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Spatial coherence between predators and prey has rarely been observed in pelagic marine ecosystems. We used measures of the environment, prey abundance, prey quality, and prey distribution to explain the observed distributions of three co-occurring predator species breeding on islands in the southeastern Bering Sea: black-legged kittiwakes (Rissa tridactyla), thick-billed murres (Uria lomvia), and northern fur seals (Callorhinus ursinus). Predictions of statistical models were tested using movement patterns obtained from satellite-tracked individual animals. With the most commonly used measures to quantify prey distributions--areal biomass, density, and numerical abundance--we were unable to find a spatial relationship between predators and their prey. We instead found that habitat use by all three predators was predicted most strongly by prey patch characteristics such as depth and local density within spatial aggregations. Additional prey patch characteristics and physical habitat also contributed significantly to characterizing predator patterns. Our results indicate that the small-scale prey patch characteristics are critical to how predators perceive the quality of their food supply and the mechanisms they use to exploit it, regardless of time of day, sampling year, or source colony. The three focal predator species had different constraints and employed different foraging strategies--a shallow diver that makes trips of moderate distance (kittiwakes), a deep diver that makes trip of short distances (murres), and a deep diver that makes extensive trips (fur seals). However, all three were similarly linked by patchiness of prey rather than by the distribution of overall biomass. This supports the hypothesis that patchiness may be critical for understanding predator-prey relationships in pelagic marine systems more generally.

Entanglement in marine debris and fishing gear is an increasing problem for the world’s pinnipeds and a contributing factor in Steller sea lion (Eumetopias jubatus) injury and mortality. From 2005–2009, we surveyed (n = 389 days) two haul-outs on the central Oregon coast containing a combined median of 402 animals (range 33–1240, or ca. 1–19% of the Oregon coast population). We recorded 72 individuals entangled in marine debris (n = 70) or with ingested salmon hook-and-line fishing gear (n = 2). Of the identifiable neck entanglements, black rubber bands were the most common neck-entangling material (62%), followed by plastic packing bands (36%), nets (1.2%), yellow rubber bands (0.4%), and a flying disc (0.4%). The estimated prevalence of entanglement for individuals in Oregon was 0.34%. Juveniles were the most frequently entangled age class (60%), followed by adult females (28%), and subadult males (12%). Supply chain and industry-based solutions are needed to prevent entangling debris from entering the ocean, along with eliminating, modifying, or cutting entangling loops of synthetic material.

Among the varied adaptations for avian flight, the morphological traits allowing large-bodied albatrosses to capitalize on wind and wave energy for efficient long-distance flight are unparalleled. Consequently, the biogeographic distribution of most albatrosses is limited to the windiest oceanic regions on earth; however, exceptions exist. Species breeding in the North and Central Pacific Ocean (Phoebastria spp.) inhabit regions of lower wind speed and wave height than southern hemisphere genera, and have large intrageneric variation in body size and aerodynamic performance. Here, we test the hypothesis that regional wind and wave regimes explain observed differences in Phoebastria albatross morphology and we compare their aerodynamic performance to representatives from the other three genera of this globally distributed avian family. In the North and Central Pacific, two species (short-tailed P. albatrus and waved P. irrorata) are markedly larger, yet have the smallest breeding ranges near highly productive coastal upwelling systems. Short-tailed albatrosses, however, have 60% higher wing loading (weight per area of lift) compared to waved albatrosses. Indeed, calculated aerodynamic performance of waved albatrosses, the only tropical albatross species, is more similar to those of their smaller congeners (black-footed P. nigripes and Laysan P. immutabilis), which have relatively low wing loading and much larger foraging ranges that include central oceanic gyres of relatively low productivity. Globally, the aerodynamic performance of short-tailed and waved albatrosses are most anomalous for their body sizes, yet consistent with wind regimes within their breeding season foraging ranges. Our results are the first to integrate global wind and wave patterns with albatross aerodynamics, thereby identifying morphological specialization that may explain limited breeding ranges of two endangered albatross species. These results are further relevant to understanding past and potentially predicting future distributional limits of albatrosses globally, particularly with respect to climate change effects on basin-scale and regional wind fields.

