Patrick D. O'Hara

WESTERN SANDPIPERS (CALIDRIS MAURI) DURING THE NONBREEDING SEASON: SPATIAL SEGREGATION ON A HEMISPHERIC SCALE

Abstract The nonbreeding distribution of Western Sandpipers (Calidris mauri) was documented using 19 data sets from 13 sites along the Pacific and Atlantic coasts of the Americas. Western Sandpipers showed latitudinal segregation with regard to sex and age. Females wintered farther south than males. A “U” shaped pattern was found with respect to age, with juveniles occurring at higher proportions at both the northern and southern ends of the range. Distribution of sexes might be affected by differences in bill length and a latitudinal trend in depth distribution of prey. For age class distribution, two different life-history tactics of juveniles might exist that are related to the higher cost of feather wear for juveniles compared to adults. Most juveniles complete three long-distance migrations on one set of flight feathers whereas adults complete two. Juveniles may winter either far north, thereby reducing feather wear induced by ultraviolet light, migration, or both, or far south and spend the summer on the nonbreeding area.

Differential Migration in Western Sandpipers with Respect to Body Size and Wing Length

Abstract We examined differential migration in the Western Sandpiper (Calidris mauri) with respect to body size and wing chord allometry within sex and age categories. Culmen and wing chord data were collected as indices of structural body size at three sites that vary latitudinally: Ecuador, Panama, and Mexico. Within all sex and age categories, larger individuals (i.e., those with longer culmens and wing chords) and those with a disproportionately longer wing chord relative to the culmen migrated farther south. Our results, coupled with known molting schedules, indicate that i) immature sandpipers that grow disproportionately longer primary feathers on breeding grounds migrate farther during their first southward migration, and ii) adults that fly farther grow disproportionately longer primary feathers on the nonbreeding grounds. Although no single-factor hypothesis accounts for all aspects of age, sex, and size of Western Sandpiper distributions, costs associated with flight during migration play a significant role in determining differential nonbreeding latitudinal distributions.

A preliminary spatial assessment of risk: Marine birds and chronic oil pollution on Canada's Pacific coast

Chronic oil pollution poses substantial risks to marine birds and other marine wildlife worldwide. On Canadas Pacific coast, the negative ecological consequences to marine birds and marine ecosystems in general remain poorly understood. Using information relating to oil spill probability of occurrence, areas of overall importance to marine birds, and the at-sea distribution and density of 12 marine bird species and seven bird groups, including multiple Species at Risk, we undertook a spatial assessment of risk. Our results identify two main areas important to marine birds potentially at higher risk of exposure to oil. For individual bird species or species groups, those predicted to have elevated bird densities near the mainland and the northeast coast of Vancouver Island were identified as being at higher potential risk of exposure. Our results, however, should be considered preliminary. As with other anthropogenic stressors, in order to better understand and subsequently mitigate the consequences of chronic oil pollution on marine birds, improved information relating to marine birds and the occurrence of oil spills on Canadas Pacific coast is needed.

The Grand Challenges in Researching Marine Noise Pollution from Vessels: A Horizon Scan for 2017

Chronic anthropogenic underwater noise, such as vessel noise, is now recognized as a world-wide problem. Marine noise from vessels, ranging from super tankers to small motorboats is increasingly recognized as being both a persistent and pervasive pollutant. Furthermore, due to its spatial and temporal variability, vessel noise pollution represents a particular challenge for marine conservation, management and planning. This paper presents the outputs of a horizon scanning exercise that brought together a group of 40 individuals from across Canada, including: researchers, policy makers, NGOs and other end-users who work in the field of marine acoustics. The goal was to identify priority information needs, related to marine vessel acoustics, to inform new research and address policy needs. Via an iterative Delphi style process, participants identified ten priority research questions related to marine vessel acoustic science; for example, How important is it to identify and maintain acoustic refugia? What attributes of marine vessels are the most effective indicators of marine noise? The questions were then further considered in terms of extent of current knowledge, time scale by which they can be achieved, the financial resources required and the importance of answering the question. Subsequently, the authors conducted a search of the peer-reviewed literature to situate the challenges highlighted by the horizon scanning exercise within the broader global research. Results show that investigating the attributes of marine vessels that are the most effective indicators of marine noise is a viable research question to tackle first. In addition, underpinning many of these questions is the need of long-term data collection and monitoring of both vessel traffic and marine mammal populations.

Exploratory spatial analysis of illegal oil discharges detected off canada's pacific coast

In order to identify a model that best predicts spatial patterns it is necessary to first explore the spatial properties of the data that will be included in a predictive model. Exploratory analyses help determine whether or not important statistical assumptions are met, and potentially lead to the definition of spatial patterns that might exist in the data. Here, we present results from exploratory analyses based on data describing illegal oil spills detected by the National Aerial Surveillance Program (NASP) in Canadas Pacific Region, and marine vessel traffic, the possible source of these oil discharges. We identify and describe spatial properties of the oil spills, surveillance flights and marine traffic, to ultimately identify the most suitable predictive model to map areas where these events are more likely to occur.

