Expedition of the Scotian Shelf conservation areas OFI BEcoME Cruise

By Ana Belen Yanez and Emmeline Broad

The summer 2022 expedition of the BEcoME (Benthic Ecosystem Mapping & Engagement) project aimed to collect high-resolution multibeam bathymetry, seabed images and sediment samples from three distinct areas on the Scotian Shelf.

Figure 1. Leeway Odyssey research vessel

Our journey started in Yarmouth in southwestern Nova Scotia on the first of July (Canada day!). It was all hands on deck as we loaded all the research equipment (and multiple backups!) we would likely need onto the vessel R/V Leeway Odyssey which served as our home for 15 days (Figure 1). The charismatic marine life in the waters of Nova Scotia was plentiful, starting from the harbor and accompanying us until the last day (Figures 2 and 3)

Figure 2. Cormorant during our first day of the expedition in the Nova Scotian waters.

Figure 3. Grey seal during our second day of the expedition

Our first station was a coral and sponge conservation area known as Jordan Basin. We deployed the drop camera system (Figure 4) and had the delightful opportunity to document the benthic communities that inhabit this zone.

Figure 4. Recovery of drop camera after survey

Figure 5. Sponges video recorded in Sambro Back

We made a quick stop in Dartmouth to install and test multispectral multibeam in the Bedford basin. After rigorous testing in the harbor close to Halifax, we navigated offshore to map the Sambro Bank sponge conservation area. This area is protected from disturbance (such as that caused by fishery activity) due to dense aggregations of the glass sponge Vazella pourtalesi (Beasley et al., 2018). Our video footage showed that some of the sponges were very tall and abundant! (Figure 5). While half of the team was deploying the camera, a curious sunfish came to explore the vessel, swimming around the whole vessel (Figure 6). We were delighted. These were the type of events that kept our energy high while working hard (Figure 7).

Figure 6. Sunfish around Sambro Bank

Figure 7. Part of the team right after conducting a camera survey

We additionally collected sediment samples from the seabed using a Van Veen grab sampler. After carefully taking the subsamples for microplastic analysis, we were excited to know what was in the sediment. Marine biologists and geographers without distinction were happy to get their hands dirty in the muddy sediment to find fascinating creatures in the samples taken 150 meters under the ocean surface! (Figure 8).

Figure 8. Sieving sediments to observe some of the benthic organisms living at 150m depth

The working days at sea can be intense. During this expedition, we worked in shifts to cover 24 hours a day. However, in the hours of transit to the next site, we could share time with each other by playing table games, enjoying the view, photographing wildlife, relaxing and reading.

The ship's crew knew that we were arriving at our next station, Georges Bank, without the need to check the map due to the abundance of marine life. Herds of dolphins came to meet us, attracted by the bow waves formed by the vessel's passing (Figure 9). During the video sampling, we observed the presence of the sea scallop (Placopecten magellanicus) occurring in patches across the sandy seabed.

Figure 9. Dolphin swimming in Georges Bank's waters

We were fortunate with the weather conditions, and we enjoyed warm sunny days along with the sea breeze during our working hours in Georges Banks. Here we had the pleasure of seeing a pelagic shark swim past the vessel; it was around three meters long! Offshore sunsets and starry nights were breathtaking (Figure 10, 11). However, one night, in particular, was like no other. While mapping Georges Bank, we were lucky enough to witness the last "super moon" of 2022. (Figure 12 ).

Figure 10. Sunset in the Nova Scotian Shelf seen on board RV/Leeway Odyssey

Figure 11. Part of the team enjoying the good weather and candy cotton sky

Figure 12. Supermoon in the Nova Scotian Shelf seen on board RV/Leeway Odyssey

The ocean was rough during our transit as we returned to Jordan Basin to collect some more multibeam. With the rough seas, the vessel rolled a lot. For many, keeping inside the bunk beds when sleeping was a challenge. But, it was worth it. There were plenty of whales and more dolphins playing in the midday sun at Jordan Basin. We obtained good multibeam and the last sediment samples needed to finish all the work we planned for this expedition. We enjoyed our last dinner and got ready to head back to Yarmouth to avoid the forecasted bad weather the following day. Some of us woke up at 5 am to the sound of the vessel already mooring in the harbor. The resident grey seals were curious to accompany us in the last minutes of what will be an unforgettable expedition (Figure 13).

Figure 13. The team arriving back in Yarmouth in southwestern Nova Scotia after more than two weeks of OFI BEcoME expedition. (Picture credits:Emily Gilbert from Ocean School)