Patterns of fish biodiversity in the Salish Sea

Background/Question/Methods

Biogeographic and temporal patterns in community assembly can provide insights regarding the processes driving rocky reef fish diversity in the Salish Sea. However, relatively few sets of broadly distributed observations on marine fish assemblages exist in Salish Sea. The Reef Environmental Education Foundation (REEF) Survey Project was launched in the Pacific Northwest in 1998. REEF participants collect distribution and abundance data on all marine fishes and a sub-set of invertebrates using a standardized, non-point visual method. To date, over 700 divers have conducted 12,307 surveys at over 800 sites in Washington and British Columbia. Using the REEF dataset, we examine patterns of species richness, co-occurrence, and abundance of nearshore rocky reef fishes throughout the Salish Sea. We explore community patterns in observational data from an array of sites using multivariate techniques. To yield inference regarding the relative roles of time and space in community variability, we formally test explanatory factors using PERMANOVA and PERMDISP. 

Results/Conclusions

We evaluated the fish communities of the Salish Sea by three factors – geography, eco-regions, and invertebrate communities. The strongest patterns were seen in the eco-regional analysis. Fish communities of the outer Washington coast and the San Juan/Gulf Islands were more similar, as were those found inside the Puget Sound and Hood Canal. Individual species identified to be driving these patterns included several species of rockfish, flatfish, and perch.  Latitude gradients along the Salish Sea also appear to be driving patterns of fish diversity. Results demonstrate how the REEF regional monitoring effort can be used to generate multivariate ecosystem status metrics for the Salish Sea.