Climate change and the green energy paradox: the consequences for twaite shad Alosa fallax from the River Severn, U.K.
Article first published online: 11 OCT 2010
© 2010 The Authors. Journal of Fish Biology © 2010 The Fisheries Society of the British Isles
Journal of Fish Biology
Special Issue: Fishes and Climate Change
Volume 77, Issue 8, pages 1912–1930, November 2010
How to Cite
Aprahamian, M. W., Aprahamian, C. D. and Knights, A. M. (2010), Climate change and the green energy paradox: the consequences for twaite shad Alosa fallax from the River Severn, U.K. Journal of Fish Biology, 77: 1912–1930. doi: 10.1111/j.1095-8649.2010.02775.x
- Issue published online: 16 NOV 2010
- Article first published online: 11 OCT 2010
- impact assessment;
- stock and recruitment;
A stock–recruitment model with a temperature component was used to estimate the effect of an increase in temperature predicted by climate change projections on population persistence and distribution of twaite shad Alosa fallax. An increase of 1 and 2° C above the current mean summer (June to August) water temperature of 17·8° C was estimated to result in a three and six-fold increase in the population, respectively. Climate change is also predicted to result in an earlier commencement to their spawning migration into fresh water. The model was expanded to investigate the effect of any additional mortality that might arise from a tidal power barrage across the Severn Estuary. Turbine mortality was separated into two components: (1) juvenile (pre-maturation) on their out migration during their first year and on their first return to the river to spawn and (2) post-maturation mortality on adults on the repeat spawning component of the population. Under current conditions, decreasing pre-maturation and post-maturation survival by 8% is estimated to result in the stock becoming extinct. It is estimated that an increase in mean summer water temperature of 1° C would mean that survival pre and post-maturation would need to be reduced by c. 10% before the stock becomes extinct. Therefore, climate change is likely to be beneficial to populations of A. fallax within U.K. rivers, increasing survival and thus, population persistence.