scholarly journals Thermal sensitivity and flow-mediated migratory delays drive climate risk for coastal sockeye salmon

FACETS ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 71-89
Author(s):  
William I. Atlas ◽  
Karl M. Seitz ◽  
Jeremy W.N. Jorgenson ◽  
Ben Millard-Martin ◽  
William G. Housty ◽  
...  

Climate change is subjecting aquatic species to increasing temperatures and shifting hydrologic conditions. Understanding how these changes affect individual survival can help guide conservation and management actions. Anadromous Pacific salmon ( Oncorhynchus spp.) in some large river systems are acutely impacted by the river temperatures and flows encountered during their spawning migrations. However, comparatively little is known about drivers of en route mortality for salmon in smaller coastal watersheds, and climate impacts may differ across watersheds and locally adapted salmon populations. To understand the effects of climate on the survival of coastal sockeye salmon ( Oncorhynchus nerka; hísn in Haíɫzaqv), we tagged 1785 individual fish with passive integrated transponders across four migration seasons in the Koeye River—a low-elevation watershed in coastal British Columbia—and tracked them during their relatively short migration (∼13 km) from river entry to spawning grounds. Overall, 64.7% of sockeye survived to enter the spawning grounds, and survival decreased rapidly when water temperatures exceeded 15 °C. The best-fitting model included an interaction between river flow and temperature, such that temperature effects were worse when flows were low, and river entry ceased at the lowest flows. Results revealed temperature-mediated mortality and migration delays from low water that may synergistically reduce survival among sockeye salmon returning to coastal watersheds.

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Josh Murauskas ◽  
Kim Hyatt ◽  
Jeff Fryer ◽  
Elliot Koontz ◽  
Skyeler Folks ◽  
...  

Abstract Background Okanagan River Sockeye Salmon Oncorhynchus nerka (Okanagan Sockeye) are one of two remaining self-sustaining Sockeye Salmon populations in the Columbia River Basin. We used detection histories of smolts implanted with passive integrated transponder (PIT) tags between 2012 and 2019 to estimate survival and behavioral metrics during reintroduction efforts and changing environmental conditions over the monitoring period. Results Smolts migrating to McNary Dam, whose route includes 130 km of the Okanagan River and 388 km of the Columbia River, generally had high survival (mean of 87.0% per 100 km) and fast migration speeds (up to 50 km/day) relative to other salmonids in the region. Smolt-to-adult returns (SARs) ranged from 0.4 to 6.1% and were greater for fish originating from Skaha Lake compared to cohorts tagged in Osoyoos Lake. Most adults returned after 2 years in the ocean (69%), followed by jacks (27%), and adults that spent 3 years at sea (4%), though Skaha Lake adults had a significantly younger age structure than cohorts from Osoyoos Lake. Survival of adults from Bonneville Dam (rkm 235) upstream to Wells Dam (rkm 830) was generally high (80–92%), and migration speed decreased in upstream reaches. Survival from Wells Dam to the Okanagan River was only estimable in 2018, where 64% of adults survived to the spawning grounds. The upstream migration of adult Okanagan Sockeye was significantly compromised during the drought of 2015 when less than 5% of Okanagan Sockeye that returned to the Columbia River reached spawning grounds. Conclusions Our results indicate that Okanagan Sockeye have exceptional survival and migratory ability relative to other salmonids, though poor ocean conditions combined with warming water temperatures in freshwater habitats in recent years have the potential to devastate the population. The success of reintroduction efforts to increase spatial structure and diversity of Okanagan Sockeye is, therefore, critical to maintaining the population in years to come.


2020 ◽  
Vol 200 (2) ◽  
pp. 270-291
Author(s):  
E. A. Shevlyakov ◽  
S. V. Shubkin

Aerial survey of the pacific salmon spawning grounds was conducted in the water bodies of Chukotka belonged to the Bering Sea basin (the Anadyr, Velikaya, Tumanskaya Rivers and Meinypilgyno lake-river system) in 2019, for the first time since 1992. Total flight time was 35 hours, approximate length of the transects was 3,800 km. Number of the spawners was estimated as 660.7 . 103 ind. for chum salmon, 112.2 . 103 ind. for sockeye salmon, and 3678.0 . 103 ind. for pink salmon, features of their distribution are described.


