Highly valued, hunted, controlled and traded by indigenous people for at least 12,000 years, sea otters and humans along North America's northwest coast share a deep history. This book chapter synthesizes archaeological evidence, historical records, traditional knowledge and contemporary ecological data to illuminate how coastal First Nations used, managed and conserved sea otters and our shared ocean home. (Read the book chapter here)
Through the lens of Western science and traditional Native knowledge, art and photography the authors uncover the ecological, social and economic causes of coastal ecosystem change on Alaska’s Kenai Peninsula. The reader is offered a rare opportunity to share experiences, perspectives and knowledge of Sugpiaq Elders and village residents whose lives and intuitions are shaped by the rhythms of the sea. This collaboration illuminates the resilience and limits of marine ecosystems and the vast archive of knowledge and expertise held by different cultures. (Read the book here)
Sunflower stars enhance the resilience of kelp forests by eating small and medium sea urchins left uneaten by sea otters. When sunflower star populations collapsed due to an outbreak of Wasting Disease, there was a 30% decline in the density of kelp forests on the central coast of BC. (Read the public summary here) (Read full text paper here)
In a worldwide analysis, we found that kelp in 38 % of regions showed declines, 27 % of regions had increases, and 35 % did not net change. In contrast to the dominant effect of global drivers affecting coral reefs and eelgrass, kelp forests appear to be more influenced by local stressors. This highlights the resilience of kelp forests and the opportunity for managing them on a local scale. (Read the full text paper here)
Size-selective predation by sea otters affects sea urchin size structure which then influences urchin per capita grazing rates. Smaller urchins each less kelp, which reduces their overall impact on standing densities of kelp. (Read the full text paper here)
While abalone numbers can be reduced by up to 16x with the recovery of sea otters, more of them tend to hide and exist at deeper depths, in part because of the expansion of kelp forests.
Small-scale harvest of the highly productive giant kelp, Macrocystis, has minimal effects on kelp biomass and recovery, and abundances of reef associated fish, yet sites with warmer seawater temperatures recover slower after being harvested. These results facilitate our ability to navigate the trade-offs between conservation, food security and poverty alleviation within the context of climate change. (Read the full text paper here)
Ancient clam gardens - intertidal rock-walled terraces constructed by humans during the late Holocene on the Northwest Coast of North America - can double clam production relative to unmodified clam beaches. (Read the full text paper here)
Evidence form BC’s central coast shows clam gardens are just one innovation embedded within a broad portfolio of traditional Indigenous management and stewardship practices that likely conferred resilience to coupled human-ocean systems in deep time. (Read the full text paper here)
Switches between kelp-forests and barren rocky reefs are a classic example of a regime shift. This worldwide analysis shows that tipping points between these two states can differ by an order of magnitude in urchin biomass (ie. kelp forest collapse is much easier than kelp forest recovery). This is a management concern as recovery of desirable kelp beds requires reducing sea urchin grazers to levels well below the initial number that caused the system to collapse. (Read full text paper here)
Only by weaving together ecological evidence, traditional knowledge and archeological data, can we learn what is driving declines of a culturally-important intertidal chiton in Alaska. We show that 1) spatial concentration in harvest effort through time, 2) increased harvest efficiency, 3) recovery of sea otters, and 4) serial depletion of alternative shellfish prey, all led to intensified predation on chitons by humans and sea otters - and thus its localized decline. (Read full text paper here)
Researchers measured the carbon and nitrogen isotopes within the bones of rockfish found in late-Holocene archaeological sites on Haida Gwaii as evidence to suggest that 1) rockfish in different habitats had different isotopic signatures, 2) Haida targeted rockfish from mostly nearshore waters, and 3) local kelp sources likely declined following the extirpation of sea otters during the maritime fur trade. (Read full text paper here).