Small fish, big fish, red fish, blue fish: size-biased extinction risk of the world's freshwater and marine fishes
Article first published online: 16 JUN 2007
Global Ecology and Biogeography
Volume 16, Issue 6, pages 694–701, November 2007
How to Cite
Olden, J. D., Hogan, Z. S. and Zanden, M. J. V. (2007), Small fish, big fish, red fish, blue fish: size-biased extinction risk of the world's freshwater and marine fishes. Global Ecology and Biogeography, 16: 694–701. doi: 10.1111/j.1466-8238.2007.00337.x
- Issue published online: 16 JUN 2007
- Article first published online: 16 JUN 2007
- Biological traits;
- body size;
- invasive species;
- life-history strategies;
- Red List;
- threatened species.
Aim In light of the current biodiversity crisis, there is a need to identify and protect species at greatest risk of extinction. Ecological theory and global-scale analyses of bird and mammal faunas suggest that small-bodied species are less vulnerable to extinction, yet this hypothesis remains untested for the largest group of vertebrates, fish. Here, we compare body-size distributions of freshwater and marine fishes under different levels of global extinction risk (i.e. listed as vulnerable, endangered or critically endangered according to the IUCN Red List of Threatened Species) from different major sources of threat (habitat loss/degradation, human harvesting, invasive species and pollution).
Location Global, freshwater and marine.
Methods We collated maximum body length data for 22,800 freshwater and marine fishes and compared body-size frequency distributions after controlling for phylogeny.
Results We found that large-bodied marine fishes are under greater threat of global extinction, whereas both small- and large-bodied freshwater species are more likely to be at risk. Our results support the notion that commercial fishing activities disproportionately threaten large-bodied marine and freshwater species, whereas habitat degradation and loss threaten smaller-bodied marine fishes.
Main conclusions Our study provides compelling evidence that global fish extinction risk does not universally scale with body size. Given the central role of body size for trophic position and the functioning of food webs, human activities may have strikingly different effects on community organization and food web structure in freshwater and marine systems.