Assessing conservation priorities in the Benguela ecosystem, South Africa: analysing predation by seals on threatened seabirds

David, J. H. M.; Cury, Philippe; Crawford, Robert J. M.; Randall, R. M.; Underhill, Les G.; Meÿer, MA

doi:10.1016/s0006-3207(03)00018-1

Cited by 44 publications

(40 citation statements)

References 12 publications

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“…They proposed, instead, a decision pathway to help determine when control may be effective or necessary, for example when a problem is caused by a few individual predators. The selective removal (either lethal or non-lethal, by translocation) of 'problem' or 'rogue' individuals has become a paradigm in the management of large carnivores that kill domestic (Linnell et al, 1999) or wild prey species (David et al, 2003). However, the underlying assumption that only a small proportion of the individuals in the predator population are responsible, either by specializing in feeding in certain areas or on certain prey species, has rarely been tested (Linnell et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

Do ‘rogue’ seals exist? Implications for seal conservation in the UK

et al. 2011

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The management of conflict between people and large carnivores frequently focuses on the selective removal of the so-called 'problem' or 'rogue' animals. However, the existence of such individuals has rarely been examined. Recent management of seal-salmon fishery conflict in Scotland follows this approach, and under the Moray Firth Seal Management Plan the lethal removal of perceived problem individuals is permitted in salmon rivers. However, the efficacy of this strategy depends on (1) the existence of river-specialist individuals; (2) these individuals having a greater per capita impact on salmon fisheries than individuals in the general population. Using data collected in three rivers from March 2005 to February 2008, we show using photo-identification that a small fraction of the population ( 1%) comprises individual seals that specialize in using rivers. This behaviour was more pronounced for grey seals Halichoerus grypus than harbour seals Phoca vitulina, and a greater proportion of individual harbour seals were seen only once during the study. A higher percentage of digestive tract samples collected from seals in rivers tested positive for salmon and trout DNA compared with seal scats collected at coastal sites, although the sample size was small. These results indicate that targeting individual seals present in rivers is more likely to remove those individuals consuming salmon, and have a larger per seal benefit to salmon compared with targeting seals hauled out in estuaries. This lends rare scientific support to the established management paradigm of problem-individual removal.

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Section: Introductionmentioning

confidence: 99%

Do ‘rogue’ seals exist? Implications for seal conservation in the UK

et al. 2011

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“…Translocation of problem individuals generally fails (Linnell et al 1997;Fischer & Lindenmayer 2000) because seals typically return to their capture site (Lalas et al 2007). Culling of the observed predatory individuals is another option; for example, in South Africa between 1993 and 2001 a total of 153 Cape fur seals were culled to protect fledgling Cape gannet chicks (David et al 2003).…”

Section: Discussionmentioning

confidence: 99%

Notes on New Zealand mammals 8. Predation on nesting southern royal albatrossesDiomedea epomophoraby a New Zealand sea lionPhocarctos hookeri

Moore

Charteris²,

Larsen

2008

New Zealand Journal of Zoology

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This note documents unusual predation of southern royal albatrosses Diomedea epomophora on land by an individual New Zealand sea lion Phocarctos hookeri. During a survey of albatross nests on Campbell Island in the New Zealand subantarctic in January 2005, 128 corpses of adult albatrosses were found at or near nests within a 230 ha area. Flattened vegetation and flipper prints near the nests suggested sea lion predation, and subsequently a male sea lion was found near a line of freshly killed birds. The predation rate was estimated to be at least seven birds per day over a number of weeks; similar skeletal remains from the previous year were observed in a neighbouring area. The impact of one Z07058; Online publication date 27 June 2008 Received 27 November 2007 accepted 11 March 2008 threatened species on another can be a dilemma for conservation managers. In this case, apparently only one male sea lion was involved and, because of the ongoing impact to the albatross population, permission was obtained to cull that individual on 17 January 2005. No further incidents were observed over the following three seasons .

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“…, work on MPAs (Attwood et al 1997a, b, Beaumont 1997, Hockey and Branch 1997, studies relating seabird survival and population size to availability of food (e.g. Crawford 1998Crawford , 1999Crawford , 2003Crawford , 2004 and research into the development of subsistence fisheries in South Africa (Branch 2002).…”

Section: Research and Sciencementioning

confidence: 99%

“…Acknowledging the poor conservation status of these seabirds, the South African Government took the decision to control seals in specific cases where the individuals responsible for killing seabirds can be identified. To this end, 153 seals, which were seen to kill fledgling gannets, have so far been culled at Malgas Island off the Western Cape (David et al 2003). Other methods employed to protect seabirds are through the prevention or control of seals invading the seabird breeding areas.…”

Section: Cochrane Et Al: Eaf In the Southern Benguela 2004mentioning

confidence: 99%