The art of preserving a blue marlin | Natural History Museum

The art of preserving a blue marlin | Natural History Museum

January 7, 2020 100 By Bernardo Ryan


So here we are in Hintze Hall, our newly renovated
space. On this ground floor we have ten Wonder Bays, which show the sorts of collections
that we’ve got. So on the east side we have we have extinct
specimens, and on the west side we have extant specimens
that are still in the world today. In one of the Wonder Bays we have a blue marlin
specimen, which represents our wet collections. There’s an amazing story behind how we acquired
this specimen, and it was a very complex journey to get it into the tank. The blue marlin is a species we expect to
see on the other side of the Atlantic. This is only the second blue marlin ever to visit the UK, and the first time we’ve actually been able to preserve a specimen. In September 2016 it stranded itself on a
beach in Pembrokeshire. It showcases the sort of work we do in the Museum, provides a specimen for future research and tells a very interesting current story. Today it’s come out of the freezer.
When thawing is complete we’ll be able to start making it ready for its display tank. Normally, our specimens are preserved in alcohol, but we wanted to use something that was a lot safer. So for the first time in the UK
we’re actually going to preserve the blue marlin in glycerol. Today’s our big day for moving our four-metre
marlin into Hintze Hall. It’s fragile in certain parts of the body, which we must protect during transit. So this is a crucial stage for us.
No going back now. It’s the heaviest specimen I’ve moved for
the Museum, certainly. We estimate it at about 350 kilos. So we’ve finally got the marlin above the tank.
There’s tethers at three points along the body, so this is a tense moment just to
make sure that we’re ready to immerse. From elation at the look of it going into
a tank, we’ve met a setback. [You need to come down here.] The flotation force is much greater than we
thought, the lines are stretching. So we’ve got to stabilise the fish for the night
and think again about these tethers. Initially, it was thought we could use a fluorocarbon
wire, but the marlin proved too much for that, so we’re using marine-grade stainless steel.
We then had to put weights in the tank to hold it down, and we’re gradually stepping
up the concentration of glycerol. So we just need to wait. It will get heavier, and then what it will do is equilibrate. I think it’s really been worth the effort
to get this on public display. I think this is an amazing specimen,
and people can get very close to it and see it in detail, and that’s what I think the public will really
enjoy.