scholarly journals Population, habitat, and marine location effects on early marine survival and behavior of Puget Sound steelhead smolts

Ecosphere ◽  
2017 ◽  
Vol 8 (5) ◽  
pp. e01834 ◽  
Author(s):  
Megan E. Moore ◽  
Barry A. Berejikian
2018 ◽  
Vol 30 (2) ◽  
pp. 103-118 ◽  
Author(s):  
M. F. Chen ◽  
S. M. O'Neill ◽  
A. J. Carey ◽  
R. H. Conrad ◽  
B. A. Stewart ◽  
...  

Orca ◽  
2018 ◽  
Author(s):  
Jason M. Colby

The call came by ship-to-shore radio from a Washington State ferry. The skipper on the Seattle-Bremerton route had just spotted killer whales headed south, and he thought Ted Griffin should know. Shouting his thanks, the aquarium owner raced down the dock, leapt into Pegasus, and tore off in the direction of the sighting. Clocked at sixty miles per hour, the shallow-draft runabout may have been the fastest boat on Puget Sound, and it overtook the orcas near Vashon Island. But as Griffin throttled down, he realized to his disbelief that someone else was already chasing them. There, clear as day, was a blue helicopter hovering over the whales. Incensed, Griffin steered Pegasus closer, until he could almost touch the helicopter’s pontoons. Looking up, he spotted a burly man leaning out the cabin door and eying the pod. “Get away from my whales!” Griffin shouted. “Your whales?” the man laughed. “You’ll have to catch them first.” It was the first time Griffin had met Don Goldsberry, ex-fisherman and animal collector for the Point Defiance Aquarium (formerly the Tacoma Aquarium). The two men’s shared pursuit of orcas would soon bind them together. On this day, however, Griffin left feeling a bit embarrassed, having behaved, as he put it, “like a rancher possessive of his herd.” Some part of him knew his quest to capture and befriend a killer whale was becoming unhealthy. He had a struggling aquarium in Seattle and a growing family on Bainbridge Island. Orcas were his obsession, but they weren’t paying the bills. At home, he still talked and laughed with Joan and played with his little sons, Jay and John. But he had whales on the brain. He dreamed of them when asleep and sometimes mumbled about them when awake. With each reported sighting, he dropped everything—to Joan’s increased annoyance. In time, Griffin had come to see patterns in the animals’ migrations and behavior. He noted that they appeared when chinook salmon were running and that they seemed to cling to the west side of Puget Sound when headed south and to the east side when swimming north.


2011 ◽  
Vol 68 (2) ◽  
pp. 232-240 ◽  
Author(s):  
Elisabeth J Duffy ◽  
David A Beauchamp

We examined the effect of early marine entry timing and body size on the marine (smolt-to-adult) survival of Puget Sound Chinook salmon ( Oncorhynchus tshawytscha ). We used data from coded wire tag release groups of hatchery Chinook salmon to test whether hatchery release date, release size, and size in offshore waters in July and September influenced marine survival. Marine survival was most strongly related to the average body size in July, with larger sizes associated with higher survivals. This relationship was consistent over multiple years (1997–2002), suggesting that mortality after July is strongly size-dependent. Release size and date only slightly improved this relationship, whereas size in September showed little relationship to marine survival. Specifically, fish that experienced the highest marine survivals were released before 25 May and were larger than 17 g (or 120 mm fork length) by July. Our findings highlight the importance of local conditions in Puget Sound (Washington, USA) during the spring and summer, and suggest that declines in marine survival since the 1980s may have been caused by reductions in the quality of feeding and growing conditions during early marine life.


2007 ◽  
Vol 27 (2) ◽  
pp. 465-480 ◽  
Author(s):  
Jason D. Toft ◽  
Jeffery R. Cordell ◽  
Charles A. Simenstad ◽  
Lia A. Stamatiou

2017 ◽  
Vol 45 (3) ◽  
pp. 278-290 ◽  
Author(s):  
KATHRYN L. SOBOCINSKI ◽  
CORREIGH M. GREENE ◽  
MICHAEL W. SCHMIDT

SUMMARYCoho salmon (Oncorhynchus kisutch), Chinook salmon (Oncorhynchus tshawytscha) and steelhead (Oncorhynchus mykiss) in Puget Sound and the Strait of Georgia have exhibited declines in marine survival over the last 40 years. While the cause of these declines is unknown, multiple factors, acting cumulatively or synergistically, have likely contributed. To evaluate the potential contribution of a broad suite of drivers on salmon survival, we used qualitative network modelling (QNM). QNM is a conceptually based tool that uses networks with specified relationships between the variables. In a simulation framework, linkages are weighted and then the models are subjected to user-specified perturbations. Our network had 33 variables, including: environmental and oceanographic drivers (e.g., temperature and precipitation), primary production variables, food web components from zooplankton to predators and anthropogenic impacts (e.g., habitat loss and hatcheries). We included salmon traits (survival, abundance, residence time, fitness and size) as response variables. We invoked perturbations to each node and to suites of drivers and evaluated the responses of these variables. The model showed that anthropogenic impacts resulted in the strongest negative responses in salmon survival and abundance. Additionally, feedbacks through the food web were strong, beginning with primary production, suggesting that several food web variables may be important in mediating effects on salmon survival within the system. With this model, we were able to compare the relative influence of multiple drivers on salmon survival.


PLoS ONE ◽  
2012 ◽  
Vol 7 (11) ◽  
pp. e49645 ◽  
Author(s):  
Megan Moore ◽  
Barry A. Berejikian ◽  
Eugene P. Tezak

2020 ◽  
Vol 188 ◽  
pp. 102419
Author(s):  
Kathryn L. Sobocinski ◽  
Neala W. Kendall ◽  
Correigh M. Greene ◽  
Michael W. Schmidt

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