Pliable Plastics: An Assessment of Microplastic Loads in the Gills and Digestive Tracts of Pelagic Fish in Lake Ecosystems

Abstract

Microplastics have plagued fish communities since the inception of industrialization, and regulations have not been keeping pace. In the environment, these particles have become ubiquitous and are found in air, soil, and remote lakes. Microplastics are defined as particulates that are less than 5 mm in size and are characterized by type (e.g., fragment, fiber, film, foam, bead, and pellet), color, polymer, and size. Fish uptake particulates via ingestion, gill-filament adhesion, and absorption. These microplastics have the potential to reduce reproduction, feeding, and survival. We conducted a survey of microplastics in fish harvested from ice derbies in Chazy Lake, Chateaugay Lake, and Lake Colby (spring 2024) in northern, NY. We use wet peroxide oxidation to isolate microplastics within digestive tracts and gill filaments and the separated samples by size (e.g., 1 mm, 355 µm, 125 µm). We quantified and characterized particulates under a dissecting microscope. Results show that all particulates (n=476) were fibers. Fish in Upper Chateaugay Lake had 1.81 plastics/g tissue, 4 and 2 times greater than Chazy Lake and Lake Colby respectively which can be explained by the greater surface area of the lake. Additionally, (yellow perch) Perca flavescens contained 3.2 plastics/g tissue, 11 and 7 times greater than that of (lake trout) Salvelinus namaycush and (Atlantic salmon) Salmo salar respectively. This can be explained as a function of bioaccumulation over their lifetime, as most perch were approximately 10 years of age. In addition, yellow perch are visual predators who shift their prey base and foraging microhabitat at different ontogenetic stages helping to explain higher loads. In terms of organs, microplastic loading via ingestion was 0.78 plastics/g of tissue, 23% higher than adhesion to gills (0.62 plastics/g tissue). Anglers should consider microplastic risks if fish are a major dietary component.