Eastern Sand Darter (Ammocrypta pellucida) Ontario populations: report on the progress of recovery strategy implementation for the period 2017 to 2022

Refine knowledge of seasonal habitat requirements for all life stages, especially juvenile.

Research and Monitoring; R1. Habitat requirements

A diet and trophic niche study found that Eastern Sand Darter in the Thames River have a narrow trophic niche with a high probability of overlap with co-occurring benthic and benthopelagic feeders (Burbank et al. 2019). Specifically, niche overlap with Blackside Darter and Johnny Darter could mean potential competition with these species if prey were to become scarce.

Occupancy models confirmed that sites with higher proportions of sandy and fine gravel substrates were more likely to be occupied (Lamothe et al. 2019). These same models showed that the probability of occupancy increased with water depth, clarity, and velocity.

A study identifying early life stages of fishes in the Sydenham River found Eastern Sand Darter eggs and larvae at 2 sites (Gallage et al. 2023).This study was part of a multi-month larval fish sampling program implemented by DFO to document the occurrence of eggs and larval fishes in the Sydenham River, including Eastern Sand Darter.

Firth et al. (2021) assessed critical thermal maximum (CTmax) of individuals from the Grand and Thames rivers using stream-side field trials. For Grand River individuals, CTmax ranged from 27°C to 37°C, with mean stream temperature during the previous 24 hours being the most important determinant. The study also found that for Thames River individuals living in a turbid environment, turbidity did not affect CTmax.

Metabolic rate and hypoxia tolerance of Eastern Sand Darter was investigated for Grand River individuals (Firth et al. 2023). The study found that water temperature was the most important predictor of these 2 physiological parameters; however, it was a weak predictor overall.

ii

All

Fisheries and Oceans Canada (DFO), University of Toronto, University of Waterloo

Evaluate and map the distribution, quantity, and quality of habitat in the vicinity of known populations.

Research and Monitoring; R2. Habitat surveys and mapping

The St. Clair Region Conservation Authority (SCRCA) monitored water quality and sampled for benthic invertebrates in the Sydenham River watershed in 2017 and 2018 as part of their funding through the Habitat Stewardship Program (HSP) and the Species at Risk Stewardship Program (SARSP), and in 2021 and 2022 as part of their funding through the Canadian Nature Fund for Aquatic Species at Risk (CNFASAR). Family biotic index scores, based on benthic invertebrates, showed that water quality ranged from good to poor, depending on the subwatershed.

Aquatic habitat mapping using an acoustic doppler current profiler was conducted by DFO and MNR for occupied stretches of the Grand River in 2022, and by DFO for the Thames River in 2021. Results indicated that occupied sections of the Grand River contained enough depositional substrates that suitable habitat is likely not limiting for the species in the Grand River (DFO unpublished data; Illes et al. 2024).

Occupied sites on the Grand River were sampled for dissolved oxygen, water surface temperature, and substrate in August 2022. Mean dissolved oxygen at the surface was 8.03 mg/l while substrate was dominated by medium gravel (>8 mm) or sand gravel (0.063 mm – 8 mm) (Firth pers. comm. 2024).

i, ii

All

DFO, Ministry of Natural Resources (MNR), SCRCA, Ministry of the Environment, Conservation and Parks (MECP)

Develop a long-term monitoring rogram that includes standardized sampling protocol to monitor for trends over time in distribution and abundance for all life stages. Incorporate findings into a routine population monitoring program.

Research and Monitoring; R3. Background surveys and monitoring – extant, historical and potential new locations

Although a long-term standardized monitoring program has not been implemented, a variety of monitoring projects targeted towards Eastern Sand Darter have been conducted.

DFO surveyed multiple rivers and tributaries in Southern Ontario since 2017. This includes the sampling of 2 historical watersheds, the Ausable River and Big Otter Creek, where the last confirmed records were from 1928 and 1955, respectively. In 2018, 9 sites were surveyed in the Ausable River while 52 sites were surveyed in Big Otter Creek (Barnucz et al. 2020). No Eastern Sand Darter were found during those targeted surveys.

Targeted sampling in the Thames River occurred at 8 sites in 2020, with 59 Eastern Sand Darter captured (Barnucz et al. 2022a). This also included the collection of habitat data.

