Coexistence of mesopredators in an intact polar ocean ecosystem: The basis for defining a Ross Sea marine protected area

Ballard, Grant; Jongsomjit, Dennis; Veloz, Sam; Ainley, David G.

doi:10.1016/j.biocon.2011.11.017

Cited by 98 publications

(94 citation statements)

References 48 publications

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“…Our research on the foraging of Adélie penguins from Ross Island, using tags that identify geographic position and diving activity (e.g. Lescroël et al 2010, 2014, Ford et al 2014, provides evidence supporting predator-driven tropho-dynamics -facilitated by extensive diet overlap among penguins and cetaceans (Ainley et al 2006, Ballard et al 2012) -though they likely forage differently (see Discussion). By investigating phytoplankton biomass and penguin prey abundance where penguins do and do not forage, we might better understand the spatial and temporal components of the trophic interactions that occur within the pelagic food web.…”

Section: Introductionmentioning

confidence: 70%

“…the interaction between study day and depth of prey would be significant because prey would be increasingly less available). We included a factor for 'day' (04:00 to 21:00 h local time) and 'night' (22:00 to 03:00 h local time) among predictors in the model, as foraging behavior of penguins can be sensitive to irradiance levels in the water column (Ainley & Ballard 2012). Note that photoperiods were 24 h during the entire study, but local light levels varied by time of day, with lowest levels during the 'night' period described above (sun level lowest, and behind the high mountains of Ross Island; G. Ballard & D. Ainley pers.…”

Section: Statistical Modelingmentioning

confidence: 99%

“…Consistent with this high primary productivity, the populations of the highest trophic levels are immense, e.g. 38% of the world's Adélie penguins Pygoscelis adeliae, 25% of emperor penguins Aptenodytes forsteri, 30% of Antarctic petrels Thalassoica antarctica, and substantial populations of marine mammals (Ballard et al 2012, Smith et al 2014a). However, the estimated standing stocks of middle trophic levels (herbivores such as copepods and krill; secondary consumers such as small fish) are surprisingly low, more than an order of magnitude lower, for example, than in the Scotia Sea (Deibel & Daly 2007).…”

Section: Introductionmentioning

confidence: 97%

“…The Ross Sea is the least anthropogenically affected continental shelf on Earth (Halpern et al 2008); it still has substantial cetacean and other apex and mesopredator populations, and until recently has experienced little fishing (Ainley 2010, Ainley & Pauly 2014. The effects on penguins of changing cetacean populations in decades past have been investigated , as has the alteration in penguin foraging behavior in the presence of killer whales Orcinus orca and leopard seals Hydrurga leptonyx (Ainley & Ballard 2012; see also Ainley et al 2005). Environmental changes related to changing physical properties have been assessed (reduced salinity, increasing sea ice concentrations, and altered sea-ice season: Jacobs et al 2002, Jacobs 2006, Stammerjohn et al 2008, 2012, as have population responses by major mesopredators as exhibited by the penguins ) and seals (Ainley et al 2015).…”

Section: Introductionmentioning

confidence: 99%

“…We predicted that we would observe longer distance and duration of penguin foraging trips and deeper diving as the penguin breeding season proceeded, and that there would be a correlated deepening of the main penguin prey species, also associated with the num ber of minke whales and killer whales in the study area. Both whale species are common in the area and can forage significantly deeper than the penguins (reviewed by Ballard et al 2012). …”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Trophic cascades in the western Ross Sea, Antarctica: revisited

Ainley¹,

Ballard²,

Jones³

et al. 2015

Mar. Ecol. Prog. Ser.

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Section: Introductionmentioning

confidence: 70%

Section: Statistical Modelingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Trophic cascades in the western Ross Sea, Antarctica: revisited

Ainley¹,

Ballard²,

Jones³

et al. 2015

Mar. Ecol. Prog. Ser.

