Going to almost certainly be less than 1. Moving further up the food chain results in energy losses. Those fish are going to use energy for their own body and such
Moreover there’s high mortality rates inside of fish farms for fish themselves. From the linked earlier article
Fish mortality has more than quadrupled, from 3% in 2002 to about 13.5% in 2019, in Scottish salmon farms alone. About a fifth of these deaths are recorded as being due to sea lice infestations, but about two thirds are unaccounted for so the real mortality owing to sea lice – which feed on salmon skin and mucus, effectively eating the fish alive – could be much higher.