New research offers a potential strategy to enhance the effectiveness of lumpfish as a solution to the persistent sea lice problem in salmon farming.
A recent study from the University of New Hampshire’s Agricultural Experiment Station has found that adjusting light levels and fish density in lumpfish hatcheries can improve survival rates and reduce aggressive behavior among the fish.
Lumpfish, which naturally feed on sea lice, offer a sustainable mitigation method. However, their tendency to exhibit aggression towards younger lumpfish has limited their utility. According to the study from UNH published in the North American Journal of Aquaculture, altering environmental conditions in rearing tanks can mitigate these aggressive behaviors.
“Lumpfish are crucial in addressing the high demand for cleaner fish in salmonid farming, but their aggressive behavior, including cannibalism, poses a challenge,” said Elizabeth Fairchild, a research associate professor with UNH’s College of Life Sciences and Agriculture (COLSA).
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“Understanding the factors that exacerbate lumpfish aggression, and providing guidelines for mitigating this behaviour to aquaculturists, are essential for increasing hatchery production and rearing efficiency.”
The research team, including Brittany Jellison, an assistant professor in UNH’s biological sciences department, and Shelby Perry, a Master of Science student in COLSA’s marine biology program, conducted their experiments at UNH’s Coastal Marine Lab.
They discovered that for smaller lumpfish, aggression decreased significantly under a 12-hour light/12-hour dark cycle compared to constant light and when fish density was reduced.
Flexibility
Fairchild noted that these management conditions become less critical as lumpfish grow larger, offering more flexibility in rearing practices. However, further research is needed to understand the long-term impacts and develop comprehensive guidelines for lumpfish rearing.
Improving lumpfish management is vital for the salmon aquaculture industry, which faces significant challenges from sea lice, estimated at $1.3 million per site over a two-year cycle.
Optimizing lumpfish development can enhance their role as cleaner fish, providing a more sustainable and efficient solution.
“By adopting these recommendations, fish farmers can improve lumpfish hatchery production, reduce juvenile mortality, and enhance the sustainability of salmonid farming through effective sea lice management,” said Perry. “Increasing aquaculture sustainability and efficiency is vital to meeting the future demand for animal protein and protecting the planet.”
