Interannual measures of nutritional stress during a marine heatwave (the Blob) differ between two North Pacific seabird species

Abstract

‘The Blob’, a mass of anomalously warm water in the Northeast Pacific Ocean peaking from 2014 to 2016, caused a decrease in primary productivity with cascading effects on the marine ecosystem. Among the more obvious manifestations of the event were seabird breeding failures and mass mortality events. Here, we used corticosterone in breast feathers (fCort), grown in the winter period during migration, as an indicator of nutritional stress to investigate the impact of the Blob on two sentinel Pacific auk species (family Alcidae). Feathers were collected from breeding females over 8 years from 2010 to 2017, encompassing the Blob period. Since Pacific auks replace body feathers at sea during the migratory period, measures of fCort provide an accumulated measure of nutritional stress or allostatic load during this time. Changes in diet were also measured using δ15N and δ13C values from feathers. Relative to years prior to the Blob, the primarily zooplanktivorous Cassin’s auklets (Ptychoramphus aleuticus) had elevated fCort in 2014–2017, which correlated with the occurrence of the Blob and a recovery period afterwards, with relatively stable feather isotope values. In contrast, generalist rhinoceros auklets (Cerorhinca monocerata) displayed stable fCort values across years and increased δ15N values during the Blob. As marine heatwaves increase in intensity and frequency due to climate change, this study provides insight into the variable response of Pacific auks to such phenomena and suggests a means for monitoring population-level responses to climatological variation.

Kelpwatch: A new visualization and analysis tool to explore kelp canopy dynamics reveals variable response to and recovery from marine heatwaves

“…During the summer of 2014, an unprecedented warm water temperature event spread across the Northeastern Pacific leading to negative impacts across both nearshore and pelagic ecosystems [ 43 , 57 , 58 ]. This marine heatwave, known as ‘The Blob’, was closely followed by a strong El Niño event in 2015 to 2016, contributing to an extended period of anonymously high ocean temperatures, low seawater nutrients, and low productivity throughout the region [ 59 ].…”

Kelpwatch: A new visualization and analysis tool to explore kelp canopy dynamics reveals variable response to and recovery from marine heatwaves

“…During the summer of 2014, an unprecedented warm water temperature event spread across the Northeastern Pacific leading to negative impacts across both nearshore and pelagic ecosystems [42,59,60]. This marine heatwave, known as 'The Blob', was closely followed by a strong El Niño event in 2015-2016, contributing to an extended period of anonymously high warm ocean temperatures, low seawater nutrients, and low productivity throughout the region [61].…”

Elevated Seawater Temperature and Infection with Neoparamoeba perurans Exacerbate Complex Gill Disease in Farmed Atlantic Salmon (Salmo salar) in British Columbia, Canada

“…Thus, our observations may reflect a role of elevated salinity in promoting parasite viability, as reported elsewhere [ 4 ], despite the apparent rarity of temperature conditions in BC waters conducive to the development of AGD. However, recent occurrences of seawater thermal anomalies in the northeast Pacific Ocean [ 46 , 47 ] have coincided with episodes of increased surface temperatures in coastal zones, along with associated multitrophic ecological impacts [ 48 , 49 , 50 ]. Given the detection of N. perurans in all years, all seasons and virtually all health management zones, any warming of the oceanographic climate along Canada’s west coast, will increase the risk for the emergence of widespread AGD in addition to other proliferative gill diseases among marine-farmed salmon in BC.…”