Structure from motion images collected during marine debris surveys at coral reef sites entangled with derelict fishing nets at Pearl and Hermes Atoll in the Northwestern Hawaiian Islands in 2018 and 2021

The photographs described in this dataset were collected using a Structure from Motion (SfM) approach during in-water marine debris swim surveys conducted by snorkelers in search of derelict fishing nets. Surveys were conducted by the NOAA Fisheries, Ecosystem Sciences Division (ESD) at Pearl and Hermes Atoll in the Northwestern Hawaiian Islands (NWHI). Initial surveys occurred from September 24 - October 3, 2018 during an ESD-led marine debris removal mission aboard the NOAA Ship Oscar Elton Sette, and follow-up surveys occurred from September 13-14, 2021 on a joint mission with non-profit organization Papahanaumokuakea  Marine Debris Project aboard the M/V IMUA.

During the 2018 mission, only a subset of marine debris surveys resulted in a SfM survey. Fishing nets were located during swim surveys and selected for SfM if the net was interacting with coral or hard substrate, the depth of the net was within ~1- 4 m of the surface, and the area of the net fit within the 9 sq. meter SFM survey plot. During a SFM survey, a permanent 3 x 3 m plot was established around the center of the fishing net, and the net was photographed using a back and forth swim pattern ("before" photos) for later processing using a SfM approach. The net was then removed and the same area was photographed again in the same way ("after" photos). A nearby (>50 m distant) paired control site was also photographed using the same method ("control" photos).

During the 2021 mission, relocation of all paired sites where "after" and "control" photos were taken in 2018 was attempted; if found, the permanent 3 x 3m plot was reimaged using the same SfM approach. Only a subset of 2018 sites were successfully relocated in 2021 (12 "after" sites, 8 "control" sites), and five new nearby "control" sites had to be established to fulfill the paired study design.

Tags: aquatic habitat, bathymetry/seafloor topography, benthic, benthic habitat, biosphere, camera, central pacific ocean, coastal processes, continent, coral reef, coral reef ecology, coral reef ecosystem division, coral reef ecosystem program, coral reef studies, coral reefs, corals, country/territory, cred, crep, derelict fishing gear, doc/noaa/nmfs/pifsc, earth science, ecosystem sciences division, ecosystems, esd, fishing nets, habitats, hard seafloor substrate, hawaii, hawaiian islands, honolulu, images, in situ, m/v imua, marine debris, marine debris program, marine ecosystems, marine environment monitoring, marine submerged debris, national marine fisheries service, nmfs, noaa, north america, north pacific ocean, northwestern hawaiian islands, northwestern hawaiian islands (28n178w0000), nwhi, ocean, ocean basin, oceans, oscar elton sette, pacific islands fisheries science center, pacific ocean, papahanaumokuakea marine national monument, pearl and hermes, pearl and hermes reef (27n176w0001), photographic analysis, phr, pifsc, pmnm, reef, reef damage assessment, reef habitat, reef monitoring and assessment, sfm, structure from motion, u.s. department of commerce, united states of america, us doc, visual images, zoology
Organization: National Oceanic and Atmospheric Administration, Department of Commerce