Functional response quantifies microplastic uptake by a widespread African fish species

Area of Science:

• Environmental Toxicology
• Aquatic Ecology
• Ecotoxicology

Background:

• Microplastic pollution is globally pervasive, yet ecological impacts and species-specific responses to varying environmental concentrations remain poorly understood.
• Quantitative methods are needed to predict how aquatic species ingest microplastics across different environmental densities.

Purpose of the Study:

• To quantify microplastic uptake in banded tilapia (Tilapia sparrmanii) exposed to varying microplastic concentrations.
• To apply and develop the functional response approach for predicting microplastic ingestion rates in fish.
• To estimate key feeding behavior parameters related to microplastic consumption.

Main Methods:

• Exposure of banded tilapia (Tilapia sparrmanii) to different concentrations of microplastic particles.
• Application of the functional response model to quantify microplastic uptake.
• Estimation of attack rate, handling time, and maximum feeding rate for microplastic consumption.

Main Results:

• Tilapia consumed microplastics even at low environmental densities.
• Microplastic consumption rates showed a negative relationship with supplied concentrations, fitting a Type II functional response (inversely density-dependent).
• Parameters for attack rate, handling time, and maximum feeding rate were estimated.

Conclusions:

• The functional response approach is a useful tool for predicting microplastic uptake rates in aquatic organisms.
• This methodology can link laboratory exposure data to environmental concentrations and ecological impacts.
• It provides a framework for comparing microplastic uptake across different species and environmental contexts.