This is an early access version, the complete PDF, HTML, and XML versions will be available soon.
Well-Being of the Baltic Herring and Bycatch Fish Species from FAO Major Fishing Areas 27 According to Microplastic Pollution
Department of Environmental Chemistry and Toxicology, Institute of Geography, Pomeranian University in Słupsk, 22a Arciszewskiego Str., 76-200 Słupsk, Poland
*
Authors to whom correspondence should be addressed.
Animals 2025, 15(16), 2381; https://doi.org/10.3390/ani15162381
Submission received: 11 July 2025
/
Revised: 5 August 2025
/
Accepted: 8 August 2025
/
Published: 13 August 2025
(This article belongs to the Topic Livestock and Microplastics)
Simple Summary
The abundance of microplastics was determined in the gills, the gastrointestinal tract, and the liver of six marine fish species (Baltic herring, sprat, cod, flounder, long-spined bullhead, and lumpfish) collected from the southern and central Baltic Sea. Microplastics were analyzed in terms of their quantity, size, shape, color, and chemical composition. Four health indices were applied to assess fish well-being according to microplastic pollution. For Cyclopterus lumpus and Taurulus bubalis, K and HSI values were reported for the first time. Principal component analysis revealed a negative impact of microplastics on the health condition of the Baltic herring.
Abstract
Condition factors are essential in fishery science. They provide insights into fish well-being according to the impact of environmental stressors. The Fulton condition factor (K) and hepatosomatic index (HSI), as well as two new indices (GILSI and GITI), were used to assess the well-being of herring and bycatch species (cod, flounder, sprat, long-spined bullhead, lumpfish) from the Baltic Sea. For Cyclopterus lumpus and Taurulus bubalis, K and HSI values were reported for the first time. Fish from different basins differed according to biometric measures (weight: 6.09–750.12 g; length: 8.6–41.8 mm) and condition indices (mean K: 1.19; HSI: 0.02; GITI: 0.04; GILSI: 0.03). Microplastics (MPs) were found in all species (21% (sprat)–79% (lumpfish)), averaging 3.1 items/fish. The organ-wise analysis revealed that 46% of the gills, 16% of the livers, and 38% of the gastrointestinal tracts were contaminated with MPs. The relationship between these indices and MPs abundance in the organs of herring was examined using PCA, revealing a negative impact of MPs on fish health. The morphometric features and the chemical composition of MPs were also detected. The dominant size ranges were 0.11–0.5 mm (30%) and 1.01–5 mm (28%). Blue fibers were the most common.
