Geology topics

Josh Adams

Publications and source records attributed to Josh Adams.

At least 37 records · Page 2Linked to original sources

USGS2021

Multidecadal comparison of Red-footed Booby Sula sula diet at Ulupa'u Crater, O'ahu, Hawai'i

We describe the diet of Red-footed Boobies Sula sula nesting at Ulupaʻu Crater, Oʻahu, Hawaiʻi based on 106 regurgitations collected during 2014 and 2015. We also compare our results to a diet study at this colony five decades earlier. Both studies indicate that flying squid (Ommastrephidae) and flyingfish (Exocoetidae) are important prey for this population while provisioning chicks. In particular, purpleback flying squid Sthenoteuthis oualaniensis occurred in the majority (>70%) of the recent regurgitation samples, and their size (mantle length <11 cm) indicates that they were mostly juveniles. Moreover, the size distribution of the squid prey varied by year, indicating interannual variability in phenology of spawning and larval development. This study highlights the Red-footed Boobys reliance on the juveniles of this poorly-studied squid, and underscores their value as biological samplers of epipelagic fish and squid within their foraging areas.

Hawaii↗

USGS2021

Modeling at-sea density of marine birds to support renewable energy planning on the Pacific outer continental shelf of the contiguous United States

This report describes the at-sea spatial distributions of marine birds in Pacific OCS waters off the contiguous U.S. (Figure 1.1) to inform marine spatial planning in the region. The goal was to estimate long-term average spatial distributions for marine bird species using all available science-quality transect survey data and numerous bathymetric, oceanographic, and atmospheric predictor variables. We developed seasonal habitat-based spatial models of the at-sea distribution for 33 individual species and 13 taxonomic groups of marine birds throughout the study region. A statistical modeling framework was used to estimate numerical relationships between bird sighting data (i.e., standardized counts) and a range of temporal (e.g., Pacific Decadal Oscillation [PDO] index), spatially static (e.g., depth), and spatially dynamic (e.g., sea surface chlorophyll-a concentration) environmental variables. The estimated relationships were then used to predict spatially explicit long-term average density (individuals per km 2 ) throughout the study area for each species/group in each of four seasons. Bird sighting data came from multiple scientific survey programs and consisted of at-sea counts of birds collected between 1980 and 2017 using boat-based and fixed-wing aerial transect survey methods. Spatial environmental variables were derived from remote sensing satellite data and an ocean dynamics model.

California, Oregon, Washington↗

USGS2020

Population estimates for selected breeding seabirds at Kīlauea Point National Wildlife Refuge, Kauaʻi, in 2019

Kīlauea Point National Wildlife Refuge (KPNWR) is an important seabird breeding site located at the northeastern tip of Kauaʻi in the main Hawaiian Islands. Despite the regional significance of KPNWR as one of the most important breeding sites for red-tailed tropicbirds ( Phaethon rubricauda ), red-footed boobies ( Sula sula ), and wedge-tailed shearwaters ( Ardenna pacifica ) in the main Hawaiian Islands, robust and accurate population surveys have not been consistently conducted and recent information is lacking. In this study, we completed comprehensive population surveys for these three species during the 2019 breeding season. Using direct censusing methods (ground-searching, visual and photographic counts), we determined that 387 red-tailed tropicbird and 5,049 red-footed booby breeding pairs nested at KPNWR in 2019. Additionally, we performed surveys of aerially displaying tropicbirds to estimate a potential population of 30 white-tailed tropicbird ( Phaethon lepturus ) breeding pairs at KPNWR. Using a stratified-random plot-sampling method, we estimated that 20,998 wedge-tailed shearwater pairs nested at KPNWR in 2019. The breeding population size results in this study are greater than those reported in the past for KPNWR. We suggest that the red-tailed tropicbird breeding population has increased since the mid-2000s (when population estimates were last made), whereas red-footed booby numbers likely have remained similar and 2019 results show an increase from past estimates because of the more comprehensive methods used in this study. The results of these surveys provide current and accurate population sizes for these species that can serve as (1) benchmarks for future management and monitoring at KPNWR and (2) important components of population-level assessments of seabird vulnerability to potential offshore wind energy development in the main Hawaiian Islands.

