Table 3.
Date of sampling, species, sample sizes, mean fork lengths, mean δ 13C and mean δ 15N of fish and their trophic niche size (SEAc*; values obtained from data corrected for baseline variations across treatments.) and the extent to which B. barbus trophic niche overlaps (%) with other fish species in the community (Squalius cephalus and Leuciscus leuciscus), at (A) Chub stream and (B) Houghton stream. Error around the mean is standard error
| Date | Species | n | Mean length (mm) | Mean δ 13C (‰) | Mean δ 15N (‰) | SEAc (‰2)* | Overlap (%) |
|---|---|---|---|---|---|---|---|
| (A) | |||||||
| June 2014 | B. barbus | 7 | 209.9 ± 9.9 | −27.1 ± 0.3 | 16.2 ± 0.2 | 0.06 | |
| S. cephalus | 7 | 217.4 ± 5.7 | −26.4 ± 0.3 | 14.7 ± 0.3 | 0.11 | <0.01 | |
| L. leuciscus | 7 | 203.1 ± 2.6 | −28.1 ± 0.4 | 17.0 ± 0.3 | 0.24 | 0.40 | |
| June 2015 | B. barbus | 8 | 151.1 ± 6.5 | −22.3 ± 0.9 | 13.3 ± 0.8 | 1.66 | |
| S. cephalus | 8 | 153.6 ± 8.0 | −26.4 ± 0.4 | 16.6 ± 0.4 | 0.90 | 0 | |
| L. leuciscus | 8 | 152.6 ± 9.6 | −27.9 ± 0.2 | 17.1 ± 0.3 | 0.44 | 0 | |
| Sept 2015 | B. barbus | 4 | 212.0 ± 20.9 | −27.5 ± 0.1 | 18.6 ± 0.4 | 0.16 | |
| S. cephalus | 6 | 209.2 ± 15.3 | −26.9 ± 0.1 | 17.8 ± 0.5 | 0.30 | 0 | |
| L. leuciscus | 6 | 184.8 ± 6.6 | −28.2 ± 0.1 | 18.4 ± 0.3 | 0.31 | 0 | |
| (B) | |||||||
| June 2014 | B. barbus | 4 | 185.3 ± 9.2 | −28.2 ± 0.4 | 17.1 ± 0.5 | 0.12 | |
| S. cephalus | 6 | 194.8 ± 6.2 | −27.3 ± 1.0 | 16.0 ± 0.8 | 1.07 | 0.58 | |
| L. leuciscus | 6 | 191.7 ± 3.9 | −28.7 ± 0.1 | 17.9 ± 0.1 | 0.05 | 0.17 | |
| June 2015 | B. barbus | 6 | 159.0 ± 8.8 | −22.8 ± 0.3 | 13.4 ± 0.4 | 0.77 | |
| S. cephalus | 5 | 198.4 ± 23.7 | −27.5 ± 0.2 | 17.7 ± 0.3 | 0.28 | 0 | |
| L. leuciscus | 6 | 161.7 ± 15.1 | −28.4 ± 0.5 | 17.8 ± 0.1 | 0.20 | 0 | |