An integrated approch to the foraging ecology of marine birds and mammals

Croll, Donald A.; Tershy, Bernie R.; Hewitt, Roger P.; Demer, David A.; Fiedler, Paul C.; Smith, Susan; Armstrong, Wesley A.; Popp, Jacqueline M.; Kiekhefer, Thomas; Lopez, Vanesa R.; Urbán, Jorge; Gendron, Diane

doi:10.1016/s0967-0645(98)00031-9

Cited by 188 publications

(133 citation statements)

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“…This contrasts with the diverse foraging strategies of many other mammals that are more fluid and adapt to localized change (Croll et al, 1998;Viswanathan et al, 1999). Similar to conspecific females, it seems that male Australian sea lions exhibit fine-scale foraging specialization with male movement being invariant regardless of changes in oceanographic conditions and presumed food availability (Lowther et al, 2012).…”

Section: Does Foraging Site Fidelity Constrain Dispersal? the Limits mentioning

confidence: 94%

The Limits of Dispersal: Fine Scale Spatial Genetic Structure in Australian Sea Lions

et al. 2016

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Describing patterns of connectivity throughout a species range is critical to conservation management. In common with other mammals, pinnipeds typically display male-biased dispersal. Earlier studies using mitochondrial DNA showed that the endangered Australian sea lion (Neophoca cinerea) exhibits extreme matrilineal structure throughout its range. If male dispersal were similarly restricted, most breeding colonies may not receive sufficient levels of new genetic variation to buffer against risks associated with inbreeding and environmental change. To address these concerns we used 16 microsatellite loci to obtain a more highly resolving measure of genetic structure among colonies and determine whether dispersal is male-biased. We found that both male and female Australian sea lions are highly philopatric with limited dispersal. Within those constraints, when animals disperse between close colonies (<110 km) there is a tendency for males to move further than females. Our findings are intriguing considering the dispersal potential of Australian sea lions and the unique asynchronous breeding opportunities that might be expected to provide an incentive for male reproductive movements between geographically close colonies.

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Section: Does Foraging Site Fidelity Constrain Dispersal? the Limits mentioning

confidence: 94%

The Limits of Dispersal: Fine Scale Spatial Genetic Structure in Australian Sea Lions

et al. 2016

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“…In this area, cetacean and pinniped occurrence varies with factors such as distance from land, water temperature and depth (Huber et al 1980, Leatherwood et al 1980, Bonnell et al 1983, Dohl et al 1983, Brueggeman 1992, Allen 1994, Black 1994, Barlow 1995, Forney 2000, edges of submarine canyons (Schoenherr 1991, Croll et al 1998, Fiedler et al 1998, and chlorophyll concentration (Smith et al 1986). Patterns of distribution and habitat use of cetaceans have been related to upwelling modified waters in the eastern tropical Pacific Ocean (Reilly & Thayer 1990, Reilly & Fiedler 1994.…”

Section: Introductionmentioning

confidence: 99%

Marine mammal occurrence and ocean climate off central California, 1986 to 1994 and 1997 to 1999

Keiper¹,

Ainley²,

Allen³

et al. 2005

Mar. Ecol. Prog. Ser.

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The California Current System (CCS), a highly variable eastern boundary system, supports a rich marine mammal fauna. Variation in local coastal upwelling, coupled with larger scale processes (El Niño/La Niña) affects the productivity and distribution of marine species at all trophic levels. Herein, we present an analysis of the occurrence patterns of marine mammals in the central CCS and relate these patterns to changing ocean climate and prey availability. Data on marine mammal distributions, ocean conditions, and prey availability were collected in waters overlying the continental shelf and slope from Bodega to Monterey Bays, from 1986 to 1994 and 1997 to 1999. Occurrence patterns were investigated using geographical information system (GIS), percent similarity index (PSI), multiple logistic regression, and principal component analyses. Spatial patterns of the most frequently sighted species (California sea lion Zalophus californianus, northern fur seal Callorhinus ursinus, Pacific white-sided dolphin Lagenorhyncus obliquidens, Dall's porpoise Phocoenoides dalli, harbor porpoise Phocoena phocoena,and humpback whale Megaptera novaeangliae) were related to bathymetry and changing ocean climate, and were likely to have been mediated by changes in prey availability. Temporal changes were related to migration and significant differences in ocean structure resulting from both local and large-scale processes.

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“…As a result, they are particularly vulnerable to changes in prey abundance or distribution, or prey access (Croll et al 1998, Clapham et al 1999, Acevedo-Gutiérrez et al 2002. Repeated disturbance can reduce prey access and overall foraging success by limiting dive time if oxygen stores cannot be adequately replenished at the surface, or can force whales to move to areas of sub-optimal quality with less dense or less accessible patches of krill.…”

Section: Discussionmentioning

confidence: 99%

Increased proximity of vessels reduces feeding opportunities of blue whales in the St. Lawrence Estuary, Canada

Lesage¹,

Omrane²,

Doniol‐Valcroze³

et al. 2017

Endang. Species. Res.

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Blue whales Balaenoptera musculus occur seasonally in the St. Lawrence Estuary, Canada, where they spend most of their time foraging. Their recurrent presence has stimulated the development of a large whale-watching industry. Here, we examine the effect of vessel distance on blue whale foraging behaviour by measuring changes in surface and diving patterns. Vessels were within 2000 m of blue whales during 70% of 33 follows, and 59% of total observation time. At vessel distances ≤400 m, surface and dive times were on average 49 and 36% shorter, respectively, and the number of breaths taken by the whales was reduced by 51% compared to control observations without vessel presence within 2000 m of whales. The consequent reduction in foraging time was likely greater than 36%, given that transit time is incompressible and foraging depth is dictated by where krill densities are located. We showed that the relative proportion of lost foraging time from vessel exposure increased exponentially with prey depth. Whales were unable to compensate for lost feeding opportunities by increasing diving rate or swim speed, except when feeding within 10 to 15 m of the surface. Our results indicate that preventing vessels from entering within a 400 m radius around blue whales can help reduce the negative effects of marine recreational activities on blue whale foraging.

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An integrated approch to the foraging ecology of marine birds and mammals

Cited by 188 publications

References 0 publications

The Limits of Dispersal: Fine Scale Spatial Genetic Structure in Australian Sea Lions

The Limits of Dispersal: Fine Scale Spatial Genetic Structure in Australian Sea Lions

Marine mammal occurrence and ocean climate off central California, 1986 to 1994 and 1997 to 1999

Increased proximity of vessels reduces feeding opportunities of blue whales in the St. Lawrence Estuary, Canada

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