Habitat characterization of Boltenia ovifera and Modiolus in the Head Harbour/West Isles/Passages ecologically and biologically significant areas, New Brunswick, Canada
Authors: Mireault C A , Lawton P , Devillers R 
Published: September 2017

The Fundy Isles region of the Lower Bay of Fundy in New Brunswick, Canada, is a coastal area with a high benthic biodiversity. This has prompted the designation by the Department of Fisheries and Oceans Canada (DFO) of certain areas of this region as DFO
Ecologically and Biologically Significant Areas (EBSA). Boltenia ovifera and Modiolus are two benthic species that have been identified as Vulnerable Marine Ecosystem (VME) indicator species that aid to the uniqueness of benthic habitats, but are vulnerable to disturbance. Those species have thus
been considered a key starting point for the assessment of marine species distributions within the EBSA region.
Benthic image and video data collected at thirty stations during the summer of 2016 were analyzed for the presence and abundance of B. ovifera and M. modiolus. Target survey strata were derived using depth and slope characteristics from available multibeam data. Near-seabed drift transects were then
carried out using a surface-deployed camera system. Twenty-five minute videos were analyzed in real time in lab using Transana 3.0 video analysis software. Images were extracted from the videos using FFMPEG software at 30 second intervals and analyzed using PhotoQuad 2.4. Biological data and a 1m
resolution multibeam dataset of the region were used in General Additive Models (GAM) to produce predictive distribution models of B. ovifera and M. modiolus.
Preliminary results of these models show that seafloor slope and depth (p = &amp;lt; 0.001, n=809) are variables explaining the distribution of B. ovifera, findings that are consistent with previous studies. However, these models performed poorly in terms of the overall model output for both the
image (r2 = 16.71%) and the video analysis (r2 = 9.56%). These new surveys have added significantly to our knowledge of the area- and depth-related distribution of B. ovifera. Finding significant aggregations of this species at depths to 75m on hard substrates suggests that prior assessments
on the presence of sensitive benthic habitat in this coastal region underestimated the actual extent.
Unfortunately, there were only a limited number of observations for M. modiolus due to difficulties identifying them in the video and image data. This has precluded developing robust GAM models for M. modiolus at this time. The seabed camera was also equipped during the 2016 seabed surveys with a
Nikon digital still camera that obtained higher-resolution imagery. Those additional images will be analyzed to help increase M. modiolus observations. Further data analysis will be conducted to refine the GAM species distribution models and test other modelling techniques, such as Maximum Entropy
(MaxEnt) and Boosted Regression Tree (BRT). These models will hopefully provide insight on the impacts of the environmental factors that influence the distribution of B. ovifera and M. modiolus within the EBSA region and provide geospatial predictions of high quality habitat for consideration of
conservation planning approaches.