Towards non-invasive methods in measuring fish welfare

Cortisol levels in fish skin mucus have shown to be good stress indicators in farm fish exposed to different stressors. Its applicability in free-ranging animals subject to long-term environmental stressors though remains to be explored. The present study was therefore designed to examine whether sk...

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Bibliographic Details
Authors: Carbajal, Annaïs|||0000-0002-4339-6661, Soler, Patricia, Talló Parra, Oriol|||0000-0002-0273-9824, Isasa, Marina, Echevarria, Carlos, López Béjar, Manel|||0000-0001-9490-6126, Vinyoles, Dolors|||0000-0003-2808-769X
Format: article
Publication Date:2019
Country:España
Institution:Universitat Autònoma de Barcelona
Repository:Dipòsit Digital de Documents de la UAB
Language:English
OAI Identifier:oai:ddd.uab.cat:216714
Online Access:https://ddd.uab.cat/record/216714
https://dx.doi.org/urn:doi:10.3390/ani9110939
Access Level:Open access
Keyword:Non-invasive
Bioindicator
Pollution
Stress
Welfare
Constructed wetland
Glucocorticoid
Urban river
Description
Summary:Cortisol levels in fish skin mucus have shown to be good stress indicators in farm fish exposed to different stressors. Its applicability in free-ranging animals subject to long-term environmental stressors though remains to be explored. The present study was therefore designed to examine whether skin mucus cortisol levels from a wild freshwater fish (Catalan chub, Squalius laietanus) are affected by the habitat quality. Several well-established hematological parameters and cortisol concentrations were measured in blood and compared to variations in skin mucus cortisol values across three habitats with different pollution gradient. Fluctuations of cortisol in skin mucus varied across the streams of differing habitat quality, following a similar pattern of response to that detected by the assessment of cortisol levels in blood and the hematological parameters. Furthermore, there was a close relationship between cortisol concentrations in skin mucus and several of the erythrocytic alterations and the relative proportion of neutrophils to lymphocytes. Taken together, results of this study provide the first evidence that skin mucus cortisol levels could be influenced by habitat quality. Although results should be interpreted with caution, because a small sample size was collected in one studied habitat, the measurement of cortisol in skin mucus could be potentially used as a biomarker in freshwater fish.