Current research priorities 2017-2020

Aquaculture therapeutants

Field studies on the biological effects of current-use sea lice therapeutants on non-target aquatic species.

A current priority for DFO is field studies to assess whether any effects observed in lab-based studies on lobster life stages or other aquatic species with known sensitivities are also observed in the natural environment following application of anti-sea lice drugs (SLICE® and Ivermectin) and pesticides (Salmosan® and Paramove®50) according to label directions.

For the aquaculture drugs (SLICE® and Ivermectin), the priorities are benthic species; invertebrates, particularly crustaceans but including polychaetes or other potentially sensitive infauna or epifauna. For pesticides (Salmosan® and Paramove®50), data suggests the primary compartment of exposure is the water column, therefore priority species include zooplankton (entrained in the plume), with a priority on lobster larvae. Consider that exposures to Salmosan® or Paramove®50 would be short term exposures where non-motile species are carried in the plume or where the plume pulse may contact benthic species at shallow sites.

Two scenarios are currently of interest:

Additional considerations:

Lab studies on concentrations and durations at which current use anti-sea lice pesticides elicit effects in zooplankton

A research priority for DFO is determining concentrations and durations at which current-use anti-sea lice therapeutants (Salmosan® and Paramove®50) elicit unforeseen lethal or sublethal effects in zooplankton, with a focus on crustacean larvae, herring larvae and/or copepods. Existing dispersion modeling of an effluent plume from an aquaculture site suggests that it may take 1 to 3 h for the prescribed aquaculture treatment to be diluted by one- to two-orders of magnitude, respectively (Page and Burridge, 2014). The exposure period for plankton entrained in the effluent plume could therefore be up to several hours while the therapeutant disperses and dilutes to fractions of the initial treatment concentration.

Building upon the current knowledge base, considerations are as follows:

Lab studies on the concentrations and durations at which current use anti-sea lice therapeutants elicit effects in benthic species.

A research priority for DFO is determining concentrations and durations at which current-use anti-sea lice therapeutants (SLICE®, Ivermectin, Salmosan® and Paramove®50) elicit unforeseen lethal or sublethal effects in benthic species with a focus on crustaceans, polychaetes and/or other relevant infauna or epifauna with potential sensitivities. Building upon the current knowledge base, considerations are as follows:

Relevant Aquaculture References:


Direct application of pesticides to water: assessing exposure and effects of chemical control options for aquatic invasive species.

There is an increasing need for chemical control options to combat aquatic invasive species in Canadian waterways. The direct application of pesticides in water to control nuisance species is a unique aquatic exposure scenario relative to traditional pesticide use in conventional agricultural systems. A research priority for DFO is the characterization of exposure and effects at treatment sites where pesticides are to be applied directly in/near waterways under ‘emergency registration’ from Health Canada’s Pest Management Regulatory Agency (PMRA), specifically, the fate and behaviour of these pesticides in water, sediments, and biota, accounting for the potential dispersion, dilution, and downstream movement over time in dynamic receiving environments, as well as toxicity to non-target biota.

Current-use pesticides detected in remote areas - adverse effects on aquatic biota.

Some current-use pesticides can be transported to remote Arctic environments, and have been detected in tissues of aquatic biota. While monitoring levels and trends of pesticides in biota provides information on persistence and bioaccumulation due to long-range transport, assessments of their toxic potential remains a priority for DFO, i.e. can the levels of pesticides detected in Arctic aquatic biota be directly linked to adverse effects (acute or sublethal)? Assessing the sensitivity of Arctic aquatic species relative to those used in standard laboratory toxicity tests is also a priority for DFO (see Priority

Pesticides in the marine environment - exposure and effects on non-target aquatic biota.

Agricultural systems in coastal areas can have direct pesticide inputs to the marine environment through spray drift and runoff. Improve understanding of how agricultural practices and pesticides used in these systems interact with marine habitats, and their effects on marine organisms is a priority for DFO, including assessment of both exposure and effects on non-target aquatic biota accounting for unique aspects of the marine environment that will influence exposure (e.g. tidal flushing).

Pyrethroid / sediment interactions - bioavailability and toxicity of pesticides in sediments.

Assessing the bioavailability and toxicity of pyrethroids in sediments (or other pesticides that move to sediments) is a priority for DFO.

Oil and gas-related contaminants

Toxicological studies on oil-sands related products.

