Benthic marine debris in the Bay of Fundy, eastern Canada: Spatial distribution and categorization using seafloor video footage

Why, and where, is commercial fishing gear lost? A global review and case study of Pacific Canada

Derelict fishing gear is a global problem, damaging marine ecosystems via habitat degradation and trapping marine life, thereby impacting fisheries. We conducted a global review of reasons for commercial gear loss, and used the findings to design a survey focused on coastal British Columbia (BC), Canada. We conducted dockside and on-line surveys of commercial fishers to record their experiences with lost gear across net, line, and trap gear types. The most common reasons for gear loss from the global review were interactions with other fishing vessels and their gear, marine weather, and snagging on submerged features. Survey results of 29 fishers in BC indicated that snagging gear on rough substrate was the most important reason for loss across all gear categories, followed by seafloor type. Other reasons for gear loss varied by net, line, and trap gear type. Understanding reasons for gear loss is important to reduce losses.

Environmental and economic impacts of retrieved abandoned, lost, and discarded fishing gear in Southwest Nova Scotia, Canada

Abandoned, lost, and discarded fishing gear (ALDFG), negatively impacts marine environments. Managing ALDFG in Atlantic Canada is challenging due to knowledge gaps on loss rates, locations, data availability/accuracy, impacts, and regulatory barriers for retrieval. This study removed ALDFG in Southwest Nova Scotia in collaboration with local fishers (with local knowledge and practical ALDFG removal expertise), government, non-profit organizations, and academia. A total of 29,298 kg of ALDFG was retrieved, including 24,630 kg using towed grapples covering ~3986 km of seafloor and 4668 kg from shorelines (comprising, 68 % lobster traps and 12 % dragger cable by weight). Traps ranged from <1 to 37 years old (median, 10 years). Traps continued to catch target and non-target species with 25 species released, including 652 individual lobsters (82 % were market-sized) and 57 fish (42 were species-at-risk). Based on estimated 2 % trap losses, annual commercial losses from ALDFG were $155,836 CAD in Lobster Fishing Area 34.

Sedimentological features of asbestos cement fragments in coastal environments (Taranto, southern Italy)

Asbestos cement materials (ACMs) are widespread in coastal environments as result of illegal dumping activities. This study focuses on the Taranto area (Italy) in the Mar Grande basin within the northern sector of the Ionian Sea. The complex history of dumping building materials containing high amounts of ACM into the coastal zone, and the erosion, transport and deposition in Marechiaro Bay is a serious environmental hazard. An interdisciplinary research methodology defines the temporal dumping succession, and the erosional processes and phases, the diffusion of ACM, the mineralogical characteristics, and existing physical status of the ACM. A multiscale investigation was conducted. Results show that from 1992 to 2000 a significant increment of dumping operations have occurred. The current cliff has been subject to erosion and redeposition phases, developing a new beach composed of these polluted man-made sediments. The findings persuade the local authorities to close the beach requiring remediation interventions.

Quantification and characterization of plastics in near-shore surface waters of Atlantic Canada

Plastics are a ubiquitous pollutant in the marine environment. Despite growing concerns, quantitative and qualitative data on microplastics in aquatic and marine environments of Atlantic Canada is just emerging. Surface water plastics were measured and categorized by morphology (thread, microfibre, fragment, foam, film, pellet, and microbead) in two locations in Nova Scotia and one in Newfoundland and Labrador, Canada. All sites within the three locations contained plastic with an average abundance of 9669 items/km². Most plastics (68 %) were sized as microplastics (0.425-5 mm), and plastic fragments were the most common morphological type. Polyethylene accounted for a third (30 %) of all particles found across all three locations, followed by polypropylene (23 %). Results can inform future research for community-based environmental groups, government, and academia.

A rapid assessment technique for coastal plastic debris sampling: Applications for remote regions and community science

Marine debris is an environmental issue of increasing importance worldwide, with 80% of marine plastics estimated to originate from land-based sources. While much work has been conducted to quantify plastics in coastal environments, many of these approaches are site-specific and not amenable to rapid surveys. We surveyed beaches around Nova Scotia, Canada for plastic and other anthropogenic debris to: 1) quantify debris density on the high tide line; and 2) test a rapid survey technique using digital photos, with applications for community science and remote regions. Most (72%) beaches in Nova Scotia contained debris, but plastic densities along the daily high tide line were relatively low (mean 0.2 debris/m²) with little interannual variation. Despite small differences in plastic densities between observers, this rapid assessment technique appears viable for relative quantification and monitoring of plastic debris on beaches across large geographic scales to assess trends and sources.

