New publication: Crude oil exposure during gametogenesis affects gametes and offspring in Atlantic cod
A new study published in Archives of Environmental Contamination and Toxicology shows that exposing adult Atlantic cod to crude oil during late gametogenesis accelerates spawning readiness, reduces egg size, and leads to maternal transfer of petroleum compounds to eggs — including monoaromatic hydrocarbons not typically captured by standard PAH analyses.
We are pleased to share a new publication from our team, led by PhD candidate Claudia Erhart. This study investigated how exposure of mature Atlantic cod to a water-soluble fraction of crude oil during the final stages of gonad maturation affects gamete quality and offspring development.
Adult cod were exposed for 20 days, after which females from both groups were repeatedly strip-spawned over the following month. Eggs were fertilized in vitro with sperm from unexposed males, allowing the team to isolate maternal effects across multiple egg batches throughout the spawning season. Oil-exposed females showed signs of advanced spawning readiness, with a higher proportion ready to spawn earlier than controls. Their eggs were significantly smaller, and chemical analyses confirmed the maternal transfer of petroleum-derived aromatic hydrocarbons, including monoaromatic compounds that are often overlooked in standard PAH-focused assessments. Sperm from exposed males also showed reduced curvilinear velocity and linearity. Despite these effects on parents and gametes, no significant differences in larval malformations or cardiac function were observed at hatching — suggesting that the primary driver of intergenerational toxicity was the direct impairment of adult reproductive physiology rather than classical embryotoxic mechanisms.
The study highlights the importance of looking beyond conventional early life-stage endpoints and standard PAH analyses when assessing the ecological risks of oil contamination, and underscores the need for multigenerational studies to capture delayed or transgenerational effects.
This work is part of the FRAM Centre flagship project PARENTOX (2020) and was supported by ARCEx (Research Council of Norway, grant #228107) and the TOXIGEN project (grant #334541).
Congratulations to the whole team!
Full reference: Erhart, C., Nahrgang, J., Creese, M.E., Dubourg, P., Frantzen, M., Hansen, B.H., Hansen, Ø.J., Meador, J.P., Michon, E., Odei, D.K., Puvanendran, V., & Sørensen, L. (2026). Crude oil exposure during gametogenesis in the batch-spawning Atlantic cod (Gadus morhua): Effects on gametes and maternally exposed offspring development. Archives of Environmental Contamination and Toxicology, 90, 4. https://doi.org/10.1007/s00244-025-01170-5