Fish Community Responses to Intertidal Shellfish Aquaculture

Shellfish aquaculture is a dominant feature of Baynes Sound, British Columbia. Upwards of 90% of an available 1,530 hecatares of intertidal habitat falls under commercial aquaculture tenure. Concurrently, the area holds tremendous ecological significance, providing some of the most critical waterbird, salmon, and herring habitat in all of North America. This project assesses nearshore fish community responses to habitat modifications associated with the shellfish aquaculture industry, such as the addition of fences, anti-predator nets, and unnaturally high densities of bivalves. In the summer of 2014, nearshore fish were sampled at three paired aquaculture/non-aquaculture beaches in Baynes Sound. Fish were collected over 24-hour periods using modified fyke nets. All fish were identified to species and small subsets were sampled for body size and diet. Fish density was higher at aquaculture sites, but diversity was quite variable among sampling locations. To investigate the ecological consequences of variable fish diversity, functional diversity will be determined. This metric can be used as a proxy for the level of ecosystem function. Findings will indicate if shellfish aquaculture habitat modifications are significant drivers of intertidal habitat value and fish community dynamics.