Nano-sized polystyrene plastics toxicity to microalgae Chlorella vulgaris: Toxicity mitigation using humic acid

Polystyrene nanoplastics (PS-NPs) can cause toxicity in aquatic organisms, but presence of natural organic matter (NOM) may alter toxicity of PS-NPs. To better understand effects of NOM on acute toxicity of PS-NPs, humic acid (HA) as a model of NOM was added to green microalga Chlorella vulgaris medium in the presence of amino-functionalized polystyrene nanoplastics (PS-NH₂). Acute toxicity tests of PS-NH₂ to C. vulgaris biomass and chlorophyll a content showed statistical differences between media treated with different concentrations of PS-NH₂ and control groups (p<0.05). HA significantly mitigated PS-NH₂ toxicity to C. vulgaris biomass and chlorophyll a end-points (p<0.05). Additionally, high HA concentration was more effective than low concentration (10 vs 5 mg/L), showing a greater ameliorative effect on PS-NH₂ acute toxicity (p<0.05). Algae exposed to higher PS-NH₂ concentrations showed greater morphological changes (i.e., diminution of photosynthetic pigments, reduction of algal size and formation of more cellular aggregates). Formation of high amounts of algal aggregates under influence of PS-NH₂ was presumably related to the high electrostatic tendency of these particles (with positively charged surfaces) to C. vulgaris polysaccharide walls (having negative charge). Formation of aggregates was significantly reduced in the presence of HA. HA with dominant negatively charged functional groups (following sorption by PS-NH₂ via reduction of PS-NH₂ zeta potential), could decrease electrostatic attraction between PS-NH₂ and algae, thereby substantially ameliorating cellular aggregation and cell size reduction.

Opportunities for single-use plastic reduction in the food service sector during COVID-19

The COVID-19 pandemic caused a surge in consumption of single-use plastics (SUPs), particularly in the food service sector, due to concerns for public health and safety. To follow public health guidelines, food services have been limited to takeout service and have restricted use of personal reusable items. This study investigated opportunities to reduce increased use of SUPs in Nova Scotia food services sparked by the COVID-19 pandemic using semi-structured interviews and focus groups with stakeholders from the food service sector. Many participants had already implemented SUP reduction strategies prior to COVID-19. However, the COVID-19 pandemic forced businesses to rely on SUPs and to pause SUP reduction strategies. Obstacles to SUP reduction included operational challenges from COVID-19 restrictions, misunderstanding of local waste management systems, costs of transitioning to zero plastic waste, poorly manufactured alternatives, greenwashing, and ingrained societal convenience culture. Whilst not all SUP consumption patterns were attributed to COVID-19, these barriers prevented food retailers, waste managers and consumers from achieving zero-plastic waste goals. Food services should adopt SUP reduction strategies, including re-introducing reusables, implementing exchange programs for bulk items and takeout, providing education and awareness to staff and consumers, and sourcing sustainable SUP alternatives. SUP reduction strategies can be implemented immediately as public health officials and researchers agree reusable items can be used safely when using basic hygiene measures. Food services across Nova Scotia should adapt their operational procedures and create behaviour change to reduce SUPs.

Environmental and Economic Impacts of Mismanaged Plastics and Measures for Mitigation

The mismanagement of plastic materials has grown to become a mounting global pollution concern that is closely implicated in unsustainable production and consumption paradigms. The ecological, social, and economic impacts of plastic waste mismanagement are currently transboundary in nature and have necessitated numerous methods of government intervention in order to address and mitigate the globalized and multifaceted dilemmas posed by high rates and volumes of plastic waste generation. This review examines the current landscape of a plastics economy which has operated with a linear momentum, employing large quantities of primary resources and disincentivizing the functioning of a robust recycling market for collecting plastic waste and reintegrating it into the consumer market. This contextualizes an increasing plastic pollution crisis that has required global efforts to address and mitigate the ecological risks and socio-economic challenges of mismanaged plastic waste. A timeline of government interventions regarding plastic pollution is described, including numerous international, regional, and local actions to combat plastic waste, and this is followed by an examination of the relevance of the extended producer responsibility principle to improve plastic waste management and obligate industry to assume responsibility in waste collection and recycling.

Offshore benthic habitat mapping based on object-based image analysis and geomorphometric approach. A case study from the Slupsk Bank, Southern Baltic Sea

Benthic habitat mapping is a rapidly growing field of underwater remote sensing studies. This study provides the first insight for high-resolution hydroacoustic surveys in the Slupsk Bank Natura 2000 site, one of the most valuable sites in the Polish Exclusive Zone of the Southern Baltic. This study developed a quick and transparent, automatic classification workflow based on multibeam echosounder and side-scan sonar surveys to classify benthic habitats in eight study sites within the Slupsk Bank. Different predictor variables, four supervised classifiers, and the generalisation approach, improving the accuracy of the developed model were evaluated. The results suggested a very high significance for the classification performance of specific geomorphometric features that were not used in benthic habitat mapping before. These include, e.g., Fuzzy Landform Element Classification, Multiresolution Index of the Valley Bottom Flatness, and Multiresolution Index of the Ridge Top Flatness. Comparison of classification results with manual maps demonstrated that Random Forest had the highest performance of four tested supervised classifiers. Because the current needs include benthic habitat mapping for the whole area of the Polish Exclusive Economic Zone, the key findings of this study may be further applied to extensive areas in the Polish waters and other vast areas worldwide.

