3.3 Correlations between prey items and relative specialization
Correlation analysis between diet proportions of prey orders and\(\text{PS}_{i}\) revealed that eight orders out of twelve showed significant correlations (alpha = 0.0038, Bonferroni correction, Table 3). Adult Salmoniformes, a largely pelagic group, were correlated with a generalist diet (rho = 0.27, p < 0.001) while juvenile Salmoniformes showed no significant correlation. Clupeiformes, another largely pelagic group, correlated with a generalist diet as well (rho = 0.24, p < 0.001). Conversely, Pleuronectiformes, a demersal and benthic group, correlated with a specialist diet (rho = -0.38, p < 0.001). Further, Gadiformes, which has both pelagic and demersal representatives, showed no correlation (rho = -0.04, p = 0.38).
Correlations performed with just data from female scat showed similar patterns. All orders of prey showed the same relationship with\(\text{PS}_{i}\), or were no longer significant, such as Salmoniformes (Table 4). The only new order to show significance was Batrachoidiformes. Correlations performed with only male scat once again showed similar patterns. New orders to show significance were Chimaeriformes (with a specialist diet) and adult Salmoniformes (with a generalist diet) (Table 5).
The correlation between proportion of benthic species in each scat and\(\text{PS}_{i}\) suggested a positive relationship between the amount of benthic species consumed and the level of relative specialization (rho = -0.384, p > 0.001). A similar relationship was observed when the female and male data sets were examined separately (rho = -0.407, p > 0.001; rho = -0.35, p > 0.001 respectively).