In 2019, DFO conducted non-standardized sampling methods to target and catch Eastern Sand Darter in the Grand River for streamside physiology work. A total of 521 Eastern Sand Darter were captured near Cockshutt Bridge during 187 seine hauls and 61 benthic trawl tows (Gáspárdy and Drake 2021).

In 2022, DFO conducted targeted sampling at 101 sites (303 seine hauls) in the Grand River from Brantford to Newport, and Caledonia to Cayuga where sand and fine gravel substrates were dominant. A total of 625 Eastern Sand Darter were captured across 36 sites, including 174 from a single site downstream of Cockshutt Bridge (Gáspárdy et al. 2025).

LeBaron et al. (2020) conducted targeted surveys for Eastern Sand Darter in beach habitats of the Great Lakes. In total, 195 sites were seined between 2009 and 2018. In 2018, 4 Eastern Sand Darter were caught at 3 of 18 sites in Rondeau Bay. This was the first confirmed record there since 2005.

Sampling in Mitchell’s Bay, Lake St. Clair in 2017 captured 2 individuals (MNR unpublished data).

The LTVCA conducted environmental DNA (eDNA) sampling coupled with seining at 7 locations in the lower Thames River in 2022. Seining captured 6 young-of-the-year at 1 station and eDNA sampling detected Eastern Sand Darter at 4 stations. In 2021, eDNA sampling occurred at 12 sites, with Eastern Sand Darter detected at 2 sites only.

The UTRCA conducted fish monitoring in the upper Thames River watershed as part of their HSP funding in 2021 and 2022. This sampling included both electrofishing and seining and no Eastern Sand Darter were captured.

The SCRCA conducted 29 fish surveys in the Sydenham River watershed in 2019. In 2020, they conducted fish monitoring at 12 sites, capturing 1 Eastern Sand Darter. In an effort to detect trends over time, monitoring occurred at the same 10 index sites in both 2021 and 2022 but failed to detect the species.

The ABCA conducted fish sampling on the Ausable River at 3, 10, and 5 stations in 2019, 2020, and 2022, respectively. No Eastern Sand Darter were captured.

The power to detect changes in occupancy and abundance of SARA-listed freshwater fishes was investigated in Lamothe et al. (2023b). This paper determined the relationship between the number of survey sites and statistical power to describe changes in occupancy and abundance over time.

Reid and Dextrase (2017) compared the beach seine versus the bag seine in catching Eastern Sand Darter at lacustrine sites. They found that the beach seine is better at determining occupancy of sites and it is also better at detecting young-of-the-year of the species.

Balasingham et al. (2018) developed a custom-designed group-specific primer to detect Eastern Sand Darter from eDNA samples. They successfully detected the species during their eDNA study on the Grand and Thames rivers.

Detection probabilities between eDNA and seine-based sampling were compared at sites in West Lake (Reid and Haxton 2020). The authors found that while eDNA was successful at detecting Eastern Sand Darter at known occupied sites, it was not better at determining occupancy than traditional methods.

DNA barcoding was successfully used to identify Eastern Sand Darter eggs and larvae from multi-species batch samples in the Sydenham River (Gallage et al. 2023; DFO unpublished data) and DNA barcoding was successfully used to identify individual larval Eastern Sand Darter (DFO unpublished). Eastern Sand Darter larvae were detected at 3 locations: Alvinston, Oil Springs, and Florence; Eastern Sand Darter eggs were detected at Florence.This work was part of a multi-month egg and larval sampling program in the Sydenham River.

 i, iii, v

All

DFO, Ausable Bayfield Conservation Authority (ABCA), Lower Thames Valley Conservation Authority (LTVCA), MNR, SCRCA, University of Toronto, University of Windsor, Upper Thames River Conservation Authority (UTRCA)

Investigate and evaluate the significance of habitat threat factors that may be impacting extant populations. Take steps to mitigate immediate threats identified.

Research and Monitoring; R4. Threat clarification - habitat

As anthropogenic stressors are likely to increase water temperatures, Firth et al. (2021) assessed critical thermal maximum (CTmax) of individuals (See broad strategy R1 in this table for further details).

Metabolic rate and hypoxia tolerance of Eastern Sand Darter was investigated for Grand River individuals (Firth et al. 2023). The study found that water temperature was the most important predictor of these 2 physiological parameters; however, it was a weak predictor overall. Mean dissolved oxygen levels ranged from 6.75 to 11.12 mg/L at occupied sites.

