SalMar loses salmon in jellyfish attack

Apolemia uvaria - also known as pearl norman, or string jellyfish

Around a million young salmon have been lost at a SalMar site in Senja, Norway during a jellyfish incident, it has been disclosed.

SalMar said in a statement last night that in mid-November its fish farmers at the location Ørnfjordbotn in Senja observed a significant and threatening influx of (what are known in Norway as) pearl normans or perles normanetes.

The species, Apolemia uvaria, is also known as “string jellyfish” and is a type of siphonophore colonial organism.

SalMar said: “Some dead fish were also recorded. A few days later, the extent of jellyfish increased further and the extent of damage to the fish increased in strength.

“For fish welfare reasons, SalMar therefore decided to destroy all the fish on the site. Our staff worked together with people from an external emergency boat intensively on a 24-hour basis to deal with the acute and deplorable situation that arose due to this unusual and violent invasion of pearl normans.”

The operation was completed over three to four days.

“Perles normanetes have also been observed at other locations in central and northern Norway, but to a limited extent,” SalMar added.

The company said jellyfish are one of several risk factors in fish farming, but it is very rare that they cause damage to the fish as in this case.

The  SalMar location on Frøya has been exposed to powerful jellyfish attacks over a number of years, the company said.

The company said the incident will not affect SalMar financially beyond the value of the destroyed fish and nor will it have an impact on guided slaughter volume.

The location had approximately 1.2 million salmon with an average weight of 0.3 kilos. Until the jellyfish attack, the mortality rate at the location was approximately one per cent.

At the same time, SalMar has reports an incident with mortality and destruction of fry with a weight of approx. 7 grams at its hatchery in Jøvika, Senja.

The incident was a consequence of defective installation of barriers in a fish tank – in this case the centre strainers in the tank. The fish had ended up in the RAS facility, biofilter and fish trap.

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