About 62,000 dead or dying common murres (Uria aalge), the trophically dominant fish-eating seabird of the North Pacific, washed ashore between summer 2015 and spring 2016 on beaches from California to Alaska. Most birds were severely emaciated and, so far, no evidence for anything other than starvation was found to explain this mass mortality. Three-quarters of murres were found in the Gulf of Alaska and the remainder along the West Coast. Studies show that only a fraction of birds that die at sea typically wash ashore, and we estimate that total mortality approached 1 million birds. About two-thirds of murres killed were adults, a substantial blow to breeding populations. Additionally, 22 complete reproductive failures were observed at multiple colonies region-wide during (2015) and after (2016-2017) the mass mortality event. Die-offs and breeding failures occur sporadically in murres, but the magnitude, duration and spatial extent of this die-off, associated with multi-colony and multi-year reproductive failures, is unprecedented and astonishing. These events co-occurred with the most powerful marine heatwave on record that persisted through 2014-2016 and created an enormous volume of ocean water (the \"Blob\") from California to Alaska with temperatures that exceeded average by 2-3 standard deviations. Other studies indicate that this prolonged heatwave reduced phytoplankton biomass and restructured zooplankton communities in favor of lower-calorie species, while it simultaneously increased metabolically driven food demands of ectothermic forage fish. In response, forage fish quality and quantity diminished. Similarly, large ectothermic groundfish were thought to have increased their demand for forage fish, resulting in greater top-predator demands for diminished forage fish resources. We hypothesize that these bottom-up and top-down forces created an \"ectothermic vise\" on forage species leading to their system-wide scarcity and resulting in mass mortality of murres and many other fish, bird and mammal species in the region during 2014-2017.

Capture and handling are essential methods for many studies of wild animals but can induce several harmful effects on individuals being studied. The relationship between physiological and behavioral responses in individuals exposed to these effects is not well known. We measured the blood level of muscle enzymes, aspartate aminotrasnsferase (AST) and creatine kinase (CK), indicating muscle damage in handreared short-tailed albatross (Phoebastoria albatrus) chicks before and after prolonged restraint for transmitter attachment beyond the usual feeding. We analyzed the relationships between enzyme levels and albatross pre-and post-fledging behaviors. Prolonged restraint for transmitter attachment elevated the blood levels of AST and CK in chicks. In chicks with higher levels of these enzymes, fledging date was earlier and the period to sustained flight after fledging was longer. These results indicated that prolonged handling for transmitter attachment on pre-fledging albatross chicks caused moderate muscle damage and behavioral changes before and after fledging. Although immediate post-fledging survival (the first 2 weeks at sea) did not appear to be affected, whether longer-term survival may be influenced is unknown. Reducing handling time for albatross chicks is important to reduce muscle damage and behavioral consequences.

Seabirds are integral components of marine ecosystems and, with many populations globally threatened, there is a critical need for effective and scalable seabird monitoring strategies. Many seabird species nest in burrows, which can make traditional monitoring methods costly, infeasible, or damaging to nesting habitats. Traditional burrow occupancy surveys, where possible, can occur infrequently and therefore lead to an incomplete understanding of population trends. For example, in Oregon, during the last three decades there have been large changes in the abundance of Leach’s storm-petrels ( Hydrobates leucorhoa ), which included drastic declines at some colonies. Unfortunately, traditional monitoring failed to capture the timing and magnitude of change, limiting managers’ ability to determine causes of the decline and curtailing management options. New, easily repeatable methods of quantifying relative abundance are needed. For this study, we tested three methods of remote monitoring: passive acoustic monitoring, time-lapse cameras, and radar. Abundance indices derived from acoustics and imagery: call rates, acoustic energy, and counts were significantly related to traditional estimates of burrow occupancy of Leach’s storm-petrels. Due to sampling limitations, we were unable to compare radar to burrow occupancy. Image counts were significantly correlated with all other indices, including radar, while indices derived from acoustics and radar were not correlated. Acoustic data likely reflect different aspects of the population and hold the potential for the further development of indices to disentangle phenology, attendance of breeding birds, and reproductive success. We found that image counts are comparable with standard methods (e.g., radar) in producing annual abundance indices. We recommend that managers consider a sampling scheme that incorporates both acoustics and imaging, but for sites inaccessible to humans, radar remains the sole option. Implementation of acoustic and camera based monitoring programs will provide much needed information for a vulnerable group of seabirds.

