A new scientific report reveals Norway's second-longest fjord faces serious environmental constraints. The Hardangerfjord cannot handle significant increases in fish production due to nutrient pollution risks, researchers concluded.
Research director Vivian Husa from the Institute of Marine Research stated the current situation remains manageable but warned against expansion. "Today things are okay, but there's little room for major increases in fish production due to nutrients," Husa said in the report.
The comprehensive study examined all measurement data from the 180-kilometer fjord, assessing eutrophication risks—commonly called over-fertilization. This condition can cause oxygen depletion in worst-case scenarios.
The investigation began after the County Governor of Vestland expressed concern about declining oxygen levels in the fjord's bottom waters. Increased plant plankton production matched rising nitrogen inputs from fish farming operations.
This prompted temporary halts to all new aquaculture permits in the fjord earlier this year.
Copper and zinc from fish farms emerge as particular concerns. "Many facilities have problems with excessively high copper concentrations near their operations," Husa explained. "This is because facilities have been there a long time and used copper on their nets."
While the industry has shifted to alternative methods, legacy contamination remains. Researchers specifically identified areas around Varaldsøy, Skåneviksfjorden and Onarheimsfjorden as particularly vulnerable due to existing farm concentrations.
"This is the first time we've simulated that increasing production in the fjord would cause over-fertilization problems," Husa noted. Such conditions could trigger chain reactions including increased plant and animal plankton production, more organic matter settling on the seabed, and eventual oxygen problems.
The findings mark a turning point in understanding production limits. "This is the first time we show that it's not just salmon lice that limits production in Hardangerfjord," Husa emphasized. "Nutrient salts can also become problematic, making future facility placement crucial."
Environmental authorities must now decide whether to permit additional fish production in the sensitive waterway. The report will support the County Governor's evaluation of aquaculture applications.
Researchers issued a final warning about protecting the fjord's unique ecosystems, including large coral reefs and bamboo coral. "We're particularly concerned that if new facilities are established, vulnerable bottom types must be mapped first to avoid negative impacts," Husa added.
The situation highlights the delicate balance between economic activity and environmental protection in Norway's iconic fjords. With wild salmon, seabirds and deep-sea life at stake, the decisions made now will shape the fjord's future for generations.