Stephanie Avery-Gomm

Quantifying ingested debris in marine megafauna: a review and recommendations for standardization

Plastic pollution has become one of the largest environmental challenges we currently face. The United Nations Environment Program (UNEP) has listed it as a critical problem, comparable to climate change, demonstrating both the scale and degree of the environmental problem. Mortalities due to entanglement in plastic fishing nets and bags have been reported for marine mammals, turtles and seabirds, and to date over 690 marine species have been reported to ingest plastics. The body of literature documenting plastic ingestion by marine megafauna (i.e. seabirds, turtles, fish and marine mammals) has grown rapidly over the last decade, and it is expected to continue grow as researchers explore the ecological impacts of marine pollution. Unfortunately, a cohesive approach by the scientific community to quantify plastic ingestion by wildlife is lacking, which is now hindering spatial and temporal comparisons between and among species/organisms. Here, we discuss and propose standardized techniques, approaches and metrics for reporting debris ingestion that are applicable to most large marine vertebrates. As a case study, we examine how the use of standardized methods to report ingested debris in Northern Fulmars (Fulmarus glacialis) has enabled long term and spatial trends in plastic pollution to be studied. Lastly, we outline standardized metric recommendations for reporting ingested plastics in marine megafauna, with the aim to harmonize the data that are available to facilitate large-scale comparisons and meta-analyses of plastic accumulation in a variety of taxa. If standardized methods are adopted, future plastic ingestion research will be better able to inform questions related to the impacts of plastics across taxonomic, ecosystem and spatial scales.

Differential Declines among Nesting Habitats of Breeding Herring Gulls (Larus argentatus) and Great Black-Backed Gulls (Larus marinus) in Witless Bay, Newfoundland and Labrador, Canada

Abstract. Environmental conditions in eastern Newfoundland have changed considerably since the 1970s, as both bottom-up oceanographic and anthropogenic influences on seabird populations have fluctuated considerably. The diet, reproductive success, and presumably survival of gulls are intrinsically linked to these processes, and breeding populations have declined considerably through the 1980s and 1990s. To assess the populations of breeding large gulls in the Witless Bay Ecological Reserve in eastern Newfoundland and Labrador, Canada, nests were surveyed and clutch size determined for Herring Gulls (Larus argentatus) and Great Black-backed Gulls (L. marinus) breeding on Great, Gull, and Pee Pee Islands in 2011–2012. The total number of breeding gulls of these two species combined decreased by 41% on Gull Island, 78% on Great Island and 51% on Pee Pee Island since 2000. However, the declines differed among habitat type, with modest declines on puffin slopes (-15% to -52%) and the steepest declines in meadows (-70% to -88%), suggesting that large-scale causative factors are not solely responsible for changes in population size. Clutch size did not differ from that in 2000. Differential recruitment among highly philopatric gulls stemming from bottom-up diet-related variation in breeding success may be responsible for different changes in populations among different habitats.

A study of wrecked Dovekies (Alle alle) in the western North Atlantic highlights the importance of using standardized methods to quantify plastic ingestion

Quantification of plastic ingestion across a range of seabirds is required to assess the prevalence of plastics in marine food webs. We quantified plastic ingestion in beached Dovekies (Alle alle), following a wreck in Newfoundland, Canada. Of 171 birds, 30.4% had ingested plastic (mean 0.81±0.30 SE pieces per bird, mass 0.005±0.002 SE g per bird). Most plastics were fragments of polyethylene and polypropylene. Surprisingly, 37% were burned or melted, indicating a previously unreported source of ingested plastics (incinerated waste). We found no relationship between plastic ingestion and age, sex or body condition. By comparing our results with a similar nearby study, we illustrate the need for researchers to adopt standardized methods for plastic ingestion studies. We underline the importance of using histological techniques to reliably identify gastric pathologies, and advise caution when inferring population level trends in plastic ingestion from studies of emaciated, wrecked birds.

Plastic pollution in the Labrador Sea: An assessment using the seabird northern fulmar Fulmarus glacialis as a biological monitoring species

Plastic is now one among one of the most pervasive pollutants on the planet, and ocean circulation models predict that the Arctic will become another accumulation zone. As solutions to address marine plastic emerge, is essential that baselines are available to monitor progress towards targets. The northern fulmar (Fulmarus glacialis), a widely-distributed seabird species, has been used as a biological monitor for plastic pollution in the North Sea, and could be a useful monitoring species elsewhere. We quantified plastic ingested by northern fulmars from the southeastern Canadian waters of the Labrador Sea with the objective of establishing a standardized baseline for future comparisons. Over two years we sampled 70 fulmars and found that 79% had ingested plastic, with an average of 11.6 pieces or 0.151g per bird. Overall, 34% of all fulmars exceeded the Ecological Quality Objective for marine litter, having ingested >0.1g of plastic.

