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Barnacles are a foundation species in intertidal habitats. During the Pacific Marine Heatwave (PMH), intertidal barnacle cover increased in the northern Gulf of Alaska (GoA); however, the role of pelagic larval supply in this increase was unknown. Using long-term monitoring data on intertidal benthic (percent cover) and pelagic larval populations (nauplii and cyprid concentrations), we examined potential environmental drivers (temperature, chlorophyll-a, mixed layer depth) of larval concentration and whether including larval concentration at regional and annual scales improved intertidal barnacle percent cover models in two study regions in the GoA. In both regions, larval concentrations were slightly higher following the PMH. Percent cover models were improved by including cyprid concentrations (but not nauplii), and the effect strength varied by site and tidal elevation. This indicates that larval concentration contributes as a bottom–up driver of benthic barnacle abundance. There is little evidence of a direct effect of the PMH on either life stage. Instead, our results may illustrate the positive feedback between life stages, where higher adult benthic abundance increased larval concentrations, which then supplied more new recruits to the benthos. As heatwaves continue to occur, integrating various data types can provide insights into factors influencing both benthic and pelagic communities. [ABSTRACT FROM AUTHOR]

Warm conditions in the North Pacific in 2014-15 were a result of the continuation of the North Pacific marine heat wave, a large area of exceptionally high SST anomalies that originated in the Gulf of Alaska in late 2013. The North Pacific heat wave interacted with an El Niño developing in the equatorial Pacific in 2015. Weekly periods of exceptionally high temperature anomalies (>2˚C) occurred until the start of the El Niño (winter of 2015), when SSTs were still high but not as high as those due to the marine heat wave. During the 2015-16 El Niño, the depth of the 26.0 kg m-3 isopycnal (d26.0) was considerably shallower than during the 1982- 83 and 1997-98 events. The area affected by the marine heat wave and the 2015-16 El Niño in the mixed layer was comparable to the 1997-98 El Niño, but lasted longer. Water column stratification in the upper 100 m during 2015-16 was as strong as the most extreme values during the 1997-98 El Niño. This stratification was primarily driven by the warming of the upper 100 m. Despite notable perturbations, the effects of the 2015- 16 El Niño on hydrographic properties in the CalCOFI domain were not as strong as those observed during the 1997-98 El Niño. Warm ocean conditions, stratification, nutrient suppression, and silicic acid stress likely favored initiation of a toxic Pseudo-nitzschia bloom in fall 2014. Very low zooplankton displacement volumes were associated with anomalously warm and saline surface waters off Baja California. In contrast, during the 1997-98 El Niño, zooplankton volume was near average. Off California, pelagic red crab (Pleuroncodes planipes) adults were abundant in the water column and frequently washed up on beaches of southern California from January 2015 into 2016, and central California by September 2015. Glider measurements of integrated transport up to June 2015 did not detect anomalous northward advection. As expected, HF radar indicated northward surface currents along the central California coast in fall and winter 2015-16. Northward advection appeared to be much stronger during the 1997-98 El Niño. Throughout 2015-16, the zooplankton community on the Oregon shelf was dominated by lipid-poor tropical and sub-tropical copepods and gelatinous zooplankton, indicating poor feeding conditions for small fishes that are prey for juvenile salmon. The presence of rarely encountered species increased copepod species richness during 2015-16 to levels higher than the 1998 El Niño. We infer that the unusual copepod vagrants of 2015-16 originated from an offshore and southwesterly source; an important difference from the southerly origin of vagrants during the 1997-98 El Niño. The very warm conditions caused sardine spawning to shift from central California to Oregon. Mesopelagic fish assemblage off southern California exhibited higher abundances of species with southern affinities, and lower abundances of species with northern affinities. Forage fish (Pacific herring, northern anchovy, and Pacific sardine) were much less abundant in 2015-16 compared to previous years. In contrast, catches of salmon were close to average off northern California. Catches of young-ofthe- year rockfishes were high off central California, but low off both northern and southern California. Seabirds at Southeast Farallon Island in 2015 exhibited reduced breeding populations, reduced breeding success, lower chick growth rates, and lower fledging weights. Common murres were negatively affected in central and northern California, but seabird responses were species-specific. It is clear from the results presented here that the warm anomaly effects on the ecosystem were complicated, regionally specific, and that we do not fully understand them yet.

This report reviews the state of the California Current System (CCS) between winter 2012 and spring 2013, and includes observations from Washington State to Baja California. During 2012, large-scale climate modes indicated the CCS remained in a cool, productive phase present since 2007. The upwelling season was delayed north of 42°N, but regions to the south, especially 33° to 36°N, experienced average to above average upwelling that persisted throughout the summer. Contrary to the indication of high production suggested by the climate indices, chlorophyll observed from surveys and remote sensing was below average along much of the coast. As well, some members of the forage assemblages along the coast experienced low abundances in 2012 surveys. Specifically, the concentrations of all lifestages observed directly or from egg densities of Pacific sardine, Sardinops sagax, and northern anchovy, Engraulis mordax, were less than previous years’ survey estimates. However, 2013 surveys and observations indicate an increase in abundance of northern anchovy. During winter 2011/2012, the increased presence of northern copepod species off northern California was consistent with stronger southward transport. Krill and small-fraction zooplankton abundances, where examined, were generally above average. North of 42°N, salps returned to typical abundances in 2012 after greater observed concentrations in 2010 and 2011. In contrast, salp abundance off central and southern California increased after a period of southward transport during winter 2011/2012. Reproductive success of piscivorous Brandt’s cormorant, Phalacrocorax penicillatus, was reduced while planktivorous Cassin’s auklet, Ptychoramphus aleuticus was elevated. Differences between the productivity of these two seabirds may be related to the available forage assemblage observed in the surveys. California sea lion pups from San Miguel Island were undernourished resulting in a pup mortality event perhaps in response to changes in forage availability. Limited biological data were available for spring 2013, but strong winter upwelling coastwide indicated an early spring transition, with the strong upwelling persisting into early summer.

