Oral Session 2

Insights into detecting surface Calanus finmarchicus populations in the optically complex waters of the Gulf of Maine: leveraging ocean color remote sensing

The planktonic copepod Calanus finmarchicus (C. finmarchicus) is a primary food source for many pelagic species, including the critically endangered North Atlantic right whale (NARW) in the Gulf of Maine (GoM). Changes in C. finmarchicus distribution may impact the migratory patterns of NARW. The astaxanthin pigment in C. finmarchicus influences the optical properties of water during surface swarming. Therefore, utilizing ocean color remote sensing to detect the surface abundance of C. finmarchicus in the GoM could facilitate tracking this keystone species on a regional scale, ultimately supporting its monitoring efforts. This study investigates the potential of ocean color remote sensing in detecting C. finmarchicus populations in the GoM. Employing a technique developed off the coast of Norway, which integrates satellite imagery with radiative transfer modeling, we aim to estimate surface C. finmarchicus concentration in the optically complex waters of the GoM. We detected the presence of C. finmarchicus swarms in ocean color imagery, with our study revealing significant potential to observe and quantify swarms of C. finmarchicus in the GoM. However, we also identified a number of limiting factors that require further work before the technique can be routinely applied in optically complex waters. Results point to being able to identify astaxanthin-based anomalies in ocean color signals, with a requirement for local knowledge of sources in order to convert to species abundances.

Rebekah Shunmugapandi, Bigelow Laboratory for Ocean Sciences, USA

Jong-Kuk Choi, Korea Institute of Ocean Science and Technology (KIOST), Republic of Korea

Jae Hyun Ahn, Korea Institute of Ocean Science and Technology (KIOST), Republic of Korea

Code of Conduct