Troubled waters

Another week gone! Time is running out but we are very focused on the day to day. Yesterday we took 6 hauls that gave enough to do. Here we always talk about the target species, but yesterday a total of 112 species of fish where collected, plus the invertebrates. And the catch per species ranged from 1g to 1t. The “cloud range” was less variable, from thick fog to completely overcast. But at least the fog vanished in the evening and when the sun went below the clouds there was a very beautiful sunset that Jose Luis photographed.

Atardecer en el Gran Banco por Jose Luis del Río

 

Teo's team at full throttle: Jose Luis V, Jose, José and David in the background, Fergus, Vanessa C and Rubén.

Today is way windier than yesterday, but the salts in the bridge know their trade and we are working normally. The weather may worsen tomorrow but we hope we will be able to work. So far today we have been between 40 and 60 m, and the hauls have been quite unequal in terms of catch, but always dominated by yellowtail flounder. Now we are looking for deeper bottom for the next haul. Meanwhile Nair carries on, with the CTDs and typing data. The CTD casts take their time, because they are not just about throwing the data logger overboard. Nair has to start it before each haul, record cast number and coordinates, download the data when the CTD comes back on board (which requires drying the plugs very well), check that the data logger worked properly, and at night it is necessary to clean the tubes through which the water circulates. I would not be surprised if she wraps it in a blanket before she goes to sleep. But the fact is that the CTD is working better than ever.

Nair does not waste a minute.

 But let’s talk fish. In the deepest haul we took yesterday we caught these tiny spiny lumpfish, barely 5 cm in length. They are called Eumicropterus spinosus and they are fairly common in the North Atlantic, but I have seen in an article by Casey and Myers (1998) that they are best caught at night. I opened one of them and it turned out to be a spawning female, and the eggs, orange coloured, had a diameter about 3 mm. Quite big for a tiny fish. Like in other lumpfish, the pelvic fins are modified like a disc with which they adhere to the bottom. These fish are passive to the point of being caught by divers, so the Norwegians Berge and Nahrgang (2013) were very surprised when they found in their stomachs plenty of amphipods called Themisto libellula, which move fast and are pelagic – they do not live on the seabottom. Berge and Nahrgang carried out further sampling to verify if the discovery had been just chance, but no, those amphipods seem to be the favorite course of spiny lumpfish. It is known that the zooplankton (of which the amphipods are part) undertakes daily vertical migrations: they go to the surface at night to feed and during the day they hide in deeper layers. What Berge and Nahrgang proposed is that perhaps many of the zooplankton species actually make it all the way to the seabed, rather than simply descending into layers where light is scarce. In other words, the spiny lumpfish have their food home delivered.

"Will he EVER shut up? Where is lunch?"