On the west coast of North America, bears are major consumers of salmon and are important agents of salmon nutrient transfer from aquatic to terrestrial habitats. The salmon spawning period is critical to coastal bears as they receive most (33-94%) of their yearly protein from salmon, and this positively effects their body size, population productivity, mean litter size, and population density.

Reimchen observed extensive nocturnal foraging by bears in salmon streams on the southern end of Haida Gwaii (Queen Charlotte Islands) and on average, bears were more successful at salmon capture during darkness than during daylight. My research interests focus on the behavioural ecology of mainland coastal black bears and grizzly bears during daylight and darkness and how the foraging behaviour contributes to the nutrient flow dynamics inherent to these salmon systems. At present, I have found that these bears also fish throughout the day and night, and have slightly higher capture success during darkness than in daylight. 

 

We suggest that darkness is a preferred foraging period as a consequence of increased access to high quality feeding areas, reduced evasive tendencies of the salmon and high capture efficiencies. Bears appear to exploit the salmon spawning period to maximize consumption rates of an ephemeral resource.