Identification and Characterization of Atlantic Halibut (Hippoglossus
hippoglossus) Habitats with Bathymetric Data Supplemented with Seafloor
Video Observations
Abstract
The utilization of first-order information about seafloor morphology,
derived from multibeam sonar data, has become common in the
investigation of deep-sea benthic habitats. When combined with
complementary datasets, these data can be used to study deep-sea coral
ecosystems and predict environments that are favorable for fish
spawning, larval nurseries, and juvenile fish habitats. The
identification and protection of these environments is critical where
biodiversity is vulnerable or unique in order to rehabilitate or
maintain ecological communities and encourage higher fecundity. In
August of 2019, the expedition Deep Connections: Exploring Atlantic
Canyons and Seamounts was conducted to explore understudied deep-sea
environments aboard the NOAA Ship Okeanos Explorer off the coast of the
United States and Canada (EX1905L1 and EX1905L2). This expedition
included multibeam mapping and seafloor exploration with a Remotely
Operated Vehicle (ROV). Observations from ROV dives include several fish
species including multiple sightings of Atlantic halibut (Hippoglossus
hippoglossus), which is considered endangered on the International Union
for Conservation of Nature Red List of Threatened Species. Identifying
and classifying the habitats where Atlantic halibut is observed would
facilitate future endeavors of protection or rehabilitation. Spawning
events are known to coincide with areas of increased seafloor slope
associated with high energy systems such as canyons. Utilizing multibeam
data included in the Global Multi-Resolution Topography (GMRT)
Synthesis, we characterize canyons at the edges of George’s and Brown’s
Banks based on morphology, roughness, and seafloor slope and aspect. We
combine these data with observations of Atlantic halibut from ROV video
to seek correlations that can be used to identify potential habitats.
This information can be used to guide further exploration and
characterization of the seafloor to better understand the spatial extent
of Atlantic halibut habitat in the region.