Danswell Starrs, Australian National University.

I don’t remember the title of the book. I was pretty young – maybe 4 years old. It was a children’s book, and it depicted Archimedes leaping out of the bathtub, shouting ‘EUREKA!’ at the top of his voice, followed by a nudie run down the street.

Fast forward 20-something years and I am at the Australian National University, doing my PhD research under the supervision of Chris Fulton and Brendan Ebner. Im working on the impossibly small otoliths of larval Eastern rainbowfish and Purple-spotted gudgeons.

During my PhD candidature I had two ‘Eureka’ moments. Multiple theoretical issues bugged me for weeks and months, swirling in my head but not quite forming a lucid picture I could put to paper. However, I quickly learnt that my subconscious works on these problems at night when I sleep. This article is about those moments.

Twice I woke up around 4am in the morning, with the answer clear in my mind. I didn’t go to bed thinking about the problem, but subconsciously, I had been working on it for months.

The first idea didn’t go anywhere. I raced into uni at 5am in the morning and wrote it all down. It’s still somewhere in a word document on my computer. Untouched. I can’t recall what it was about, but I have no inclination to dig it up.

The second moment I remember clearly. I had been struggling for months, trying to place my Purple-spotted gudgeon growth experiment (Starrs et al. 2013) into a broader framework – what is the significance of rapid growth in larvae, and how can that be put in the context of selective mortality? I knew there had to be a way to put these together, but I couldn’t figure it out in a way that made sense to me. Other people had done it, but not in the way I was thinking it should be done. Growth is a physiological process, and a population model should be built on the underlying physiology, not some surrogate halfway between.

Then, early one morning it hit me. I woke up, and it was right there. I had it! Using the same analytical framework I had studied in my Bachelor of Economics degree, I could combine the natural variation in growth response to temperature and food supply into a graphical model that could partition mortality, and reveal the proportion of any population that will experience selective pressure due to changes in their thermal environment, food supply and intrinsic physiology. For the next week, I crafted this idea. I think it works!

It currently sits on my computer, unfinished. A little bit of empirical data and some more modelling and it might be worth a neat little paper. Since then, similar ideas have appeared in the literature (Johnson et al. 2014). However, regardless of whether I revisit it or not, it still remains my ‘Eureka!’ (I didn’t do the nudie run).



Johnson, D.W., Grorud-Colvert, K., Sponaugle, S., and B. X. Semmens (2014) Phenotypic variation and selective mortality as major drivers of recruitment variability in fishes. Ecology Letters. doi: 10.1111/ele.12273

Starrs, D., Ebner, B.C., and C. J. Fulton (2013) Can backcalculation models unravel complex larval growth histories in a tropical freshwater fish? Journal of Fish Biology 83: 96-110 doi: 10.1111/jfb.12152


Danswell has recently handed in his PhD and is working at ANU. His passion for the motoring world continues as does his passion for fish science.

Danswell Starrs

Evolution Ecology and Genetics

Research School of Biology

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