Assessing the coastal occurrence of endangered killer whales using autonomous passive acoustic recorders

Hanson, M. Bradley; Emmons, Candice K.; Ward, Eric J.; Nystuen, Jeffrey A.; Lammers, Marc O.

doi:10.1121/1.4821206

Cited by 23 publications

(15 citation statements)

References 22 publications

(21 reference statements)

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“…5). Also, previous studies have shown that K and L pods are typically absent from their usual summertime areas during December− May (Ford 2006), and seem to make use of outer coast areas like Swiftsure (as in the present study) and waters from Washington down to California (Hanson et al 2013, Rice et al 2017. Although monitoring at all of these outer coast sites during the winter months has resulted in relatively low rates of encounter compared to summertime encounter rates in critical habitat, taken collectively this suggests that Southern Residents range widely in the winter and rely on the shelf waters of this outer coast region in its entirety in the wintertime.…”

Section: Discussionsupporting

confidence: 67%

Passive acoustic monitoring off Vancouver Island reveals extensive use by at-risk Resident killer whale (Orcinus orca) populations

Riera¹,

Pilkington²,

Ford³

et al. 2019

Endang. Species. Res.

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Two sympatric populations of fish-eating Resident killer whales inhabit the coastal waters of British Columbia, Canada: Southern and Northern Resident killer whales. These populations are listed under Canada's Species at Risk Act (SARA) as 'endangered' and 'threatened', respectively. Relatively little is known about their habitat use outside of the sheltered waters along the east coast of Vancouver Island, especially during the winter. SARA requires the identification of critical habitat for these populations. High densities of Chinook salmon-their primary preyare found around Swiftsure Bank, an area identified as potential critical habitat for Southern Residents. However, it is a difficult area to survey for whales using conventional small-boat approaches. Here, we used 2 yr of data collected from an autonomous acoustic recorder deployed at Swiftsure Bank from 2009−2011 to assess the year-round habitat use of this area by Resident killer whales. Overall, Resident killer whales were detected on 244 of 680 monitored days (36%). Southern Residents were heard in all months, with activity peaking during the summer. Northern Residents were also heard throughout the year, but were mostly detected in the spring and fall, which indicates the 2 populations may differ in their strategies for using this common foraging area. High levels of use by both of these populations highlights the importance of Swiftsure Bank to both, supporting the expansion of Resident killer whale critical habitat to include this site.

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Section: Discussionsupporting

confidence: 67%

Passive acoustic monitoring off Vancouver Island reveals extensive use by at-risk Resident killer whale (Orcinus orca) populations

Riera¹,

Pilkington²,

Ford³

et al. 2019

Endang. Species. Res.

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“…Presumably, this occurred because the whales arrived after feeding on the fat rich Columbia River Chinook. SRKW were detected twice as frequently at the Columbia River in early spring than expected by chance [28]. This argument is further supported by increases in serum thyroid stimulating hormone, T4 and T3 in fasting humans and rats in response to leptin injections [20].…”

Section: Introductionmentioning

confidence: 95%

“…During our late May through October study period, the SRKWs primarily feed on Chinook salmon, increasingly dominated by Fraser River Chinook (FRC) returning to spawn in nearby rivers [28,29]. SRKWs generally spend the remainder of the year outside the Salish Sea, moving up and down the Pacific Coast, from CA to Southeast AK [6].…”

Section: Introductionmentioning

confidence: 99%

“…Temporal patterns in fecal GC and T3 concentrations [5], combined with radio-tagging data [28], suggest that early spring interior race Columbia River Chinook (CRC) runs are also important to SRKW nutrition. The CRC run increases from mid-March to the end of May based on estimates at the Bonneville dam [31] and have some of the highest fat content of any adult salmon to support their extremely long freshwater spawning migration [32,33].…”

Section: Introductionmentioning

confidence: 99%

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Population growth is limited by nutritional impacts on pregnancy success in endangered Southern Resident killer whales (Orcinus orca)

