Managing the decline of Pacific salmon: metapopulation theory and artificial recolonization as ecological mitigation

1999 ◽  
Vol 56 (9) ◽  
pp. 1700-1706 ◽  
Author(s):  
Kyle A Young

Pacific salmon (Oncorhynchus spp.) in the Pacific Northwest of North America have suffered regional declines and local extinctions primarily because of freshwater habitat destruction and overexploitation by fisheries. Management efforts to reverse this trend have correctly focused on habitat restoration and enhancement and stricter regulation of fisheries. Metapopulation theory and the ecology of the genus suggest that the addition of management efforts that artificially increase the rate of colonization of presently unoccupied habitats may promote the recovery and persistence of Pacific salmon in an ecologically realistic way. Such programs are conceptually and operationally different from traditional stock transfer and enhancement programs, which aimed to maintain a harvestable surplus of salmon in the face of habitat destruction and overfishing. I argue that artificial recolonization programs should be viewed as ecological mitigation, aimed at hastening the return of natural demographic and evolutionary processes, and hope here to promote an open discussion of their merits and risks as such.

2004 ◽  
Vol 61 (2) ◽  
pp. 283-291 ◽  
Author(s):  
David P Larsen ◽  
Philip R Kaufmann ◽  
Thomas M Kincaid ◽  
N Scott Urquhart

In the northwestern United States, there is considerable interest in the recovery of Pacific salmon (Oncorhynchus spp.) populations listed as threatened or endangered. A critical component of any salmon recovery effort is the improvement of stream habitat that supports various life stages. Two factors in concert control our ability to detect consistent change in habitat conditions that could result from significant expenditures on habitat improvement: the magnitude of spatial and temporal variation and the design of the monitoring network. We summarize the important components of variation that affect trend detection and explain how well-designed networks of 30–50 sites monitored consistently over years can detect underlying changes of 1–2% per year in a variety of key habitat characteristics within 10–20 years, or sooner, if such trends are present. We emphasize the importance of the duration of surveys for trend detection sensitivity because the power to detect trends improves substantially with the passage of years.


1988 ◽  
Vol 62 (4) ◽  
pp. 626-655 ◽  
Author(s):  
Dianne Newell

An industry may fail to adopt or to extend new technology for many reasons other than lack of entrepreneurial vision. In the following article, Professor Newell considers the halting and incomplete diffusion of mechanization and continuous-process technology in the salmon-canning industry of the Pacific Northwest. She shows that the fragile and cyclical character of the natural resource, the labor system employed, and the remote and isolated locations of individual production units all affected cannery operators' decisions about technology adoption, and that the persistence of manual labor reflected rational, not reactionary, business choices.


2021 ◽  
Author(s):  
Colby L. Hause ◽  
Gabriel P. Singer ◽  
Rebecca A. Buchanan ◽  
Dennis E. Cocherell ◽  
Nann A. Fangue ◽  
...  

AbstractExtirpation of the Central Valley spring-run Chinook Salmon ESU (Oncorhynchus tshawytscha) from the San Joaquin River is emblematic of salmonid declines across the Pacific Northwest. Habitat restoration and fish reintroduction efforts are ongoing, but recent telemetry studies have revealed low outmigration survival of juveniles to the ocean. Previous investigations have focused on modeling survival relative to river discharge and geographic regions, but have largely overlooked the effects of habitat variability. To evaluate the link between environmental conditions and survival of juvenile spring-run Chinook Salmon, we combined high spatial resolution habitat mapping approaches with acoustic telemetry along a 150 km section of the San Joaquin River during the spring of 2019. While overall outmigration survival was low (5%), our habitat-based classification scheme described variation in survival of acoustic-tagged smolts better than other candidate models based on geography or distance. There were two regional mortality sinks evident along the longitudinal profile of the river, revealing poor survival in areas that shared warmer temperatures but that diverged in chlorophyll-α, fDOM, turbidity and dissolved oxygen levels. These findings demonstrate the value of integrating river habitat classification frameworks to improve our understanding of survival dynamics of imperiled fish populations. Importantly, our data generation and modeling methods can be applied to a wide variety of fish species that transit heterogeneous and diverse habitat types.