The LTVCA produced an in-depth threat assessment report at the subwatershed level for all waters within their authority. This was produced from 2018 to 2022 through the HSP and CNFASAR programs. The report states that subwatersheds in the western region of the lower Thames River were exposed to more threats than other subwatersheds, which includes Big Creek, a historical location for Eastern Sand Darter, where tile drainage is extensive and water quality parameters are poor.

iv

All habitat- related threats (barriers to movement, altered flow regimes, shoreline modifications)

DFO, LTVCA, University of Waterloo

Investigate the mechanisms of impact of Round Goby on Eastern Sand Darter. Monitor distribution of Round Goby in areas of Eastern Sand Darter populations.

Research and Monitoring; R5. Threat clarification – exotic species

In the Sydenham River, a study found that following invasion, a number of ecologically significant diet overlaps between Round Goby and benthic fishes were observed (Firth et al. 2020). This observation indicated that Round Goby may be leading to community-level changes in feeding strategy, in addition to diet overlap with Eastern Sand Darter. For this reason, the authors state that Eastern Sand Darter should be monitored for any potential habitat shifts in the future.

A study on the impacts of Round Goby showed that the species is associated with reduced relative abundance of several darter species in Big Otter Creek and the Ausable River (McAllister et al. 2022).

iv

Exotic species

DFO, University of Waterloo

Where repatriations are deemed appropriate for restoring populations (historical or degraded), develop a repatriation plan.

Research and Monitoring; R6. Captive rearing and repatriations

In an effort to better understand Eastern Sand Darter co-occurrence patterns with other stream fishes, Lamothe et al. (2019) found that the species is negatively associated with Rosyface Shiner in the Grand River but positively associated with Northern Hogsucker, Silver Shiner, and Mimic Shiner.

Lamothe et al. (2021) conducted a modelling exercise which showed that translocation of Eastern Sand Darter can be successful with minimal impacts to source populations. The models assumed that the source population was abundant and stable (generally greater than 20,000 individuals) and that suitable habitat was available.

A recent habitat study was conducted in Big Otter Creek to determine the quality of habitat at historical and targeted sites for possible Eastern Sand Darter translocation (Barnucz et al. 2022b). The results of this work indicated high proportions of sand cover at both the targeted and historical survey sites.

The ability of translocation to work as a species at risk recovery approach was assessed in a framework developed by Lamothe et al. (2023a).

In 2022, The University of Windsor carried out a study on techniques for minimizing transport stress of Eastern Sand Darter, which is important research for any future repatriations.

See broad strategy R3 in this table for further details.

v

All

DFO, University of Windsor

Examine the degree of genetic variation and isolation within, and among, (that is, small populations and inbreeding concerns) populations across its North American range.

Research and Monitoring; R7. Conservation genetics

The genetic structure of northern populations was assessed by Walter et al. (2022). The study confirmed support for the existing 2 designatable units identified by COSEWIC in Ontario.

v

All

University of Toronto, University of Windsor

Develop a predictive habitat model to identify potential Eastern Sand Darter sites and significant habitat areas.

Research and Monitoring; R8. Habitat modelling

Using occupancy models, Lamothe et al. (2019) determined that the probability of occupancy was higher at sites with greater proportions of sand and fine gravel. The probability of occupancy also increased with water depth, clarity, and velocity.

See broad strategies R1, R2, and R3 in this table for further details.

i

All

DFO

Work with relevant organizations (for example, conservation authorities, MNR), First Nations, and ecosystem/single species recovery teams to share knowledge and to implement recovery actions.

Management and Habitat Protection; M1. Coordination with other recovery teams and relevant organizations

Through annual DFO species at risk (SAR) outreach, responsible agencies are informed about aquatic (fishes/mussels) SAR within their jurisdiction and are encouraged to incorporate SAR guidance into planning documents, including municipal official plans, with a goal of informing proponents early in the planning stage of any sensitive species in their project area.

Stewardship and outreach projects with funding from HSP, CNFASAR, and the Aboriginal Fund for Species at Risk (AFSAR) target species at risk, including Eastern Sand Darter. DFO works with, and funds, relevant organizations through its Grants and Contributions programs to implement recovery actions.

