Do you ever wonder what the bottom of the ocean actually looks like? For starters, it’s a pretty dark place. But shine a little light and you can learn a lot about the animals that live there and what the ecosystem looks like.
I am a field scientist on the Gulf of Maine Bottom Longline Survey. For more than a decade, we have been collecting data on species that prefer rocky habitats, which are challenging to sample using trawl gear. We conduct our survey in the western and central Gulf of Maine in partnership with the region’s commercial fishing industry. The data we collect complements data collected during the science center’s fall and spring Bottom Trawl Surveys. The data from both surveys help us understand changes in fishery stock abundance and distribution, information that is critical to fisheries management.
Capturing Video on the Ocean Floor
In addition to setting and hauling longline gear, our team also deploys a drop camera system at each of our stations after we set the gear. After more than a decade of deploying equipment to the bottom of the ocean, we have refined our design to combat some of the challenges that come with gathering video data from the ocean floor.
The frame of our camera system is constructed out of plastic-coated wire. It is heavy and shaped like a pyramid to minimize the cage tipping over, although this still occurs occasionally. Fixed to the frame are three dive lights that are rated to 1,000 feet because our stations range from 60–900 feet deep. We place a GoPro camera on top of the frame to capture video footage of the bottom composition at each of the stations, which we annotate after the survey season. This involves classifying the habitat composition by rock size diameter and documenting the invertebrate and fish species seen on video.
In addition to the fish composition, we can learn a lot from this footage of the seafloor and set expectations for how much weighing, measuring, and sampling of fish we might be working through when our fishing gear comes back onboard in the next 90 minutes. For example, a smooth station that is free of rocks will likely result in less catch. Whereas a hard bottom area with boulders, cobble, or gravel is likely to produce a bountiful haul. This is because fish, especially groundfish species, are attracted to structured bottom areas as they often provide opportunities for shelter and feeding.
Encounters with Marine Life and Human Influence
Throughout the years and hundreds of drops to the bottom, our team has seen some interesting things, including a propeller from a boat, hagfish and—my personal favorite—an octopus. In rare instances, we have encountered visitors on our way down to the bottom. On one occasion, a curious porbeagle shark decided to check out our camera cage. The team continues to see new things. On our most recent fall 2025 survey, the bottom video captured a rare sighting of a thorny skate on video.
Whether it is a new sighting or a staple encounter such as red hake, which are infatuated with the illumination supplied by our dive lights, every descent inspires awe and curiosity from scientists and crew alike. It is exciting how a small glimpse of light can help the captains we work with form a better understanding of their second home, which largely remains unseen from above.