Retrieval of abandoned, lost, and discarded fishing gear in Southwest Nova Scotia, Canada: Preliminary environmental and economic impacts to the commercial lobster industry

Southwest Nova Scotia (SWNS) is Canada's most productive lobster (Homarus americanus) fishing region. Abandoned, lost, and discarded fishing gear (ALDFG) is widespread. This baseline study provides the first preliminary assessment of environmental and economic impacts of ALDFG on the commercial lobster industry in SWNS. Fishers conducted 60 retrieval trips, searched ~1523 km² of the seafloor and removed 7064 kg of ALDFG (comprising 66% lobster traps and 22% dragger cable). Results showed that lost traps continued to capture target and non-target species until gear degraded. A total of 15 different species were released from retrieved ALDFG, including 239 lobsters (67% were market-sized) and seven groundfish (including five species-at-risk). The present findings, combined with information on regional fishing effort and market prices, estimate that commercial losses from ALDFG can exceed $175,000 CAD annually. This baseline assessment provides useful data for government and commercial fishing stakeholders to improve ALDFG management.

Effects of the 2011 Tohoku earthquake and tsunami on the abundance and composition of anthropogenic marine debris on the continental slope off the Pacific coast of northeastern Japan

The abundance and composition of anthropogenic marine debris from 2012 to 2014 was assessed according to three bottom trawl surveys conducted on the upper continental slope between 198 m and 501 m off the Pacific coast of northeastern Japan. The surveys quantitated marine debris as follows: 33.52-164.62 items km^-2 (January to July 2012), 91.68-215.11 items km^-2 (November 2012 to May 2013), and 160.13-178.19 items km^-2 (November 2013 to May 2014). Plastic bags or household materials mainly dominated terrestrial sources of debris. Principal component analysis latitudinally divided the study area according to debris abundance caused by geographical and hydrodynamic features. The long-term effect of tsunami-associated debris on the seafloor environment was recognized, because terrestrial sources such as heavy household materials were most abundant throughout the study period, with the additional accumulation of fishing gear and plastic bags.

The long-term legacy of plastic mass production

Mismanaged plastic waste is transported via rivers or city drains into the ocean where it accumulates in coastal sediments, ocean gyres and the deep ocean. Plastic harms marine biota and may ultimately return to humans via the food chain. Private initiatives proposing to collect plastic from the sea and rivers have gained widespread attention, especially in the media. However, few of these methods are proven concepts and it remains unclear how effective they are. Here we estimate the amount of plastic in the global surface ocean to assess the long-term legacy of plastic mass production, calculate the time required to clean up the oceans with river barriers and clean up devices, and explore the fate of collected plastic waste. We find that the projected impact of both single and multiple clean up devices is very modest. A significant reduction of plastic debris in the ocean can be only achieved with collection at rivers or with a combination of river barriers and clean up devices. We also show that the incineration and production of plastic has a significant long-term effect on the global atmospheric carbon budget. We conclude that a combination of reduced plastic emissions and reinforced collection is the only way to rid the ocean of plastic waste.

Seabed Mapping: A Brief History from Meaningful Words

Over the last few centuries, mapping the ocean seabed has been a major challenge for marine geoscientists. Knowledge of seabed bathymetry and morphology has significantly impacted our understanding of our planet dynamics. The history and scientific trends of seabed mapping can be assessed by data mining prior studies. Here, we have mined the scientific literature using the keyword “seabed mapping” to investigate and provide the evolution of mapping methods and emphasize the main trends and challenges over the last 90 years. An increase in related scientific production was observed in the beginning of the 1970s, together with an increased interest in new mapping technologies. The last two decades have revealed major shift in ocean mapping. Besides the range of applications for seabed mapping, terms like habitat mapping and concepts of seabed classification and backscatter began to appear. This follows the trend of investments in research, science, and technology but is mainly related to national and international demands regarding defining that country’s exclusive economic zone, the interest in marine mineral and renewable energy resources, the need for spatial planning, and the scientific challenge of understanding climate variability. The future of seabed mapping brings high expectations, considering that this is one of the main research and development themes for the United Nations Decade of the Oceans. We may expect a new higher resolution ocean seafloor map that might be as influential as The Floor of the Oceans map.