Thermal landscapes in a changing climate: biological implications of water temperature patterns in an extreme year

2019 ◽  
Vol 76 (10) ◽  
pp. 1740-1756 ◽  
Author(s):  
E. Ashley Steel ◽  
Amy Marsha ◽  
Aimee H. Fullerton ◽  
Julian D. Olden ◽  
Narasimhan K. Larkin ◽  
...  

Record-breaking droughts and high temperatures in 2015 across the Pacific Northwest, USA, provide an opportunistic glimpse into potential future thermal regimes of rivers and their implications for freshwater fishes. We applied spatial stream network models to data collected every 30 min for 4 years at 42 sites on the Snoqualmie River (Washington, United States) to compare water temperature patterns, summarized with relevance to particular life stages of native and nonnative fishes, in 2015 with more typical conditions (2012–2014). Although 2015 conditions were drier and warmer than what had been observed since 1960, patterns were neither consistent over the year nor on the network. Some locations showed dramatic increases in air and water temperature, whereas others had temperatures that differed little from typical years; these results contrasted with existing forecasts of future thermal landscapes. If we will observe years like 2015 more frequently in the future, we can expect conditions to be less favorable to native, cool-water fishes such as Chinook salmon (Oncorhynchus tshawytscha) and bull trout (Salvelinus confluentus) but beneficial to warm-water nonnative species such as largemouth bass (Micropterus salmoides).

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.


Author(s):  
Colin L. Nicol ◽  
Jeffrey C. Jorgensen ◽  
Caleb B. Fogel ◽  
Britta Timpane-Padgham ◽  
Timothy J. Beechie

In the Pacific Northwest, USA, climate change is expected to result in a shift in average hydrologic conditions and increase variability. The relative vulnerabilities to peak flow changes among salmonid species within the same basin have not been widely evaluated. We assessed the impacts of predicted increases in peak flows on four salmonid populations in the Chehalis River basin. Coupling observations of peak flows, emissions projections, and multi-stage Beverton–Holt matrix-type life cycle models, we ran 100-year simulations of spawner abundance under baseline, mid-century, and late-century climate change scenarios. Coho (Oncorhynchus kisutch) and spring Chinook salmon (Oncorhynchus tshawytscha) shared the highest projected increase in interannual variability (SD = ±15%). Spring Chinook salmon had the greatest reduction in median spawner abundance (–13% to –15%), followed by coho and fall Chinook salmon (–7% to –9%), then steelhead (Oncorhynchus mykiss) (–4%). Our results show that interspecies and life history variability within a single basin is important to consider. Species with diverse age structures are partially buffered from population variability, which may increase population resilience to climate change.


2019 ◽  
Vol 76 (3) ◽  
pp. 447-462 ◽  
Author(s):  
Benjamin W. Nelson ◽  
Carl J. Walters ◽  
Andrew W. Trites ◽  
Murdoch K. McAllister

Predation risk and competition among conspecifics significantly affect survival of juvenile salmon, but are rarely incorporated into models that predict recruitment in salmon populations. Using densities of harbour seals (Phoca vitulina) and numbers of hatchery-released Chinook salmon (Oncorhynchus tshawytscha) smolts as covariates in spatially structured Bayesian hierarchical stock–recruitment models, we found significant negative correlations between seal densities and productivity of Chinook salmon for 14 of 20 wild Chinook populations in the Pacific Northwest. Changes in numbers of seals since the 1970s were associated with a 74% decrease (95% CI: −85%, −64%) in maximum sustainable yield in Chinook stocks. In contrast, hatchery releases were significantly correlated with Chinook productivity in only one of 20 populations. Our findings are consistent with recent research on predator diets and bioenergetics modeling that suggest there is a relationship between harbour seal predation on juvenile Chinook and reduced marine survival in parts of the eastern Pacific. Forecasting, assessment, and recovery efforts for salmon populations of high conservation concern should thus consider including biotic factors, particularly predator–prey interactions.