Wasser¹,

Lundin²,

Ayres³

et al. 2017

PLoS ONE

125

107

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The Southern Resident killer whale population (Orcinus orca) was listed as endangered in 2005 and shows little sign of recovery. These fish eating whales feed primarily on endangered Chinook salmon. Population growth is constrained by low offspring production for the number of reproductive females in the population. Lack of prey, increased toxins and vessel disturbance have been listed as potential causes of the whale’s decline, but partitioning these pressures has been difficult. We validated and applied temporal measures of progesterone and testosterone metabolites to assess occurrence, stage and health of pregnancy from genotyped killer whale feces collected using detection dogs. Thyroid and glucocorticoid hormone metabolites were measured from these same samples to assess physiological stress. These methods enabled us to assess pregnancy occurrence and failure as well as how pregnancy success was temporally impacted by nutritional and other stressors, between 2008 and 2014. Up to 69% of all detectable pregnancies were unsuccessful; of these, up to 33% failed relatively late in gestation or immediately post-partum, when the cost is especially high. Low availability of Chinook salmon appears to be an important stressor among these fish-eating whales as well as a significant cause of late pregnancy failure, including unobserved perinatal loss. However, release of lipophilic toxicants during fat metabolism in the nutritionally deprived animals may also provide a contributor to these cumulative effects. Results point to the importance of promoting Chinook salmon recovery to enhance population growth of Southern Resident killer whales. The physiological measures used in this study can also be used to monitor the success of actions aimed at promoting adaptive management of this important apex predator to the Pacific Northwest.

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“…Ongoing research since 2004 has shown sufficient use of additional areas outside of Puget Sound and the Salish Sea to potentially meet the US definition of critical habitat (NOAA, 2015). The critical habitat geographic area is in review upon petition to expand the range, using acoustic (Hanson, Emmons, & Ward, 2013), satellite tagging, and prey availability data (NOAA, 2015). Previously, the spatial range of this endangered population of 74 whales was not sufficiently known, but efforts to incorporate new spatial data as well as threats (limited prey availability, anthropo-3 | TRACKING THE SPATIAL DIMENSIONS OF MARINE MAMMAL POPULATIONS from systematic census and targeted research-partly based on wellestablished data-sharing agreements between the agencies of two countries-can result in the extension of critical habitat designations to new areas.…”

Section: The Photoidentification and Acoustic Research Has Been Centrmentioning

confidence: 99%

Looking beyond the horizon: An early warning system to keep marine mammal information relevant for conservation

Agardy¹,

Cody

Hastings

et al. 2019

Aquatic Conservation

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Important marine mammal areas (IMMAs) are discrete portions of habitat, important to marine mammal species, that have the potential to be delineated and managed for conservation. Although IMMAs are not a blueprint for marine protected areas or other conservation designations, they are useful for providing a foundation for marine spatial planning and systematic conservation planning that can then lead to protected areas or special spatial regulations. To be most useful for supporting management and conservation, however, the information coming out of IMMAs needs to reflect current conditions. An ‘early warning system’ is proposed with a generic set of indicators to flag when marine mammal species in IMMAs require management interventions due to changing distributions or decreasing populations. Rather than signifying that quantitative thresholds have been reached, these indicators comprise alerting information derived from visual or acoustic census, satellite imagery analysis, whale‐watching logs, or increases in mortality reported by stranding networks that can trigger additional targeted research. Although it is possible that in some regions data will be sufficient to provide quantifiable indicators, the system is meant to rely on existing data sources, and be adaptable to the circumstances of each region. Regional expert groups can utilize early warning system information and feed it into IMMA‐related spatial planning in two ways: by nominating additional areas of interest, and by providing a scientific rationale for revising IMMA boundaries, to be considered at the next decadal IMMA regional expert workshop. IMMA‐driven consolidation of information that is as current as possible will prove valuable for enhancing regional cooperation to conserve marine mammals, and will be useful as countries implement new protected areas to conserve marine mammals and other marine biodiversity.

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Assessing the coastal occurrence of endangered killer whales using autonomous passive acoustic recorders

Cited by 23 publications

References 22 publications

Passive acoustic monitoring off Vancouver Island reveals extensive use by at-risk Resident killer whale (Orcinus orca) populations

Passive acoustic monitoring off Vancouver Island reveals extensive use by at-risk Resident killer whale (Orcinus orca) populations

Population growth is limited by nutritional impacts on pregnancy success in endangered Southern Resident killer whales (Orcinus orca)

Looking beyond the horizon: An early warning system to keep marine mammal information relevant for conservation

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