Author(s):  
K. M. Malykh ◽  
D. V. Demchenko ◽  
V. A. Dubynin ◽  
M. N. Kovalenko

Results of in situ testing of BioSonics DT-X and Didson hydroacustic systems set on migrating path to spawning grounds of adult sockeye salmon in the Ozernaya River are presented. Two million 374 thousand fishes was recognized and counted for the whole working period of the systems, including one million 276 thousand individuals registered by BioSonics DT-X echo-sounder and 1 million 98 thousand – by Didson imaging sonar. The data on the assessment of Pacific salmon escapement in the Ozernaya River allow to make recommendations on the use of the BioSonics DT-X and Didson hydroacustic systems as a tool for assessment of Pacific salmon escapement in rivers of Kamchatka.


Author(s):  
M. V. Koval ◽  
O. B. Tepnin ◽  
S. L. Gorin ◽  
E. S. Fadeev ◽  
O. V. Zikunova ◽  
...  

Hydrological regime and morphodynamics of the outlet part of the Kamchatka River, dynamics of mixing zone, patterns of juvenile Pacific salmon distribution and migration in the coastal waters of Kamchatsky Gulf in the zone of operating trap nets were analyzed on the results of complex field works prowided in summer period in 2018–2019; fishing and specifics of sockeye salmon spawning run in the river was described. In the course of analyzing the entire complex of available long-term data, an assessment of the likely impact of some key factors on the dynamics of anadromous migration of sockeye salmon in the Kamchatka River was made; biological statistics of spawners and current state of reproduction of this stock was demonstrated. It is found, that natural environmental factors, neither abiotic nor biotic (including fish health as population internal factor), could not cause disturbance of sockeye salmon spawning run dynamics in the Kamchatka River in recent years. Smoller body size and physiological imperfection of the spawners before the anadromous migration due to effects of high number of pink salmon in recent years are suggested to be the most likely cause of spawning run delay in late sockeye salmon morph. Regime of commercial use of the stock and general increasing pressure on the spawning stock by coastal fisheries are demonstrated to be the strongest outer factors to affect modern state of the resources and sockeye salmon population structure in the Kamchatka River, causing permanent escapement deficiency on spawning grounds in the river basin (first of all in the late morph), and also infact lead to disballance between different subpopulation groups in the composition of the stock. Recommendations in order to provide recovery and sustainable level of the Kamchatka River sockeye salmon stock are given in the perspective of more efficient commercial use of the stock next several years; highlights for further researches are outlined.


1999 ◽  
Vol 56 (2) ◽  
pp. 297-310 ◽  
Author(s):  
Terry D Beacham ◽  
Chris C Wood

Spawning escapements of individual Pacific salmon stocks returning to remote spawning locations throughout large river systems can in theory be estimated by mixed-stock analysis of appropriately weighted samples from test fisheries near the river mouth. However, the feasibility of this approach has usually been limited by practical difficulties in identifying closely related populations within the same watershed. Microsatellite DNA techniques offer new promise for overcoming these limitations as illustrated for sockeye salmon (Oncorhynchus nerka) in the Nass River of northern British Columbia. Variation at six microsatellite DNA loci (Omy77, Ots3, Ots100, Ots103, Ots107, and Ots108) was surveyed from about 1400 fish from nine stocks in the Nass River drainage as well as from 249 fish in a test fishery conducted in the lower river during 1996. Five stocks were surveyed in more than one year, and variation in allele frequencies among stocks was, on average, about 10 times greater than annual variation within stocks. Allele frequencies of stocks where the juveniles do not rear in lakes ("riverine" or "sea type") were more similar to each other compared with frequencies from lake-rearing stocks. Significant differences in allele frequencies were observed among most stocks at all loci. About 4.5% of observed variation over all loci was attributable to stock differentiation. Simulated mixed-stock samples suggested that the six microsatellite DNA loci surveyed should provide the ability to provide relatively accurate and precise estimates of stock composition when utilized for fishery management applications. The estimated proportion of Meziadin Lake sockeye salmon in the 1996 test fishery was about 73%, in close agreement with an estimate derived from direct tagging of fish in the test fishery.


