Ship biofouling is a major vector for the introduction and spread of harmful marine species globally; however, its importance in Arctic coastal ecosystems is understudied. The objective of this study ...was to provide insight regarding the extent of biofouling (i.e., percent cover, abundance, and species richness) on commercial ships operating in the Canadian Arctic. A questionnaire was used to collect information on travel history, antifouling practices, and self-reported estimates of biofouling extent from ships operating in the region during 2015–2016. Twenty-five percent of ships operating in the region during the study period completed the questionnaire (
n
= 50). Regression trees were developed to infer the percent cover of biofouling, total abundance of fouling invertebrates, and fouling species richness on respondent ships based on previous underwater wetted surface assessments of commercial ships in Canada. Age of antifouling coating system was the only significant predictor of percent cover and total abundance of biofouling invertebrates, while the number of biogeographic realms previously visited and port residence time were significant predictors for fouling species richness. Comparison of relevant travel history features reported through the questionnaire to the regression tree models revealed that 41.9% of 43 respondent ships had antifouling coating systems older than 630 days and are therefore inferred to have relatively high (> 9.3%) biofouling percent cover. More than half of respondent ships (62.8%) had antifouling coating systems older than 354 days and are therefore inferred to have a relatively high total abundance (over 6,500 individuals) of fouling invertebrates. Nearly half of respondent ships (45.9% of 37 ships) had visited at least three biogeographic realms during their last 10 ports-of-call and are therefore inferred to have relatively high fouling species richness (mean 42 taxa). Self-reported estimates of biofouling cover were unreliable, being much lower than model inferences. Although the regression tree models have relatively low predictive power, explaining only 15–33% of the variance in biofouling extent, this study indicates that commercial ships are an active pathway for the transportation of non-indigenous aquatic species to Canadian Arctic coastal ecosystems via biofouling.
With the entry into force of the International Maritime Organization's International Ballast Water Management Convention in September 2017, ships have begun to install and operate onboard ballast ...water management systems (BWMS) to reduce the number of live organisms in ballast water. Scientific methods were developed to assess the effectiveness of BWMS at reducing the number of live organisms in ballast water. However, detecting low organism concentrations in treated ballast water is challenging when considering the small sample volume (6 mL) analyzed for organisms in the 10–50 μm size class. The volume analyzed can be increased by concentrating the sample prior to analysis, but it is important to assess the effects of the sample concentration method due to potential cell loss experienced during the concentration step. Therefore, laboratory experiments were conducted to assess the effects of a gravity filtration method to concentrate samples to a factor of 40:1. Experiments were conducted for both low and high organism abundances. For unpreserved samples at low organism abundances (∼10 cells mL−1), concentrated samples had on average 31% fewer live cells mL−1 than unconcentrated samples for four out of five experiments. At high organism abundances (≥ 120 cells mL−1), unpreserved concentrated samples had on average 55% fewer live cells than unconcentrated samples. Alternatively, with preserved samples at low organism abundances, concentrated samples had on average 4.5× more cells than unconcentrated samples. At high organism abundances, concentrated samples had on average 6.4× more cells than unconcentrated samples. Differences were also observed between preserved and unpreserved samples. These findings can help to improve ballast water monitoring procedures and BWMS assessments, addressing a critical challenge to maritime environmental protection.
•Concentration by gravity filtration led to cell loss in live phytoplankton samples.•Alternate concentration methods should be explored to mitigate cell loss.•Concentrating had different effects on live and preserved samples.•Concentrating samples is important to improve precision at low abundances.•Counting six subsamples improved precision in low abundance samples.
The movement of ballast water by commercial shipping is a prominent pathway for aquatic invasions. Ships' ballast water management is now transitioning from open ocean exchange to a ballast water ...performance standard that will effectively require use of onboard treatment systems. Neither strategy is perfect, therefore, combined use of ballast water exchange plus treatment has been suggested to provide greatest protection of aquatic ecosystems. This study compared the performance of exchange plus treatment against treatment alone by modeling establishment rates of nonindigenous zooplankton introduced by ballast water across different habitat types (fresh, brackish, and marine) in Canada. Treatment was modeled under two efficacy scenarios (100% and 50% of ship trips) to consider the possibility that treatment may not always be successful. The model results indicate that exchange plus treatment will be more effective than treatment alone at reducing establishments when recipient ports are freshwater (58 140 vs 11 338 trips until ≥1 establishment occurs, respectively). Exchange plus treatment also serves as an important backup strategy if treatment systems are partially effective (50% of trips), primarily for freshwater recipient ecosystems (1442 versus 585 trips until ≥1 establishment occurs, respectively).
