Centre of gravity analysis for 3LNOPs capelin and sand lance in the spring bottom trawl survey

Current Davoren Lab Master's student Scott Morrison has been investigating the patterns of abundance of forage fish species in Newfoundland using long term datasets collected by the Department of Fisheries and Oceans Canada during their spring bottoms trawl survey (1996-2015). Using this data Scott was able to track the abundance of both mature and immature capelin (Mallotus villosus) and sand lance (Ammodytes spp) in the 3LNOP divisions around Newfoundland. See below to watch his centre of gravity videos displaying the changing shape of forage fish abundance in these regions over a span of nearly 2 decades!

Figure 1: Center of gravity (x) and spatial variance (i.e., inertia; ellipse) from the spring multi-species bottom trawl from 1996-2015. Survey shown in red and capelin in blue

Figure 2: Center of gravity (x) and spatial variance (i.e., inertia; ellipse) from the spring multi-species bottom trawl from 1996-2015. Survey shown in red and sand lance in blue

Figure 3: Center of gravity (x) and spatial variance (i.e., inertia; ellipse) from the spring multi-species bottom trawl from 1996-2015. Survey shown in red and immature capelin in blue

Figure 4: Center of gravity (x) and spatial variance (i.e., inertia; ellipse) from the spring multi-species bottom trawl from 1996-2015. Survey shown in red and immature sand lance in blue

Stay tuned for more findings from Scott after his thesis defence in December!