A current priority for DFO is research on the effects of oil-sands related products such as natural bitumen, diluted bitumen, synthetic crude oil and bitumen blended with synthetic crude oil on:

  1. estuarine species,
  2. algae/phytoplankton/primary production,
  3. sedentary invertebrates,
  4. intertidal vascular plants,
  5. habitat forming organisms such as sponges, corals, underwater algae etc. and
  6. fish and marine mammals.

Specific priorities include the following:

Biological effects of petroleum product spills in freshwater environments, as well as in the Canadian Arctic, cold environments and under various ice conditions.

Oil and gas related products shipped throughout the country may affect freshwater ecosystem if a spill occurs. Furthermore, with more petroleum products being transported in Northern Canada, information on the biological effects of oil and gas related products in these environments would contribute to providing advice to the Government of Canada.

DFO priorities include the following:

Oil dispersants and chemically dispersed oil (marine environment).

Use of dispersants is an alternate response measure following oil spills in the marine environment. When dispersants are used after an oil spill, the product will contribute to breaking the oil in smaller droplets, which may change its bioavailability and toxicity.

Evaluating the biological effects of the oil dispersants alone on aquatic organisms, as well as evaluating the biological effects of the chemically dispersed oil, in water or under various ice conditions remains a priority for DFO. The outcomes of the research will inform the establishment of conditions for applications of alternative response measures.

Contaminants and issues of emerging concern

Copper Redhorse (Species at Risk) - effects of contaminants.

This species, listed under the Species at Risk Act (SARA), has a small population and limited distribution within the St. Lawrence River system. Anthropogenic activities, including the release of contaminants in aquatic ecosystems, may put considerable pressure on the recovery of this population. A potential threat is reduced reproductive capacity due to contamination of the water with endocrine-disrupting chemicals. Determining the primary contaminants of concern and pathways of effects is a priority for DFO.

Biological effects of contaminants on aquatic species - assessing sensitivity of aquatic biota, including Arctic species.

Arctic aquatic species are exposed to contaminants due to both long-range transport and local point sources. Research is required to support Ecological Risk Assessments for northern sites, through the development of Toxicity Reference Values for contaminants. Toxicity assessments (including standardized toxicity tests) typically employ temperate species that may not be representative of the Canadian North. A priority for DFO is to understand how contaminant sensitivities differ between Arctic and temperate species in both freshwater and marine environments.

Beluga Whale St. Lawrence Estuary population (Species at Risk) - effects of contaminants.

The St. Lawrence Estuary population of beluga whale is listed under SARA. The effects of contaminants on beluga, their key prey (as pathways of contaminants), and on sentinel species, is a priority for DFO. This knowledge will contribute to understanding if contaminants are linked to natal and post-natal mortality in this population, along with birth defects, which may ultimately contribute to the species decline.

Microplastics - effects on aquatic biota.

Microplastics are detected in diverse marine and freshwater environments, and there are growing concerns about uptake and potential effects in biota. Assessing the effects of microplastics on aquatic biota in the Canadian marine or freshwater environments, including Arctic ecosystems is a priority for DFO, including uptake of microplastics into biota, trophic transfer, physical effects, and toxicity of associated contaminants.

Biological effects of contaminants on Atlantic Salmon (early life exposure, impacts on adults/returns).

Contaminants are among the various anthropogenic factors that can influence the development of salmon smolts and survival in the marine environment. Exposure to contaminants in early life stages in freshwater and coastal environments may impact physiological development and endocrine control in Salmonids (i.e. reproductive and thyroid axes), which may ultimately influence adult survival and return rates. Assessing the effects of early life stage exposure on adults is a priority for DFO.

Flame retardant chemicals.

Flame retardant chemicals are used in textiles, electronics, building materials, and various other products and applications. They can be liberated from these products and enter the aquatic environment, where they can persist, bioaccumulate, and have toxic effects in biota.

While certain flame retardants may be phased out of production, they can persist in the environment and may undergo conversion to other toxic forms. Understanding potential effects of past and current-use products, as well as proposed replacement products is a priority for DFO.

Perfluorooctane Sulfonate (PFOS)

PFOS is a synthetic chemical historically used as a surfactant/repellent in various products and applications; it is sometimes detected at sites associated with transportation and defense activities. Given that PFOS is detected in high Arctic aquatic and terrestrial biota and can have toxic effects, assessing the bioaccumulation / biomagnification and toxicity risks to upper trophic levels in the aquatic environment is a priority for DFO.

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