Day 10: Fish and Ships

Today's blog is written by Rosanna from the University of Glasgow, about her fishy interests!

Live High-Def ROV footage
So unlike most of the other scientists on board the ship, my main interest on this cruise is not in the deep-water corals themselves, but rather in the role they play in providing habitats for fish. As we go deeper into the ocean depths, the amount of hard substrate available for animals to live on decreases rapidly, which means that there is mostly only mud for animals to live in. Places where there are rocky or biological reefs provide more complex structures for animals to live in, which means in turn that there is more space for lots of different animals to live there. For small invertebrates, deep-water coral reefs have been shown to support a much higher diversity and abundance of species than surrounding soft sediment areas, with the highest diversities being found in the areas of dead coral rubble that surround living reefs. However, the importance of deep-water corals for fish species is less clear and that’s where I come in.

The ROV command centre
At the moment, I’m studying for a PhD at the University of Glasgow (Scotland) which is looking at the effects of human and natural factors affecting deep-sea fishes in a variety of different areas and habitats. So, what I’m interested in studying during this cruise is to look at how the coral reefs affect the distribution of different fish and whether the species found around the reef areas are different from those from the off-reef areas. This in turn will allow me to compare the results of this study to other studies I’m conducting on spatial patterns of habitat use in abyssal regions (4500m-4800m) and also to a study on how fish react to oil-production structures on the shelf slope (1500m).

Happy Scientists in the sun
 Although I’m not able to conduct a specifically designed transect survey during this cruise due to the extreme time pressures placed on the ROV (everyone’s got work to do with it after all), there is plenty of ‘opportunistic’ footage which I can use while all these other activities take place, and I’ve so far got some nice habitat surveys at Mingulay and across part of a reef at Rockall so far as well. The visibility wasn’t too great at Mingulay since we’re right in the middle of the spring plankton bloom, but now we’re at the deeper site things are looking much better and we’re getting some great footage of the reefs already, and there are fish everywhere!