Compliance and enforcement efforts by DFO continue on an annual basis. Conservation and Protection officers within DFO continue to inspect all works or activities that impact species at risk. In 2017 an incidence of habitat destruction on the Thames River ultimately led to restoration of that habitat by the proponent via a Fisheries Act Corrective Measures Order.

vi, vii

All

DFO

Ensure planning and management agencies, including local First Nations, recognize the importance of fluvial and long-shore processes and sources of sand bedload in the maintenance of Eastern Sand Darter habitats. Ensure that flow requirements of the Eastern Sand Darter are considered in the management of water supply and flow regimes.

Management and Habitat Protection; M2. Habitat management and policy

No progress has been made in this area from 2017 to 2022.

iii, iv

All habitat threats

Not applicable

In cooperation with relevant ecosystem recovery teams and First Nations, address watershed-scale stressors to populations and their habitat.

Management and Habitat Protection; M3. Assessment of watershed-scale stressors

A study by Smyth and and Drake (2021) modelled possible impacts of Bayluscide application, a lampricide used in the Great Lakes, to fishes and mussels. The study found that the application of granular Bayluscide over 100 years could significantly impact Eastern Sand Darter populations, but this was dependant on application cycle and population size. For example, depending on the density estimates used, a maximum modelled decline in abundance could be 13% or 90%, if Bayluscide applications occurred annually. These modelling results relied on several assumptions, including the inability of a species to recover following mortality. However, a relative risk assessment by Andrews et al. (2021) found that risk to Eastern Sand Darter from Bayluscide was relatively low in comparison to other fish species at risk. This risk was partly due to low overlap between past Bayluscide application locations and the range of Eastern Sand Darter.

Urban wastewater and industrial effluents are a pervasive threat to Eastern Sand Darter throughout its range. In the Grand River, metabolic and morphological impacts to darter species have been observed downstream of wastewater treatment plants (WWTP) (Mehdi et al. 2018, Hodgson et al. 2020). There have been major upgrades to several wastewater treatment plants on the Grand River in recent years. These upgrades include the Kitchener WWTP and Waterloo WWTP and has resulted in reduced pharmaceuticals, endocrine disruptors, and ammonia in the effluent. Following upgrades at the Kitchener WWTP, a study found that a major reduction in intersex in Rainbow Darters below the WWTP was associated with improved effluent quality (Hicks et al. 2017).

vi

All

DFO

Develop a management plan addressing potential risks and proposed actions in response to the arrival or establishment of exotic species.

Management and Habitat Protection; M4. Exotic species management plan

The action plan for the Ausable River in Canada: an ecosystem approach (DFO 2020) outlines best management practices (BMP) to address threats to species at risk in this ecosystem, including invasive species.

Ontario launched the Early Detection and Distribution Mapping System (EDDMapS Ontario), an initiative that enhances monitoring and early detection of invasive species in the province (EDDMapS Ontario 2018)

vi, vii

Exotic species

DFO, MNR

Encourage municipalities and First Nations to include the concerns about Eastern Sand Darter habitat conservation in the municipal planning documents.

Management and Habitat Protection; M5. Municipal planning

Municipal public works and planning departments have been included in aquatic species at risk outreach activities conducted by DFO’s species at risk program staff. DFO has developed and distributed aquatic species at risk official plan guidance for municipalities (that is, Regional Planning Commissioners of Ontario) to incorporate into municipal official plan updates. This guidance includes providing a review on critical habitat orders to municipal planners and government agencies in 2018, as well as providing species at risk outreach to the Regional Planning Commissioners of Ontario in 2019. In 2021, species at risk outreach was provided to conservation authorities and their respective municipalities including the Essex Region Conservation Authority (ERCA), LTVCA, QCA (Quinte Conservation Authority), and SCRCA.

vi, vii

All habitat threats

DFO

Encourage and strengthen stewardship efforts with managers, stakeholders, First Nations, and citizens aimed at protecting Eastern Sand Darter habitats.

Stewardship, Outreach and Education; S1. Stewardship - awareness

Through HSP, a number of habitat restoration projects occurred from 2017 to 2022 that benefit Eastern Sand Darter, which includes the following:

