Correspondence between scale growth, feeding conditions, and survival of adult Chinook salmon returning to the southern Salish Sea: implications for forecasting

There is increasing evidence that predation by harbour seals on out-migrating salmon smolts may be responsible for the low return of adult coho and Chinook salmon in the Salish Sea. However, little attention has been given to understanding where and when this predation occurs and the extent to which it might be conducted by few or many seals in the population. We equipped 17 harbour seals with data loggers to track seal movements and used accelerometry to infer prey encounter events (PEEs) following the release of ~384000 coho (May 4, 2015) and ~3 million Chinook (May 14, 2015) smolts into the Big Qualicum River. We found a small proportion (5.7%) of all PEEs occurred in the estuary where salmon smolts entered the ocean—and that only one-quarter of the seals actively fed there. PEE counts increased in the estuary after both species of smolts were released. However, the response of the seals was less synchronous and occurred over a greater range of depths following the release of the smaller-bodied and more abundant Chinook smolts. Harbour seals feeding in the estuary appeared to target coho smolts at the beginning of May but appeared to pursue predators of Chinook smolts in mid-May. PEE counts in the estuary increased as tide height rose and were higher at dusk and night—especially during full moonlight. Such fine-scale behavioural information about harbour seals in relation to pulses of out-migrating smolts can be used to design mitigation strategies to reduce predation pressure by seals on salmon populations.

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Differential susceptibility of Yukon River and Salish Sea stocks of Chinook salmon Oncorhynchus tshawytscha to ichthyophoniasis

Diseases of Aquatic Organisms ◽

10.3354/dao03577 ◽

2021 ◽

Author(s):

DG Elliott ◽

CM Conway ◽

CL McKibben ◽

AH MacKenzie ◽

LM Hart ◽

...

Keyword(s):

Chinook Salmon ◽

Oncorhynchus Tshawytscha ◽

Differential Susceptibility ◽

Salish Sea ◽

Yukon River

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Declining spring usage of core habitat by endangered fish-eating killer whales reflects decreased availability of their primary prey

Pacific Conservation Biology ◽

10.1071/pc17041 ◽

2018 ◽

Vol 24 (2) ◽

pp. 189 ◽

Cited By ~ 3

Author(s):

Monika W. Shields ◽

Jimmie Lindell ◽

Julie Woodruff

Keyword(s):

British Columbia ◽

Chinook Salmon ◽

Oncorhynchus Tshawytscha ◽

Prey Availability ◽

The United States ◽

Killer Whales ◽

Salish Sea ◽

Critical Habitat ◽

Endangered Fish ◽

The North

The salmon-eating Southern Resident killer whales (Orcinus orca) of the north-eastern Pacific Ocean are listed as endangered both in the United States and Canada. Their critical habitat has been defined as the region of the inland waters of Washington State and British Columbia known as the Salish Sea, where they have traditionally spent much of their time from spring through fall. Using reports from experienced observers to sightings networks, we tracked the daily presence of the Southern Residents in these waters from 1 April to 30 June from 1994 through 2016. We found that the escapement estimates of spring Chinook salmon (Oncorhynchus tshawytscha) on the Fraser River in British Columbia were a significant predictor of the cumulative presence/absence of the whales throughout the spring season. There was also a difference in both whale presence and salmon abundance before and after 2005, suggesting that the crash in Chinook salmon numbers has fallen below threshold where it is worthwhile for the whales to spend as much time in the Salish Sea. The use of the Salish Sea by the Southern Residents has declined in the spring months as they are either foraging for Chinook salmon elsewhere or are shifting to another prey species. In order to continue providing necessary protections to this endangered species, critical habitat designations must be re-evaluated as this population of killer whales shifts its range in response to prey availability.

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Salish Sea Chinook salmon exhibit weaker coherence in early marine survival trends than coastal populations

Fisheries Oceanography ◽

10.1111/fog.12222 ◽

2017 ◽

Vol 26 (6) ◽

pp. 625-637 ◽

Cited By ~ 13

Author(s):

Casey P. Ruff ◽

Joseph H. Anderson ◽

Iris M. Kemp ◽

Neala W. Kendall ◽

Peter A. Mchugh ◽

...

Keyword(s):

Chinook Salmon ◽

Salish Sea ◽

Marine Survival

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The Matter of Mapping Multispecies Entanglements of Mourning—A Manifesto’s Shout, An Orca’s Tour of Grief

Matter: Journal of New Materialist Research ◽

10.1344/jnmr.v2i1.33376 ◽

2021 ◽

Vol 2 (1) ◽

pp. 99-119

Author(s):

Jacqueline Viola Moulton

Keyword(s):

New York ◽

New York City ◽

Chinook Salmon ◽

York City ◽

Gilles Deleuze ◽

Killer Whale ◽

Felix Guattari ◽

Salish Sea ◽

The Aesthetic ◽

Ethical Response

Mapping entanglements is work—work of care, maintenance, and mourning. This project utilises a new materialist methodology inherited from the work of Gilles Deleuze and Félix Guattari, who follow lines of becoming to track compositions which compose worlds. To map (non-linear, temporal, and situated) lines of loss across multispecies landscapes is material work of more-than-human mourning. The New York City-based performance artist Mierle Laderman Ukeles—alongside scholars such as María Puig de la Bellacasa and Donna J. Haraway—reorient configurations of work and care, which enable these lines to be followed into more-than-human worlds. Mapping lines of mourning into multispecies worlds is material work of the aesthetic-ethical response within shared and troubled landscapes. The key storytellers within the narrative of mourning and joy woven into this paper are the Salish Sea, the Lummi Nation, the Chinook Salmon, and the Southern Resident killer whale; the voices and cries to which this project, in work and care, is dedicated.

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