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Catching plankton, fish and jellyfish

Bottom trawling was conducted today on shallow depths close to the coast. Unfortunately, there were no big catches of gobies or hakes. The research vessel will therefore head offshore to deeper waters in the hope of larger catches for the marine biological experiments on board.

Above:
The sun also rises over ”G.O. Sars” on its cruise at Skeleton Coast.

Today’s research has primarily focused on behavioural studies on gobies. One aim was to study the goby preference for seafloor; sand or mud. So far it appears that the goby prefers mud, but the scientists will continue with the experiments before concluding. Another behavioural study concerns the relationship between gobies and jellyfish. The researchers have put a fence between gobies and jellyfish. This allows gobies to move between the empty and the jellyfish compartment, while the jellyfish is stuck in one of the compartments. This is done to study if the fish associate with, or is indifferent to jellyfish. So far, it seems like the goby is totally indifferent to the jellyfish, and has no hesitations visit its poisonous neighbour, on the other side of the fence.


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It seems like the goby is indifferent to the jellyfish’ poison, and has no hesitations visit its poisonous neighbour, on the other side of the fence.

One of the more exiting equipments is the MOCNESS plankton net. The equipment is invented by the American Peter H. Wiebe, who participated in “G.O. Sars”’ previous Antarctic cruise. The MOCNESS has several environment sensors, and collect environmental data such as salinity, temperature and light levels. One of the advantages is that the MOCNESS can be operated from the control room of the ship, and at the same time compare its data with those read from other instruments on board. It has also several nets which can be opened and closed at chosen depths in the pelagic or at different times. Various animals migrate to the upper part of the ocean at different times. The MOCNESS creates the possibility to catch organisms from specific depths and at chosen times to study these processes by using open and closing devices on the nets.


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The MOCNESS is being put to ocean. It is a plankton collector with various sensors and nets which can be opened and closed at chosen time and depths.
ukkes etter behov.

 

Written by

Kim E. Andreassen
University of Bergen