• Grand River Conservation Authority (GRCA) restored riparian areas along 19 km of shoreline on the Grand River and its tributaries through vegetation/tree plantings. The GRCA also carried out 3 stormwater management projects, which included the creation of a series of wetland cells and 2 water and sediment control basins (WASCOBs) to minimize run-off. An outreach program was also initiated whereby the GRCA gave several webinars and presentations to inform the public on species at risk stewardship
• ERCA restored 8.4 ha of habitat along Lake St. Clair while SCRCA restored 18.8 ha of riparian and aquatic habitat along the Sydenham River and its tributaries. Two landowners improved an additional 10 ha of wetland and shoreline through the installation of cattle fencing. Three erosion control programs were also implemented in the Sydenham River watershed and a total of 3.7 ha of wetland were created
• The Upper Thames River Conservation Authority created 1,700 m of riparian buffer habitat and eliminated an all-terrain vehicle (ATV) crossing on Wabuno Creek. This work was supported by the SARSP
• The LTVCA improved 31.4 ha of habitat in the Thames River watershed, and Rondeau Bay, which included plantings along riparian buffers and wetland habitat creation
• The ABCA restored 3 wetlands in the Ausable river watershed in 2018 and restored 250 m2 of riparian buffer habitat in 2021. This work was also supported, in part, by the SARSP
• The Catfish Creek Conservation Authority restored 5 ha of riparian habitat and 525 m of shoreline in the Catfish Creek watershed through plantings

The CNFASAR provided funding for a number of habitat restoration projects from 2017 to 2022 that benefit Eastern Sand Darter including the following:

• Approximately 29 hectares of habitat that were improved by the SCRCA through riparian plantings, wetland habitat creation, and cattle exclusion fencing in the Sydenham River watershed
• The LTVCA restored 14.7 hectares of habitat through riparian buffer plantings and wetland habitat creation. Also, stream habitat was protected through the installation of 1.2 km of cattle fencing
• 21.4 hectares of habitat were improved in the Ausable River watershed by the ABCA through riparian buffer plantings, and wetland habitat restoration. In addition to this, 5,710 m of riparian buffer was improved. The ABCA also worked with multiple landowners to create a total of 6 WASCOBs in 2022

v

All

DFO, ABCA, Catfish Creek Conservation Authority (CCCA), ERCA, GRCA, LTVCA, SCRCA, UTRCA 

Work with landowners and First Nations to implement BMPs in areas that will provide the most benefit. Encourage the completion and implementation of Environmental Farm Plans and Nutrient Management Plans.

Stewardship, Outreach and Education; S2. Stewardship – implementation of BMP’s

See broad strategies S1 and S6 for further details.

Turbidity and sediment loading, contaminants and toxic substances, nutrient loading, shoreline modifications

DFO, conservation authorities

Develop a communication and awareness-raising plan that identifies partners and target audiences. Raise the awareness and develop information products, educational and outreach opportunities, stewardship resources, and specific BMP’s that will assist with the recovery of Eastern Sand Darter.

Stewardship, Outreach and Education; S3. Communication plan

An outreach strategy was developed for SAR in southwestern Ontario targeting the following audiences:

• local municipal staff – managers, planners, engineers, field staff, and consultants
• urban developers – representatives of local development industries and/or their consultants
• landowners – representatives of the local landowners, farmers, and cottagers, as well as recreational groups such as ATV/trail users
• conservation/environmental/steward-ship organizations – fish and game clubs, naturalist and environmental protection organizations, students, and stewardship councils

In July 2020, TVOKids aired an episode of their Leo’s FishHeads - YouTube (11:00 minutes) TV show that showcased Eastern Sand Darter through a partnership with DFO.

DFO delivered outreach on SAR to partners, including indigenous groups, Conservation Authorities and the public on an annual basis. DFO provided outreach at 24 events that targeted species at risk, including Eastern Sand Darter, reaching a total of 4,025 people.

From 2017 to 2022, a variety of species at risk outreach programs were delivered through HSP:

• The LTVCA hosted 28 outreach events that reached 6,272 people, which included messaging about aquatic species at risk, including Eastern Sand Darter, threats to SAR, projects that can be undertaken to benefit these species, and agricultural best management practices. Flyer mail-outs were used to provide information on species at risk and stewardship opportunities to locals. LTVCA also started a social media campaign that aimed to increase public awareness and shift people’s actions in relation to road salt use in winter
• The GRCA held several webinars and presentations to inform the public on species at risk stewardship
• The SCRCA conducted a large outreach program from 2018 to 2019 where SAR newsletters were sent out to more than 64,000 households and held several community events where SAR messaging reached approximately 900 people at schools and other venues. This work was also supported, in part, by the SARSP
• Outreach on species at risk was provided by the Toronto Zoo in 11 school boards, reaching 12,000 students in 2018 and 2019. This work was also supported by the SARSP

