Ocean research peeps, especially any of you who study animal movement, I've got a question for you. I've got data from the Labrador Sea in Nov/Dec that appears to show lots of swimming creatures(?) that comes upwards in the water column (from below 15m to about 10m) when it's daylight and disappear back down at night. It's definitely correlated with light (not there on completely overcast days), and it's definitely movement (ADCP scattering that's not at the bulk water velocity). What's weird is that it seems to come up during the day. Has anyone got any idea what that might be?
I'm seriously wondering whether it's because herring sleep at night and swim during the day. Is that at all reasonable?
@helenczerski it sounds like you should talk to the Greenland natural resources institute - I can put you in touch if you need a contact!