Occurrence and percent cover of the colonial invasive tunicate Didemnum vexillum from near-seafloor drift transect video imagery and high-resolution digital still images in the western Bay of Fundy

Occurrence and percent cover of the colonial invasive tunicate Didemnum vexillum from near-seafloor drift transect video imagery and high-resolution digital still images in the western Bay of Fundy Funded under DFO's Marine Conservation Targets Program, this optical imagery benthic survey documents the occurrence and estimated percent cover of the invasive colonial tunicate, Didemnum vexillum in seven drift-camera transects in the 'Head Harbour/West Isles Archipelago/The Passages' Ecologically and Biologically Significant Area (ESBA, ~113km2) in the western Bay of Fundy, New Brunswick, Canada. Occurrence data was derived from the use of high-resolution still images (n=386) taken periodically throughout each transect, and simultaneous continuous high-definition video. Video was divided into 20-second segments (here, we report the start and end location of each segment within a transect) and when D. vexillum was present in a video segment, frequency of occurrence was classified as common (continuous coverage/patches throughout the video segment), occasional (individual colonies of various sizes encountered >5 times throughout the video segment), or rare (small, isolated colonies encountered ≤5 times throughout the video segment). A video segment was deemed unusable and removed from the dataset if there was too much turbidity, or if the camera position was too high off-bottom to reliably image the seafloor. For still images, when D. vexillum was observed in an image, colony percent cover was categorized as >50%, 26-50%, 6-25%, or ≤5% of the images field of view (FOV). Distance travelled and distance between still images (m) was calculated using ArcGIS tools. FOV was estimated by measuring the length and width of a subset of still images and video frame grabs in ImageJ2, using 10-cm lasers for scale. FOV was standardized for each reported altitude, and area sampled (m2) along a continuous video segment was estimated by multiplying the average FOV by the distance travelled in that segment. D. vexillum was found in 44% of the area sampled at depths from 34 to 118m, deeper than previous reports globally of ~80m. 2024-04-11 Fisheries and Oceans Canada Peter.Lawton@dfo-mpo.gc.ca Nature and EnvironmentScience and TechnologyRegional and National Core fundsMarine Conservation TargetOceansEnvironmentInvasive speciesAquatic ecosystemsCoastal waters Data dictionaryCSV https://api-proxy.edh.azure.cloud.dfo-mpo.gc.ca/catalogue/records/8ea6c28a-3d6c-47ef-8cf7-56790ee0c7f5/attachments/Data_Dictionary.csv Percentage Cover Image D vexillum Bay of Fundy 2022CSV https://api-proxy.edh.azure.cloud.dfo-mpo.gc.ca/catalogue/records/8ea6c28a-3d6c-47ef-8cf7-56790ee0c7f5/attachments/PercentageCover_Image_D_vexillum_BayFundy_2022.csv Start End Video Transect D vexillum Bay of Fundy 2022CSV https://api-proxy.edh.azure.cloud.dfo-mpo.gc.ca/catalogue/records/8ea6c28a-3d6c-47ef-8cf7-56790ee0c7f5/attachments/Start_End_Video_Transect_D_vexillum_BayFundy_2022.csv Occurrence Percent Cover Transect Video D vexillumFGDB/GDB https://api-proxy.edh.azure.cloud.dfo-mpo.gc.ca/catalogue/records/8ea6c28a-3d6c-47ef-8cf7-56790ee0c7f5/attachments/Occurrence_PercentCover_TransectVideo_D_vexillum.zip Occurrence and percent cover of the colonial invasive tunicate Didemnum vexillum from near-seafloor drift transect video imagery and high-resolution digital still images in the western Bay of FundyESRI REST https://gisp.dfo-mpo.gc.ca/arcgis/rest/services/FGP/Bay_of_Fundy_Occurence_PercentageCover_Didemnum_Vexilum/MapServer Occurrence and percent cover of the colonial invasive tunicate Didemnum vexillum from near-seafloor drift transect video imagery and high-resolution digital still images in the western Bay of FundyESRI REST https://gisp.dfo-mpo.gc.ca/arcgis/rest/services/FGP/Bay_of_Fundy_Occurence_PercentageCover_Didemnum_Vexilum/MapServer

Funded under DFO's Marine Conservation Targets Program, this optical imagery benthic survey documents the occurrence and estimated percent cover of the invasive colonial tunicate, Didemnum vexillum in seven drift-camera transects in the 'Head Harbour/West Isles Archipelago/The Passages' Ecologically and Biologically Significant Area (ESBA, ~113km2) in the western Bay of Fundy, New Brunswick, Canada. Occurrence data was derived from the use of high-resolution still images (n=386) taken periodically throughout each transect, and simultaneous continuous high-definition video. Video was divided into 20-second segments (here, we report the start and end location of each segment within a transect) and when D. vexillum was present in a video segment, frequency of occurrence was classified as common (continuous coverage/patches throughout the video segment), occasional (individual colonies of various sizes encountered >5 times throughout the video segment), or rare (small, isolated colonies encountered ≤5 times throughout the video segment). A video segment was deemed unusable and removed from the dataset if there was too much turbidity, or if the camera position was too high off-bottom to reliably image the seafloor. For still images, when D. vexillum was observed in an image, colony percent cover was categorized as >50%, 26-50%, 6-25%, or ≤5% of the images field of view (FOV). Distance travelled and distance between still images (m) was calculated using ArcGIS tools. FOV was estimated by measuring the length and width of a subset of still images and video frame grabs in ImageJ2, using 10-cm lasers for scale. FOV was standardized for each reported altitude, and area sampled (m2) along a continuous video segment was estimated by multiplying the average FOV by the distance travelled in that segment. D. vexillum was found in 44% of the area sampled at depths from 34 to 118m, deeper than previous reports globally of ~80m.

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Delivery Point: 125, Marine Science Drive

City: St. Andrews

Administrative Area: New Brunswick

Postal Code: E5B 0E4

Country: Canada

Electronic Mail Address: Laura.Teed@dfo-mpo.gc.ca

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