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Fishing for Data

July 15
Day 1: Home is where the Hjort is

​"The object can never be fully attained; new questions will constantly arise, as the knowledge obtained creates the demand for new, and it will always be possible to increase and intensify our comprehension of the vital conditions affecting the organisms in question." Johan Hjort

Johan Hjort was one of the first names I got acquainted with upon starting work at ICES. Not being of scientific pedigree, I half expected to see his name on the staff telephone list; not quite, he'd been dead for over half a century. Although, as astronomers might attest, the Norwegian star's light has continued to burn through the universe of marine biology decades later.

Hjort was an oceanographer, fisheries scientist, and marine zoologist. He penned a book which broke new ground in his field, pioneering fish measurement and aging techniques in the process. He invented things (a gizmo for extricating whale oil from blubber). He had an arsenal of interests. He was also a supporter of the women's rights movements.

Decades later, the lending of his name to a research vessel can be added to the list of legacies. Here is said vessel, posing in the photo underneath. Built in 1990, she's 65 metres long, with 3,000 horsepower and kitted out with everything from acoustic instruments and trawling gear to the device that's dropped into the water to measure its conductivity, temperature and depth (CTD – more on that in the near future). Nine scientists, three guests (two in IT and me) and the crew will call her home for the next 12 days.

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​​Harvesting data

The vessel will plough a number of conceptual North Sea rectangles each 30 x 30 nautical miles​​ (that's 55 terrestrial kilometres​​​ to me and you)​ and based on one degree longitutde and half a degree latitude. Every plot will be surveyed twice: once by Norway on this cruise and then once by either Germany, Scotland or Denmark - three of the other participants - who will also ​​carry out a haul.

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Above is a map of the ICES statistical rectangles that this boat will cover. That's Norway on the right, the tip of the UK in the bottom left and the Shetland Islands brushing the outer border of our area. 

The large black perimeter indicates the bottom trawl survey zone. The vertical yellow strips show where we'll be picking up a saithe - a white fish related to the pollock​​ - via echo-sounding​​​ in  a project unrelated to the IBTS. There's also a special request to search for a record information on hake (blue pen square in top right). This marine mission has many objectives. 

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Here's a zoomed-out version of the previous map with the entire grid of sites to be monitored across the North Sea. You can't really see, but each box has the initials of two the two countries taking care of the trawling printed in it. 

So this (the first map) is the scale that the Johan Hjort will have to cover, cruising across transects​ and trawling at specially designated sites for either 15 minutes or half an hour. Once all the biological data's collected, it will be passed through the mathematical and statistical machine in order for a picture of the fish stocks to be created. We'll get down into the detail over the course of the next few blogs. 

For now, after a four-hour pit stop for refuelling and a choppy welcome to the wider sea beyond the reaches of the fjords, it's just a case of acclimatising to the new home. 

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