Chinook salmon digestion data within predatory largemouth bass and channel catfish through controlled feed trials

Diet analysis is a vital tool for understanding trophic interactions and is frequently used to inform conservation and management. Molecular approaches can identify diet items that are impossible to distinguish using more traditional visual-based methods. Yet, our understanding of how different variables, such as predator species or prey ration size, influence molecular diet analysis is still incomplete. Here, we conducted a large feeding trial to assess the impact that ration size, predator species, and temperature had on digestion rates estimated with visual identification, qPCR, and metabarcoding. Our trial was conducted by feeding two rations of Chinook salmon (Oncorhynchus tshawytscha) to two piscivorous fish species (largemouth bass (Micropterus salmoides)) and channel catfish (Ictalurus punctatus)) held at two different temperatures (15.5°C and 18.5°C) and sacrificed at regular intervals up to 120 hours from the time of ingestion to quantify the prey contents remaining in the dig...,
Overview
We dissected digestives tracts from largemouth bass and channel catfish that were sacrificed at regular intervals post ingestion of a meal to determine how different covariates affect digestion rates. We define digestion rates as the reduction in prey item DNA detected in predator gut contents through time due to the processes of degradation, digestion, and evacuation. We used two different molecular methods to quantify the amount of DNA within the digestive tracts at each time interval and then used generalized linear models to quantify effects of multiple covariates (i.e., species, ration size, and temperature) on digestion rates.
Controlled Experiment
We conducted experiments on wild-caught and hatchery-reared largemouth bass (n fish=382) and hatchery-reared channel catfish (n fish=220) to investigate how temperature, predator species, and ration size influence digestion rates (Table 1). Hatchery largemouth bass (n = 202) and channel catfish (n = 220) were obtained from a p..., Microsoft Office Excel or alternative spreadsheet software such as Google Sheets, etc.Â