Manatees play a crucial role in the trophic transfer of microplastics because they graze in seagrass beds where many microplastics accumulate. Manatees from the Marine Mammal Pathobiology Lab were necropsied using their standard protocols, including manual palpation of the digestive tract and visual examinations. The digestive tracts were sub-sampled into five categories (stomach, duodenum, cecum, distal and proximal colon) in search of smaller plastic particles. The sub-sample were then concentrated on a 212 µm sieve and a visual inspection method was used to look for microplastics. Manatees have a high cellulose diet, which is why the entire gut contents were not fully digestible. Nile Red staining was used to identify the plastic particles.
The data collected from 18 manatee carcasses between 2017-2019 showed that there was a high frequency of microplastic contamination and showed that plastic was present in all of segments of the GI tract that were examined.
Particles of plastic found in the segments of the GI tract of the manatees