BaySys is a 4-year collaboration among industry partner Manitoba Hydro (Hydro Québec and Ouranos) and the Universities of Manitoba, Northern British Columbia, Québec à Rimouski, Alberta, Calgary, Laval and Trent to conduct oceanographic research in Hudson Bay. The overarching goal of the project is to understand the role of freshwater in Hudson Bay marine and coastal systems, and in particular, to create a scientific basis to distinguish climate change effects from those of hydroelectric regulation of freshwater on physical, biological and biogeochemical conditions in Hudson Bay.

In late September 2016, five oceanographic moorings were deployed (Hornby et al., 2016)in the eastern Hudson Bay and at the entrance to James Bay (Figure 1). These moorings were supposed to be recovered in summer 2017 during the BaySys cruise onboard CCGS Amundsen or R/V William Kennedy. Later, a decision was made on turning the moorings from R/V William Kennedy instead of recovery. Due to the slow progress of the ship’s inspection from Transport Canada, the 2017 cruise was cancelled. An opportunistic cruise onboard CCGS Henry Larsen was successfully conducted on October 26 – November 1, 2017, for retrieval and re-deployment of some of BaySys moorings accompanied by the concurrent CTD and water sampling (Kirillov et al., 2018, 2020; Petrusevich et al., 2020). Unfortunately, mooring JB02 was not recovered during that operation. Finally, MV William Kennedy was ready for field operations in 2018, therefore there was conducted a cruise on September 1-14, 2018 with the main goal of recovery of the mooring JB02 and conducting additional bathymetry surveys, water sampling and CTD casts during transects and in Nelson River estuary