Distribution of Herbivorous Fish Is Frozen by Low Temperature
Vejříková, I., Vejřík, L., Syväranta, J., Kiljunen, M., Čech, M., Blabolil, P., . . . Peterka, J. (2016). Distribution of Herbivorous Fish Is Frozen by Low Temperature. Scientific Reports, 6, 39600. doi:10.1038/srep39600
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Scientific ReportsAuthors
Date
2016Discipline
Akvaattiset tieteetCopyright
© The Author(s) 2016. This work is licensed under a Creative Commons Attribution 4.0 International License.
The number of herbivores in populations of ectothermic vertebrates decreases with increasing
latitude. At higher latitudes, fish consuming plant matter are exclusively omnivorous. We assess
whether omnivorous fish readily shift to herbivory or whether animal prey is typically preferred.
We address temperature as the key factor causing their absence at higher latitudes and discuss the
potential poleward dispersion caused by climate changes. A controlled experiment illustrates that
rudd (Scardinius erythrophthalmus) readily utilize plant matter at water temperatures above 20°C
and avoid its consumption below 20°C. Field data support these results, showing that plant matter
dominates rudd diets during the summer and is absent during the spring. Utilizing cellulose requires the
enzyme cellulase, which is produced by microorganisms growing at temperatures of 15–42°C. Water
temperatures at higher latitudes do not reach 15°C year-round; at our latitude of 50°N~150 days/year.
Hence, the species richness of omnivorous fish decreases dramatically above 55° latitude. Our results
provide support for the hypothesis that strict herbivorous specialists have developed only in the tropics.
Temperatures below 15°C, even for a short time period, inactivate cellulase and cause diet limitations
for omnivorous fish. However, we may expect increases in herbivory at higher latitudes caused by
climate change.
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