Niche variation in burying beetles (Nicrophorus spp.) associated with marine and terrestrial carrion

2007 ◽  
Vol 85 (3) ◽  
pp. 437-442 ◽  
Author(s):  
M.D. Hocking ◽  
C.T. Darimont ◽  
K.S. Christie ◽  
T.E. Reimchen
Keyword(s):  
Pink Salmon ◽  
Isotope Analysis ◽  
Odocoileus Hemionus ◽  
Oncorhynchus Gorbuscha ◽  
Oncorhynchus Keta ◽  
Burying Beetle ◽  
Catharus Ustulatus ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Niche Variation ◽  
Catharus Guttatus

Ecological opportunity can influence niche variation within and among species. Forensic reconstruction of diet has been made possible with the now widespread use of stable isotope analysis, although it has not to date been applied to communities based on carrion resources. Within a salmon-bearing watershed in coastal British Columbia, we reconstructed the dietary niches of two burying beetle species (Silphidae: Nicrophorus investigator Zetterstedt, 1824 and Nicrophorus defodiens Mannerheim, 1846) using stable isotopes (δ15N, δ13C). We separated available carrion sources for beetles of chum salmon ( Oncorhynchus keta (Walbaum, 1792)) and pink salmon ( Oncorhynchus gorbuscha (Walbaum, 1792)), the shrew Sorex monticolus Merriam, 1890, songbirds ( Troglodytes troglodytes (L., 1758), Catharus ustulatus (Nuttall, 1840), Catharus guttatus (Pallas, 1811)), and black-tailed deer ( Odocoileus hemionus hemionus (Rafinesque, 1817)) into three isotopically homogeneous subsets: (1) salmon, (2) shrews and songbirds, and (3) deer. The majority (86.5%) of N. investigator individuals were raised on a diet of salmon carrion, while 100% of N. defodiens individuals had a larval diet consistent with carrion from shrews and songbirds. Larger isotopic variance predicts wider dietary niches, which may be useful for testing functional ecological variation within and among species.

Consumption and distribution of salmon (Oncorhynchus spp.) nutrients and energy by terrestrial flies

2006 ◽  
Vol 63 (9) ◽  
pp. 2076-2086 ◽  
Author(s):  
Morgan D Hocking ◽  
Thomas E Reimchen
Keyword(s):  
Chum Salmon ◽  
Pacific Salmon ◽  
Pink Salmon ◽  
Isotope Analysis ◽  
Terrestrial Ecosystems ◽  
Oncorhynchus Gorbuscha ◽  
Oncorhynchus Keta ◽  
The North ◽  
Terrestrial Habitats ◽  
Salmon Carcasses

Anadromous Pacific salmon (Oncorhynchus spp.) subsidize terrestrial food webs with their nutrients and carcasses, a process driven largely by selective foraging by bears (Ursus spp.). We quantify wildlife transfer of salmon carcasses to riparian zones on two watersheds in coastal British Columbia and estimate total terrestrial fly production from remnant carcasses. Large-bodied chum salmon (Oncorhynchus keta) were transferred into the forest at a greater rate than were pink salmon (Oncorhynchus gorbuscha) (chum salmon mass = 6089–11 031 kg, 16%–48% of salmon run; pink salmon mass = 2266–2808 kg, 4%–6% of salmon run). Blow flies (genus Calliphora) and other Diptera dominated colonization (>90% of salmon carcasses). Between the two watersheds, 196 and 265 g of Calliphora larvae per metre of spawning length (4 and 7 million larvae for whole watersheds) were generated from salmon carcass transfer. Stable isotope analysis of δ15N and δ13C of spring-emerging adult Calliphora revealed that >80% of individuals had salmon-based signatures. Flies are a dominant consumer and vector of salmon nutrients in terrestrial habitats and supplement the diet of at least 16 vertebrate and 22 invertebrate species. Anticipated further declines of salmon in the North Pacific can be expected to further erode the complex associations coupling marine and terrestrial ecosystems.

Effects of salmon on the diet and condition of stream-resident sculpins

2014 ◽  
Vol 71 (4) ◽  
pp. 521-532 ◽  
Author(s):  
Noel R. Swain ◽  
Morgan D. Hocking ◽  
Jennifer N. Harding ◽  
John D. Reynolds
Keyword(s):  
Chum Salmon ◽  
Pacific Salmon ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Oncorhynchus Keta ◽  
Nitrogen Stable Isotope ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Carbon And Nitrogen ◽  
Stable Isotope Signatures ◽  
The Individual

