The start-up phase of the project involved recruiting and training the team, setting up the aquarium rooms, testing protocols for whole-animal measurements of animal performance (e.g. locomotor performance), developing methods for quantifying use of refuges (using PIT tag detectors embedded in refuges) and use of energy (by means of changes in body shape assessed from analysis of photographs), developing methods for mitochondrial respirometry, collecting fish, testing the assays and conducting the first experiments. The covid outbreak caused a significant interruption to the programme of work, but once life returned to near-normal the experimental programme was rearranged and modified, with only minor omissions from the original plan.
The project successfully measured performance in a range of ecological contexts (e.g. swimming against variable water flow rates, defending feeding territories in semi-natural streams, competing for food and mates, performing parental care etc), and demonstrated that the efficiency of ATP production by the mitochondria varies substantially between individual animals of the same age and species, and that this variation often (but not always) predicts how well the animal can perform. For instance, fish with more efficient mitochondria tended to be socially dominant, were better at defending a feeding territory, and were better at providing parental care. They also consumed larger meals and grew faster – but only when environmental conditions were more challenging. This has allowed a re-evaluation of the links between ecology and metabolic rate. This work is either already published, submitted for publication or in an advanced state of analysis and write-up.
