Taking movement data to new depths: Inferring prey availability and patch profitability from seabird foraging behavior

Chimienti, Marianna; Cornulier, Thomas; Owen, Ellie; Bolton, Mark; Davies, Ian; Travis, Justin M. J.; Scott, Beth E.

doi:10.1002/ece3.3551

Cited by 40 publications

(27 citation statements)

References 100 publications

(171 reference statements)

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“…Further, it has been well demonstrated that the bottom time of a dive is positively related to the rate of prey encounters for elephant seals foraging in open ocean systems 26,50–52 . This has also been observed in a range of other diving predators 53–56 . More specifically, hunting time, as defined by reduced vertical movement rates, has recently been validated as the foraging index associated with the highest number of prey capture attempts for the types of summarised dive profiles we use in this study 57,58 .…”

Section: Seals Reveal the Distribution And Abundance Of Mesopelagic Psupporting

confidence: 66%

Finding mesopelagic prey in a changing Southern Ocean

McMahon

Hindell

Charrassin

et al. 2019

Sci Rep

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Mesopelagic fish and squid occupy ocean depths extending below the photic zone and their vertical migrations represent a massive pathway moving energy and carbon through the water column. Their spatio-temporal distribution is however, difficult to map across remote regions particularly the vast Southern Ocean. This represents a key gap in understanding biogeochemical processes, marine ecosystem structure, and how changing ocean conditions will affect marine predators, which depend upon mesopelagic prey. We infer mesopelagic prey vertical distribution and relative abundance in the Indian sector of the Southern Ocean (20° to 130°E) with a novel approach using predator-derived indices. Fourteen years of southern elephant seal tracking and dive data, from the open ocean between the Antarctic Polar Front and the southern Antarctic Circumpolar Current front, clearly show that the vertical distribution of mesopelagic prey is influenced by the physical hydrographic processes that structure their habitat. Mesopelagic prey have a more restricted vertical migration and higher relative abundance closer to the surface where Circumpolar Deep Water rises to shallower depths. Combining these observations with a future projection of Southern Ocean conditions we show that changes in the coupling of surface and deep waters will potentially redistribute mesopelagic prey. These changes are small overall, but show important spatial variability: prey will increase in relative abundance to the east of the Kerguelen Plateau but decrease to the west. The consequences for deep-diving specialists such as elephant seals and whales over this time scale will likely be minor, but the changes in mesoscale vertical energy flow have implications for predators that forage within the mesopelagic zone as well as the broader pelagic ecosystem.

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Section: Seals Reveal the Distribution And Abundance Of Mesopelagic Psupporting

confidence: 66%

Finding mesopelagic prey in a changing Southern Ocean

McMahon

Hindell

Charrassin

et al. 2019

Sci Rep

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“…Modeled krill distributions have also been used to better understand spatial and temporal aspects of their patchiness (Dorman et al, 2015;Messie and Chavez, 2017). The feeding data for tagged blue and fin whales presented here can offer further insight into the distribution and scale of prey patches across southern and central California waters, similar to how seabird foraging tracks have been used to infer prey availability and patch quality in other areas (Chimienti et al, 2017). Since direct observations of prey abundance were not available for this study, linking blue and fin whale feeding bouts to modeled krill distribution could be an additional step to both validate krill models and tie the overserved whale behavior more directly to prey abundance.…”

Section: Discussionmentioning

confidence: 94%

Scales of Blue and Fin Whale Feeding Behavior off California, USA, With Implications for Prey Patchiness

et al. 2019

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Intermediate-duration archival tags were attached to eight blue whales (Balaenoptera musculus; four females, three males, one of unknown sex), and five fin whales (B. physalus; two females, one male, two of unknown sex) off southern California, USA, in summer 2014 and 2015. Tags logged 1-Hz data from tri-axial accelerometers, magnetometers, and a depth sensor, while acquiring Fastloc GPS locations. Tag attachment duration ranged from 18.3 to 28.9 d for blue whales and 4.9-16.0 d for fin whales, recording 1,030-4,603 dives and 95-3,338 GPS locations per whale across both species. Feeding lunges (identified from accelerometer data) were used to characterize "feeding bouts" (i.e., sequences of feeding dives with <60 min of consecutive non-feeding dives), within-bout behavior, and to examine the spatial distribution of feeding effort. Whales fed near the tagging locations (Point Mugu and San Miguel Island) for up to 7 d before dispersing as far south as Ensenada, Mexico, and north to Cape Mendocino, California. Dispersal within southern California waters differed by sex in both species with males undertaking offshore, circuitous excursions, while females remained more coastal, suggesting that movement patterns on the feeding grounds may not be exclusively related to energy gain. Feeding bout characteristics were similar for both species, with the median bout having 24 dives and lasting 3.3 h for blue whales (n = 242), and 19 dives while lasting 2.7 h for fin whales (n = 59). Bout duration was positively correlated with the number of feeding lunges per dive within a bout for both species, suggesting whales left poor-quality prey patches quickly but fed intensively for up to 34.9 h when prey was abundant. Feeding bouts occurred further apart as the distance from shore increased, but there was no corresponding difference in the number of feeding lunges per dive, suggesting the whales were feeding at the same rate throughout their range, but that prey was more dispersed in offshore waters. This may be evidence of two feeding strategies, with spatially aggregated foraging around highly localized, topographically forced upwelling centers nearshore, and more dispersed foraging in larger areas of elevated, but patchy, productivity offshore.

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“…1 kg) and play a key role in the energy flow through circumpolar marine food webs in temperate and sub-Arctic waters (Gaston and Jones, 1998;Montevecchi, 2000;de L Brooke, 2004). Owing to small wings that reduce underwater drag, they are the deepest diving bird that can fly (250 m; Chimienti et al, 2017) with lower than expected metabolic costs during diving but higher than expected flight costs (Elliott et al, 2013). Emerging insights into the physiological processes during diving, involving reductions in blood flow to metabolically expensive organs (Niizuma et al, 2007) and reductions in core temperature and heart rate (Wilson et al, 1992;Elliott et al, 2013) suggest the metabolic costs of diving for murres may be lower than previously predicted, and possibly even decrease with depth which may allow them to extend their aerobic dive limit (Gerlinsky et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Taking the Bite Out of Winter: Common Murres (Uria aalge) Push Their Dive Limits to Surmount Energy Constraints

Burke

Montevecchi

2018

Front. Mar. Sci.

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Diving seabirds that overwinter at high latitudes experience persistent cold exposure, short days and associated declines in ocean productivity that can challenge their ability to balance daily energy budgets. We used dive-immersion geo-locators to test the hypothesis that pursuit-diving Common murres (Uria aalge) will respond to the challenges of winter in the North Atlantic through increased daily energy expenditures (DEE) that will be met by increased foraging effort and adjustments in dive tactics. Largely flightless in winter (<5% of daylight hours flying), murres spent most of their time on the water (>85% resting and swimming). Accordingly, when sea surface temperatures (SST) were consistently near freezing in late winter (1.9 ± 0.8 • C), mean DEE (2463.2 ± 10.9 kJ day −1 ) exceeded the theoretical limit to sustainable energy expenditure in vertebrates (i.e., 7 X Basal Metabolic Rate or 2450 kJ day −1 for murres). Consistently deep (70% >50 m) and long dives in late winter, 38% of which exceeded their calculated aerobic dive limit indicate that targeted prey was distributed in deep (dark) waters. Consequently, foraging was largely diurnal; likely because capture efficiency of deep-water prey is poor under low light. Murres responded to these late winter time and energy constraints with a nearly two-fold increase in daily time spent diving (95.2 ± 5.6 and 178.3 ± 6.3 min day −1 during early and late winter, respectively), an increase in dive bout frequency and duration, and correspondingly less time resting between bouts. Uniquely adapted for deep-diving, pursuit-diving can push their dive limits to maximize daily energy intake when energy demands are high and prey are distributed in deep water. Our study highlights late winter as an extremely challenging phase in the annual cycle of North Atlantic murres and provides critical insights into the behavioral mechanisms underlying their winter survival.

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Taking movement data to new depths: Inferring prey availability and patch profitability from seabird foraging behavior

Cited by 40 publications

References 100 publications

Finding mesopelagic prey in a changing Southern Ocean

Finding mesopelagic prey in a changing Southern Ocean

Scales of Blue and Fin Whale Feeding Behavior off California, USA, With Implications for Prey Patchiness

Taking the Bite Out of Winter: Common Murres (Uria aalge) Push Their Dive Limits to Surmount Energy Constraints

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