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Movements, diving behaviour and diet of type‐C killer whales (Orcinus orca) in the Ross Sea, Antarctica

Lauriano

Pirotta

Joyce

et al. 2020

Aquatic Conservation

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1. The fish-eating, type-C ecotype, killer whale is a top predator in the Ross Sea, Antarctica. Increasing knowledge of this animal's foraging habitats, diet and movement patterns is listed amongst the research priorities adopted under the framework of the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). 2. To contribute to this goal, satellite transmitters were deployed on 10 type-C killer whales and skin biopsies were obtained from seven individuals in Terra Nova Bay (Ross Sea) during austral summer (January-February) 2015. Hierarchical switching state-space models (hSSSM) were applied to Argos satellite tracking data to describe the movements of tagged whales, which were then paired with available diving data. Stable isotopes analyses were performed on the biopsy samples to describe the diet. 3. A total of 8,803 Argos locations were available to fit the hSSSM. All whales engaged in potential foraging activity in localized areas along the Ross Sea coastline, followed by uninterrupted travel (i.e. migration) outside Antarctic waters, with no evidence of foraging activity. The pattern of deeper dives matched the occurrence of encamped behaviour indicated by the hSSSM results. The stable isotopes analysis indicated that Antarctic toothfish comprised the largest component (35%) of the prey biomass, raising concerns since this species is targeted by commercial fishery in the Ross Sea Region. 4. These results provide new insights into the ecology of type-C killer whales in the Ross Sea Region, underlining a potential threat from commercial fishing in the area. Considering the recent establishment of the Ross Sea Region Marine Protected Area, these findings will contribute to the required Research and Monitoring Programme of the Marine Protected Area and provide new empirical evidence to inform conservation measures in the existing Terra Nova Bay Antarctic Special Protected Area.

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Does perspective matter? A case study comparing Eulerian and Lagrangian estimates of common murre (Uria aalge) distributions

Phillips

Horne

Zamon

et al. 2019

Ecology and Evolution

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Studies estimating species' distributions require information about animal locations in space and time. Location data can be collected using surveys within a predetermined frame of reference (i.e., Eulerian sampling) or from animal‐borne tracking devices (i.e., Lagrangian sampling). Integration of observations obtained from Eulerian and Lagrangian perspectives can provide insights into animal movement and habitat use. However, contemporaneous data from both perspectives are rarely available, making examination of biases associated with each sampling approach difficult. We compared distributions of a mobile seabird observed concurrently from ship, aerial, and satellite tag surveys during May, June, and July 2012 in the northern California Current. We calculated utilization distributions to quantify and compare variability in common murre ( Uria aalge ) space use and examine how sampling perspective and platform influence observed patterns. Spatial distributions of murres were similar in May, regardless of sampling perspective. Greatest densities occurred in coastal waters off southern Washington and northern Oregon, near large murre colonies and the mouth of the Columbia River. Density distributions of murres estimated from ship and aerial surveys in June and July were similar to those observed in May, whereas distributions of satellite‐tagged murres in June and July indicated northward movement into British Columbia, Canada, resulting in different patterns observed from Eulerian and Lagrangian perspectives. These results suggest that the population of murres observed in the northern California Current during spring and summer includes relatively stationary individuals attending breeding colonies and nonstationary, vagile adults and subadults. Given the expected growth of telemetry studies and advances in survey technology (e.g., unmanned aerial systems), these results highlight the importance of considering methodological approaches, spatial extent, and synopticity of distribution data sets prior to integrating data from different sampling perspectives.

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Coexistence of mesopredators in an intact polar ocean ecosystem: The basis for defining a Ross Sea marine protected area

Cited by 98 publications

References 48 publications

Trophic cascades in the western Ross Sea, Antarctica: revisited

Trophic cascades in the western Ross Sea, Antarctica: revisited

Movements, diving behaviour and diet of type‐C killer whales (Orcinus orca) in the Ross Sea, Antarctica

Does perspective matter? A case study comparing Eulerian and Lagrangian estimates of common murre (Uria aalge) distributions

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