Biomonitoring of Microplastics in the Caribbean Sea with Invasive Lionfish
Description
We collected invasive lionfish (Pterois spp.) from southwest Puerto Rico and analyzed the stomach contents and gills for microplastics (MPs). Given their widespread population and broad ecological niche, the life history characteristics of invasive lionfish are well suited for biomonitoring of MPs. We collected 56 lionfish from different depths and reefs in the same region and used both dissection and acid digestion techniques to analyze tissue. We found a high prevalence of MPs with an average load of 6.4 MPs ± 3.2 per lionfish with no pattern associated with depth, reef, or size of lionfish. Most MPs were microfibers and were blue, black, or clear in appearance. There was also a high incidence rate, 98% of lionfish had MPs in their stomach and 79% had MPs in their gills.
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Steps to reproduce
A total of 56 lionfish (≥13 cm in length) were collected between June and August 2023 by spearfishing at 2–44 m depth on SCUBA . Stomachs (n=56) and gills (n=14) were removed and labeled, frozen at -20°C, and stored at -80°C prior to analysis. Thawed samples of stomach and gills were inspected under a dissecting microscope (10x–40x magnification) using an ultraviolet (UV, 315-400 nm) flashlight to enhance the visibility of fluorescent microplastics (MPs). Stomach samples only were acid digested to isolate MPs from organic content. Each stomach was placed in a 230-ml glass jar and digested in 15 ml of 70% nitric acid (HNO₃) per gram of tissue. Samples were heated to 40°C for 2–2.5 hours on a hotplate, dissolving organic matter while preserving synthetic polymers. Following digestion, liquified samples were diluted with deionized water (1:10 v/v) and filtered through 1.6-µm glass fiber filters using a vacuum filtration system in a disinfected hood. Filters were dried at 60°C for 48 hours and subsequently analyzed under a microscope with both white and UV light to identify and characterize MPs.
Institutions
- Villanova University