From 2017 to 2022, a variety of species at risk outreach programs were delivered through CNFASAR:

• The SCRCA distributed 185,000 species at risk newsletters to homeowners on their lands. They also promoted BMPs at 6 agricultural events and reached thousands of kids through species at risk sessions presented at schools. Their social media outreach campaign reached approximately 310,000 individuals and was aimed at species at risk stewardship
• The LTVCA hosted 56 outreach events that reached almost 7,000 individuals. They distributed over 3,100 flyers to the public and worked with the Chippewas of the Thames First Nation to develop an agricultural management plan
• The ABCA mailed postcards to over 3,100 landowners to engage on stewardship incentives. They also developed 2 educational videos posted on Youtube which focused on fish, including species at risk. They conducted 4 social media outreach campaigns and provided 11 educational presentations on species at risk to 244 students. In 2020, they developed agricultural BMP guides for landowners in the Old Ausable Channel. In 2022, they held 5 targeted outreach sessions that focused on threats to species at risk and agricultural BMPs

v, vi

All

DFO, ABCA, GRCA, LTVCA, SCRCA, Toronto Zoo

Collaborate with relevant groups, including First Nations groups and recovery teams to address recovery actions to benefit Eastern Sand Darter.

Stewardship, Outreach and Education; S4. Coordination with other groups

See broad strategies M1, M5, S1, S3, S5 and S6 for further details.

v, vi

All

DFO

Increase public awareness of the impacts of invasive species on the natural ecosystem, and encourage the use of the Ontario invasive species reporting system.

Stewardship, Outreach and Education; S5. Exotic species - awareness

DFO provided a SAR and invasive species outreach education session to Friends of Pinery Provincial Park in 2021.

v, vi

Exotic species and Disease

DFO

Facilitate access to funding sources for landowner and local community groups engaged in stewardship activities.

Stewardship, Outreach and Education; S6. Stewardship- financial assistance/   incentives

Federal funding was available through AFSAR, the HSP, and CNFASAR. HSP funding was provided by DFO through contribution agreements to support local stewardship initiatives led primarily by environmental non-government organizations, while AFSAR funding supported the development of Indigenous capacity to participate actively in the implementation of SARA. CNFASAR funding supported stewardship projects that help recover and protect aquatic species at risk. Collectively, the activities supported the implementation of measures, such as BMPs associated with water quality improvements, and reducing sedimentation. From 2017 to 2022, HSP and CNFASAR funding resulted in a number of habitat improvement projects in the Ausable River, Thames River, Sydenham River, Rondeau Bay and its tributaries, and watersheds of the Grand River.

Similarly, the Ontario Ministry of the Environment, Conservation and Parks administered the Species at Risk Stewardship Program, which provided money for similar stewardship activities to those described above for HSP. These activities included the Species at Risk Farm Incentive Program that provided funding to agricultural landowners interested in completing habitat creation, enhancement, and protection BMPs that supported species at risk.

iv

All

DFO, Environment and Climate Change Canada (ECCC), MECP

Conduct studies to determine the habitat requirements for all life stages.

2011 to 2014

In Progress

Eastern Sand Darter eggs and larvae were identified from batch samples in the Sydenham River (Gallage et al. 2023). Eggs were detected during the month of June and larvae were present from June through August. The Florence site where the eggs were collected was dominated by sandy substrate.

A population model indicated that the rate of population increase was most sensitive to 0+ survival rates, clutch size, and clutch number (Finch et al. 2017). For this reason, the authors stated that management actions should be focused on the stewardship of spawning and juvenile habitats.

For further details on studies that helped determine habitat requirements for different life stages, please see broad strategies R1 and R2 in Table 2 above.

Fisheries and Oceans Canada (DFO), Ministry of Natural Resources (MNR), University of Toronto, University of Waterloo

Survey and map habitat quality and quantity within historical and current sites, as well as sites adjacent to currently occupied habitat.

2011 to 2014

In Progress

DFO conducted targeted surveys for Eastern Sand Darter in the Ausable River, Thames River, Big Otter Creek, and Grand River from 2017 to 2022. During these surveys, DFO has also collected habitat data to further our understanding of Eastern Sand Darter distribution. During this same time period, the SCRCA have conducted water quality monitoring and benthic invertebrate sampling in the Sydenham River.

