Simple Video System Used to Validate Bottom Stratification in the Design of a Pilot Cooperative Bottom Longline Survey of Rocky Habitat in the Gulf of Maine

In an effort to supplement the limited data from complex rocky habitat currently sampled by bottom trawl surveys (BTS), the Northeast Cooperative Research Program (NCRP) at the Northeast Fisheries Science Center (NEFSC) initiated a Gulf of Maine pilot bottom longline survey (LLS). The LLS allowed for opportunities to sample species that inhabit complex bottom that mobile (BTS) gear sometimes has difficulty sampling. Building off the BTS depth and area stratified random design; the LLS further stratified using a bathymetric model that classified bottom ruggedness into smooth and rough classes. Lights and GoPro camera housings built to withstand depths exceeding 250m were mounted on a weighted vertical stand designed to be deployed and retrieved using the hydraulic haulers on the small commercial survey vessels. Bottom types commonly observed ranged from sand and mud to cobble and medium sized boulders. In addition to several species of fish, invertebrates such as anemones and echinoderms were also observed which informed the species composition between the bottom classes. The footage collected aids in the reclassification and auditing of the data for bottom type and improves the LLS design, the results of which will inform the assessments for several species.