Several people have asked why the water went from a clean, clear, inviting bath to a rather horrible-looking soup over the course of the squid defrosting.
The answer is that a number of frozen fluids in the ice block were gradually released into the brine. The first unsalubrious additive was a yellow slurry of fish waste that had gotten mixed into the ice cake on top of the squid, in a layer about 10cm thick. As we examined and dissected the smaller colossal and the giant squid, some of their body fluids (ink and leakage from the digestive gland – sorry you asked yes?) also inevitably got mixed into the main tank from our waders, in spite of being rinsed.
Because we have not dissected the large colossal specimen, we don’t know what condition its internal organs are in, but it is likely that similar fluids (in higher volumes) would also have been released into the brine as it defrosted, plus haemolymph (the squid’s blue, copper-based ‘blood’).
As a cranchiid, Mesonychoteuthis also possesses a large sac within the mantle (the coelom) filled with ammonium chloride to assist its buoyancy. This may also have leaked into the tank. Finally, by the time the innermost ice had melted, the outermost parts of the specimen had been defrosted for over 36 hours and had entered the very early stages of decomposition. The bacteria present would have begun to break down the tissues and also release chemicals and compounds into the water.
This does not mean, however, that parts of the specimen have rotted – we were able to add the formalin at a time when all parts of the squid were thawed and in good condition. If the squid had defrosted in air, the outer parts would certainly have rotted before we even saw the inside, so the cooled brine solution worked well – even if we had to wade through squid soup by the end. 
- Kat Bolstad