Both National Wildlife Areas located at Long Point were surveyed for fishes during the period of this report. Parsons Inc., a contractor for Environment and Climate Change Canada, conducted fish community surveys at Big Creek National Wildlife Area from 2020 to 2022. Fyke nets with a mesh size of 6mm and seine nets with a mesh size of 3mm were used but no Eastern Sand Darter were captured (Dunn 2025). In 2017, fish sampling using seine and fyke nets occurred at the Long Point National Wildlife Area but no Eastern Sand Darter were captured (Montgomery 2019).

For further details on habitat surveys, please see broad strategy R2 in Table 2 above.

DFO, Ministry of Natural Resources (MNR), St. Clair Region Conservation Authority (SCRCA),

Conduct additional species surveys to fill in distribution gaps, and to aid in determining population connectivity.

2011 to 2014

In Progress

Targeted surveys for Eastern Sand Darter were conducted in beaches of Lake Huron, Ausable River, Thames River, Rondeau Bay, Big Otter Creek, and Grand River. Northern Madtom surveys conducted by DFO in the Sydenham River (2019) and Thames River (2022) captured Eastern Sand Darter. These surveys contributed to our overall understanding of the known distribution of Eastern Sand Darter.

In 2017, the ABCA surveyed under-sampled reaches in the Upper, Middle and Lower Ausable River for Eastern Sand Darter with funding from the Species at Risk Stewardship Program. No Eastern Sand Darter were captured (Desy 2025).

DFO, Conservation Authorities (CAs), MNR, MECP

Create a population-habitat supply model for each life stage.

2014 to 2016

In Progress

Although a population-habitat supply model has not been developed, several studies were necessary pre-cursors, which includes aquatic habitat mapping using an acoustic doppler current profiler for occupied stretches of the Grand River in 2022, and for the Thames River in 2021. Results indicated that occupied sections of the Grand River contained enough depositional substrates that suitable habitat is likely not limiting for the species in the Grand River (DFO unpublished data; Illes et al. 2024).

An Ichthyoplankton study identifying early life stages of fishes in the Sydenham River found Eastern Sand Darter eggs and larvae at 2 sites (Gallage et al. 2023).This study was part of a multi-month larval fish sampling program implemented by DFO to document the occurrence of eggs and larval fishes in the Sydenham River, including Eastern Sand Darter.

A study published in 2021 lists several technological and statistical methods for measuring habitat supply for Canadian freshwater fishes (Castañeda et al. 2021).

DFO, MNR

Based on information gathered, review population and distribution goals. Determine amount and configuration of critical habitat required to achieve goal if adequate information exists. Validate model.

2014 to 2016

In Progress

In 2022, COSEWIC placed the Ontario populations of Eastern Sand Darter into 2 designatable units (DU) based on genetic differentiation and their occurrence in unique habitats (COSEWIC 2022). To date, no progress has been made on updating population and distribution goals.

With respect to critical habitat, a population model by Lamothe et al. (2021) is an important outcome that will be useful for determining population viability and the amount and configuration of critical habitat required for Eastern Sand Darter.

DFO, Committee on the Status of Endangered Wildlife in Canada (COSEWIC)

Monitoring indicates that populations remain extant at known sites. Implementation of management measures in table 7 of the Eastern Sand Darter Recovery Strategy.

Partially met, underway

Targeted sampling has occurred at beaches of Lake Huron, Ausable River, Thames River, Rondeau Bay, Big Otter Creek, and Grand River. During those sampling events, individuals were captured from the Thames River, Sydenham River, Lake St Clair, Rondeau Bay, and Grand River. No individuals were captured from Detroit River, Catfish Creek, Big Creek, West Lake, or Long Point Bay during this same time period. However, no targeted surveys were conducted in these areas.

Existing populations and historical sites and potential habitats have been sampled.

Partially met, underway

Same as above. Historical sites such as Big Otter Creek and the Ausable River were surveyed for Eastern Sand Darter, suggesting these populations have been extirpated. Other historical areas such as Big Creek and Long Point Bay have not had targeted surveys for Eastern Sand Darter in over a decade, with the last specimens captured in 2008 and 1996, respectively.

Gained knowledge of currently occupied and potential of historical habitats.

Partially met, underway

A recent habitat study was conducted in Big Otter Creek where Eastern Sand Darter are believed to be extirpated. The goal of the study was to determine the quality of habitat at historical and targeted sites for possible Eastern Sand Darter translocation (Barnucz et al. 2022b).

