NMDS plot of fourth-root transformed catch per effort for fish species in the Sacramento-San Joaquin Delta.

<p>Arrows indicate general direction of increasing species abundance. Only species possessing correlation vectors with high R² (>0.4) and low p-value (<0.01) are shown. Grey shading indicates significant SIMPROF cluster based on 1,000 permutations. Significant results for Mann-Kendall trend test and Kendall rank correlation tests are shown (α = 0.05).