1994 ◽  
Vol 51 (12) ◽  
pp. 2843-2855 ◽  
Author(s):  
Richard J. Beamish ◽  
Chrys-Ellen M. Neville ◽  
Barbara L. Thomson ◽  
Paul J. Harrison ◽  
Mike St. John

We identified years of anomalously high and low discharge from the Fraser River and compared these years with indices of anomalously high and low production of Pacific salmon (Oncorhynchus spp.) and Pacific herring (Clupea pallasi). For chinook (O. tshawytscha) and coho salmon (O. kisutch), we found that brood years that went to sea in a year when the Fraser River discharge was very high compared with the previous year virtually never had an index of production that was higher than the previous year. Similarly, brood years that went to sea in a year when the Fraser River discharge was very low compared with the previous year almost never had an index of productivity that was lower than the previous year. The analysis identified a weaker association between extreme discharge anomalies and chum salmon (O. keta) production. A close association was not found between extreme discharge anomalies and pink salmon (O. gorbuscha), sockeye salmon (O. nerka), or herring production. The relationships identify a connection between annual fluctuations in river flow and production of some marine fishes and may be of use in forecasting abundance changes.


2019 ◽  
Vol 76 (6) ◽  
pp. 918-927 ◽  
Author(s):  
Boris Espinasse ◽  
Brian P.V. Hunt ◽  
Yago Doson Coll ◽  
Evgeny A. Pakhomov

The high seas phase of Pacific salmon life history remains particularly data-limited, and the potential implications of climate impacts on ocean productivity for salmon condition and reproductive success is poorly understood. We used carbon and nitrogen stable isotopes (SI) from salmon scales to reconstruct aspects of the marine environment experienced by Rivers Inlet sockeye salmon (Oncorhynchus nerka) over the last century (1915–2016). Time series of SI compositions of salmon scales showed a greater variability after 1950, probably linked to more dynamic high seas environmental conditions. However, climate indices (e.g., Pacific Decadal Oscillation, El Niño Southern Oscillation) did not explain the SI variability. We assessed the time series with respect to changes in food web dynamics, including shifting trophic baselines, changes in prey–salmon diet, and changes in salmon foraging location. A significant correlation (r = 0.53) between sea surface temperature and δ13C enabled us to define the area of potential salmon distribution in the open ocean for approximately 9 months prior to sampling. This method shows high potential for stock-specific high seas distribution mapping that could be combined with prey isotope values to inform stock-specific foraging experience.


2011 ◽  
Vol 68 (2) ◽  
pp. 250-259 ◽  
Author(s):  
Kimberly A. Hruska ◽  
Scott G. Hinch ◽  
David A. Patterson ◽  
Michael C. Healey

Some female Pacific salmon ( Oncorhynchus spp.) arrive at spawning grounds but fail to complete spawning prior to death. One hypothesis regarding egg retention is that some individuals do not have sufficient time on spawning grounds for successful completion of spawning. We investigated this hypothesis by quantifying the relationships among arrival timing, reproductive longevity, and egg retention in female sockeye salmon ( Oncorhynchus nerka ) from Weaver Creek Spawning Channel (British Columbia, Canada) in 2006. 250 females were tagged over three sampling periods and followed until death. Earlier-arriving females lived longer than later-arriving females (p < 0.001), but patterns of egg retention were not different across sampling dates (p > 0.40). Complete spawners tended to establish a redd sooner after arrival than incomplete spawners (p = 0.001); there was no relationship between spawning completion and reproductive maturity or fork length (p > 0.30). Consistent with the time limitation hypothesis, females retained a lower proportion of eggs with increasing reproductive longevity. Several long-lived females (>7 days) failed to spawn completely before death, indicating that time limitation was not a factor for spawning success in all females. Further research examining the role of individual-specific behavioural physiology on egg retention in sockeye salmon is needed.


2014 ◽  
Vol 496 ◽  
pp. 71-84 ◽  
Author(s):  
SM Wilson ◽  
SG Hinch ◽  
SM Drenner ◽  
EG Martins ◽  
NB Furey ◽  
...  

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