Hawaii↗

USGS2020

Genetic analysis of the diet of red‐footed boobies (Sula sula) provisioning chicks at Ulupa'u Crater, O'ahu

The diet of red‐footed boobies ( Sula sula ) provisioning chicks was quantified using 106 regurgitations collected from 81 adults over two study years with contrasting oceanographic conditions: 2014 and 2015. A total of 1,049 prey items were sorted into three broad categories (fish, squid, and other, consisting of highly‐digested ‘mush’ and parasitic isopods) and assigned a categorical freshness value of 1 (perfect condition), 2 (superficial digestion), or 3 (highly digested and incomplete). A total of 492 undigested prey items (freshness 1 and 2) were measured and sampled for genetic identification with 401 (82%) successfully identified. Rarefaction analyses suggested robust diet sampling, with 32 documented species: 29 fishes and three squids. While the prey‐specific index of relative importance highlighted that fish dominated the diet in 2014 (32.3% fish, 15.1% squid) and in 2015 (29.9% fish, 22.3% squid), diet composition varied significantly between the two study years. The purpleback flying squid ( Stenoteuthis oulaniensis ) accounted for 98.7% (232 of 236) of the identified squid specimens. Mantle lengths were significantly longer in 2015 (7.2 ± 1.1 SD cm) than in 2014 (6.3 ± 1.7 SD cm). These results indicate a higher relative abundance and size of the epipelagic squids available to foraging red‐footed boobies in 2015, during warm‐water conditions associated with the positive phase of the El Niño Southern Oscillation. Due to their diverse diet, red‐footed boobies are useful bioindicators of epipelagic nekton assemblages during changing oceanographic conditions. Moreover, their reliance on the purpleback flying squid makes these seabirds ideal samplers of the juveniles of this poorly studied species. Understanding how interannual and longer‐term oceanographic variability affects central‐place foraging seabirds and the recruitment and abundance of their squid prey is critical for precautionary ecosystem‐based fisheries management of oceanic islands and the surrounding marine environment.

Hawaii↗

USGS2020

Genetic diversity, population structure, and historical demography of a highly vagile and human‐impacted seabird in the Pacific Ocean: The red‐tailed tropicbird, Phaethon rubricauda

Many seabird breeding colonies have recovered from heavy anthropogenic disturbance after conservation actions. The widely distributed red‐tailed tropicbird, Phaethon rubricauda , was used as a model species to assess potential anthropogenic impacts on the genetic diversity of breeding colonies in the Pacific Ocean. Cytochrome c oxidase subunit I and control region sequences analyses were conducted across the range of the species in the Pacific Ocean. The study sites were at islands without human‐related disturbance (non‐impacted islands) and with human‐related disturbance (impacted islands). We hypothesized that (i) breeding colonies of the red‐tailed tropicbird on impacted islands have lower genetic diversity compared with colonies on non‐impacted islands, and (ii) breeding colonies of the red‐tailed tropicbird show significant fine and broad‐scale genetic structure across the Pacific Ocean. Bayesian skyline analyses were conducted to infer past changes in population sizes. Genetic diversity was similar between impacted and non‐impacted islands. There was significant broad‐scale genetic structure among colonies separated by over 6,000 km, but a lack of significant fine‐scale genetic structure within Australasia and Hawai'i, although a significant level of differentiation was found within Chile with Φ ST analyses. Skyline analyses showed that effective population sizes remained relatively constant through time, but experienced either a slight decrease or the end of an expansion event through the last 1,000 years. These changes may be related to the arrival of humans on Pacific islands. Impacted islands may have received immigrants from other relatively close islands, buffering the loss of genetic diversity. However, it is also possible that colonies have retained ancestral variation or that a large effective population size coupled with a long generation time (13 years) has prevented the loss of genetic diversity in human‐impacted islands. Future research using higher‐resolution markers is needed to resolve the population genetic structure of the red‐tailed tropicbird in an ecological time‐scale.

