2023 Early Hearing Detection & Intervention Conference

March 5-7, 2023 • Cincinnati, OH

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5/24/2021 | 2:00 PM - 3:30 PM | WHERE DID ALL THE FISH PEE GO? EFFECTS OF FISH LOSS OVER 25 YEARS IN A BRAZILIAN STREAM | Virtual Platform

WHERE DID ALL THE FISH PEE GO? EFFECTS OF FISH LOSS OVER 25 YEARS IN A BRAZILIAN STREAM

In the highly diverse Rio Ubatiba in Brazil, in the last 25 years, fish abundance has been declining and invasive species have substituted native ones. Changes in fish abundance and identity can affect stream nutrient dynamics, as different species have different excretion rates, due to their differences in size, diet, and demand. We measured excretion rates of all fish species and estimated the total areal excretion over 25 years based on the changes in population density. We also focused on the effect of the substitution of one native armored catfish species with an invasive one. Overall, we found that fish-driven nutrient recycling decreased through the years, due to the general decrease in fish abundance. After the introduction of the invasive, smaller-sized catfish, areal nutrient excretion dropped, due to the sharp decrease in overall catfish biomass. This lack of functional replacement was mostly due to the lower biomass of the invasive catfish after the invasion compared to the native species before the invasion. The loss of fish species, introduction of invasive species, and reduction in fish biomass can strongly affect nutrient dynamics and other ecosystem processes in fast-changing human-impacted tropical streams

Functional extinction
Tropical streams and lakes
Stoichiometry

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Presenters/Authors

Eugenia Zandona (), Universidade do Estado do Rio de Janeiro, eugenia.zandona@gmail.com;