Abstract
A number of ballast water compliance monitoring devices (CMDs) have been made commercially available to verify the efficacy of ballast water management systems by quantifying the living ...organisms for both plankton size classes (≥50 μm and ≥10–<50 μm). This study aimed to examine whether new CMDs can provide a reliable indication of compliance regarding Regulation D-2 and to evaluate their performance for indicative analysis of organisms by assessing their accuracy (comparison to microscopy) and precision (comparison within measurement). Challenge fresh water samples were collected in four locations of Lake Ontario, Canada, whereas marine challenge water samples were collected around the Bay of Fundy, New Brunswick, Canada. Ballast water samples were collected from ships visiting several ports across Canada. Overall, accuracy was higher (>80%) in estimating organisms from prepared-challenge water (Ballast Eye and BallastWISE) than from ballast water samples (>70%) (B-QUA only). The sensitivity ranged from 50 to 100% for the ≥50 μm organism size class, whereas for the ≥10–<50 μm organism size class, it was higher for freshwater samples (>75%) than for marine samples (>50%). The performance of CMDs should be assessed under real-world conditions for a better understanding and to improve their use.
The International Convention for the Control and Management of Ships' Ballast Water and Sediments (BWM Convention) aims to mitigate the introduction risk of harmful aquatic organisms and pathogens ...(HAOP) via ships’ ballast water and sediments. The BWM Convention has set regulations for ships to utilise exceptions and exemptions from ballast water management under specific circumstances. This study evaluated local and regional case studies to provide clarity for situations, where ships could be excepted or exempted from ballast water management without risking recipient locations to new introductions of HAOP.
Ships may be excepted from ballast water management if all ballasting operations are conducted in the same location (Regulation A-3.5 of the BWM Convention). The same location case study determined whether the entire Vuosaari harbour (Helsinki, Finland) should be considered as the same location based on salinity and composition of HAOP between the two harbour terminals. The Vuosaari harbour case study revealed mismatching occurrences of HAOP between the harbour terminals, supporting the recommendation that exceptions based on the same location concept should be limited to the smallest feasible areas within a harbour.
The other case studies evaluated whether ballast water exemptions could be granted for ships using two existing risk assessment (RA) methods (Joint Harmonised Procedure JHP and Same Risk Area SRA), consistent with Regulation A-4 of the BWM Convention. The JHP method compares salinity and presence of target species (TS) between donor and recipient ports to indicate the introduction risk (high or low) attributed to transferring unmanaged ballast water. The SRA method uses a biophysical model to determine whether HAOP could naturally disperse between ports, regardless of their transportation in ballast water. The results of the JHP case study for the Baltic Sea and North-East Atlantic Ocean determined that over 97% of shipping routes within these regions resulted in a high-risk indication. The one route assessed in the Gulf of Maine, North America also resulted in a high-risk outcome. The SRA assessment resulted in an overall weak connectivity between all ports assessed within the Gulf of the St. Lawrence, indicating that a SRA-based exemption would not be appropriate for the entire study area.
In summary, exceptions and exemptions should not be considered as common alternatives for ballast water management. The availability of recent and detailed species occurrence data was considered the most important factor to conduct a successful and reliable RA. SRA models should include biological factors that influence larval dispersal and recruitment potential (e.g., pelagic larval duration, settlement period) to provide a more realistic estimation of natural dispersal.
•Data quality is very important for conducting a reliable risk assessment.•Same locations should be confined to smallest practicable areas within a port.•Nearly all shipping routes with adequate data resulted in high-risk outcomes.•Pelagic larval traits are key factors in natural dispersal modelling assessments.
Novel derivatives of the steroid DHEA 1, a known uncompetitive inhibitor of G6PD, were designed, synthesized, and tested for their ability to inhibit this dehydrogenase enzyme. Several compounds with ...approximately 10-fold improved potency in an enzyme assay were identified, and this improved activity translated to efficacy in a cellular assay. The SAR for steroid inhibition of G6PD has been substantially developed; the 3β-alcohol can be replaced with 3β-H-bond donors such as sulfamide, sulfonamide, urea, and carbamate. Improved potency was achieved by replacing the androstane nucleus with a pregnane nucleus, provided a ketone at C-20 is present. For pregnan-20-ones incorporation of a 21-hydroxyl group is often beneficial. The novel compounds generally have good physicochemical properties and satisfactory in vitro DMPK parameters. These derivatives may be useful for examining the role of G6PD inhibition in cells and will assist the future design of more potent steroid inhibitors with potential therapeutic utility.
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