issues and experts

Marine fish survival influenced by food supply, competition

December 02, 2015

Fluctuating food supplies and competition play an integral role in the survival of adult Pacific marine reef fish, new research has found. Daniel Okamoto, a postdoctoral scholar in SFU’s School of Resource and Environmental Management (REM), carried out an analysis of survival records for the black surfperch (Embiotoca jacksoni) while working on his PhD at the University of California, Santa Barbara. His team found the survival of adults from year to year was strongly linked to both the amount of prey available and the number of fish sharing that food.

“We found that the survival rate varies through time and is driven by local-scale processes of food variability and competition for that food supply,” said Okamoto, lead author of a paper published in the journal Ecology Letters. “That can have major implications for how we think about the impact of fishing.

“Our results demonstrate that mortality from fishing or other human activities can greatly amplify fluctuations in the number of fish in a population over time. This runs counter to all management and conservations goals for harvested species.”

Okamoto is working with REM professor Anne Salomon and is also affiliated with the Hakai Institute at SFU.

For more background see:

Daniel Okamoto, Faculty of Environment (in Florida until Dec. 16 but available by phone or Skype),