At-sea behavioural responses of African penguins in relation to small-scale variability in prey distribution A fully-funded PhD project, FitzPatrick Institute of African Ornithology, DST/NRF Centre of Excellence, University of Cape Town Supervisors: Lorien Pichegru, Peter Ryan, Emilie Tew-Kai PROJECT OUTLINE The combined effects of climate change and industrial-scale fishing have affected marine ecosystems on an unprecedented scale (Jackson 2008, Brierley & Kingsford 2009). Populations of top predators, including seabirds, are declining world-wide (BirdLife 2004, Lotze & Worm 2009), despite their pivotal roles in the stability and resilience of ecosystems (Sergio et al. 2006, Baum & Worm 2009). In that context, it is important to understand the interactions between threatened top predators and their environment, in order to predict the potential consequences of environmental changes on their population trends and to take the appropriate conservation measures. Foraging strategies will determine the amount of energy available for the animals to survive and reproduce (Boggs 1992). The breeding season is a crucial energy bottleneck (Stearns 1992), because individuals will require extra energy to feed their offspring (Bevan et al. 2002). In the marine environment, the distribution and predictability of resources depend on the spatio-temporal scale considered (Fauchald et al. 2000). Marine top predators feeding on pelagic prey face high spatial and temporal variability in their food availability, and how they adapt their behaviour to such changes during the breeding season is crucial for their population dynamics. While several studies revealed flexibility in predators’ foraging behaviour between years and between localities, none investigated the question at a very fine spatiotemporal scale. We shall study flexibility in the at-sea behaviour of a marine top predator, the African Penguin Spheniscus demersus, in relation to its prey availability at a very fine spatio-temporal scale. We shall record simultaneously the penguins’ foraging behaviour with GPS loggers and their prey distribution with real-time acoustic surveys. We shall relate the data collected with oceanographic data from the South African Environmental Observation Network (SAEON) in the study area, as well as high resolution remote sensing data. The study also builds on four years of existing data on penguin foraging effort recorded at two sites from 2008 to 2011. African Penguins are endemic to southern Africa and are listed as globally Endangered (IUCN 2010). The recent dramatic decline in their population (a loss of 60% of their global population in the last 5 years, Crawford et al. 2011) requires an understanding of their relationship with their environment, in parallel with active conservation measures, such as the creation of Marine Protected Areas around their key breeding localities. African Penguin population dynamics are tightly linked to small pelagic fish availability (Crawford et al. 2008) and recently both Anchovy (Engraulis encrasicolus) and Sardine (Sardinops sagax) populations shifted from being mainly located on the west coast, where most seabird colonies are distributed, to the south coast, 500 km away, and out of reach of breeding seabirds (van der Lingen et al. 2006, Roy et al. 2007, Coetzee et al. 2008). This shift might be due to environmental variability and climate change, but heavy fishing pressure persists in areas with low fish abundance because of the distribution of land-based processing plants (Pichegru et al. 2009). Understanding the mechanisms of interaction of the African Penguin with its environment would thus help for appropriate conservation measures. METHODS African Penguin foraging behaviour Breeding African Penguins will be studied on St Croix Island (33°48’S, 25°46’E) and at Bird Island (33°50’S, 26°17’E), Nelson Mandela Bay. Birds will be equipped with GPS-TD loggers (a GPS recorder combined with a time-depth recorder; 96 x 39 x 26.5 mm; earth&OCEAN Technologies, Germany) that record latitude and longitude at 1 min-intervals to an accuracy of <10 m, and depth at 1 s intervals to the nearest 0.1 m. The devices weigh <2.5% of adult body mass and are housed in streamlined fibrecomposite containers. They are attached to the penguins’ lower back feathers with waterproof tape, causing no damage to the plumage. Handling usually lasts <6 min from capture to release and these methods are approved by University of Cape Town’s animal ethics committee. After deployment, nest sites of instrumented birds are monitored until the adult carrying the GPS returns, allowing it to be recaptured and the logger removed. The data are then downloaded onto a computer and the device re-deployed on another individual. Prey distribution Prey abundance and distribution will be estimated with acoustic surveys from a dedicated research vessel. The surveys will cover the area within a 20 km radius around the islands over 1-2 days. Biomass estimation is based on a specific routine, weighting of transects by length and variance estimation between transects. We shall compare where penguins forage, and the effort they expend finding food, with the known distribution of pelagic fish. Marine habitat To define the marine habitat of African penguins and their prey, we will use a combination of oceanographic data (underwater temperature, currents) collected by the South African Environmental Observation Network (SAEON) in the study area, data collected by penguins from highly sensitive Temperature-Depth recorders, and high resolution remote sensing data (Sea Surface Temperature, ocean coulours). They will be used to describe submesoscale and fine scale physical structures of the areas used by African penguins and their prey. APPLICATIONS AND FUNDING Applicants should have an MSc or excellent BSc Hons in Zoology and some field experience with seabirds, or equivalent experience. Although they will form part of an existing research team, they will be required to organize and conduct field work independently on isolated islands, often under trying conditions and with minimal comfort. The successful applicant will be awarded a PhD bursary of R100 000 per year through the Percy FitzPatrick CoE. REFERENCES Baum JK, Worm B 2009 Cascading top-down effects of changing oceanic predator abundances. Journal of Animal Ecology 78: 699-714. Bevan RM, Butler, PJ, Woakes AJ & Boyd IL (2002) The energetics of Gentoo Penguins, Pygoscelis papua, during the breeding season. Functional Ecology 16: 175-190. BirdLife International (2004) State of the world's birds 2004: indicators for our changing world. BirdLife International, Cambridge, U.K. Boggs CL (1992) Ressource allocation: exploring connections between foraging and life history. Functional Ecology 6: 508-518. Brierley A, Kingsford MJ (2009) Impacts of climate change on marine organisms and ecosystems. Current Biology 19: R602-R614. Coetzee JC, van der Lingen CD, Hutchings L, Fairweather TP (2008) Has the fishery contributed to a major shift in the distribution of South African sardine? 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