Hawaii↗

USGS2020

Abundance and productivity of marbled murrelets ( Brachyramphus marmoratus ) off central California during the 2019 breeding season

Marbled murrelets ( Brachyramphus marmoratus ) have been listed as “endangered” by the State of California and “threatened” by the U.S. Fish and Wildlife Service since 1992 in California, Oregon, and Washington. Information regarding marbled murrelet abundance, distribution, population trends, and habitat associations is critical for risk assessment, effective management, evaluation of conservation efficacy, and ultimately, to meet Federal and State recovery efforts for this species. During June–August 2019, the U.S. Geological Survey Western Ecological Research Center continued previously established, long-term (1996–2019), at-sea surveys to estimate abundance and productivity of marbled murrelets in U.S. Fish and Wildlife Service Conservation Zone 6 (San Francisco Bay to Point Sur in central California). Using conventional distance sampling methods, we estimated marbled murrelet abundance using 125 detections of 216 murrelets (mean group size, 1.72) observed on 8 surveys. The abundance estimated for the entire study area using all surveys in 2019 was 404 birds (95-percent confidence interval, 272–601 birds). Estimated abundance from 2019 is comparable to most prior years of study. In 2019, we estimated reproductive productivity (calculated as the hatch-year [HY] to after-hatch-year [AHY] ratio) using three detections of three HY murrelets observed on six surveys. After date-correcting HY and AHY counts to account for birds expected to be absent from the water while inland at nests, the date-corrected juvenile ratio was 0.025±0.020 standard error. We discuss changes in methodologies during 1996–2019 that could be addressed in re-analysis of this long-term dataset. We updated a synthesized database of all Zone 6 marbled murrelet survey data since 1999 with 2019 data to allow scientists and managers to evaluate established survey methods and assess trends in abundance and productivity estimates.

California↗

USGS2020

Spatial and temporal diving behavior of non-breeding common murres during two summers of contrasting ocean conditions

Successful foraging of marine predators depends on environmental conditions, which also influence prey availability. Neutral or negative El Niño Southern Oscillation and Pacific Decadal Oscillation ocean conditions during the summer of 2013 and strongly positive conditions during the summer of 2015 in the northern California Current System provided a case study to evaluate a marine predator's response to anomalously warm conditions. We used satellite transmitters with saltwater switches to track movements and estimate dive behavior among non-breeding common murres (Uria aalge) off Oregon prior to and during a marine heatwave. We quantified differences in space-use between years, applied linear mixed models to determine environmental influences (e.g. sea surface temperature, surface salinity, chlorophyll a, ocean depth, and calendar date) on dive frequency and dive duration, and contrasted dive activity between time of day, year, and sexes. The majority of birds dispersed away from capture locations, which were situated near the southern range limit of their population. In both years, murres used the Salish Sea and the Columbia River plume; however, murres spent more time foraging in the Columbia River plume and in continental slope habitat during the marine heatwave of 2015. During 2015, dive frequency was reduced, and dive durations were almost twice as long during daytime indicating deeper or more dispersed prey. Increased dive frequency was positively associated with temperature, chlorophyll a, and crepuscular periods. Cluster analysis of dive activity and the top-ranked predictive dive duration model revealed associations between longer-duration dives and decreased dive frequency, marine slope habitat, and cooler ocean temperatures. Murres were relatively inactive throughout the night and we found no sex differences in dive activity. Changes in common murre foraging tactics were associated with ocean warming and revealed selectivity in spatial and temporal use of foraging habitats. Productive marine features including the Columbia River plume provided refuge for murres during apparently poor ocean conditions associated with the marine heatwave. Identifying refuge areas used by highly mobile species experiencing varying ocean conditions is critical for adaptive marine spatial planning that can accommodate a changing ocean climate.

