Brook trout impacts on Chinook salmon survival - original data

Levin et al. 2002 studied the impacts of brook trout introduced for sport fishing on native Chinook salmon. Whitlock & Shulter used a subset of these data as an example in their textbook Analysis of Biological Data.

brook_trout

Format

A data frame, including:

site

Name of study site or stream

trout.PRES.ABS

Are brook trout present in the stream or absent from it?

release

Number of Chinook salmon released

recap

Number of juvenile chinook salmon "recaptured" by detecting their PIT tag; this was not reported in original paper but was estimated using published survival rate. The survival rate estiamted using mark-recapture methods to account for detection probabilities.

surv

survival rate

Source

http://rspb.royalsocietypublishing.org/content/269/1501/1663.short

References

Levin et al. 2002. Non-indigenous brook trout and the demise of Pacific salmon: a forgotten threat? PRSB 269. DOI: 10.1098/rspb.2002.2063

Whitlock & Schulter. 2nd ed. Analysis of Biological Data.

Examples

## t-test on survival rate (ignores years)
t.test(surv ~ trout.PRES.ABS, data = brook_trout)
#> 
#> 	Welch Two Sample t-test
#> 
#> data:  surv by trout.PRES.ABS
#> t = 2.5974, df = 53.693, p-value = 0.0121
#> alternative hypothesis: true difference in means is not equal to 0
#> 95 percent confidence interval:
#>  0.0133692 0.1038965
#> sample estimates:
#>  mean in group abs mean in group pres 
#>          0.2208084          0.1621756 
#>