Seasonal variability in vulnerability for Cassin's auklets (Ptychoramphus aleuticus) exposed to microplastic pollution in the Canadian Pacific region

Marine plastic pollution is an emerging global conservation challenge, potentially impacting organisms at all trophic levels. However, currently it is unclear to what extent plastic pollution is impacting marine organisms at the population, species or multispecies level. In this study, we explore seasonal exposure (i.e., vulnerability) of Cassins Auklet (Ptychoramphus aleuticus) to plastic pollution with exposure models during boreal summer and winter seasons. Based on these models, we infer exposure at the population level for this species, in the Canadian Pacific region where approximately 75% of the global population of this species breeds. The models quantify plastic exposure by determining seasonal core foraging areas and plastic concentrations found in those same areas. Core foraging areas were determined using a Generalized Additive Model based on at-sea observation data (collected year round: 1990-2010) and 50% Home Range Kernels based on aerial telemetry data (May and June 1999-2001). Plastic concentrations within these core areas were interpolated based on seawater microplastic concentrations from the summer of 2012. We found that during the boreal summer, Cassins Auklets were exposed to relatively low concentrations of plastics. During the winter, auklet distribution shifted towards the coast where plastic concentrations are considerably higher. Model derived seasonal variability in exposure was consistent with necropsy results from bird carcasses recovered during the winter of 2014, and from a multiyear study on chick provisioning during the summer. Local oceanography likely plays a role in determining seasonal shifts in both marine bird as well microplastic concentrations, and hence exposure. As well, individual sensitivity (i.e., dose-dependent effect) may vary with annual cycles. Currently, research is focusing on determining how sensitive individual birds are to microplastic concentrations, and our models will help translate sensitivity found at the individual level to potential impacts at population or species level.

Are ocean conditions and plastic debris resulting in a ‘double whammy’ for marine birds?

We report a mortality event of Red Phalaropes (Phalaropus fulicarius) that occurred from October to November 2016 on the north coast of British Columbia, Canada. All individuals were severely underweight and showing signs of physiological stress. The guts of all carcasses contained ingested plastics (100%, n = 9). Distribution modelling from pelagic bird surveys (1990-2010) indicated that Red Phalaropes are not typically found in the study area during fall months. Ocean conditions during fall 2016 were unusually warm, coinciding with reduced upwelling in the study area. eBird records since 1980 indicated Red Phalaropes are observed closer to shore during periods associated with reduced upwelling. These results suggest that distribution shifts of Red Phalaropes closer to shore, where plastic debris occurs in higher concentrations, may lead phalaropes to feed on plastic debris while in a weakened state, resulting in a combination of two adverse circumstances.

Orcasound lab: A soundscape analysis case study in killer whale habitat with implications for coastal ocean observatories

Orcasound lab is a cabled hydrophone array located near the shoreline of Haro Strait, the core summertime habitat of the endangered southern resident killer whales (SRKWs). In 2016–2017, we began to record data continuously on local hard drives and in 2018 are archiving both lossy and lossless data 24/7 in an AWS/S3 bucket. We discuss our statistical characterization of the soundscape from these continuous audio recordings, contextualized with the AIS data (to quantify sources of ship noise) and image data (to quantify sources of non-AIS boat noise). Of particular interest to ocean observatories are our methods of establishing non-anthropogenic acoustic baselines and then ranking noise pollution sources relative to these baselines. We explore the statistical consequences of selecting different averaging times (from seconds to years) and frequency band widths (spectrum to broadband levels) when computing baselines and pollution metrics, including “delta” metrics that may be most-relevant to SRKWs. Finally, we explain how soundscape analysis (with attention to tidal, diurnal, seasonal, or decadal time variations) could be implemented with cloud-based data in near-real-time and be enriched by citizen scientists interacting with a time-stamped live audio stream and other environmental data.Orcasound lab is a cabled hydrophone array located near the shoreline of Haro Strait, the core summertime habitat of the endangered southern resident killer whales (SRKWs). In 2016–2017, we began to record data continuously on local hard drives and in 2018 are archiving both lossy and lossless data 24/7 in an AWS/S3 bucket. We discuss our statistical characterization of the soundscape from these continuous audio recordings, contextualized with the AIS data (to quantify sources of ship noise) and image data (to quantify sources of non-AIS boat noise). Of particular interest to ocean observatories are our methods of establishing non-anthropogenic acoustic baselines and then ranking noise pollution sources relative to these baselines. We explore the statistical consequences of selecting different averaging times (from seconds to years) and frequency band widths (spectrum to broadband levels) when computing baselines and pollution metrics, including “delta” metrics that may be most-relevant to SRKWs. Finally,...

Modelling and Mapping the Probability of Occurrence of Operational Oil Discharges from Marine Vessels in Canada's Pacific Region

The cost and time needed to patrol large geographical regions, such as Canada’s Pacific region, often constrain the effectiveness of aerial surveillance programs such as NASP. There are a number of factors that difficult the positive detection of these discharges on the waster surface, including: weather and sea conditions, look-a-likes, aircraft operability and equipment, and clandestine behavior of the polluters. As a result, a significant number of oil discharges often remain unaccounted for or without a clearly identified source.

Exploratory Spatial Analysis of Illegal Oil Discharges Detected off Canada's Pacific Coast

In order to identify a model that best predicts spatial patterns it is necessary to first explore the spatial properties of the data that will be included in a predictive model. Exploratory analyses help determine whether or not important statistical assumptions are met, and potentially lead to the definition of spatial patterns that might exist in the data. Here, we present results from exploratory analyses based on detected illegal oil spills by the National Aerial Surveillance Program (NASP) in Canadas Pacific Region, and marine vessel traffic, the possible source of these oil discharges. We identify and describe spatial properties of the oil spills, surveillance flights and marine traffic, to ultimately identify to most suitable predictive model to map areas where these events are more likely to occur.