Farmed salmon need zinc to avoid getting sick. But zinc in the ocean harms the environment
Either farmed fish health or the environment suffers.
A 250 kilo Atlantic bluefin tuna had a satellite tag attached to its back in the autumn of 2020. A year later, the researchers located the same tuna again outside Florø, Norway’s westernmost town. It had swum the equivalent of more than a third of the way around the equator.
This parasite costs Norwegian salmon farming almost 500 million euros each year. Could noise be the solution? Sound-emitting speakers weaken the lice's appetite. They fall off more easily and their reproduction drops dramatically, according to experiments in a Norwegian fjord.
The aquaculture industry doesn’t do a good enough job supervising the use of cleaner fish, and many die. Unless the industry does a better job documenting the welfare of cleaner fish, it will need to stop using them, the Norwegian Food Safety Authority states in new report.
Salmon are briefly immersed in warm water so the lice lose their grip. The treatment is the most common non-chemical delousing method used at Norwegian fish farms. But its imminent ban comes as new research reveals the pain and injury to the salmon.
The amount of fish in the world is being reassessed upwards. Some ten billion tonnes of fish that live at depths down to a kilometre are not fished at all. A University of Bergen professor thinks this biomass will be much more important for humankind in the future.
Cod migrate from the Barents Sea to the Lofoten Islands in North Norway to spawn every winter. The fishing season for these large spawning cod, called skrei in Norwegian, is currently open. A traditional North Norwegian serving of the fish is a super source of vitamin D.
Zebrafish have been used as a research standard to help scientists expand our understanding of everything from skin cancers to cardiovascular disease. But one Norwegian researcher cautions that research that relies on zebrafish might be less reliable because the fish are not fed a standardised diet.