Variable ocean conditions can greatly impact prey assemblages and predator foraging in marine ecosystems. Our goal was to better understand how a change in ocean conditions influenced dietary niche overlap among a suite of midtrophic-level predators. We examined the diets of three fishes and one seabird off central Oregon during two boreal summer upwelling periods with contrasting El Nino (2010) and La Nina (2011) conditions. We found greater niche specialization during El Nino and increased niche overlap during La Nina in both the nekton and micronekton diet components, especially in the larger, more offshore predators. However, only the two smaller, more nearshore predators exhibited interannual variation in diet composition. Concurrent trawl surveys confirmed that changes in components of predator diets reflected changes in the prey community. Using multiple predators across diverse taxa and life histories provided a comprehensive understanding of food-web dynamics during changing ocean conditions., Introduction Although ecological theory predicts that predators would have specialized foraging strategies to avoid direct competition with one another when food resources are limited (Schoener 1971; Greene 1986), many marine […]

Albatrosses (Diomedeidae) are the most threatened family of birds globally. The three North Pacific species (Phoebastria Reiehenbach. 1853) are listed as either endangered or vulnerable, with the population of Short-tailed Albatross (Phoebastria albaints (Pallas, 1769)) less than 1% of its historical size. All North Pacific albatross species do not currently breed sympatrically. yet they do co-occur at-sea during the nonbreeding season. We incorporated stable isotope analysis with the first simultaneous satellite-tracking study of all three North Pacific albatross species while syinpatric on summer (nonbreeding season) foraging grounds off Alaska. Carbon isotope ratios and tracking data identify differences in primary foraging domains of continental shelf and slope waters for Short-tailed Albatrosses and Black-footed Albatrosses (Phoebastria nigripes (Audubon, 1839)) versus oceanic waters for Laysan Albatrosses (Phoebastria immutabilis (Rothschild, 1893)). Short-tailed and Black-fooled albatrosses also fed at higher trophic levels than Laysan Albatrosses. The relative trophic position of Black-footed and Laysan albatrosses, however, appears to differ between nonbreeding and breeding seasons. Spatial segregation also occurred at a broader geographic scale, with Short-tailed Albatrosses ranging more north into the Bering Sea than Black-footed Albatrosses, which ranged more to the southeast, and Laysan Albatrosses more to the southwest. Differences in carbon isotope ratios among North Pacific albatross species during the nonbreeding season likely reflect the relative proportion of neritic (more carbon enriched) versus oceanic (carbon depleted) derived nutrients, and possible differential use of fishery discards, rather than latitudinal differences in distribution. Les albatros (Diomedeidae) sont, a l'echelle globale, la famille d'oiseaux la plus menacee. Les trois especes du Pacifique Nord (Phoebastria Reiehenbach, 1853) sont considerees comme en peril ou vulnerables et la population d'albatros a queue courte (Phoebastria albatrus (Pallas. 1769)) represente moins de 1 % de sa taille du passe. Tous les albatros du Pacifique ne se reproduisent pas actuellement en sympatrie, mais ils coexistent en mer hors de la saison de reproduction. Nous combinons une analyse des isotopes stables a la premiere etude de localisation simultanee par satellite des trois especes d'albatros du Pacifique Nord alors qu'elles se retrouvent ensemble sur les sites d'alimentation d'ete (en periode non reproductive) au large de l'Alaska. Les rapports des isotopes de carbone et les donnees de teledetection permettent d'identifier des differences dans les domaines principaux de recherche de nourriture, soit les eaux du plateau continental el du talus continental pour les albatros a queue courte et a pieds noirs (Phoebastria nigripes (Audubon, 1839)) et les eaux oceaniques pour l'albatros de Laysan (Phoebastria immutabilis (Rothschild, 1893)). Les albatros a queue courte et a pieds noirs se nourrissent aussi a un niveau irophique plus eleve que les albatros de Laysan. Les positions trophiques relatives des albatros a pieds noirs el de Laysan semblent cependant differer entre la saison de reproduction el la saison non reproductive. Il se produit aussi une segregation spatiale a une echelle geographique plus large, car les albatros a queue courte se repartissent plus au nord dans la mer de Bering que les albatros a pieds noirs qui se retrouvent plus vers le sud-est; les albatros de Laysan sont plus repandus vers le sud-ouest. Les differences de rapports des isotopes de carbone au sein des especes d'albatros du Pacifique Nord hors de la saison de reproduction refletent vraisemblablement les proportions relatives des nutriments derives des regions neritiques (plus enrichis en carbone) par rapport a ceux des regions oceaniques (plus appauvris en carbone), ainsi que leur utilisation differente possible des rejets de la peche, plutot que des differences latitudinales dans leurs repartitions. [Traduit par la Redaction], Introduction Despite the immensity of ocean habitat, highly mobile species often congregate in specific regions that provide enhanced foraging opportunities. Among the most far-ranging marine species, albatrosses often forage within [...]