California↗

USGS2020

Post-release survival of fallout Newell’s Shearwater fledglings from a rescue and rehabilitation program on Kauai, Hawaii

Light attraction impacts nocturnally active fledgling seabirds worldwide and is a particularly acute problem on Kaua‘i (the northern-most island in the main Hawaiian Island archipelago) for the Critically Endangered Newell’s shearwater Puffinus newelli . The Save Our Shearwaters (SOS) program was created in 1979 to address this issue and to date has recovered and released to sea more than 30500 fledglings. Although the value of the program for animal welfare is clear, as birds cannot simply be left to die, no evaluation exists to inform post-release survival. We used satellite transmitters to track 38 fledglings released by SOS and compared their survival rates (assessed by tag transmission duration) to those of 12 chicks that fledged naturally from the mountains of Kaua‘i. Wild fledglings transmitted longer than SOS birds, and SOS birds with longer rehabilitation periods transmitted for a shorter duration than birds released immediately or rehabilitated for only 1 d. Although transmitter durations from grounded fledglings were shorter (indicating impacts to survivorship), some SOS birds did survive and dispersed out to sea. All surviving birds (wild and SOS) traveled more than 2000 km to the southwest of Kaua‘i, where they concentrated mostly in the North Pacific Equatorial Countercurrent Province, revealing a large-scale annual post-breeding aggregation zone for fledgling Newell’s shearwaters. While there was reduced survival among birds undergoing rehabilitation, SOS remains an important contribution toward the conservation of Newell’s shearwater because a proportion of released birds do indeed survive. However, light attraction, the root cause of fallout, remains a serious unresolved issue on Kaua’i.

Hawaii↗

USGS2020

Habitat affinities and at-sea ranging behaviors among main Hawaiian Island seabirds: Breeding seabird telemetry, 2013–2016

Recent Hawaiʻi state clean energy policy mandates and federal interest in developing offshore renewable energy resources have prompted unsolicited lease requests for offshore wind energy infrastructure (OWEI) to be located in ocean waters off Hawaiʻi. This study describing at-sea ranging behaviors for five seabirds was intended to provide new information on Hawaiian breeding seabird distribution at sea, habitat utilization, and ranging behaviors within near-island waters and throughout outer continental shelf (OCS) waters surrounding the main Hawaiian Islands (MHI). We also estimate the percentage of time the five study species spent flying at altitudes equivalent to an expected rotor-swept-zone (RSZ; 30–194 m) for an offshore wind turbine and discuss potential collision risk from OWEI to the seabirds studied here. The MHI supports important seabird breeding populations and individual seabirds can now be equipped with a wide-variety of data loggers and location tracking devices that can provide complex, high-resolution information on movement patterns at sea. In this study, we used GPS loggers and temperature-depth-recorders (TDRs) to examine the at-sea distributions and ranging behaviors of five abundantly breeding species in the MHI: Red-tailed Tropicbird, Laysan Albatross, Wedge-tailed Shearwater, Brown Booby, and Red-footed Booby. We tracked these breeding seabirds from 14 different sites throughout the MHI; study colonies were located on the main islands of Maui, Oʻahu, Kauaʻi, and on associated islets. We used the Residence in Space and Time (RST) algorithm to classify behavior into resting, transiting, and searching/foraging (Torres et al. 2017). We used GPS altitude measurements to examine species-specific flight height and to estimate time spent flying in the RSZ. We mapped rediscretized tracking data for seabirds at each study colony according to behavioral class and trip type (when applicable) using kernel density estimates. During 2014–2016, we obtained GPS and TDR data from 59 and 34 Red-tailed Tropicbirds, respectively. Taken together, individuals revealed a bimodal (short- [~3 h, <100 km range] and long- [>3 d, >800 km range]) trip foraging strategy. While ranging at sea, we estimated that Red-tailed Tropicbirds spend 70.6% (95% confidence interval [CI] 70.1–71.0%) of flight time in the RSZ. TDR data for tropicbirds was noisy and we could not reliably identify dives. During 2014 and 2016, we obtained GPS data from 35 Laysan Albatrosses nesting on Kauaʻi and Oʻahu. Individuals during the mid- to late-chick rearing period engaged in a bimodal short- (<6 d, <400 km range) and long- (>6 d, >2,000 km range) trip foraging strategy. While ranging at sea, we estimated that Laysan Albatrosses spend 2.57% (95% CI 2.50–2.64%) of flight time in the RSZ. During 2013–2015, we obtained GPS and TDR data from 313 and 55 Wedge-tailed Shearwaters, respectively. Considering all the data together, individuals revealed a multi-modal trip duration foraging strategy consisting of intra-day (<24 h, <100 km range), short (<4 d, ~200 km range), and long (>4 d, ~100–400 km range) trips. While ranging at sea, we estimated that Wedge-tailed Shearwaters spend 5.20% (95% CI 5.13–5.27%) of flight time in the RSZ. Wedge-tailed Shearwaters dove to a mean (± SD) depth of 1.78 ± 1.35 m (median = 1.38 m); the deepest dive recorded was to 10.06 m. The mean dive duration for Wedge-tailed Shearwaters was 3.12 ± 3.44 s (median = 1.80 s). During 2014–2015, we obtained GPS and TDR data from 42 and 37 Brown Boobies, respectively. Almost all foraging trips (97%) were single-day trips and we did not detect any bimodality in the distribution of single-day trip durations. Brown Boobies foraged relatively close to their colony (<60 km range) and focused their at-sea use in nearshore, coastal waters off Kauaʻi and Niʻihau. While foraging at sea, we estimated that Brown Boobies spend 3.41% (95% CI 3.16–3.67%) of flight time in the RSZ

