Filipa Bessa

Widespread microplastic ingestion by fish assemblages in tropical estuaries subjected to anthropogenic pressures

Our aim was to quantify microplastic ingestion by fish assemblages in two tropical Brazilian estuaries and to evaluate whether biological and ecological factors influence the ingestion of microplastics by fish species. Of 2233 fish from both estuaries (from 69 species) examined in this study, 9% of the individuals (24 species) had microplastics in their gut contents. Microplastic ingestion occurred irrespective of fish size and functional group. The diet of fish species was analyzed based on prey items identified in the fishs full stomach contents and five feeding guilds were defined. Microplastics were common throughout all feeding guilds. Low (average ingestion values 1.06±0.30 items/total fish) but widespread occurrence among estuaries also indicates proliferation of microplastic pollution. Our findings highlight the need to focus on assemblage level studies to understand the real magnitude of the problem and emphasize the urgency of mitigation measures directed at microplastic pollution in estuarine ecosystems.

Occurrence of microplastics in commercial fish from a natural estuarine environment

Microplastic ingestion has been reported for several marine species, but the level of contamination in transitional systems and associated biota is less known. The aim of this study was to assess the occurrence of microplastic ingestion in three commercial fish species: the sea bass (Dicentrarchus labrax), the seabream (Diplodus vulgaris) and the flounder (Platichthys flesus) from the Mondego estuary (Portugal). Microplastics were extracted from the gastrointestinal tract of 120 individuals by visual inspection and digestion solution. A total of 157 particles were extracted from 38% of total fish (96% fibers), with 1.67 ± 0.27 (SD) microplastics per fish. Significantly higher amount of ingested microplastics was recorded for D. vulgaris (73%). The dominant polymers identified by μ-FTIR were polyester, polypropylene and rayon (semi-synthetic fiber). It is reported for the first time the presence of this pollutant in fish populations from the Mondego estuary raising concerns on their potential negative effects.

The parasite Sacculina carcini Thompson, 1836 (Cirripedia, Rhizocephala) in the crab Carcinus maenas (Linnaeus, 1758) (Decapoda, Portunidae): influence of environmental conditions, colour morphotype and sex

Parasitism is increasingly recognized as an important factor that can influence the structure and function of natural communities. The presence of externae of the parasite Sacculina carcini Thompson, 1836 was investigated in a population of the crab Carcinus maenas (Linnaeus, 1758) from the Mondego estuary, Portugal. A seasonal pattern of the S. carcini externae presence was observed with the highest values recorded in winter and the lowest in summer, ranging from 0.6 to 10%. The parasite seems to affect more females than males and the red morphotype presented higher prevalence than the green one. The size class [25, 35 mm[ was the one with the highest prevalence. The mouth of the estuary was the area where the most externally sacculinized crabs were caught. Apparently, the presence of the parasite tends to promote crabs migration to the mouth. This area coincides with the preferential spawning local of non-parasitized females. The infection by S. carcini influences the crab’s demography and its life history.

Microplastics in Juvenile Commercial Fish from an Estuarine Environment

Microplastic ingestion has been reported by a range of marine fish species, but less known is the level of microplastic contamination by fish species from transitional ecosystems such as estuaries. The aim of this study was to assess the ingestion of microplastics by three important commercial fish species: the sea bass (Dicentrarchus labrax), the commom two-banded seabream (Diplodus vulgaris) and the European flounder (Platichthys flesus) from the Mondego estuary (Portugal). Microplastics were extracted from the gastrointestinal tract of 120 individuals after a digestion solution (10% KOH). A total of 157 microplastics were extracted from the total fish (96% fibers and 4% fragments), with 1.67 ± 0.27 (SD) microplastics per fish. The main plastic polymers identified by μ-FTIR were polyethylene, polypropylene, rayon, polyester, polyacrylonitrile and nylon.