Can Changes in the Distribution of One Fish Lead to Irreparable Harm to a Culture?

Forage fishes are ecologically and economically important low trophic level species, and in recent years interest in their biology and management has intensified.   Pacific herring are emblematic of the management issues facing forage species—they are central components of the Northeast Pacific pelagic food web and support important commercial fisheries.  In addition, their importance to indigenous peoples have made them cultural keystone species. Herring are an archetypal forage fish; however, much more so than other forage fishes, they are at the foundation of cultural and social systems in the Northeastern Pacific.  With this socio-cultural centrality comes complexity for fisheries management.

Here, we report on our social-ecological research in Gwaii Haanas National Park Reserve and Haida Heritage Site.  Gwaii Haanas was established in 1988 to protect the natural and cultural resources of an archipelago of 138 islands, 130 km off the coast of northern British Columbia.  From mountain tops to the seafloor, Gwaii Haanas embraces interconnections between land, sea and people.  However, managing herring, simultaneously, for the diverse goals of the complete socio-ecological system requires new scientific approaches.  This is particularly true in systems prone to crossing tipping points-- when small shifts in human pressures or environmental conditions bring about large, abrupt changes.  Our research explores how marine species, and the human communities that depend upon them respond to a suite of pressures, and how we can best predict tipping points in the ecosystem.   To do this we are characterizing ecosystem state, testing hypothesis for what led to past ecosystem shifts, and evaluating future states and trade-offs associated with different management strategies.  

Our results suggest that the spatial structure of herring historically provided a  “portfolio effect”.  Like a stock portfolio, the ups and downs of individual stocks evened out to provide a stable “return” of herring for use by predators and people.  However, this portfolio effect is now gone, decreasing the resilience of herring to fishing, predation and climate change.  Our work also reveals that climate does impact herring, but its effect was historically weak. However, climate is very important for depleted stocks - in these stocks (most of them these days), the small effect of climate is enough to cause a population to grow or decline.  Thus, it appears fishing may amplify the importance of climate, putting both the ecosystem and cultures at risk.