Author(s):  
Donald A Larsen ◽  
Abby E. Fuhrman ◽  
Deborah L. Harstad ◽  
David A Venditti ◽  
Brian R Beckman

Age of maturation in many salmonid species is phenotypically plastic and dependent on exceeding a genetically set threshold in growth, often described as a probabilistic maturation reaction norm (PMRN). Hatchery supplementation programs for Chinook salmon in the Pacific Northwest US have been developed to minimize differences between hatchery and wild fish by integrating natural-origin adults into broodstock, potentially affecting PMRNs. We raised fish from 10 Chinook salmon stocks with variable levels of natural-origin integration in a common garden environment to explore potential genetic variation in PMRNs for precocious male maturation as age 2 minijacks. Proportion minijacks varied ≈10-fold (0.043 to 0.443) and the PMRN WP50 (predicted weight at 50% maturation) varied by ≈18 g (24.1 to 41.7g). The propensity for minijack maturation was generally higher in stocks with higher levels of natural origin integration. These findings demonstrate the effect of genotype by environment interactions on life history of salmonids and the need for stock specific tailoring of rearing regimes to regulate differences between hatchery and wild fish, when wild fish are used in broodstocks.


1995 ◽  
Vol 52 (4) ◽  
pp. 855-863 ◽  
Author(s):  
Peter Fritz Baker ◽  
Franklin K. Ligon ◽  
Terence P. Speed

Data from the U.S. Fish and Wildlife Service are used to investigate the relationship between water temperature and survival of hatchery-raised fall-run chinook salmon (Oncorhynchus tshawytscha) smolts migrating through the Sacramento – San Joaquin Delta of California. A formal statistical model is presented for the release of smolts marked with coded-wire tags (CWTs) in the lower Sacramento River and the subsequent recovery of marked smolts in midwater trawls in the Delta. This model treats survival as a logistic function of water temperature, and the release and recovery of different CWT groups as independent mark–recapture experiments. Iteratively reweighted least squares is used to fit the model to the data, and simulation is used to establish confidence intervals for the fitted parameters. A 95% confidence interval for the upper incipient lethal temperature, inferred from the trawl data by this method, is 23.01 ± 1.08 °C This is in good agreement with published experimental results obtained under controlled conditions (24.3 ± 0.1 and 25.1 ± 0.1 °C for chinook salmon acclimatized to 10 and 20 °C, respectively): this agreement has implications for the applicability of laboratory findings to natural systems.


2014 ◽  
Vol 71 (7) ◽  
pp. 1671-1682 ◽  
Author(s):  
D. Patrick Kilduff ◽  
Louis W. Botsford ◽  
Steven L. H. Teo

Abstract Knowledge of the spatial and temporal extent of covariation in survival during the critical ocean entry stage will improve our understanding of how changing ocean conditions influence salmon productivity and management. We used data from the Pacific coastwide coded-wire tagging program to investigate local and regional patterns of ocean survival of Chinook salmon (Oncorhynchus tshawytscha) from the Central Valley of California to southeastern Alaska from 1980–2006. Ocean survival of fish migrating as subyearlings covaried strongly from Vancouver Island to California. Short-term correlations between adjacent regions indicated this covariability increased, beginning in the early 1990s. Chinook salmon survivals exhibited a larger spatial scale of variability (50% correlation scale: 706 km) than those reported for other northeast Pacific Ocean salmon. This scale is similar to that of environmental variables related to ecosystem productivity, such as summer upwelling (50% correlation scale: 746 km) and sea surface temperature (50% correlation scale: 500–600 km). Chinook salmon ocean survival rates from southeastern Alaska and south of Vancouver Island were not inversely correlated, in contrast to earlier observations based on catch data, but note that our data differ in temporal and spatial coverage from those studies. The increased covariability in Chinook salmon ocean survival suggests that the marine phase contributes little to the reduction in risk across populations attributable to the portfolio effect. In addition, survival of fish migrating as yearlings from the Columbia River covaried with Chinook salmon survival from the northernmost regions, consistent with our understanding of their migration patterns.


