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Juvenile salmon usage of the Skeena River estuary.

Carr-Harris C, Gottesfeld AS, Moore JW - PLoS ONE (2015)

Bottom Line: We captured six species of juvenile anadromous salmonids throughout the estuary in both years, and found that areas proposed for development support some of the highest abundances of some species of salmon.These fish support extensive commercial, recreational, and First Nations fisheries throughout the Skeena River and beyond.Our results demonstrate that estuary habitats integrate species and population diversity of salmon, and that if proposed development negatively affects the salmon populations that use the estuary, then numerous fisheries would also be negatively affected.

View Article: PubMed Central - PubMed

Affiliation: Skeena Fisheries Commission, 3135 Barnes Crescent, Kispiox, British Columbia, Canada; Earth to Ocean Research Group, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada.

ABSTRACT
Migratory salmon transit estuary habitats on their way out to the ocean but this phase of their life cycle is more poorly understood than other phases. The estuaries of large river systems in particular may support many populations and several species of salmon that originate from throughout the upstream river. The Skeena River of British Columbia, Canada, is a large river system with high salmon population- and species-level diversity. The estuary of the Skeena River is under pressure from industrial development, with two gas liquefaction terminals and a potash loading facility in various stages of environmental review processes, providing motivation for understanding the usage of the estuary by juvenile salmon. We conducted a juvenile salmonid sampling program throughout the Skeena River estuary in 2007 and 2013 to investigate the spatial and temporal distribution of different species and populations of salmon. We captured six species of juvenile anadromous salmonids throughout the estuary in both years, and found that areas proposed for development support some of the highest abundances of some species of salmon. Specifically, the highest abundances of sockeye (both years), Chinook in 2007, and coho salmon in 2013 were captured in areas proposed for development. For example, juvenile sockeye salmon were 2-8 times more abundant in the proposed development areas. Genetic stock assignment demonstrated that the Chinook salmon and most of the sockeye salmon that were captured originated from throughout the Skeena watershed, while some sockeye salmon came from the Nass, Stikine, Southeast Alaska, and coastal systems on the northern and central coasts of British Columbia. These fish support extensive commercial, recreational, and First Nations fisheries throughout the Skeena River and beyond. Our results demonstrate that estuary habitats integrate species and population diversity of salmon, and that if proposed development negatively affects the salmon populations that use the estuary, then numerous fisheries would also be negatively affected.

No MeSH data available.


Related in: MedlinePlus

GAM coefficients for parametric region covariates for sockeye (a), coho (b) and Chinook (c) salmon.Coefficients are related to the (log) mean normalized catch per trawl set for each region in 2007 (black) and 2013 (grey ). Thus, a value of 0 indicates a mean normalized trawl catch of 1. Error bars indicate ± 2 standard errors.
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pone.0118988.g006: GAM coefficients for parametric region covariates for sockeye (a), coho (b) and Chinook (c) salmon.Coefficients are related to the (log) mean normalized catch per trawl set for each region in 2007 (black) and 2013 (grey ). Thus, a value of 0 indicates a mean normalized trawl catch of 1. Error bars indicate ± 2 standard errors.

Mentions: Our observations of the relative abundances of the different salmon species among the different regions were supported by general additive modeling which accounted for seasonal variation. Specifically, the GAMs statistically indicated that juvenile sockeye salmon were most abundant in the IN region in both years, and juvenile coho salmon were most abundant in the IN region in 2013 (Fig. 6). The β coefficient for sockeye in the IN region was 1.74 ± 0.36 (p < 0.0001, this and the following represent the best estimate of the coefficient ± 1 SE and P-value of the coefficient) in 2007 and 1.56 ± 0.34 (p < 0.0001) in 2013 (Fig. 6). The predicted abundances for sockeye in the IN region were 2–8 x higher than in the other regions in both years. For example, the back transformed predicted abundances of sockeye for May 28 were 24 sockeye (per 20 minute set) in the IN, 11 in the IS, and 7 in the OS region in 2013, and 27 in the IN, 13 in the IS, 9 in the OS, 3 in the MID and 4 in the ON in 2007. The β coefficients for coho salmon in the IN region were 0.63 ± 0.28 (p = 0.0262) in 2007 and 0.45 ± 0.19 (p = 0.022) in 2013 (Fig. 6). The predicted abundances of coho were 2–7 x higher in the IN than in other regions in 2013, and 2–7 x higher in the IN and MID regions than in other regions in 2007. Chinook salmon appeared to be most abundant in the IN region in 2007 and in the IS region in 2013, however neither of these values were significant (p > 0.05). The delta-AIC score comparing each species-year model to an analogous version that excluded region was greater than 2, thus demonstrating support for including region for all year-species combinations except Chinook salmon in 2013. Because we sampled the top 4.5 meters of the water column over sites of varying depth, the juvenile salmon abundances are representative only of the surface layer of each region—this surface layer is where juvenile salmon are known to feed during the daylight hours in which we sampled [14,50].


