Travels of a Fish Nut

As one of my friends said, academia doesn’t have many perks, but the fieldwork is definitely one of them. I don’t really know where to start... The Kimberley is amazing. Just amazing. Every sunrise, every sunset, and all the hours in between have been one incredible experience after another. I’ve only been back a couple of weeks and already it feels like some unbelievable dream. Being at sea is a bit surreal anyway. Add on being in the Kimberley and you’ve got yourself an once-in-a-lifetime experience. The trip was focused around the islands in the north of Camden Sound, Our stops The Islands The geology of the Kimberley is fascinating. Unfortunately I don’t know enough geology to explain it to you so I’m just going to show some pretty pictures. One thing that really struck me was how skewed my perspective was. The lack of anything manmade to give a sense of scale meant that islands which looked really flat and unimpressive from not that far away…  Pyren...

The invitation to go to Camden Sound came only a few short weeks before the trip was due to take place, so I had no time to waste. After I got the ok from my supervisors I had to work out what I was going to do. I wanted to sample oxygen and strontium isotopes, and trace elements. Oxygen and strontium are both measures of salinity but oxygen can also vary due to things like latitude, depth and temperature. We have had some interesting results from our comparison of oxygen and strontium in the otoliths so trying to understand their relationship in the water itself will be a great help. Trace elements are supposed to vary geographically and are used as ‘tags’ to locate fish to specific sites, but this can only be done when you know the trace element composition at each site. I emailed around to find labs that could analyse the samples and that could tell me how to collect them. Oxygen isotopes were sorted fairly quickly – I only needed 20ml water filtered through a 0.45 𝜇m filter an...

A few weeks ago, completely out of the blue, I was invited to join a research trip to Camden Sound to take water chemistry samples. Why am I being asked to do water chemistry? I’ve been in search of water chemistry data for the Kimberley to help provide a context for my otolith geochemistry results. Otolith geochemistry is based on a number of assumptions and one assumption is that the water chemistry at each sampling site is constant, so any changes we see in otolith chemistry is due to movement of the fish rather than changes in the water. The Kimberley region has some of the highest tides in the world (comparable to the Severn!). It’s also a tropical environment with the year divided into wet and dry seasons which suggests, to my inexpert mind, that the water chemistry may be quite variable over all sorts of time scales. To try and see if this is the case I’ve been emailing all sorts of people in various institutions in Western Australia to try and get water chemistry data,...