Key Hypotheses

The Marine Survival Project began with an appreciation for the complexity of our ecosystems: how multiple factors may be interacting and contributing to the fate of juvenile salmon and steelhead in the Salish Sea. To address this, we convened scientists from U.S. and Canada to develop a comprehensive, multi-disciplinary, and highly coordinated research program at an ecologically relevant scale: the entire Salish Sea.

The scientists concluded the key hypotheses are, in order:

  1. Early marine survival is determined by bottom-up ecological processes: weather, water conditions, and productivity that determine the food supply for salmon and result in variation in size and growth rate. Salmon may also compete among themselves or with other fishes for food.
  2. Early marine survival is determined by top-down ecological processes. Predation is likely the direct cause of mortality, but salmon may be affected by other biological factors (e.g., disease and contaminants), increasing their susceptibility to predation, directly killing them, or affecting their condition such that overall marine survival is reduced.
  3. Multiple factors may interact and have cumulative effects in determining early marine survival. These may be additive, synergistic, or dampening.

Full descriptions of the hypotheses and findings from the project are available in the Synthesis Report documents.

Download complete list of hypotheses