Lucas A. Le Tarte Collin Farrell Alex Gatch Georgia Hoffman Brian O'Malley Melanie Croft-White Jessica Goretzke Michael Connerton Brent Metcalfe Dimitry Gorsky Kyle Morton R Josephine Johnson Olivia Mitchinson Brian Weidel Emma Bloomfield Tim Johnson Sarah Larocque Jon Midwood Krystal Dixon Alec Cimini 20250411 tabular digital data Reston, VA U.S. Geological Survey Lucas A. Le Tarte, U.S. Geological Survey Great Lakes Science Center, https://orcid.org/0009-0003-6253-2352; Collin J. Farrell, U.S. Fish and Wildlife Service, https://orcid.org/0000-0001-7591-6775; Alexander Gatch, U.S. Geological Survey Great Lakes Science Center, https://orcid.org/0000-0003-4429-1121; Georgia Hoffman, U.S. Geological Survey Great Lakes Science Center, https://orcid.org/0000-0002-9769-0436; Brian P. O'Malley, U.S. Geological Survey Great Lakes Science Center, https://orcid.org/0000-0001-5035-3080; Melanie Croft-White, Fisheries and Oceans Canada, https://orcid.org/0000-0001-6705-6920; Jessica Goretzke, New York State Department of Environmental Conservation, https://orcid.org/0000-0003-2504-3712; Michael J. Connerton, New York State Department of Environmental Conservation ; Brent Metcalfe, Ontario Ministry of Natural Resources and Forestry; Dimitry Gorsky, U.S. Fish and Wildlife Service, https://orcid.org/0000-0003-1708-539X; Kyle Morton, U.S. Fish and Wildlife Service, https://orcid.org/0009-0008-2231-9000; Olivia Mitchinson, U.S. Geological Survey Great Lakes Science Center, https://orcid.org/0009-0002-7999-1160; Brian Weidel, U.S. Geological Survey Great Lakes Science Center, https://orcid.org/0000-0001-6095-2773; Emma Bloomfield, Ontario Ministry of Natural Resources and Forestry; Tim Johnson, Ontario Ministry of Natural Resources and Forestry; Sarah Larocque, Fisheries and Oceans Canada, https://orcid.org/0000-0002-2088-4988; Jon Midwood, Fisheries and Oceans Canada; Krystal Dixon, U.S. Geological Survey Great Lakes Science Center, https://orcid.org/0009-0000-6104-2536; Alec Cimini, U.S. Geological Survey Great Lakes Science Center, https://orcid.org/0009-0002-7704-8603 https://doi.org/10.5066/P142DF65 This dataset is the result of international collaborative efforts by the United States Geological Survey, the United States Fish and Wildlife Service, the New York State Department of Environmental Conservation, the Ontario Ministry of Natural Resources and Forestry, and the Canadian Department of Fisheries and Oceans. These data provide substrate information along the shoreline of Lake Ontario between 3 and 30 meters in depth. We used drop camera videos to classify substrates with the goal to quantify the amount of quality habitat that could potentially be used for Lake Trout (Salvelinus namaycush) spawning and egg incubation. The videos described within this data release are in zipped files, organized by the collecting agency. Data were collected as part of the Lake Ontario 2023 Cooperative Science Monitoring Initiative project to assess substrates across the near-shore areas of the Lake. The data sets are intended for use by Lake Ontario fisheries managers, biologists, and the public. This data is reported to provide information regarding the quantity and quality of lithophilic spawning habitat, particularly for Lake Trout (Salvelinus namaycush), and to inform future habitat restoration projects within Lake Ontario. This dataset includes date/time information for data collection and video analysis. 20230801 20241105 ground condition Complete None planned Lake Ontario -79.7700 -76.1200 44.2900 43.1800 ISO 19115 Topic Category environment inlandWaters USGS Thesaurus lakebed characteristics fish freshwater ecosystems USGS Metadata Identifier USGS:6793732cd34e88f5864c50af None Spawning Habitat Ground Truth Lake Trout Salvelinus namaycush Common Geographic Areas Lake Ontario No access constraints No use constraints Lucas A. Le Tarte Fish Biologist mailing and physical

