Prevalence of Chinook salmon is higher for southern than for northern resident killer whales in summer hot-spot feeding areas DOI Creative Commons

Burak Saygili,

Andrew W. Trites

PLoS ONE, Journal Year: 2024, Volume and Issue: 19(10), P. e0311388 - e0311388

Published: Oct. 10, 2024

Differences in the availability of prey may explain low numbers southern resident killer whales and increase northern British Columbia Washington State. However, in-situ data on their preferred (Chinook salmon, Oncorhynchus tshawytscha) core feeding areas used by these two populations fish-eating have been lacking to test this hypothesis. We multi-frequency echosounders (38, 70, 120, 200 kHz) estimate densities adult Chinook (age-4+, > 81 cm) within 16 hot-spot during summer 2020 Salish Sea North Island Waters. found were generally concentrated 50 m from bottom deep waters, tended be absent near surface shallow waters (< m). In general, we encountered highest as fish entered (from Swiftsure Bank south) Johnstone Strait Queen Charlotte north)-and declined migrated eastward along shoreline Vancouver Island. Median for all sampled combined 0.4 ind.·1000 m-2 foraging areas, 0.9 whale (p < 0.05, Mann-Whitney U test). Thus, salmon twice prevalent versus whales. This implies that greater access compared residents summer-and any food shortage encountering is occurring at other times year, or elsewhere range.

Language: Английский

Warning sign of an accelerating decline in critically endangered killer whales (Orcinus orca) DOI Creative Commons
Rob Williams, Robert C. Lacy, Erin Ashe

et al.

Communications Earth & Environment, Journal Year: 2024, Volume and Issue: 5(1)

Published: April 2, 2024

Abstract Wildlife species and populations are being driven toward extinction by a combination of historic emerging stressors (e.g., overexploitation, habitat loss, contaminants, climate change), suggesting that we in the midst planet’s sixth mass extinction. The invisible loss biodiversity before have been identified described scientific literature has termed, memorably, dark critically endangered Southern Resident killer whale ( Orcinus orca ) population illustrates its contrast, which term bright extinction; namely noticeable documented precipitous decline data-rich Here use viability analysis to test sensitivity this variability age structure, survival rates, prey-demography functional relationships. Preventing is still possible but will require greater sacrifices on regional ocean use, urban development, land practices, than would case had threats mitigated even decade earlier.

Language: Английский

Citations

7
RESPIRATORY INTERVALS AND SWIMMING SPEED AS REMOTELY SENSED HEALTH METRICS IN FREE-RANGING KILLER WHALES (ORCINUS ORCA) DOI Creative Commons
Rob Williams, Erin Ashe, Kimberly A. Nielsen

et al.

Journal of Wildlife Diseases, Journal Year: 2025, Volume and Issue: 61(1)

Published: Jan. 31, 2025

Respiratory rate (mean number of breaths per minute) and respiratory interval time between breaths) can offer insight into a diving mammal's activity state, metabolic rate, behavior, synchronization due to social cohesion. Also, reflect an individual animal's health has the potential be informative remotely assessed metric for monitoring animal in endangered whale species populations such as southern resident killer whales (Orcinus orca). Using data collected from noninvasive, land-based theodolite tracking, we analyzed swimming speed surfacing intervals (i.e., mean dive or 20,613 surfacings 98 individuals two fish-eating, ecotype, namely, one growing (northern resident) declining (southern population. Focal sampling was used measure behavior known age sex various states. Our objective evaluate variability generate normal ranges speeds Northeast Pacific Ocean resident, fish-eating ecotype identify baseline intervals. We found that median were 26 29 s all states varied by state. Median similar foraging traveling (1.6 1.7 m/s, respectively), but significantly slower during resting (1.1 m/s) (1.3 Three poor body condition (had scores lowest 20th percentile population) swam at reduced had shorter than outwardly healthy sex. rates, intervals, are valuable sensed metrics free-swimming whales, especially when combined with other is standard veterinary examinations.

