Working Papers

Summary: Macroplastics, microplastics, and nanoplastics are increasingly becoming pollutants of great concern in the world’s oceans. Many studies have revealed adverse health impacts in marine ecosystems and organisms resulting from microplastic and nanoplastics exposure, ingestion and contamination. Marine biodiversity is readily affected by plastic pollution and coastal communities strongly relying on traditional seafoods and commercial fishing for subsistence are particularly susceptible to the global footprint of ocean plastics. Understanding potential bioaccumulation and biomagnification processes of microplastics in marine foodwebs is critical to advance microplastic science. Concerted bioaccumulation studies and foodweb bioaccumulation modelling of microplastics, addressing trophic transfer, ingestion, bioaccumulation potential and elimination/egestion rates in marine biota and in foodwebs are urgently needed as part of ecotoxicological and human risk assessments. To address these research gaps, this report presents primary research fronts focused on: 1) key contributions from the development of a comprehensive foodweb-bioaccumulation and biomagnification modeling approach for microplastics, using the well-known Chinook salmon-southern resident killer whale foodweb of the Northeastern Pacific, as a practical tool to understand the bioaccumulation and biomagnification behaviour of microplastics; 2) a synthesis of the application of trophic dynamic-ecosystem modeling applying Ecopath and Ecosim (EwE) models with the Ecotracer module; 3) the projection of the global ocean distribution and concentration levels of microplastics, using the databases Litterbase and the Global Microplastic Initiative to track the bioaccumulation and biomagnification potential in tandem with the development of the global microplastic footprint exposure index in selected marine ecosystems and Indigenous coastal communities of the world’s ocean; and, 4) a critical narrative of the implications for plastic pollution mitigation and socially equitable interventions and solutions for addressing marine plastic pollution. In conclusion, continued biomonitoring efforts and application of sound bioaccumulation modelling tools in tandem with the prioritization of knowledge mobilization and community participation via equitable interventions is of paramount importance to ensure effective solutions and mitigation policies that are socially and equitably fair to reduce inequalities and halt marine plastic pollution, following preventive measures and the precautionary approach.

Summary: Habitat degradation and loss are key drivers of population decline in some species of seahorses, pipefishes, and their relatives (family Syngnathidae). To better understand the distribution and habitat associations of syngnathids in Biscayne National Park (BNP), a coastal Marine Protected Area (MPA) of international conservation significance in southeastern Florida, we conducted underwater visual surveys for syngnathids at 79 sites stratified into three dominant habitat categories (Reef, Continuous Submerged Rooted Vegetation (CSRV), and Discontinuous Submerged Rooted Vegetation (DSRV)). Non-parametric statistical tests indicate that sites where syngnathids occurred were characterized by fine/muddy sediment, reduced horizontal visibility, relatively high seagrass coverage, and low coverage of sessile benthic invertebrates. No syngnathids were recorded at Reef sites, despite reef-associated species being previously reported in BNP. Logistic regression indicated that the presence of fine sediment (an indicator of low-velocity conditions) and relatively high seagrass coverage were significant predictors of syngnathid presence. Variation in habitat use among the three most abundant sympatric syngnathids (Hippocampus zosterae, Syngnathus scovelli, and Syngnathus floridae) suggests niche partitioning based on salinity and/or local hydrodynamic regime. Many conservation assessments assume that, for seagrass associated syngnathids, all available seagrass area is suitable habitat, however this study suggests that sheltered, low-energy seagrass beds characterized by fine sediment may provide a more suitable habitat for the most common syngnathids of BNP. Identification of habitat associations that maximize occurrence within apparently suitable habitat is a useful approach for guiding conservation of data-poor species, especially in the context of ongoing regional and global habitat loss.

