Bear and salmon research in Heiltsuk Territory

Grizzly bear (Ursus arctos horribilis), fishing for salmon (Oncorhynchus sp.), coastal British Columbia.

This progress report provides a 2013 update for the Salmon Carnivore project – a study that looks at the relationship between bear health and salmon abundance – being undertake with the Heiltsuk in their traditional territory of BC’s Great Bear Rainforest.

Download 2013 Salmon Carnivore Project Update

Three seasons of bear research-cover

Important findings in this report include:

  •  Cortisol, an important hormone associated with general long-term stress levels, decreased as salmon consumption increased in grizzly bears, suggesting stress from poor salmon years was physiological and directly related to limitation of a critical food source (pg 12)
  • In black bears, cortisol was more related to total salmon availability (amount of salmon in the area streams, as opposed to salmon actually eaten), suggesting competition among bears over poor salmon returns might be causing greater stress than starvation (pg 12)
  • In both grizzlies and black bears, testosterone, an important hormone related to aggression and competition, decreased in years with high salmon returns, suggesting that these years corresponded with less competition among bears. (pg 12)
  • Our analyses compared the distribution of government-modeled spring habitat across the territory to distribution and relative abundance of grizzly bears detected from our field work. While number of detected grizzlies and modeled habitat suitability are different metrics, the government’s estimates of grizzly populations are based on modeled habitat suitability (pg 10) … Some important discrepancies were noted. Of highest concern, government models only predicted medium densities of high quality bear habitat in the Koeye/Nootum landscape unit, whereas our study has detected a high density of bears (pg 10).

 

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