Hawaii↗

USGS2020

Pacific Continental Shelf Environmental Assessment (PaCSEA): Characterization of Seasonal Water Masses within the Northern California Current System Using Airborne Remote Sensing off Northern California, Oregon, and Washington, 2011–2012

Here, we use ocean color measurements (Figure 1) and sea surface temperature (SST) data collected using sensors mounted on low-flying aircraft to characterize NCCS water masses and identify patterns among seasons and between years. To accomplish this, we applied k-means clustering to measured and derived ecologically-relevant physical and bio-optical variables (SST, Chla, absorbance by colored dissolved organic matter [aCDOM], proxy particle load). These classifications will be used in the future to evaluate species habitat distributions in the NCCS.

California, Oregon, Washington↗

USGS2019

Trends in mammalian predator control trapping events intended to protect ground-nesting, endangered birds at Haleakalā National Park, Hawaiʻi: 2000–14

Predation and habitat degradation by non-native species are principal terrestrial threats to the federally endangered Hawaiian Petrel (ʻuaʻu, Pterodroma sandwichensis ) and Hawaiian Goose (nēnē, Branta sandvicensis ) within Haleakalā National Park (HALE), Maui, Hawaiʻi. Since 1981, HALE has maintained a network of live traps to control invasive mammalian predators and protect these endangered birds. To evaluate trapping efficiency in HALE, we evaluated four types of trap outcomes for the years 2000–14: Bait Lost (62 percent), No Event (23 percent), Trap Triggered (10 percent), and Predator Event (Rat Caught, Cat Caught, or Mongoose Caught; 4 percent). We used a multinomial logistic regression model to explore trends in the probabilities of broad outcomes (No Event, Other Event [Bait Lost or Trap Triggered], or Predator Event [Rat Caught, Cat Caught, or Mongoose Caught]). Temporal variations in the probabilities of No Event, Other Event, or Predator Event were best explained by ʻuaʻu season (off-season, pre-laying, incubation, or nestling), month, year, and seasonal rainfall with greater probabilities of Predator Event during the ʻuaʻu nestling period (July–October). The probability of Predator Event or Other Event decreased with increased rainfall. Spatial analysis showed that percent vegetative cover and vegetation type best explained variations in the probabilities of trapping outcomes with the probability of Predator Event being greatest in developed and tree covered areas. The proportion of trapping events that resulted in Rat Caught was at least 20 times greater than the proportions of events resulting in Cat or Mongoose Caught throughout the 15-year management period. Temporal analysis showed that season, year, and maximum temperature best explained variations in probabilities of Predator Event; the probability of Rat Caught was greatest during the ʻuaʻu pre-laying and incubation periods (February–June), was greater during periods of warmer maximum temperatures, and overall, increased over the 15-year management period. The probability of Mongoose Caught was greatest during the ʻuaʻu offseason (November–January), decreased through time (2000–14), and decreased with increasing weekly maximum temperatures. Trends in Cat Caught were hard to detect because of small sample sizes, though slight trends indicated cat captures were most frequent during the ʻuaʻu off season and less frequent through time (2000–14). The probability of a Cat Caught event was also negatively correlated with weekly temperatures. Spatial analysis showed elevation best explained variations in probabilities of capture for rats, cats, and mongoose. Overall, predator catches were fewer at higher elevations, and of predators caught at higher elevations, the clear majority were rats. Our results are being used by HALE Endangered Wildlife Management staff to evaluate existing methods for predator control and efficacy of existing trap-based control strategies intended to protect ʻuaʻu and nēnē.