Pacific salmon (Oncorhynchus spp.) can subsidize freshwater food webs with marine-derived nutrients from their eggs, juveniles, and carcasses. However, trophic interactions between spawning salmon and freshwater fish across natural gradients in salmon subsidies remain unclear. We tested how salmon affected the diets and condition of two dominant freshwater consumers — prickly and coastrange sculpins (Cottus asper and Cottus aleuticus, respectively) — across a wide gradient of pink salmon (Oncorhynchus gorbuscha) and chum salmon (Oncorhynchus keta) biomass from 33 streams in the Great Bear Rainforest of British Columbia, Canada. Sculpin diets shifted from invertebrates and juvenile salmonids to salmon eggs when salmon arrived in autumn, with salmon-derived nutrient contributions to diets and sculpin condition increasing with increasing biomass of spawning salmon among streams. Season, habitat, and individual sculpin body size and species also mediated the effects of salmon on sculpin diet as inferred from their carbon and nitrogen stable isotope signatures. This study shows the timing and pathways by which spawning salmon influence the diets and condition of freshwater consumers, and some of the individual and environmental factors that can regulate uptake of salmon nutrients in streams, thus informing ecosystem-based management.

Developmental stability and heterozygosity in chum (Oncorhynchus keta) and pink (Oncorhynchus gorbuscha) salmon

1987 ◽  
Vol 65 (7) ◽  
pp. 1823-1826 ◽  
Author(s):  
T. D. Beacham ◽  
R. E. Withler
Keyword(s):  
Fluctuating Asymmetry ◽  
Chum Salmon ◽  
Pink Salmon ◽  
Morphological Characters ◽  
Developmental Stability ◽  
Oncorhynchus Gorbuscha ◽  
Oncorhynchus Keta ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Gill Raker ◽  
Fin Length

We compared developmental stability as measured by fluctuating asymmetry within individual adults for gill raker and branchiostegal ray number and pectoral and pelvic fin length for three populations of chum salmon (Oncorhynchus keta) and one of pink salmon (Oncorhynchus gorbuscha). There was no association between individual heterozygosity calculated at 10 electrophoretic loci for chum salmon and 13 loci for pink salmon and magnitude of fluctuating asymmetry for the four morphological characters examined. More heterozygous individuals were not less asymmetrical, and thus our results provide no evidence to suggest that increased heterozygosity results in an increased canalization of morphology during development and growth.

The relative importance of prey density and social dominance in determining energy intake by bears feeding on Pacific salmon

2004 ◽  
Vol 82 (1) ◽  
pp. 75-85 ◽  
Author(s):  
S M Gende ◽  
T P Quinn
Keyword(s):  
Energy Intake ◽  
Social Dominance ◽  
Ursus Arctos ◽  
Pacific Salmon ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Oncorhynchus Keta ◽  
Small Stream ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Coastal Streams

We quantified foraging behavior of brown bears (Ursus arctos) feeding on adult chum (Oncorhynchus keta) and pink salmon (Oncorhynchus gorbuscha) at three small coastal streams in southeastern Alaska from streamside tree stands. These observations revealed that social dominance was much more important in determining intake rates among bears than salmon densities. Each small stream supported one large, socially dominant bear that directly displaced other bears in aggressive encounters or was avoided in "passive deferrals". Although the number of fish killed per foraging bout was positively correlated with salmon density, energy intake was determined primarily by foraging effort, as dominant bears visited the stream more often and foraged for longer periods than subdominant bears. Capture efficiency (fish captured per minute searching) was highly variable and increased only marginally with salmon density and among social ranks. Subdominant bears were more vigilant, used a smaller fraction of each stream, and carried salmon much farther into the forest prior to consumption, presumably to minimize interactions with other bears. Social dominance may play an important role in regulating reproductive success when salmon densities are low and may have important implications for managers in bear-viewing areas.

Supplementary Checks on the Scales of Pink Salmon (Oncorhynchus gorbuscha) and Chum Salmon (O. keta)

1965 ◽  
Vol 22 (6) ◽  
pp. 1477-1489 ◽  
Author(s):  
H. T. Bilton ◽  
W. E. Ricker
Keyword(s):  
British Columbia ◽  
Chum Salmon ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Commercial Fisheries ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Clear Cut ◽  
Second Year Of Life ◽  
Second Year ◽  
Similar Incidence

Among 159 central British Columbia pink salmon that had been marked by removal of two fins as fry and had been recovered in commercial fisheries after one winter in the sea, the scales of about one-third showed a supplementary or "false" check near the centre of the scale, in addition to the single clear-cut annulus. This evidence from fish of known age confirms the prevailing opinion that such extra checks do not represent annuli, hence that the fish bearing them are in their second year of life rather than their third. Unmarked pink salmon from the same area, and some from southern British Columbia, had a generally similar incidence of supplementary checks. In both marked and unmarked fish the supplementary checks varied in distinctness from faint to quite clear. In a sample of scales of 14 double-fin marked chum salmon which were known to be in their 4th year, all fish had the expected 3 annuli, and 12 fish had a supplementary check inside the first annulus.

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