Language: Английский

Citations

0
Widespread parasite infections in living resident killer whales in the Northeast Pacific Ocean DOI
Natalie Mastick, Amy M. Van Cise, Kim M. Parsons

et al.

Published: July 16, 2024

ABSTRACT Multiple populations of resident ecotype killer whales ( Orcinus orca ater ) inhabit the Northeast Pacific, but southern whale (SRKW) population is most at-risk. SRKWs were listed as endangered in United States 2005 and have since shown little sign recovery. Several factors been identified key threats to this population, previously published studies suggest may be energetically stressed. Underlying health risks, such parasitism, contributing population’s failure recover, known about parasite infections living individuals from natural populations. To assess prevalence internal Northeastern Pacific whales, we examined scat SRKW (n = 25) compared two conspecific that are not decline: northern (NRKW, n 2) Alaska (SARKW, 7), one offshore (OKW, 1). We analyzed 35 fecal samples collected 27 wild using both microscopic identification eggs genetic detection parasites through DNA metabarcoding. used body condition indices derived concurrent aerial photogrammetry evaluate whether infection status was associated with individual condition. found sampled (94%) positive for Anisakis spp. – a parasitic nematode intestines cetaceans. These detected across populations, correlated condition, based on limited paired data. results widespread among Pacific. The detections here emphasizes need further work understand potential impacts synergistic effects other environmental stressors.

Language: Английский

Citations

1
Spatial and seasonal foraging patterns drive diet differences among north Pacific resident killer whale populations DOI Creative Commons
Amy M. Van Cise, M. Bradley Hanson, Candice K. Emmons

et al.

Royal Society Open Science, Journal Year: 2024, Volume and Issue: 11(9)

Published: Sept. 1, 2024

Highly social top marine predators, including many cetaceans, exhibit culturally learned ecological behaviours such as diet preference and foraging strategy that can affect their resilience to competition or anthropogenic impacts. When these species are also endangered, conservation efforts require management strategies based on a comprehensive understanding of the variability in behaviours. In northeast Pacific Ocean, three partially sympatric populations resident killer whales occupy coastal ecosystems from California Alaska. One population (southern whales) is while another Alaska has exhibited positive abundance trends for last several decades. Using 185 faecal samples collected both between 2011 2021, we compare provide insight into differences patterns may be linked with relative success decline populations. We find broad similarities two populations, arising spatiotemporal resource use patterns, especially timing shifts target prey species. The results described here highlight importance longitudinal monitoring ecology inform highly predators.

Language: Английский

Citations

1
Prevalence of Chinook salmon is higher for southern than for northern resident killer whales in summer hot-spot feeding areas DOI Creative Commons

Burak Saygili,

Andrew W. Trites

PLoS ONE, Journal Year: 2024, Volume and Issue: 19(10), P. e0311388 - e0311388

Published: Oct. 10, 2024

Differences in the availability of prey may explain low numbers southern resident killer whales and increase northern British Columbia Washington State. However, in-situ data on their preferred (Chinook salmon, Oncorhynchus tshawytscha) core feeding areas used by these two populations fish-eating have been lacking to test this hypothesis. We multi-frequency echosounders (38, 70, 120, 200 kHz) estimate densities adult Chinook (age-4+, > 81 cm) within 16 hot-spot during summer 2020 Salish Sea North Island Waters. found were generally concentrated 50 m from bottom deep waters, tended be absent near surface shallow waters (< m). In general, we encountered highest as fish entered (from Swiftsure Bank south) Johnstone Strait Queen Charlotte north)-and declined migrated eastward along shoreline Vancouver Island. Median for all sampled combined 0.4 ind.·1000 m-2 foraging areas, 0.9 whale (p < 0.05, Mann-Whitney U test). Thus, salmon twice prevalent versus whales. This implies that greater access compared residents summer-and any food shortage encountering is occurring at other times year, or elsewhere range.

Language: Английский

Citations

0