Hawaii↗

USGS2019

Overlap of Pink-footed Shearwaters and central Chilean purse-seine fisheries: Implications for bycatch risk

Understanding susceptibility of seabirds to fisheries bycatch requires quantifying overlap of seabird at-sea habitat with fisheries’ distribution and effort. Pink-footed Shearwaters (Ardenna creatopus) are vulnerable seabirds that breed only in Chile. Recently, high rates of Pink-footed Shearwater bycatch (i.e. >1,500 observed mortalities 2015–2017) were documented by observers in central Chilean purse-seine fisheries. We present analysis of Pink-footed Shearwater at-sea movements and overlap with central Chilean purse-seine fleets targeting common sardine (Strangomera bentincki), Peruvian anchoveta (Engraulis ringens), and Chilean jack mackerel (Trachurus murphyi). To determine overlap during 2015–2017, we paired locations from 49 Pink-footed Shearwaters rearing nestlings at Isla Mocha, Chile, with locations and number of observed purse-seine sets in central Chile. Pink-footed Shearwaters typically visited waters ≤30 km offshore throughout central Chile. Foraging trip durations varied interannually, with longer trips in 2016, but all years revealed persistent foraging hotspots near Valdivia, the Gulf of Arauco, and Isla Mocha, Chile. Greatest overlap between Pink-footed Shearwaters and fisheries occurred with the sardine/anchoveta fleet near Valdivia (artisanal and industrial) and the Gulf of Arauco (artisanal); overlap with the jack mackerel fleet was minimal. Given Pink-footed Shearwater bycatch documented in these fisheries, this overlap may indicate risk of bycatch for these birds, although we did not directly quantify shearwater–fisheries interaction. Our results can inform further fishery monitoring efforts, as well as collaboration among scientists, managers, and fishers to identify, quantify, and reduce fisheries bycatch of Pink-footed Shearwaters within Chile and internationally.

The Condor↗

USGS2019

Does perspective matter? A case study comparing Eulerian and Lagrangian estimates of common murre (Uria aalge) distributions

