The weight–length relationship (WLR) of fish is a crucial tool in fish biology research and has received extensive attention. However, fish growth is influenced by many factors, and the WLR also changes accordingly. Our aim was to investigate how fish body shape is affected by various factors by analyzing the existing parameters of the relationship between fish body length and weight. We analyzed 198,354 fish specimens belonging to 402 species of 82 families in China and investigated the change of fish body shape in the function of their ecology. Herbivorous fish tended to be shorter and fatter than carnivorous fish, and omnivorous fish fall somewhere in between. This difference could be due to variations in feeding habits and the availability of food sources. Additionally, fish living in lentic waters tended to have a shorter and fatter body shape compared to those living in lotic waters. This could be attributed to differences in swimming behavior in these environments. Furthermore, our results showed that the b value decreased as altitude increased, and fish tended to be thinner and longer due to lower oxygen and temperature levels in high-altitude waters. Overall, our study provides valuable insights into the WLR of fish and the impact of multiple factors on fish body shape.
Climate change and eutrophication are two environmental threats that can alter the structure of freshwater ecosystems and their service functions, but we know little about how ecosystem structure and function will evolve in future scenarios of climate warming. Therefore, we created different experimental climate scenarios, including present-day conditions, a 3.0 °C increase in mean temperature, and a "heatwaves" scenario (i.e., an increase in temperature variability) to assess the effects of climate change on phytoplankton communities under simultaneous stress from eutrophication and herbicides. We show that the effects of climate warming, particularly heatwaves, are associated with elevated cyanobacterial abundances and toxin production, driven by a change from mainly nontoxic to toxic Microcystis spp. The reason for higher cyanobacterial toxin concentrations is likely an increase in abundances because under the dual pressures of climate warming and eutrophication individual Microcystis toxin-producing ability decreased. Eutrophication and higher temperatures significantly increased the biomass of Microcystis, leading to an increase in the cyanobacterial toxin concentrations. In contrast, warming alone did not produce higher cyanobacterial abundances or cyanobacterial toxin concentrations likely due to the depletion of the available nutrient pool. Similarly, the herbicide glyphosate alone did not affect abundances of any phytoplankton taxa. In the case of nutrient enrichment, cyanobacterial toxin concentrations were much higher than under warming alone due to a strong boost in biomass of potential cyanobacterial toxin producers. From a broader perspective our study shows that in a future warmer climate, nutrient loading has to be reduced if toxic cyanobacterial dominance is to be controlled.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.