2019 ◽  
Vol 10 (2) ◽  
pp. 517-524 ◽  
Author(s):  
Jeffrey C. Jolley ◽  
Kenneth M. Lujan

Abstract Interest in conservation, management, and captive rearing of Pacific Lamprey Entosphenus tridentatus in the Pacific Northwest has risen in recent years. General and specific information regarding the occurrence of fish pathogens and the risk of Pacific Lamprey as a vector for pathogens to other species is not well understood. Specific efforts to captively rear or artificially propagate Pacific Lamprey at facilities that are used for Pacific salmon Oncorhynchus spp. have increased. We performed fish health surveys on wild-caught larval and adult Pacific Lamprey from locations that were used as lamprey sources for captive research to determine the occurrence of bacteria, viruses, and parasites that may be pathogens. A variety of potential pathogens was detected, most notably Aeromonas hydrophila and Vibrio vulnificus from larval Pacific Lamprey and A. salmonicida from adult lampreys. There was a general lack of pathogenic activity and absence of viral detections from all lampreys. The diversity of bacteria encountered from the larvae in our study could be indicative of the wide diversity of bacteria that is known to be associated with larval lamprey in general. Further efforts to understand pathogenic risk from Pacific Lamprey to salmonid propagation programs are warranted.


2007 ◽  
Vol 15 (3) ◽  
pp. 494-505 ◽  
Author(s):  
Stephen L. Katz ◽  
Katie Barnas ◽  
Ryan Hicks ◽  
Jeff Cowen ◽  
Robin Jenkinson

2005 ◽  
Vol 62 (10) ◽  
pp. 2285-2293 ◽  
Author(s):  
Monika Winder ◽  
Daniel E Schindler ◽  
Jonathan W Moore ◽  
Susan P Johnson ◽  
Wendy J Palen

In coastal areas of the Pacific Northwest bears (Ursus spp.) prey heavily on spawning Pacific salmon (Oncorhynchus spp.) and selectively kill energy-rich individuals that are the most recent arrivals on spawning grounds. Pacific salmon eventually die in spawning habitats anyway, albeit with considerably lower energetic content. We investigated whether foraging activities of bears facilitate growth of stream invertebrates by increasing the duration of salmon carcass availability and the nutritional value of carcasses for scavengers. Our survey in southwest Alaska showed that carcasses are highly colonized by caddisfly (Trichoptera) larvae. Caddisflies show a strong preference for bear-killed over senescent carcasses, which may be a result of extended temporal availability, improved accessibility of consumable tissue, and higher energetic content of bear-killed fish. Isotope analyses further indicate uptake of marine-derived nutrients in caddisflies during the salmon run, which, however, does not extend into subsequent generations. Thus, species with life histories linked to the annual marine derived nutrient pulse gain the biggest advantage from the salmon resource subsidy. A long-term survey in several creeks in this region showed that bear predation intensity varied greatly among creeks and years, therefore indirect effects of bear predation on aquatic scavengers are likely highly patchy in time and space.


<em>Abstract.</em>—The Ecosystem Diagnosis and Treatment (EDT) model is being used to build working hypotheses to direct habitat restoration and protection activities in most Pacific Northwest salmon watersheds. The EDT model is used to provide a basis for moving forward with restoration and protection activities, evaluating progress, and refining restoration strategies. The model consists of four components: 1) characterization of the aquatic environment, 2) species-habitat rating rules, 3) life history trajectories, and 4) population performance computations. The environmental characterization is a reach-scale, monthly time step, species-neutral depiction of the stream that focuses on environmental features relevant to salmonids. The species-habitat rating rules are explicit assumptions about the relationship between the stream reach characterization and species-life stage survival. Life history trajectories are multiple computer-generated pathways through the environment. Finally, life history and population performance, defined by Beverton–Holt productivity and capacity parameters, is calculated for each life history trajectory and these trajectories are combined across spatial and biological scales to compute population performance. The model is a freely accessible, web-based tool (http://edt.jonesandstokes.com).