Studies estimating species' distributions require information about animal locations in space and time. Location data can be collected using surveys within a predetermined frame of reference (i.e., Eulerian sampling) or from animal‐borne tracking devices (i.e., Lagrangian sampling). Integration of observations obtained from Eulerian and Lagrangian perspectives can provide insights into animal movement and habitat use. However, contemporaneous data from both perspectives are rarely available, making examination of biases associated with each sampling approach difficult. We compared distributions of a mobile seabird observed concurrently from ship, aerial, and satellite tag surveys during May, June, and July 2012 in the northern California Current. We calculated utilization distributions to quantify and compare variability in common murre (Uria aalge) space use and examine how sampling perspective and platform influence observed patterns. Spatial distributions of murres were similar in May, regardless of sampling perspective. Greatest densities occurred in coastal waters off southern Washington and northern Oregon, near large murre colonies and the mouth of the Columbia River. Density distributions of murres estimated from ship and aerial surveys in June and July were similar to those observed in May, whereas distributions of satellite‐tagged murres in June and July indicated northward movement into British Columbia, Canada, resulting in different patterns observed from Eulerian and Lagrangian perspectives. These results suggest that the population of murres observed in the northern California Current during spring and summer includes relatively stationary individuals attending breeding colonies and nonstationary, vagile adults and subadults. Given the expected growth of telemetry studies and advances in survey technology (e.g., unmanned aerial systems), these results highlight the importance of considering methodological approaches, spatial extent, and synopticity of distribution data sets prior to integrating data from different sampling perspectives.

Washington↗

USGS2019

Abundance and productivity of marbled murrelets (Brachyramphus marmoratus) off central California during the 2018 breeding season

Executive Summary Marbled murrelets ( Brachyramphus marmoratus ) have been listed as “endangered” by the State of California and “threatened” by the U.S. Fish and Wildlife Service since 1992 in California, Oregon, and Washington. Information regarding marbled murrelet abundance, distribution, population trends, and habitat associations is critical for risk assessment, effective management, evaluation of conservation efficacy, and ultimately, to meet Federal- and State-mandated recovery efforts for this species. During June–August 2018, the U.S. Geological Survey Western Ecological Research Center continued previously established, long-term (1999–2018), at-sea surveys to estimate abundance and productivity of marbled murrelets in U.S. Fish and Wildlife Service Conservation Zone 6 (San Francisco Bay to Point Sur in central California). Using conventional distance sampling methods, we estimated marbled murrelet abundance using 137 detections of 227 individuals observed on 9 surveys. The abundance estimated for the entire study area using all surveys in 2018 was 370 birds (95-percent confidence interval, 250–546 birds). Estimated abundance from 2018 is comparable to most prior years of study, except for 2001–03, when greater abundances were estimated. In 2018, we estimated reproductive productivity (calculated as the hatch-year [HY] to after-hatch-year [AHY] ratio) using four detections of four HY individuals observed on six surveys. After date-correcting HY and AHY counts to account for birds expected to be absent from the water while inland at nests, the date-corrected juvenile ratio was 0.047 ± 0.024 standard error. We updated a synthesized database of all Zone 6 marbled murrelet survey data since 1999 with 2018 data to allow scientists and managers to evaluate established survey methods and assess trends in abundance and productivity estimates.

California↗

USGS2019

Eastern Pacific migration strategies of pink-footed shearwaters Ardenna creatopus: Implications for fisheries interactions and international conservation

The pink-footed shearwater Ardenna creatopus has a breeding range restricted to 3 central-Chilean islands and travels north in the eastern Pacific Ocean during the non-breeding period. Despite its Vulnerable IUCN status, the locations and relative importance of core non-breeding areas and migratory pathways of the species are not well understood. During 5 years between 2006 and 2015, we tracked the movements of 42 after-hatch-year pink-footed shearwaters in the non-breeding season using satellite tags. Tracked shearwaters exhibited 2 post-breeding-season migration strategies: 28% of individuals traveled 1600-2500 km north from their colonies to spend the entire non-breeding season off Peru, and 72% traveled 8000-11000 km north to waters off western North America (Baja California, Mexico, to southernmost Canada). Individuals that traveled to North America stopped in Peruvian waters on each leg of the migration, making this a migratory bottleneck. Core non-breeding-season areas included continental shelf and slope waters off Trujillo to Lima (Peru), central Baja California (Mexico), southern to central California (USA), and central Oregon (USA) to southern Vancouver Island (Canada). Of 12 national exclusive economic zones (EEZs) encountered north of their breeding range, birds primarily utilized the USA, Peru and Mexico, and to a lesser degree Chile, Canada, and Ecuador. Bycatch in fisheries was recently identified as a significant at-sea threat to pink-footed shearwaters, and we found evidence of pink-footed shearwater bycatch in 6 EEZs encountered by tracked birds, although quantification of bycatch magnitude is variable and not all fisheries have been studied.