Although bycatch of seabirds and other long-lived species is a critical conservation issue in world fisheries, case studies documenting significant reductions in the mortality of these low-productivity species in a fishery are rare. We studied progress toward seabird conservation in the Alaskan longline fisheries, one of the largest and most diverse demersal fisheries. We generated annual seabird bycatch rates in 4 target fisheries and all fisheries combined from 23 years of fisheries observer data. We used 0-inflated negative binomial models to evaluate variables influencing seabird bycatch per unit effort (BPUE) in 2 target fisheries. Following adoption of streamer lines, at first voluntarily and then mandatorily, seabird BPUE was reduced by 77–90%, preventing mortality of thousands of birds per year. Despite this, BPUE increased significantly in 2 of 4 target fisheries since streamer lines were adopted. Although night setting yielded significant reductions (74–97%) in seabird BPUE and significant increases (7–11%) in fish catch per unit effort over daytime setting, nighttime setting increased the BPUE of Northern Fulmar (Fulmarus glacialis) by 40% and nontarget fish species by 5–17%. Thus, best practices to prevent seabird mortalities in longline fisheries varied by species assemblage and fishery. Our results inform global efforts toward fisheries bycatch reduction by illustrating that successful conservation requires fishery-specific solutions, strong industry support, constant vigilance in analysis and reporting observer data, and ongoing outreach to fleets, especially to vessels with anomalously high BPUE. Aunque la captura accesoria de aves marinas y otras especies con ciclos de vida largos es un asunto de importancia para la conservación en las pesquerías a nivel global, son raros los estudios de caso que documentan las reducciones significativas de la mortalidad de estas especies de baja productividad en las pesquerías. Estudiamos el progreso hacia la conservación de aves marinas en las pesquerías con palangre en Alaska, una de las pesquerías demersales más grandes y con mayor diversidad. Generamos tasas anuales de capturas accesorias de aves marinas para cuatro pesquerías y todas las pesquerías combinadas a partir de 23 años de datos de observación de pesquerías. Usamos modelos binomiales negativos con inflación 0 para evaluar las variables que influyen sobre la captura accesoria de aves marinas por unidad de esfuerzo (BPUE, en tnglés) en dos pesquerías. Después de la adopción de la caña de pescar, al principio voluntariamente y después de manera obligatoria, el BPUE de aves marinas se redujo entre un 77 y 90%, lo que previno la mortalidad de miles de aves por año. A pesar de esto, el BPUE incrementó significativamente en dos de las cuatro pesquerías diana desde que se adoptaron las cañas de pescar. Aunque las puestas nocturnas resultaron en reducciones significativas (74-97%) en el BPUE de aves marinas e incrementos significativos (7-11%) en la captura de peces por unidad de esfuerzo comparadas con las puestas diurnas, las puestas nocturnas incrementaron el BPUE del fulmar boreal (Fulmarus glacialis) en un 40% y entre un 5 y 17% el de las especies de peces cuya captura no es relevante para las pesquerías. Por lo tanto, las mejores prácticas para prevenir la mortalidad de las aves marinas en las pesquerías con palangre variaron dependiendo del grupo de especies y de la pesquería. Nuestros resultados informan a los esfuerzos globales hacia la reducción de la captura accesoria de las pesquerías al ilustrar que la conservación exitosa requiere de soluciones específicas por pesquería, un fuerte apoyo por parte de la industria, una vigilancia constante del análisis y el reporte de los datos de observación, y una participación continua de las flotas, especialmente en el caso de navíos con un BPUE anormalmente alto. 尽管全世界的渔场都面临着海鸟和其它寿命长的物种遭到兼捕这样ー个重要保护向题，但关于渔场中这 些低繁殖率物种的死亡率显著下降的案例分析仍然狼少。本研究分析了規模最大、种类最多的底层渔场之一 的阿拉斯加延绳钓渔场在海鸟保护方面的进展。我们根据 23 年间渔场的观察数据，获得了四个目标渔场和所 有渔场整体上毎年海鸟兼捕率的数据，并用零膨张负ニ项模型估计了两个目标渔场中影响每单位工作量的海鸟 兼捕量(bycatch per unit effort, BPUE)的因素。在从自愿到强制性地采用了飞绳钓方法之后，海鸟BPUE減 少了77-90%，毎年防止了数千只鸟的死亡。尽管如此，采用飞绳钓后，四个目标渔场中还是有两个渔场BPUE 显著增加。虽然夜间放钓竿相比于日间放钓竿，海鸟BPUE显著减少(74-97%),且每单位工作量的渔获量显著 増加77-11%),担夜间放钓竿导致暴雪鹱(Fulmarus glacialis；的BPUE増加了40%，非目标鱼种的BPUE也增加 T5-17%o因此，防止延绳钓渔场中海鸟死亡的最佳实践取决于物种群落和渔场的具体情况。我们的结果阐明 了成功的保护需要针对各个渔场_ 定解决方案、有强有力的产业支持、对观察数据的分析和报告保持谨慎，以 及要注意不断扩大的船队，特别是引起异常高BPUE的船只。这些结果为全球渔场减少兼捕的努力提供了重要 信息。

