Collecting and measuring krill

This clip shows the so called ‘mesopelagic’ net being hauled on board. Stu Hanchet, the science leader, explains the trawl for krill before the krill is emptied out of the net. Chris Jones explains the significance of krill in the food chain of the Antarctic waters before the krill is measured on an electronic board.

Points of interest for teachers:

• Students may want to think about what type of animal krill are and how they have adapted to the environment of the Ross Sea.

• Consider the size of the krill when the scientists measure them on the electronic measuring board and how many samples the scientists might have to measure to reach a point where they feel satisfied that they have a representative sample.

Transcript

STU HANCHET We’re expecting to find some krill in this net. It’s just a random trawl through the mid water. We put the net down at 230 metres and then slowly hauled it up to the surface, coming up a 100 metres every minutes or so. So it wasn’t down for that long. But there were some light krill marks that we saw on the sounder so we would expect to maybe find a few krill in it.

CHRIS JONES Now animals that would feed on this would be whales for example, probably seals, penguins, other fish species. It’s basically one of the most desirable, highly nutritious things you can find in the Ross Sea.