Endangered Species Research↗

USGS2019

Diving behavior of Pink-footed Shearwaters Ardenna creatopus rearing chicks on Isla Mocha, Chile

Recent information reporting Pink-footed Shearwater Ardenna creatopus mortality from fisheries bycatch throughout its range has encouraged fisheries managers in Chile to evaluate and consider shearwater foraging behaviors to better evaluate risk. In response, we tracked six chickrearing adult Pink-footed Shearwaters from Isla Mocha, off south-central Chile, from 19 to 28 March 2015 using global positioning sensors and time-depth recorders. We recorded seven complete trips averaging 4.2 ± 2.5 d (mean ± SD). Chick-provisioning adults foraged within 334 km (i.e., 175 ± 100 km) of Isla Mocha. Dives (n = 515) occurred throughout the measured foraging range but most frequently occurred within 5–30 km from the mainland coast, in continental shelf waters north of Valdivia. Other regions with diving behavior were within ~20 km of Isla Mocha, and from Lebu to north of Talcahuano. Based on movement behavior analysis, adults spent most of their time at sea “resting/ foraging” (62% ± 6%), with the remainder spent “searching” (16% ± 4%) and “transiting” (20% ± 5%). The proportions of total number of dives associated with these three behaviors were similar. On average, dives were relatively shallow (1.6 ± 1.2 m, maximum depth = 10.1 m) and brief (4.7 ± 4.8 s, maximum duration = 25.7 s). Dives occurred during the day, at night, and at twilight, with most activity occurring at twilight and during the day. Although based on a small sample size, our results may be useful for informing modifications to fishing gear or fisheries policy to reduce the likelihood of bycatch and thus meet Chilean conservation goals for Pink-footed Shearwaters.

Isla Mocha↗

USGS2019

Synopsis of research programs that can provide baseline and monitoring information for offshore energy activities in the Pacific region: Seabird and marine mammal surveys in the Pacific region

We assembled and tabulated information about marine bird and mammal research and monitoring programs that could provide data needed to support environmental risk assessments. This included identifying ongoing or completed research programs that contain information on species and habitats sensitive to offshore energy activities and that could provide baseline and monitoring data to understand and mitigate potential impacts of offshore energy development in the Southern California Planning Area, Washington-Oregon Planning Area, and the Hawaiian OCS of the Bureau of Ocean Energy Management (BOEM). When available, we also included information regarding programs in Alaska, but the catalog for Alaska is not comprehensive. We included programs that assessed the distribution, abundance, or biology of marine birds (seabirds, waterbirds, or sea ducks) and marine mammals (cetaceans, pinnipeds, and sea otters), some of which are protected species under the Endangered Species Act (ESA of 1973) or the Marine Mammal Protection Act (MMPA of 1972). We canvassed data providers with spreadsheet or web-based survey forms. The marine bird survey returned information on research and monitoring efforts for 28 parameters across 46 species from 36 entities. The marine mammal survey returned information on research and monitoring efforts for 24 parameters across 22 marine mammal species from 22 entities. We tabulated the parameters by species to show which parameters are most commonly measured and where there might be information gaps. Both marine bird and marine mammal research and monitoring are widespread throughout the Pacific, with 535 entries for marine mammals and 1,911 entries for marine birds. Although we provide summaries of key aspects within research and monitoring programs, the associated database can be further queried in several ways. Versioning of this database format essentially creates a “living database” that can be updated in the future as new information becomes available.

California, Oregon, Washington↗

USGS2019

Synopsis of research programs that can provide baseline and monitoring information for offshore energy activities in the Pacific region: Seabird and marine mammal surveys in the Pacific region

Alaska, California, Hawaii, Oregon, Washington↗