Commercial Gilthead Seabream (Sparus aurata L.) from the Mar Menor Coastal Lagoon as Hotspots of Microplastic Accumulation in the Digestive System

Abstract

This paper presents the results on the presence and characterization of microplastics (MP) in the gastrointestinal tract of gilthead seabream (Sparus aurata L.), a species of commercial interest from the Mar Menor coastal lagoon in Southeast Spain. This is the first time that microplastic ingestion is recorded in any species from this semi-enclosed bay. Stomach and intestine from a total of 17 specimens captured by local fishermen were processed, and microplastic particles and fibers found in all of them were displayed. Overall, 40.32% (279/692) of total isolated microparticles proved to be microplastics; i.e., <5 mm, as identified by FTIR spectroscopy. The average value by fish was 20.11 ± 2.94 MP kg−1, corresponding to average concentrations of 3912.06 ± 791.24 and 1562.17 ± 402.04 MP by kg stomach and intestine, respectively. Four MP forms were isolated: fiber (71.68%), fragment (21.15%), film (6.81%), and microbead (0.36%), with sizes ranging from 91 µm to 5 mm, an average of 0.83 ± 0.04 mm, and no statistically significant differences between mean sizes in stomach and intestine samples (F-test = 0.004; p = 0.936). Nine polymer types were detected, although most of fibers remained unidentified because of their small size, the presence of polymer additives, or closely adhered pollutants despite the oxidizing digestion carried out to eliminate organic matter. No significant correlation was found between main biological parameters and ingested microplastics, and high-density polyethylene (HDPE), low-density polyethylene (LDPE), polyethylene polypropylene (PEP), and polyvinyl (PV) were identified as the most abundant polymers. The average microplastic ingestion in this study area was higher than those reported in most studies within the Mediterranean Sea, and closely related to microplastic pollution in the surrounding area, although with a predominance of fiber form mainly due to fishery activities.

Screening of Microplastics in Aquaculture Systems (Fish, Mussel, and Water Samples) by FTIR, Scanning Electron Microscopy–Energy Dispersive Spectroscopy and Micro-Raman Spectroscopies

“…However, evidence from MPs contamination in commercial fish from the Mediterranean Coast of Egypt showed similar results to our findings, with PE (55%) and EVA (55%) as the dominant polymers in the fish digestive tracts of Sparus aurata (38.3 ± 28.4 items fish −1 ) with sizes ≤ 50 µm [65]. Furthermore, Bayo et al (2021) [66] obtained nine different polymer types, including PE (45%) and polyvinyl esters (9%), with sizes ranging from 91 µm to 5 mm and high average numbers of MP (8.53 ± 2.19) in the intestine of Sparus aurata comparable to our values. To our knowledge, polyvinyl esters such as polyvinyl butyral and polybutyl methacrylate were detected for the first time in this study in the two fish species.…”

Microplastics Determination in Gastrointestinal Tracts of European Sea Bass (Dicentrarchus labrax) and Gilt-Head Sea Bream (Sparus aurata) from Tenerife (Canary Islands, Spain)

“…To the best of our knowledge, the presence of MPs in specimens of both types of farmed fish has only been reported on very few occasions. This is the case for gilt-head sea bream from Mar Menor Lagoon (Spain) [ 15 ] as well as for European sea bass from Spain [ 7 , 16 ] and Greece [ 17 ]. Therefore, this work aims to study the presence of MPs in the gastrointestinal tracts of cultivated European sea bass and gilt-head sea bream in Tenerife (Canary Islands, Spain), the two most produced and consumed farmed fish in the region.…”