Unusual mortality of Tufted puffins (Fratercula cirrhata) in the eastern Bering Sea

Abstract

Mass mortality events are increasing in frequency and magnitude, potentially linked with ongoing climate change. In October 2016 through January 2017, St. Paul Island, Bering Sea, Alaska, experienced a mortality event of alcids (family: Alcidae), with over 350 carcasses recovered. Almost three-quarters of the carcasses were unscavenged, a rate much higher than in baseline surveys (17%), suggesting ongoing deposition and elevated mortality around St Paul over a 2–3 month period. Based on the observation that carcasses were not observed on the neighboring island of St. George, we bounded the at-sea distribution of moribund birds, and estimated all species mortality at 3,150 to 8,800 birds. The event was particularly anomalous given the late fall/winter timing when low numbers of beached birds are typical. In addition, the predominance of Tufted puffins ( Fratercula cirrhata , 79% of carcass finds) and Crested auklets ( Aethia cristatella , 11% of carcass finds) was unusual, as these species are nearly absent from long-term baseline surveys. Collected specimens were severely emaciated, suggesting starvation as the ultimate cause of mortality. The majority (95%, N = 245) of Tufted puffins were adults regrowing flight feathers, indicating a potential contribution of molt stress. Immediately prior to this event, shifts in zooplankton community composition and in forage fish distribution and energy density were documented in the eastern Bering Sea following a period of elevated sea surface temperatures, evidence cumulatively suggestive of a bottom-up shift in seabird prey availability. We posit that shifts in prey composition and/or distribution, combined with the onset of molt, resulted in this mortality event.

Responses of the Northern Bering Sea and Southeastern Bering Sea Pelagic Ecosystems Following Record‐Breaking Low Winter Sea Ice

“…Murres comprised the majority of dead or sick birds that washed up on shores around Norton Sound and on St. Lawrence Island. Seabird die‐offs occurred throughout the SEBS but were most prevalent in the NBS in 2017 and 2018, affecting primarily shearwaters and fulmars in summer and fall of 2017 and common and thick‐billed murres in spring and early summer of 2018 (Jones & Parrish, ). Mass seabird mortality events have generally coincided with anomalously warm oceans (Jones et al, ) with nearly all birds showing severe emaciation.…”

Insights about Diversity of Tetrabothriidae (Eucestoda) among Holarctic Alcidae (Charadriiformes): What Is Tetrabothrius jagerskioeldi jagerskioeldi? ?

“…A series of mortality events among different species of seabirds (alcids, larids, and procellariiforms) has been documented across the Northeastern Pacific (Gulf of Alaska) and into the Bering Sea over the past 2-3 decades (reviewed in Jones et al, 2019). A broad scale and ongoing shift in ecosystem structure has been linked to recurring episodes of elevated sea surface temperatures at high latitudes (Jones et al, 2019;IPCC, 2019).…”

“…A series of mortality events among different species of seabirds (alcids, larids, and procellariiforms) has been documented across the Northeastern Pacific (Gulf of Alaska) and into the Bering Sea over the past 2-3 decades (reviewed in Jones et al, 2019). A broad scale and ongoing shift in ecosystem structure has been linked to recurring episodes of elevated sea surface temperatures at high latitudes (Jones et al, 2019;IPCC, 2019). Signatures of oceanic warming are apparent across scales and involve: (1) outcomes of incremental climate warming over time; (2) episodic oscillations between warm and cold ocean regimes defined by such ocean-atmosphere processes as El Niño Southern Oscillation and the Pacific Decadal Oscillation (Chavez et al, 2003;Springer et al, 2007;Sydeman et al, 2015); and (3) transient and spatially persistent events of extreme atmospheric and sea surface temperatures manifested as marine heat waves (Di Lorenzo et al, 2016;reviewed in Jones et al, 2018reviewed in Jones et al, , 2019.…”

“…Perturbations in ecosystem structure and dynamics are manifested in mortality events for zooplanktivorous and piscivorous seabirds through modified phenology for prey, shifts in abundance, and altered patterns of diversity that influence the availability of suitable food resources (e.g., Baduini et al, 2001;Napp and Hunt, 2001;Jones et al, 2019). The greatest sustained or persistent marine heat wave documented to date for the Gulf of Alaska and Bering Sea, during 2016-2017, resulted in extensive breeding failures and an estimated mortality event for over 1 million common murres which represent the dominant marine avian piscivores in these oceanic systems (Piatt et al, 2020).…”

“…Archives of specimens and information are the cornerstones to reveal ecological connectivity and perturbation emerging from the acceleration of climate forcing, other anthropogenic factors, and natural events. Parasite faunal baselines will contribute to identifying and understanding the scope of ecological perturbation, including shifting production cycles, trophic dynamics, and mortality events emerging across the Bering Sea ecosystem and broader North Pacific basin (e.g., Jones et al, 2019).…”