Juvenile salmon usage of the Skeena River estuary.

Carr-Harris C, Gottesfeld AS, Moore JW - PLoS ONE (2015)

GAM coefficients for parametric region covariates for sockeye (a), coho (b) and Chinook (c) salmon.Coefficients are related to the (log) mean normalized catch per trawl set for each region in 2007 (black) and 2013 (grey ). Thus, a value of 0 indicates a mean normalized trawl catch of 1. Error bars indicate ± 2 standard errors.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4352006&req=5

pone.0118988.g006: GAM coefficients for parametric region covariates for sockeye (a), coho (b) and Chinook (c) salmon.Coefficients are related to the (log) mean normalized catch per trawl set for each region in 2007 (black) and 2013 (grey ). Thus, a value of 0 indicates a mean normalized trawl catch of 1. Error bars indicate ± 2 standard errors.
Mentions: Our observations of the relative abundances of the different salmon species among the different regions were supported by general additive modeling which accounted for seasonal variation. Specifically, the GAMs statistically indicated that juvenile sockeye salmon were most abundant in the IN region in both years, and juvenile coho salmon were most abundant in the IN region in 2013 (Fig. 6). The β coefficient for sockeye in the IN region was 1.74 ± 0.36 (p < 0.0001, this and the following represent the best estimate of the coefficient ± 1 SE and P-value of the coefficient) in 2007 and 1.56 ± 0.34 (p < 0.0001) in 2013 (Fig. 6). The predicted abundances for sockeye in the IN region were 2–8 x higher than in the other regions in both years. For example, the back transformed predicted abundances of sockeye for May 28 were 24 sockeye (per 20 minute set) in the IN, 11 in the IS, and 7 in the OS region in 2013, and 27 in the IN, 13 in the IS, 9 in the OS, 3 in the MID and 4 in the ON in 2007. The β coefficients for coho salmon in the IN region were 0.63 ± 0.28 (p = 0.0262) in 2007 and 0.45 ± 0.19 (p = 0.022) in 2013 (Fig. 6). The predicted abundances of coho were 2–7 x higher in the IN than in other regions in 2013, and 2–7 x higher in the IN and MID regions than in other regions in 2007. Chinook salmon appeared to be most abundant in the IN region in 2007 and in the IS region in 2013, however neither of these values were significant (p > 0.05). The delta-AIC score comparing each species-year model to an analogous version that excluded region was greater than 2, thus demonstrating support for including region for all year-species combinations except Chinook salmon in 2013. Because we sampled the top 4.5 meters of the water column over sites of varying depth, the juvenile salmon abundances are representative only of the surface layer of each region—this surface layer is where juvenile salmon are known to feed during the daylight hours in which we sampled [14,50].

Bottom Line: We captured six species of juvenile anadromous salmonids throughout the estuary in both years, and found that areas proposed for development support some of the highest abundances of some species of salmon.These fish support extensive commercial, recreational, and First Nations fisheries throughout the Skeena River and beyond.Our results demonstrate that estuary habitats integrate species and population diversity of salmon, and that if proposed development negatively affects the salmon populations that use the estuary, then numerous fisheries would also be negatively affected.

View Article: PubMed Central - PubMed

Affiliation: Skeena Fisheries Commission, 3135 Barnes Crescent, Kispiox, British Columbia, Canada; Earth to Ocean Research Group, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia, Canada.

ABSTRACT
Migratory salmon transit estuary habitats on their way out to the ocean but this phase of their life cycle is more poorly understood than other phases. The estuaries of large river systems in particular may support many populations and several species of salmon that originate from throughout the upstream river. The Skeena River of British Columbia, Canada, is a large river system with high salmon population- and species-level diversity. The estuary of the Skeena River is under pressure from industrial development, with two gas liquefaction terminals and a potash loading facility in various stages of environmental review processes, providing motivation for understanding the usage of the estuary by juvenile salmon. We conducted a juvenile salmonid sampling program throughout the Skeena River estuary in 2007 and 2013 to investigate the spatial and temporal distribution of different species and populations of salmon. We captured six species of juvenile anadromous salmonids throughout the estuary in both years, and found that areas proposed for development support some of the highest abundances of some species of salmon. Specifically, the highest abundances of sockeye (both years), Chinook in 2007, and coho salmon in 2013 were captured in areas proposed for development. For example, juvenile sockeye salmon were 2-8 times more abundant in the proposed development areas. Genetic stock assignment demonstrated that the Chinook salmon and most of the sockeye salmon that were captured originated from throughout the Skeena watershed, while some sockeye salmon came from the Nass, Stikine, Southeast Alaska, and coastal systems on the northern and central coasts of British Columbia. These fish support extensive commercial, recreational, and First Nations fisheries throughout the Skeena River and beyond. Our results demonstrate that estuary habitats integrate species and population diversity of salmon, and that if proposed development negatively affects the salmon populations that use the estuary, then numerous fisheries would also be negatively affected.

No MeSH data available.


Related in: MedlinePlus