We hypothesized that changes in southeastern Bering Sea foraging conditions for black-legged kittiwakes (Rissa tridactyla) have caused shifts in habitat use with direct implications for population trends. To test this, we compared at-sea distribution, breeding performance, and nutritional stress of kittiwakes in three years (2008-2010) at two sites in the Pribilof Islands, where the population has either declined (St. Paul) or remained stable (St. George). Foraging conditions were assessed from changes in (1) bird diets, (2) the biomass and distribution of juvenile pollock (Theragra chalcogramma) in 2008 and 2009, and (3) eddy kinetic energy (EKE; considered to be a proxy for oceanic prey availability). In years when biomass of juvenile pollock was low and patchily distributed in shelf regions, kittiwake diets included little or no neritic prey and a much higher occurrence of oceanic prey (e.g. myctophids). Birds from both islands foraged on the nearby shelves, or made substantially longer-distance trips overnight to the basin. Here, feeding was more nocturnal and crepuscular than on the shelf, and often occurred near anticyclonic, or inside cyclonic eddies. As expected from colony location, birds from St. Paul used neritic waters more frequently, whereas birds from St. George typically foraged in oceanic waters. Despite these distinctive foraging patterns, there were no significant differences between colonies in chick feeding rates or fledging success. High EKE in 2010 coincided with a 63% increase in use of the basin by birds from St. Paul compared with 2008 when EKE was low. Nonetheless, adult nutritional stress, which was relatively high across years at both colonies, peaked in birds from St. Paul in 2010. Diminishing food resources in nearby shelf habitats may have contributed to kittiwake population declines at St Paul, possibly driven by increased adult mortality or breeding desertion due to high foraging effort and nutritional stress.

Many endemic species, particularly those on remote islands, have been driven to extinction or near extinction by anthropogenic influences. The short-tailed albatross Phoebastria albatrus once numbered in the millions but was thought to be extinct by the mid 20th century. Albatrosses, of the family Diomedeidae, are among the most threatened birds globally as a result of commercial exploitation, introduced predators, and mortality in commercial fisheries. We applied an experimental approach over 5 years to evaluate the translocation and hand-rearing of albatross chicks by comparing growth, physiological health indices, post-fledging survival, and migration patterns with a control group of naturally reared chicks in the source population. Hand-reared chicks had comparable or superior health and similar rates of immediate post-fledging mortality (15%), with mortality strongly female-biased in both groups. Hand-reared birds had longer post-fledging drift periods before attaining sustained flight (also female-biased) but comparable, albeit somewhat wider ranging, migration patterns to naturally reared chicks during their first 6 months at sea. Recruitment to the translocation site of a breeding pair that included a hand-reared bird occurred within 5 years of the first translocation. Success will ultimately depend on continued recruitment and breeding over the coming decades, given delayed breeding in these long-lived species. The results to date, however, have exceeded initial expectations and can inform potential reintroductions of other long-lived, migratory avian species with strong natal philopatry, and reintroductions of native species to former breeding islands.

Satellite imagery of chlorophyll a concentration (chl a) provides the only holistic perspective of productivity in marine ecosystems worldwide, yet its utility for understanding and predicting the distribution of upper trophic-level predators remains equivocal. We tested the hypothesis that remotely sensed chl a measurements spanning a decade can predict marine bird movements and distributions and provide insight into persistent seabird 'hotspots'. To test this hypothesis, we developed a temporally and spatially explicit chl a variance metric that explained up to twice the variation (90%) in seabird distributions than mean chl a values in our model system, the California Current. Our chl a variance metric-the frequency of chlorophyll peaks index (FCPI)-quantifies the frequency of chl a anomalies that exceed 1 standard deviation from the mean, relative to a spatial model for the ecosystem. Using the FCPI, we identified locations of high chl a anomaly persistence amidst considerable habitat heterogeneity from British Columbia, Canada, to Baja California, Mexico. Calculating variance and persistence metrics such as FCPI over large temporal scales may be preferable to analyzing mean or median chl a values over shorter time scales if understanding or predicting predator distributions is a goal of the research. As a static habitat layer, we suggest that the FCPI integrates time lags, physical forcings, and food web processes that can thwart attempts to link primary productivity and predator distributions in pelagic ecosystems. Additionally, identifying important ecological areas reflecting persistently elevated productivity and predator abundance is critical to marine spatial management and conservation.