Nofima state that there is huge importance in how a fish is handled after catch as it can effect the quality of the product.
The quicker a fish is gutted (often on board) leads to a higher quality product as it prevents defects such as, belly bursting, discolouration and bad smell.
However, in order to utilise more of the by-products it is advantageous if the fish is gutted on land.
The problem is that, on most occasions, the fish industry receive more fish than they can deal with if the fish needs to be gutted on land.
Allowing fish to be stored ungutted until the following day would therefore be advantageous to the industry.
Nofima has, on commission from RUBIN, studied the significance for quality of the time between catch and gutting, and the optimal storage method for ungutted fish.
The scientists tested various methods used to handle cod, haddock and saithe after the fish are taken on board the boat and before they are delivered to the fish processing industry.
Nofima's senior scientist, Leif Akse, said results showed that in order for fish to be stored ungutted, the fish must be first bled in water as soon as it has been caught and then transferred to cooling tubs immediately.
Nofima did however identify that some species are suited to the prelonged storage better than others.
“Cod which is cooled in ice slurry at a temperature of -1.25 °C can be stored ungutted for up to 24 hours without reducing the quality of the fish or by-products. At higher temperatures (0 °C), the fish can be stored for around 20 hours,” said Mr Akse.
But, haddock proved to be less suited to storage ungutted than cod, and showed more signs of discolouration and smell.
However, with good cooling in ice slurry on board and on land, haddock can nonetheless be stored for 24 hours without any unacceptable reduction of quality.
The scientists are of the opinion that bled and well cooled saithe caught with gear that causes a low degree of catch damage, such as long line or seine, can probably be stored equally as long ungutted as haddock or cod without an unacceptable reduction of quality.
Nofima did stress however that, for fish to be stored ungutted, they should not have any stomach content as it is more prone to belly bursting.
Fish Can Last 24 Hours Before Gutting
NORWAY - New research carried out by Nofima has discovered that fish which are bled, cooled and stored correctly after being caught can keep for at least 24 hours before being gutted and still maintain good quality.
