Species differences in sensitivity to environmental pollutants in Gadidae in the Oslofjord

• Main Author: Kristensen, Sanne Helene
• Format: Master Thesis
• Language: English
• Published: 2022
• Subjects: ecotoxicology; biomarkers; fish; species differences; Oslofjord; Norway; atlantic cod; Gadus morhua
• Online Access: http://hdl.handle.net/10852/96431; http://urn.nb.no/URN:NBN:no-98989

Related species have been assumed to have a similar sensitivity to exposure to environmental pollution. Atlantic cod (Gadus morhua) is an important commercial fish and a key-species in monitoring. With the recent decline in Atlantic cod populations in the Oslofjord and a change in dominating species, knowledge about sensitivity in species related to Atlantic cod that are also present in the Oslofjord may be important for future monitoring and management of populations. The Oslofjord is divided into the urban inner Oslofjord and a less polluted outer Oslofjord. This study aimed to identify location differences between the urban and more polluted inner Oslofjord and the less polluted outer Oslofjord, to identify differences between species in the Gadidae family (Atlantic cod, whiting (Merlangius merlangus), Norway pout (Trisopterus esmarkii) and haddock (Melanogrammus aeglefinus)), to identify seasonal differences in exposure and effects of contaminants in the Oslofjord, and to identify differences in effect of exposure to contaminants between tissues. This was done by sampling 8 fish from each species in the inner and outer Oslofjord in the spring and fall. Concentrations of polycyclic aromatic hydrocarbon (PAH) metabolites were quantified in the bile and mercury concentration was determined in liver samples to get estimates of exposure to environmental pollution. Hepatic, gill, and heart cytochrome P4501A (CYP1A) activity was determined from the ethoxyresorufin O-deethylase (EROD) assay to get estimates of effect of exposure to environmental pollution as the activity can be induced by exposure to contaminants such as PAHs. The study identified significantly higher concentrations of PAH-metabolites in bile in the inner Oslofjord. Species differences and seasonal differences varied among the three groups of PAH metabolites, indicating differences in exposure and sources through the year. There was identified a location difference in mercury exposure in Norway pout in the inner Oslofjord, which could be due to ...