Microplastic pollution: An emerging contaminant in aquaculture

Aquaculture largely contributes to aquatic products and consequential dietary protein for many households. Aquaculture, just like every other food sector, is faced with enormous challenges such as unfavorable climatic events, environmental stressors and contaminants. Microplastics (MP) are emerging contaminants in aquaculture following their perturbing occurrence in cultured fish, fishmeal and aquafeed. Several MPs pathways into aquaculture facilities include wastewater, pipe-borne water, dilapidated aquaculture facilities, fish gears, and aquafeed stuff (fishmeal). Techniques for the digestion, identification and characterization of MPs are critical to understanding their pathways, bioavailability and bioaccumulation patterns in aquaculture species. The impacts of MPs on cultured fish species are identified as impaired growth, oxidative stress, neurotoxicity, reproductive toxicity, immunotoxicity, embryotoxicity, and histopathology. Bioaccumulation of MPs in tissues and biological systems have been evidenced in several cultured fishes. Mitigation efforts cum strategies such as upgrade of wastewater treatment facilities, screening of inlet pond water, screening of aquafeed stuff, regular maintenance and repair of culture facilities, could be effective to eradicate MP contamination in aquaculture. Additionally, regulatory policy on the use of plastics is key to mitigating the impact of MPs and ensure cleaner and sustainable aquaculture.