Summary: Reconciling conservation and resource use requires adaptive management. The Convention on International Trade of Endangered Species (CITES) is a key tool in species conservation, regulating international trade for a list of species (Appendix II) that are or may become threatened by trade. To export such species, CITES member countries are required to evaluate if their exports are damaging wild populations (dubbed making a non-detriment finding or NDF). When countries find this challenge too great, they often default to banning international trade, thus imposing economic costs on stakeholders and/or driving the trade underground where it is more difficult to control. What, then, are the easiest ways for countries to make NDFs? We propose a simplified spatial approach to making NDFs using the case study of India, which has banned catch and trade of seahorses (Hippocampus spp.), but where rampant illegal trade continues. Our approach involves mapping the answers to four questions: (1) where are the species found?; and then, for those areas, (2) what pressures do the species face?; (3) what measures are in place to manage the pressures?; and (4) how well are the measures working? Information came from fishers’ knowledge and published literature. Overall, reported seahorse presence was greatest in the southern Palk Bay region. This region theoretically offered protection to seahorses through a 3 nm bottom trawl exclusion zone and a 60 day closed season. Implementation was problematic. Both bottom trawl and dragnet fishers reported respecting the closed season but three-quarters of bottom trawl fishers reportedly catching seahorses in the trawl exclusion zone. Our conservation assessment identified the opportunity to better implement existing management measures as well as the need for further management action (that would do more than simply banning capture). This pragmatic geographic analysis provides managers in India with a tractable route towards regulating exports at sustainable levels. Our assessment approach can be deployed broadly in assessing sustainability of exploitation and provides an alternative to the current futile bans.

Summary: Marine fish stocks and the fisheries they support play a vital role in meeting the food and nutritional needs of tens of millions of people worldwide while providing jobs and incomes to many more millions. Even though marine fish stocks are renewable they are seriously threatened by many stressors, including overfishing due to ineffective management and the perverse effects of government policies such as the provision of harmful subsidies; climate change and marine pollution, e.g., ocean plastic pollution and oil spills. Here, we explore the effects of harmful fisheries subsidies in three marine ecosystems chosen for their importance in terms of food security, size and diversity (Mauritanian EEZ, South China Sea and East China Sea); and three different management scenarios, i.e., optimizing (i) economic rent; (ii) jobs; and (ii) ecological fitness. This rich modelling exercise allows us to address pertinent questions such as how much resource depletion is due to subsidies; how much rent depletion occurs due to the provision of harmful subsidies; and to what extent do differences in management regimes matter?

Summary: Environmental justice refers broadly to the distribution of environmental benefits and burdens, and the fair treatment and meaningful involvement of all people in environmental decision-making and legal frameworks. The field of environmental justice initially developed out of a concern for the disproportionate distribution and impacts of environmental pollution and hazardous waste disposal on groups that have been historically and structurally marginalized, including Black populations and socio-economically disadvantaged communities. More recent environmental justice scholarship has expanded geographically and focused on a broader set of environmental hazards and harms, such as climate change impacts, biodiversity and habitat loss, and ecosystem service declines. Yet, the impacts and distribution of environmental hazards and harms in the marine environment on coastal populations has received less attention in the environmental justice literature. This narrative review paper starts to address this gap through a focus on five key environmental hazards and harms that are occurring in the marine and coastal environment: 1) pollution and toxic wastes, 2) plastics and marine debris, 3) climate change, 4) ecosystem, biodiversity and ecosystem service degradation, and 5) fisheries declines. For each, we characterize the issue and root drivers, then examine social and distributional impacts. In the discussion, we explore how impacts are differentiated, inequitably distributed, converging and cumulative and briefly examine solutions and future research directions. In conclusion, we call for greater and more explicit attention to environmental justice in ocean research and policy.

Summary: While Canada has massive potential marine energy capacity, no utility scale developments exist at present. In our report, we examine the barriers and opportunities associated with marine renewable energies (MRE) in Canada. First, we outline the major barriers to development, namely 1) a convoluted regulatory environment; 2) a history of poor public perception and engagement; 3) a lack of available capital investment; 4) a need for additional evidence to support the viability of some MRE technologies; and 5) economic competition from terrestrial wind and solar. Despite these barriers, we find that some MREs have advantages over terrestrial renewable power sources in certain scenarios and are ready to contribute to Canada's future energy mix as it moves towards net-zero greenhouse gas emissions.

Summary: Occasionally, ecosystem modellers run into issues where gender-split populations need explicit modelling. This can occur when empirical data is only available for male or female specimens, or when males and females of key species have markedly different behaviours. We have made a small modification to the Ecopath with Ecosim (EwE) multi-stanza model (Christensen and Walters, 2004), that allows linking recruitment to ensure proportional spawning between two multi-stanza groups, and thus connecting two gender-split populations at their foundation.