Employing Predictive Spatial Models to Inform Conservation Planning for Seabirds in the Labrador Sea

Seabirds are vulnerable to incidental harm from human activities in the ocean, and knowledge of their seasonal distribution is required to assess risk and effectively inform marine conservation planning. Significant hydrocarbon discoveries and exploration licenses in the Labrador Sea underscore the need for quantitative information on seabird seasonal distribution and abundance, an area known to provide important habitat for seabirds year-round. We explore the utility of density surface modeling to improve seabird information available for regional conservation and management decision-making. We 1) develop seasonal density surface models for seabirds in the Labrador Sea using data from vessel-based surveys (2006–2014; 13,785 linear km of surveys), 2) present measures of uncertainty in model predictions, 3) discuss how density surface models can inform conservation and management decision making, and 4) explore challenges and potential pitfalls associated with using these complex modeling procedures. Models predicted large areas of high seabird density in fall over continental shelf waters (max. ~ 60 birds·km-2) driven largely by the southward migration of murres (Uria spp.) and dovekies (Alle alle) from Arctic breeding colonies. The continental shelf break was also highlighted as an important habitat feature, with predictions of high seabird densities particularly during summer (max. ~100 birds·km-2). Notable concentrations of seabirds overlapped with several significant hydrocarbon discoveries on the continental shelf and large areas in the vicinity of the southern shelf break, which are in the early stages of exploration. Some, but not all, areas of high seabird density were within current Ecologically and Biologically Significant Area (EBSA) boundaries. Building predictive spatial models required sophisticated analytical skills, and significant investments of time and computational power. Visualization of predictions and their uncertainty needed to be considered for appropriate interpretation by end users. Model uncertainty tended to be greater where survey effort was limited or where predictor covariates exceeded the range of those observed. Predictive spatial models proved useful in generating defensible estimates of seabird densities in many areas of interest to the oil and gas industry in the Labrador Sea, and will have continued use in marine risk assessments and spatial planning activities in the region and beyond.

Linking plastic ingestion research with marine wildlife conservation

Plastic is an increasingly pervasive marine pollutant. Concomitantly, the number of studies documenting plastic ingestion in wildlife is accelerating. Many of these studies aim to provide a baseline against which future levels of plastic ingestion can be compared, and are motivated by an underlying interest in the conservation of their study species and ecosystems. Although this research has helped to raise the profile of plastic as a pollutant of emerging concern, there is a disconnect between research examining plastic pollution and wildlife conservation. We present ideas to further discussion about how plastic ingestion research could benefit wildlife conservation by prioritising studies that elucidates the significance of plastic pollution as a population-level threat, identifies vulnerable populations, and evaluates strategies for mitigating impacts. The benefit of plastic ingestion research to marine wildlife can be improved by establishing a clearer understanding of how discoveries will be integrated into conservation and policy actions.

A decision tree for assessing the risks and benefits of publishing biodiversity data

Inadequate information on the geographical distribution of biodiversity hampers decision-making for conservation. Major efforts are underway to fill knowledge gaps, but there are increasing concerns that publishing the locations of species is dangerous, particularly for species at risk of exploitation. While we recognize that well-informed control of location data for highly sensitive taxa is necessary to avoid risks, such as poaching or habitat disturbance by recreational visitors, we argue that ignoring the benefits of sharing biodiversity data could unnecessarily obstruct conservation efforts for species and locations with low risks of exploitation. We provide a decision tree protocol for scientists that systematically considers both the risks of exploitation and potential benefits of increased conservation activities. Our protocol helps scientists assess the impacts of publishing biodiversity data and aims to enhance conservation opportunities, promote community engagement and reduce duplication of survey efforts.Information on species abundances and distributions is essential for developing conservation policy and assessing change. Yet publically available data increases exploitation potential. This Perspective presents a decision framework to assess the risks and benefits of publically sharing biodiversity data.

Plastic and Non-plastic Debris Ingestion in Three Gull Species Feeding in an Urban Landfill Environment

Plastic debris is recognized as a widespread, common and problematic environmental pollutant. An important consequence of this pollution is the ingestion of plastic debris by wildlife. Assessing the degree to which different species ingest plastics, and the potential effects of these plastics on their health are important research needs for understanding the impacts of plastic pollution. We examined debris (plastic and other types) ingestion in three sympatric overwintering gull species (Herring gulls Larus smithsonianus, Great Black-backed Gulls Larus marinus, and Iceland Gulls Larus glaucoides) to understand how debris ingestion differs among species, age classes and sexes in gulls. We also assessed how plastic burdens were associated with body condition to investigate how gulls may be affected by debris ingestion. There were no differences among the species, age classes or sexes in the incidence of debris ingestion (plastic or otherwise), the mass or number of debris pieces ingested. We found no correlation between ingested plastics burdens and individual condition. Gulls ingested plastic debris, but also showed high levels of other debris types as well, including metal, glass and building materials, including a metal piece of debris found within an abscess in the stomach. Thus, when the health effects of debris ingestion on gulls, and other species that ingest debris, is of interest, either from a physical or chemical perspective, it may be necessary to consider all debris types and not just plastic burdens as is often currently done for seabirds.

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.

Garbage in guano? Microplastic debris found in faecal precursors of seabirds known to ingest plastics

Plastic pollution is global environmental contaminant. Plastic particulates break down into smaller fragments in the environment, and these small pieces are now commonly found to be ingested by animals. To date, most plastic ingestion studies have focused on assessing retained plastics or regurgitated plastics, but it is likely that animals also excrete plastic and other debris items. We examined the terminal portion of the gastrointestinal tract of a seabird known to commonly ingest plastics, the Northern Fulmar (Fulmarus glacialis), to determine if seabirds excrete microplastics and other debris via their guano. We also examine how guano collections may be used as an indicator of retained plastics. The frequency of occurrence of microplastics did not correlate between the gut and faecal precursor samples, but there was a positive relationship between the number of pieces of plastics in the gut and the number of microplastics in the guano. Our findings suggest that seabirds are acting as vectors of microplastics and debris in the marine environment where their guano accumulates around their colonies. This transport of microplastics and debris by colonial seabirds needs to be further examined, and considered when designing environmental monitoring for microplastics in regions where seabird colonies are found.