Skip to main content
Dryad

Measuring egestion, excretion, fecal leaching, and foregut-hindgut %P in threespine stickleback

Data files

Sep 08, 2022 version files 106.04 KB

Abstract

Most aquatic research on animal waste production evaluates excretion and not egestion, as it is difficult both to collect feces and to accurately analyze its nutrient content. This limits our understanding of how individuals process their dietary nutrients and how animal waste production impacts ecosystems. In this study, we systematically analyzed whether incubation experiments effectively quantify egestion (at high and low temperatures), estimated fecal phosphorus (P) leaching, and evaluated foregut-hindgut analyses as a complementary method. Incubations were superficially effective but were flawed. Although 82% of fish in high temperature incubations and 75% of fish in low temperature incubations egested in 24h, a minority of fish cleared their guts (38% at high temperatures and 6% at low temperatures), making analyzing full nutrient input and output impossible. Furthermore, feces leached P rapidly and variably; a field population’s and an experimental population’s feces leached 41% and 75% of their initial P respectively. This suggests that previous egestion research that does not measure leaching underestimates fecal nutrient content. Foregut-hindgut analyses are unaffected by leaching and so effectively complemented incubations. These analyses provided enough hindgut material to estimate fecal %P and allowed us to estimate both dietary nutrient intake (when unknown) and the relative quantity of P in the diet and in the feces. Overall, we suggest that future researchers combine incubations and foregut-hindgut analyses to estimate aquatic animal waste production.