Dissertation: So long and thanks for all the fish! How does overharvesting affect fitness? (Sadler)
A researcher of the Department of Biological and Environmental Sciences Daniel Sadler discovered in his PhD thesis how size-selective fishing significantly modifies the structure of the genome. The changes in the genome continue even when fishing is halted. Non size-selective fishing (balanced harvesting) seems to have less negative effects on the quality of fish than size-selective fishing, when temperature changes.
How can we stop the effects of overharvesting?
Of course, the most obvious solution is to stop fishing, but this is not a feasible solution when fish globally represent 17% of protein we consume. The key is to harvest the fish sustainably. One such solution is to introduce a moratorium; halting harvesting for a given period to allow population recovery, however, is this enough for the underlying genetic structure to also recover, affecting adaptive potential?
- Many fisheries are size-selective and take the largest fish from the population, which can negatively alter an individual’s fitness as larger individuals usually have higher reproductive success. An alternative strategy would be a balanced harvesting approach, which is not size selective but targets a wide range of different sized fish, says Daniel Sadler from the Ģֱ.
A balanced fishery is a sustainable fishery
Daniel’s thesis utilises a model system (zebrafish) to examine how overharvesting affects adaptive potential under different fishing scenarios. More specifically he studies how these different fishing scenarios influence genetic structure after overharvesting, genetic structure after a period of recovery (i.e., no harvesting) and how they interact with temperature change to affect fitness components.
- My research find that genetic structure does indeed change after a period of overharvesting, and worryingly does not show signs of recovery after the cessation of harvesting. This work shows evidence that balanced harvesting may be the most optimum fishing strategy under future climatic scenarios. Ideally, the results of this thesis help planning fisheries management to move towards a more sustainable world, explains Sadler.
The examination of Daniel Sadler’s thesis “So long and thanks for all the fish: Fisheries erode adaptive potential” will be held on 10.5.2024 at 12:00 in S212. The opponent is Professor Neil Metcalfe (University of Glasgow) and the custos is Dr. Silva Uusi-Heikkilä (Ģֱ).
The dissertation “So long and thanks for all the fish: Fisheries erode adaptive potentia” can be read on the JYX publication archive:
