Biomonitoring of microplastics in the Caribbean Sea with invasive lionfish

Biomonitoring or using organisms to assess the distribution and bioavailability of microplastics (MPs) is one approach for improving the management of MPs that are abundant and ubiquitous in marine ecosystems. The Caribbean region lacks a target species for biomonitoring MPs. Here, we propose using the introduced lionfish (Pterois spp.) that have successfully invaded the Caribbean Sea and Western Atlantic Ocean. With their widespread population and broad ecological niche, the life history characteristics of invasive lionfish are well suited for biomonitoring. To evaluate whether invasive lionfish uptake MPs, we collected 56 lionfish from different depths and reefs in the same region and examined their stomach and gills for MPs. Using both dissection and acid digestion techniques to evaluate the lionfish tissues, we found a high abundance 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 prevalence of MPs, 98 % of lionfish had MPs in their stomach and 79 % had MPs in their gills. Our data verify the suitability of the invasive lionfish as a biomonitoring tool for MPs given their generalist behavior, wide habitat, and surplus population, with the added benefits of culling invasive species without disturbing native fish communities.