had also decreased, primarily because of large collections of eggs. Sealing activities and guano harvests may also have influenced trends. Only colonies at the periphery of the breeding distribution have increased numerically in recent times, and such increases appear to be related to the availability of suitable prey. Although the species breeds in captivity and is unlikely to become extinct, its continued survival in the wild probably relies on the continued good state of the pelagic fish resources.

An analysis is presented of records of injuries and the types of injuries to jackass penguins in Algoa Bay, South Africa, over a 10‐year‐period. Sharks are implicated in causing most of the injuries, but other possible agents are discussed. The types of injuries were categorized and compared to the dentition of sharks known to occur in the area. Using a life‐size model of a jackass penguin and preserved jaws of sharks, bites were simulated to establish the types of injury inflicted by different species. Certain injuries indicate attack by great white sharks, while others cannot be ascribed to any particular species. Most shark injuries show single jaw involvement, and range from small cuts across the feathers to the bird being cut in two. Sharks accounted for the highest number of identifiable natural causes of death, but the significance of shark attack as a mortality factor in jackass penguins is difficult to assess.

**Abstract:** Marine traffic has increased significantly since the turn of the century with associated amplification of noise fields having an important bearing on marine animals that utilise the same environment. The impacts of increased shipping traffic on seabirds is likely to become a major concern for seabirds that breed and forage close to busy maritime areas. The largest colony of the endangered African Penguin at St Croix Island is situated adjacent to one of the busiest marine traffic regions in South Africa. Marine traffic has increased significantly since 2016 when ship-to-ship bunkering activities commenced near the penguin colony. The breeding population of African Penguins here decreased by > 50 % since this time and we investigated if increased marine traffic, and associated marine noise, had any influence on this trend. To do this we compared temporal trends in location fixes of stationary and in-transit vessels in Algoa Bay, using Automatic Identification System data, to the number of penguin breeding pairs before and after significant change-points in vessel traffic volumes. The results are discussed considering the current potential for maritime influences on threatened seabird colonies and various approaches that can hopefully mitigate these threats. **Authors:** Alistair McInnes¹, Laetitia Vibert², Andrea Thiebault³, Isabelle Charrier³, Katta Ludynia⁴, Nicky Stander⁴, Tegan Carpenter-Kling¹, Lorien Pichegru² ¹BirdLife South Africa, ²Nelson Mandela University, ³University of Paris, ⁴SANCCOB

Boldness at the nest predicts foraging and diving behaviour of female but not male African penguins