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Keywords: cultural transmission; ecology of fear; human-wildlife conflict; livelihood impacts; predator-prey interactions EN cultural transmission ecology of fear human-wildlife conflict livelihood impacts predator-prey interactions 1 5 5 01/04/23 20230101 NES 230101 Killer whales ( I Orcinus orca i ) and white sharks ( I Carcharodon carcharias i ) are marine apex predators that shape prey behavior and even entire ecosystems through direct predation effects and indirect fear effects (e.g., Estes et al., [4]; Heithaus et al., [5]). " Predation on a White Shark (Carcharodon carcharias) by a Killer Whale (Orcinus orca) and a Possible Case of Competitive Displacement." Given the well-documented, predictable year-round presence of white sharks in Mossel Bay (Jewell et al., [7]; Ryklief et al., [13]), the sudden absence of white sharks for several weeks immediately after the predation event supports a flight response by surviving white sharks in the area. [Extracted from the article]

Humpback whales ( Megaptera novaeangliae) from a breeding ground off Gabon (0-4°S) and a migratory corridor/feeding ground on the west coast of South Africa (WSA; 33°S) differ genetically and in catch histories. Interpretation of the population structure is hampered by the lack of data from the intervening 3,500 km of coastline or to the north of Gabon. Here we collate all relevant nongenetic data on humpback whales from Namibia (∼23°S) from 2005 to 2012 and compare these with corresponding data from Gabon (2000-2006) and WSA (1983-2008). Data from Namibia include photographic catalogs of dorsal fin and tail fluke images, seasonal presence, and a photographic assessment of scarring and wounds from cookiecutter sharks ( Isistius sp.). No confirmed photographic identification matches could be made between Namibia and Gabon and only 2 potential matches were made between Namibia and WSA from dorsal fins. Humpback whales in Namibia show a bimodal seasonality in occurrence, with a primary peak in austral winter (July) and a secondary peak in spring (September), but generally low directionality of movement. Whales were never recorded to sing, competitive groups were rarely sighted, and very few calves were observed, making it unlikely that this is a breeding area. The prevalence of killer whale bite scars on flukes was similar at all sites. Fresh bites from cookiecutter sharks were highest in Namibia, intermediate in Gabon, but almost nonexistent in WSA. We propose that animals seen in Namibia in winter are on their northward migration and have intercepted the coast from farther offshore (where cookiecutter sharks occur), whereas animals seen in WSA in spring-summer, where they are feeding during their southward migration, have followed a slow coastwise route within the cold Benguela Ecosystem, thus allowing time for cookiecutter bites to heal. [ABSTRACT FROM AUTHOR]

Killer whales and leatherback turtles are infrequently sighted in the coastal waters of southern Africa. Year round observations in Walvis Bay, Namibia of killer whales (2003-2010) by multiple marine tour operators and opportunistic seasonal observations of leatherback turtles made during a cetacean research project in the area (2008-2010) have been collated. Visits to coastal waters by killer whales (n = 16) are sporadic and unpredictable but are slightly higher (n = 11) between late winter (August) and late summer (March). Leatherback turtles were only seen in the warmer periods of summer months (February-March) when the surface waters exceeded 15°C. Two interactions (one harassment and one probably predation) between killer whales and leatherback turtles have been recorded in Walvis Bay. This is the first report of killer whales eating leatherback turtles in the South Atlantic. These observations are noteworthy due to the low frequency of encounters of both species in the area, suggesting predation of turtles may be relatively common. Knowledge of the diet of killer whales is valuable due to the importance of dietary specialization in definition of ecotypes of the species. [ABSTRACT FROM AUTHOR]