Complete description of Eastern Sand Darter critical habitat.

Partially met, underway

Occupancy models confirmed that sites with higher proportions of sandy and fine gravel substrates were more likely to be occupied (Lamothe et al. 2019). These same models showed that the probability of occupancy increased with water depth, clarity, and velocity. A study identifying early life stages of fishes in the Sydenham River found Eastern Sand Darter eggs and larvae at both sites sampled, but a greater proportion were found at the site dominated by sand substrates compared to the site dominated by gravel (Gallage et al. 2023, Dunn pers. comm. 2024). Although these life stages are drifting, these habitat characteristics are consistent with known or suspected Eastern Sand Darter spawning and nursery habitat. Recent studies have also determined the sensitivity of Eastern Sand Darter to water temperature and dissolved oxygen levels (Firth et al. 2021; Firth et al. 2023). These studies will help inform the features, functions and attributes table of future recovery strategies, amendments to existing strategies, and/or action plans for this species.

Monitoring program has been developed.

Partially met, underway

The Eastern Sand Darter sampling conducted by Fisheries and Oceans Canada (DFO) in the Grand River in 2022 was a pilot monitoring program for the species. Much foundational research to inform monitoring program design has occurred. Examples include the progress made with respect to abiotic and biotic variables affecting site occupancy (Lamothe et al. 2019), and the effect of gear type on catch rates and life stage (Reid and Haxton 2017). A paper by Lamothe et al. (2023b) also investigated the power to detect changes in occupancy and abundance of rare freshwater fishes. Further progress has been made on the use of environmental DNA as a sampling method through development of a custom-designed group-specific primer to detect Eastern Sand Darter (Balasingham et al. 2018).

Research has been conducted to clarify number, extent, and severity of threats to Eastern Sand Darter.

Partially met, underway

For the Thames River, the Lower Thames Valley Conservation Authority (LTVCA) produced an in-depth threat assessment report at the subwatershed level. In the Sydenham River, a study found that following invasion, a number of ecologically significant diet overlaps between Round Goby and benthic fishes were observed (Firth et al. 2020). This observation indicated that Round Goby may be leading to community-level changes in feeding strategy, in addition to diet overlap with Eastern Sand Darter. For this reason, the authors state that Eastern Sand Darter should be monitored for any potential habitat shifts in the future.
More recently, 2 studies investigated the physiological response of Eastern Sand Darter to habitat stressors, including oxygen impairment and increasing water temperatures (Firth et al. 2021; Firth et al. 2023).

Research has been conducted to evaluate feasibility of translocations, repatriations, and captive rearing

Partially met, underway

A recent model showed that translocation of Eastern Sand Darter could occur with minimal impacts to source populations (Lamothe et al. 2021).
A habitat study was conducted in Big Otter Creek to determine the quality of habitat at historical and targeted sites for possible Eastern Sand Darter translocation (Barnucz et al. 2022b). As a result of improved agricultural practices, silt-free, sand and fine gravel bars in Big Otter Creek have been restored over time (Lamothe et al. 2023a).
A conservation translocation decision support framework was developed and used to assess if translocation could improve the recovery of the species in Big Otter Creek (Lamothe et al. 2023a).

Outreach program developed and materials distributed

Met, ongoing

Through DFO’s contributions programs, notably the Habitat Stewardship Program (HSP) and the Canada Nature Fund for Aquatic Species at Risk (CNFASAR), funding is provided for species at risk outreach. For this reporting period, a number of organizations received funding for species at risk outreach that includes Eastern Sand Darter. These organizations include the Ausable Bayfield Conservation Authority (ABCA), Grand River Conservation Authority (GRCA), LTVCA, St. Clair Region Conservation Authority (SCRCA), and the Toronto Zoo. Also, DFO’s Species at Risk Program delivers outreach to partners, including Indigenous groups, conservation authorities, and the public on an annual basis.

Formalized partnerships developed to increase awareness and formulate action plans towards recovery

Met, ongoing

Conservation agreements under Section 11 of the Species at Risk Act provide a mechanism to identify and implement recovery and stewardship initiatives. DFO entered into 2 formal section 11 agreements in 2018 with the GRCA and LTVCA for the purposes of ensuring a coordinated approach to the implementation of conservation measures focused on aquatic species at risk in each conservation authority’s watersheds. This approach includes identifying stewardship actions for, and communicating on, Eastern Sand Darter.