2009 ◽  
Vol 46 (4) ◽  
pp. 622-635 ◽  
Author(s):  
K. C. Grim ◽  
M. J. Wolfe ◽  
M. Edwards ◽  
J. Kaufman ◽  
S. Onjukka ◽  
...  

Abnormal growths were observed on the lips and in the oral cavities of 2- and 3-year-old Chinook salmon (Oncorhynchus tshawytscha) maintained in one freshwater and one saltwater captive fish-rearing facility in the Columbia River (Pacific Northwest). Initially presenting as bilaterally symmetrical, red, irregular plaques on oral mucosal surfaces, the lesions developed progressively into large, disfiguring masses. Of the 502 natural parr collected for captive broodstock, 432 (86%) displayed these tumors, whereas cohort salmon (i.e., same year classes) in these same facilities remained unaffected. Morphologically similar neoplasms were collected occasionally from adult Chinook salmon that had returned to their natal streams. Histologic features of the tumors suggested that they were derived from the portion of dental lamina destined to form tooth root sulci; therefore, these neoplasms were diagnosed as ameloblastomas. The lesions also resembled archived specimens of Chinook salmon oral tumors, which had been described decades earlier. Etiologic investigations performed during the current outbreak included bacteriologic, virologic, genetic, ultrastructural analyses, and cohabitation exposure studies. Results of these efforts did not indicate an obvious genetic basis for this syndrome, attempts to isolate potentially causative viruses or bacteria were negative, and disease transmission to naïve fish was unsuccessful. A few intracytoplasmic hexagonal structures, possibly consistent with viral particles (∼100 nm), were observed ultrastructurally in a tumor cell from 1 of 6 specimens submitted for transmission electron microscopy. Although the presence of these particles does not constitute sufficient evidence for causality, an infectious or multifactorial etiology seems plausible.


2016 ◽  
Vol 73 (9) ◽  
pp. 2380-2394 ◽  
Author(s):  
Saskia A. Otto ◽  
Sarah Simons ◽  
Joshua S. Stoll ◽  
Peter Lawson

Abstract Transdisciplinary research that crosses disciplinary boundaries and includes stakeholder collaboration is increasingly being used to address pressing and complex socio-ecological challenges in the Anthropocene. In fisheries, we see transdisciplinary approaches being employed to address a range of challenges, including bycatch where fine-scale data are collected by fishers to help advance spatial approaches in which fishing effort is shifted away from bycatch hotspots. However, the spatio-temporal overlap of morphologically undistinguishable fish stocks, some of which are depleted, is a major concern for some fisheries, including the Pacific Northwest troll Chinook salmon (Oncorhynchus tshawytscha) fishery. In this study, we develop and evaluate a transdisciplinary approach to avoid bycatch in the commercial Chinook salmon troll fishery off northern and central Oregon. Based on a unique genetic dataset collected by fishers, fine-scale patterns of stock distribution and spatial stock overlap were assessed. Two hotspots of weak Klamath stock in the study region were identified and related to bathymetry. Results were then fed into a simple bioeconomic model to evaluate costs and benefits of reallocating effort under two scenarios of allowable catch of a weak stock (Klamath). The scenarios demonstrate that effort reallocation could lead to a reduction in Klamath catch as well as to increases in net profit, but outcomes depend on the distance from the fleets' home port to the new fishing area. The output of the model at its current stage should be regarded strategically, providing a qualitative understanding of the types of best fleet strategies. Despite some challenges in transdisciplinarity discussed in this study and the present limitations to incorporate fine-scale changes of Chinook salmon stock distributions in management regulations, we contend that this approach to research has the potential to lead to improved management outcomes.


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