Biogeography of pelagic food webs in the North Pacific

Abstract

The tufted puffin (Fratercula cirrhata) is a generalist seabird that breeds throughout the North Pacific and eats more than 75 different prey species. Using puffins as samplers, we characterized the geographic variability in pelagic food webs across the subarctic North Pacific from the composition of ~10,000 tufted puffin meals (~56,000 prey items) collected at 35 colonies in the Gulf of Alaska (GoA) and Aleutian Archipelago. Cluster analysis of diet species composition suggested three distinct forage fish communities: (i) in the northern GoA, multiple age‐classes of coastal and shelf residents such as capelin, sand lance and herring dominated the food web, (ii) in the western GoA to eastern Aleutians, the shelf community was dominated by transient age‐0 walleye pollock, and (iii) in the western Aleutians, shelf‐edge and mesopelagic forage species such as squid, lanternfish, and Atka mackerel were prevalent. Geographic patterns of abundance of capelin and sand lance in tufted puffin diets were corroborated by independent research fisheries and diets of piscivorous fish, indicating that puffin diets reflect the local abundance of forage species, not just selection of favored species. Generalized additive models showed that habitat characteristics predict, in a non‐linear fashion, forage species distribution and abundance across two large marine ecosystems. We conclude that major biogeographic patterns in forage fish distribution follow gradients in key habitat features, and puffin diets reflect those patterns.

The role of sand lances (Ammodytes sp.) in the Northwest Atlantic Ecosystem: A synthesis of current knowledge with implications for conservation and management

“…Retrospective analyses of the conditions surrounding periods of peak abundance (e.g., the early 1980s, and around 2010) and at known sites of locally high abundance (e.g., Stellwagen Bank) could provide important insights. In addition, new data collected from alternative and novel approaches such as hydroacoustic surveys (Hazen et al, 2009), geospatial analytical techniques (Friedlaender et al, 2009), composite indices and predators as biological samplers (Piatt et al, 2018; Richardson et al, 2014) could address vertical and horizontal availability over diel, seasonal and interannual scales. Finally, recent (MAFMC, 2017) and pending (Applegate et al, 2019; HR 2236, 2019) legislation requiring information on the ecosystem role of forage fish may provide newfound support for achieving the outstanding research, conservation and management goals for Ammodytes and dependent predators in the NWA region.…”

Effects of ocean climate on the length and condition of forage fish in the Gulf of Alaska

“…In this study, we derive length and a body condition index from forage fish samples obtained during studies of seabird diets in the Gulf of Alaska (GoA) taken over multiple decades (Hatch & Sanger, ; Piatt et al, ; Sydeman, Piatt, et al, ). This application of predator‐based sampling (Mills, Laidig, Ralston, & Sydeman, ; Thayer et al, ) has been used to study basin‐scale and annual‐to‐decadal variation in forage fish availability in this region (Piatt et al, ; Sydeman, Piatt, et al, ) and elsewhere in the world.…”

“…In this study, we derive length and a body condition index from forage fish samples obtained during studies of seabird diets in the Gulf of Alaska (GoA) taken over multiple decades (Hatch & Sanger, ; Piatt et al, ; Sydeman, Piatt, et al, ). This application of predator‐based sampling (Mills, Laidig, Ralston, & Sydeman, ; Thayer et al, ) has been used to study basin‐scale and annual‐to‐decadal variation in forage fish availability in this region (Piatt et al, ; Sydeman, Piatt, et al, ) and elsewhere in the world. For example, using common murres ( Uria aalge ) and Atlantic puffins ( Fratercula arctica ) as samplers in the North Sea, Wanless et al (2005, ) showed that the energy content of sandeel ( Ammodytes marinus ) and sprat ( Sprattus sprattus ) prey was extraordinarily low in 2004 and that the overall quality of sandeels declined steadily over a 40‐year sampling period.…”

“…This includes studies on the take of (a) age‐0 cod (Gadidae) by puffins in the GoA (Hatch & Sanger, ), (b) age‐0 rockfish ( Sebastes spp.) by murres in the central California Current (Mills et al, ), (c) age‐0 and age‐1+ Pacific sand lance (PSL; Ammodytes personatus ) and capelin ( Mallotus catervarius ) by puffins in the GoA and Aleutian archipelago (Piatt et al, ), and (d) age‐0 and older anchovy ( Engraulis encrasicolus ) and sardine ( Sardinops sagax ) by Cape gannets ( Morus capensis ) in the southern Benguela ecosystem (Crawford, Sydeman, Thompson, Sherley, & Makhado, ). We therefore assume that sampling in proportion to abundance also occurred in this study.…”

The coast-wide collapse in marine survival of west coast Chinook and steelhead: slow-moving catastrophe or deeper failure?

“…Batten et al [126] identified at least 10 geographically distinct plankton communities evident in a single transect across the North Pacific that were temporally stable across years and demonstrated that geographically distinct seabird assemblages patterned similar to the plankton communities. An analysis of tufted puffin communities [127] found that different forage fish communities also were present in different sub-regions of the Aleutian Chain. Thus geographically stable and distinct biological communities exist within the North Pacific Ocean, including the pelagic offshore.…”