Lake Ontario Biological Station,Lake St and W 3rd St

Oswego NY 13126 315-343-3951 lletarte@usgs.gov Individuals from the United States Fish and Wildlife Service, the New York State Department of Environmental Conservation, the Ontario Ministry of Natural Resources and Forestry, and the Canadian Department of Fisheries and Oceans who helped to collect the videos used in this survey. Data was collected using Seaviewer recording software. Dataset structure and manipulation was conducted in Microsoft Excel. Further data manipulation, data analysis, and mapping was conducted in R studio and ArcGIS Pro. ~950 of ~6900 substrate classifications were reviewed for the sake of ensuring accuracy of the original classifications. These reviews yielded ~99% agreement. All data were reviewed for transcription errors, omissions, and duplications. Data were checked by multiple reviewers manually, and by using code in Microsoft Excel and Rstudio. The tables "LTSHSI_SUBSTRATEIMAGE_CMECS_REVIEW_RAW" and "LTSHSI_SUBSTRATEIMAGE_CMECS.csv" contain the same columns, but the "REVIEW" file does not contain Confidence data. The Confidence rating was the metric by which the original interpreter flagged videos for secondary review. Since the secondary interpreter was not flagging data for further review, the Confidence column was not necessary. Coordinates were plotted to Google Earth Pro, ArcGIS pro, and on vessel chart plotters to ensure positional accuracy. Not applicable Marine and Coastal Spatial Data Subcommittee Federal Geographic Data Committee 2012 publication https://repository.library.noaa.gov/view/noaa/27552 Digital and/or Hardcopy 2012 publication date CMECS This source was used as guidance for creating our substrate classification methods Video Collection: Each agency was equipped with a Seaviewer HD Admiral Pro drop camera setup, which consisted of a camera, ~ 30m of cable, and a base station to view and record video from a research vessel. Default camera settings were used. The camera component of the drop camera system was fitted to a stainless-steel cage that served to protect the camera, provide the videos with scale, and allow interpretations of the depth of soft sediments (e.g., silt) present at each sampling point. The camera was lowered to the lake bed from the vessel until contact was made. Depending on factors such as currents and depth, videos were typically between 10-30 seconds long. Five videos were taken at each site to reduce the bias of a single video. Videos were taken anywhere from 5-15m apart and were classified independently of the other videos at the site. Each video was saved directly to an SD card, and later uploaded for substrate classifications. We used the default system settings of the Seaviewer drop camera. 20250121 Lucas A. Le Tarte Fish Biologist mailing and physical

Lake Ontario Biological Station,Lake St and W 3rd St

Oswego NY 13126 315-343-3951 lletarte@usgs.gov Substrate Classifications: Videos were transferred to USGS for substrate classifications. We based our substrate classifications on the Coastal and Marine Ecological Classification Standard (CMECS) developed by NOAA (URL : https://repository.library.noaa.gov/view/noaa/27552). We retained the substrate size definitions for our classifications, but we did not classify substrates to the finer-scale level of CMECS. Classifications included identifying the primary subgroup, secondary subgroup, interstitial spaces, substrates under mussel reef, silt thickness, presence of vegetation, and the amount of vegetation. There were a total of 7 subgroups, broken into Geologic and Biogenic origins. Geologic subgroups included Bedrock (>4096mm), Boulder (256mm-4096mm), Cobble (64mm-256mm), Pebble (4mm-64mm), and Fines (<4mm). Biogenic subgroups included Mussel Hash (dead mussel shells) and Mussel Reef (live mussels). We limited the number of subgroups compared to the original CMECS in order to accommodate the volume of videos collected in this survey, while also allowing us to include data that we found relevant, such as information regarding interstitial spaces, silt, and vegetation. CMECS 20250121 Lucas A. Le Tarte Fish Biologist mailing and physical

Lake Ontario Biological Station,Lake St and W 3rd St

Oswego NY 13126 315-343-3951 lletarte@usgs.gov Classification Reviews: After each video had been classified by a single initial interpreter, a subset of classifications was reviewed by an additional interpreter to eliminate the bias of a single interpreter. This subset included videos that were found to be of confidence level 3 or lower and contained 924 of the 6687 total videos. Reviewers were asked to independently classify the substrate videos using the methods described above. When comparing the review classifications to the original classifications, there was a 99.3% similarity across all categories. These reviews can be seen in LTSHSI_SUBSTRATEIMAGE_CMECS_REVIEW_RAW.csv. URL : https://repository.library.noaa.gov/view/noaa/27552 20250121 Lucas A. Le Tarte Fish Biologist mailing and physical

Lake Ontario Biological Station,Lake St and W 3rd St

Oswego NY 13126 315-343-3951 lletarte@usgs.gov LTSHSI_METADATADICTIONARY.csv Comma Separated Value (CSV) file containing data. Producer Defined ENTITY_NAME name of a table in the data release Producer Defined text ATTRIBUTE_NAME name of a field or column within a given table Producer Defined . Not Applicable Producer defined text DATA_DESCRIPTION more detailed description of the ATTRIBUTE_NAME or field or column Producer Defined text UNITS the units that the data are represented in Producer Defined . Not Applicable Producer defined DATA_FORMAT the format of the data Producer Defined . Not Applicable Producer defined text NULL_VALUE are null values allowed. 'Y' for yes, 'N' for no Producer Defined N no Producer defined Y yes Producer defined . Not Applicable Producer defined NULL_VALUE_DESCRIPTION defines what a null value indicates Producer Defined . Not Applicable Producer defined text DERIVED_VALUE were the data in this column derived? 'N' for no and 'Y' for yes Producer Defined Description of zipped files: OMNRF.7Z: Zipped file that contains videos collected from the Ontario Ministry of Natural Resources and Fisheries. DFO.7Z: Zipped file that contains videos collected from the Canadian Department of Fisheries and Oceans. LOU DEC.7Z: Zipped file that contains videos collected from the Lake Ontario Unit, New York State Department of Environmental Conservation. USFWS.7Z: Zipped file that contains videos collected from the United States Fish and Wildlife Service. USGS.7Z: Zipped file that contains videos collected from the United States Geological Survey. U.S. Geological Survey - ScienceBase mailing address

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Denver CO 80225 1-888-275-8747 sciencebase@usgs.gov Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government . Digital Data https://doi.org/10.5066/P142DF65 No fees are associated with these data 20250813 Great Lakes Science Center mailing and physical

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Ann Arbor MI 48105 US 734-994-3331 GS_ASK_GLSC@usgs.gov FGDC Biological Data Profile of the Content Standard for Digital Geospatial Metadata FGDC-STD-001.1-1999