Milly: Ugly fish

Stomiid. Image: Camilla Sharkey and Julian Partridge

Milly: Ugly Fish pt 2
Milly: Ugly Fish pt 3
Milly: Ugly Fish pt 4
Milly: Ugly Fish pt 5
Milly: Ugly Fish Pt 6
Milly: Ugly Fish Pt 7

When asked about my summer holiday plans recently, I informed my friend that I would be spending a month off the coast of the UK on a months fishing trip. She laughed; I wasn't joking. Come August I'll be up to my ears in gelatinous, benthic fish brought up from thousands of meters and rather alarmingly I've been purchased full body overalls due to the "repulsive stench" of the fish that "never leaves the fabric". I'll be aboard the RSS James Cook for a month, so to stave off insanity I'm planning to blog from the ship to keeping you up to date with the latest discoveries. It seems to be a little known fact that members of the Bristol Biology department study deep sea fish and so I thought it best to bring a little of the research into the lime light.

Dr Nick Roberts, part of a team of Bristol vision scientists, has gathered together a group to investigate colour and light in nature. As part of this, a new post doc, Dr Juliette McGregor, will be looking at the effect of pressure on photoreceptors. The pressure exerted on deep sea fish is enough to alter the protein structure and this includes that of visual pigments so in August, Juliette and I will be collecting deep sea fish retinal tissue which will be used to examine their spectral properties under pressure (whilst trying not to be sick onto the specimens as we dissect stinky fish...on a rolling boat...in the dark).

Another ongoing project has been looking at the eyes of Malacosteus niger (image below) the stoplight loosejaw, a fish with red eyes, gaping mouth and a light organ underneath each eye that emits red light.

Stoplight loosejaw, Malacosteus niger

Most deep sea animals can only detect blue light (a colour common at depth as many animals produce blue bioluminescence) so by producing red light, M.niger can hunt prey or communicate with other individuals without fear of detection! Now what is particularly amazing about these creatures is what's found in their red eyes. In order to detect longwave red light, they use chlorophyll as a photosensitiser. But that's in plants I hear you shriek! Well, even stranger than that, the visual properties of the pigment is very similar to that found in small crustaceans it eats (see paper). So does M.niger use chlorophyll it obtains from its diet to alter the wavelength of light it can see?! We don't have the full story yet so watch this space...

Dolichopteryx longipes photographed from above

Another amazing discovery was made during a past research cruise by Professor Jochen Wagner (University of Tubingen), Prof. Ron Douglas (City University London) and Prof. Julian Patridge from Bristol. Whilst midwater trawling they discovered a live specimen of Dolichopteryx longipes (image right). Previously only one preserved fish was available for studying this unique species, the only vertebrate found to form images using a mirror instead of a lens which reflects light onto a second retina.

These fish appear to have four eyes and although there are just two, each is separated into two parts, one looking upwards and the other down. This allows D.longipes to detect silhouettes of animals above it, but also detect bioluminescence produced by animals below. For more info on this fascinating fish see this news article or paper.

I think that's quite enough biology for now, but I hope I leave you with a better idea of what strange things are going on in the Bristol University biological department and keep your eyes peeled for posts in August from the Porcupine Abyssal Plain, eek!