2012 ◽  
Vol 2 (2) ◽  
Author(s):  
Sandy Campbell

Tullson, Diane.  Sea Change. Victoria: Orca Book Publishers, 2010.  Print. Sea Change is an exciting story about Lucas, a 17 year-old who flies to an isolated fishing lodge in the Pacific Northwest, where his emotionally-distant father works. Lucas is left alone at the closed lodge with a young Aboriginal girl, Sumi, who is the caretaker. When Sumi is injured, Lucas, who has little experience in the wilderness or on water, must pilot the boat several hours down the foggy coast to take Sumi to a logging camp where she can get help. This is a typical “coming-of-age” plot, in which a youth sets out on an adventure, endures several tests or trials and returns a changed person. A sea change is either a “marked” or “radical” change or a “change brought about by the sea.” In this novel, Lucas undergoes both forms of sea change.  First, he proves himself on the water by successfully navigating an unfamiliar coastline under dangerous conditions. Second, he wins the respect of other men through his handling of the crisis and matures in his understanding of his father. The Orca Soundings series is designed for reluctant teen readers. The books are short, high-interest novels with reading levels from Grade 2 to Grade 4.5. In Sea Change, Diane Tullson accomplishes this combination masterfully. While the author writes at a low reading level, she also keeps the dialogue believable for a 17-year old. [Sumi] says, “What he was pissed about was me shooting so close to the helicopter.” I sit up.  “You mean you might have hit the helicopter?”  I imagine the fiery carnage.  “You could have killed us!” She takes the bottle back from me.  “And ruined a perfectly good helicopter.” “Jeez, Sumi, you have no idea how happy I am that you killed that deer.” (p.64) The first person narration draws the reader into the story and creates the sense of “being there” that will keep teen readers engaged.   For example: I fix my stare on Sumi and watch where she points. Sometimes I hear her cursing, and I know I haven’t exactly interpreted her bearing. We’re bouncing off the waves, and spray nails us in the face. I squeeze my eyes almost closed. Driving fast, the air is so much colder and my fingers are frozen on the steering tiller. She motions wildly to steer left and I cut sharply, barely scraping past a log. How she saw it, I do not know. (p. 100) Overall this is a well-written and entertaining story which will hold the attention of the reluctant teenage male reader. Sea Change would be a good addition both public and junior high and high school libraries. Recommendation:  4 stars out of 4Reviewer:  Sandy CampbellSandy is a Health Sciences Librarian at the University of Alberta, who has written hundreds of book reviews across many disciplines.  Sandy thinks that sharing books with children is one of the greatest gifts anyone can give.


2018 ◽  
Vol 75 (7) ◽  
pp. 1160-1168 ◽  
Author(s):  
Wesley A. Larson ◽  
Yniv Palti ◽  
Gunagtu Gao ◽  
Kenneth I. Warheit ◽  
James E. Seeb

Natural-origin steelhead trout (Oncorhynchus mykiss (Walbaum, 1792)) in the Pacific Northwest, USA, are threatened by a number of factors including habitat destruction, disease, decline in marine survival, and a potential erosion of genetic viability due to introgression from hatchery strains. Our major goal was to use a recently developed SNP array containing ∼57 000 SNPs to identify a subset of SNPs that differentiate hatchery and natural-origin populations. We analyzed 35 765 polymorphic SNPs in nine populations of steelhead trout sampled from Puget Sound, Washington, USA. We then conducted two outlier tests and found 360 loci that were candidates for divergent selection between hatchery and natural-origin populations (mean FCT = 0.29, maximum = 0.65) and 595 SNPs that were candidates for selection among natural-origin populations (mean FST = 0.25, maximum = 0.51). Comparisons with a linkage map revealed that two chromosomes (Omy05 and Omy25) contained significantly more outliers than other chromosomes, suggesting that regions on Omy05 and Omy25 may be of adaptive significance. Our results highlight several advantages of the 57 000 SNP array as a tool for population and conservation genomics studies.


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