The skrei is on its way
Published: 21.01.2020 Updated: 28.01.2020
Catches are increasing in northern Norway, as is usual for this time of year.
The researchers estimate that the total amount of skrei will be somewhat smaller than in 2019, but still high historically.
Spawning happens underway
The skrei spawn along the coast from Finnmark in the North to Western Norway. The spawning is an act of coreography with strict rules for courtship. The fish swim with their undersides against each other for a few seconds while releasing eggs and sperm.
"Each female can produce between half a million and 15 million eggs, depending on age and size," says researcher Bjarte Bogstad.
If the spawning is a success, the egg develops from one to many cells in hours. After a while the lump of cells begin to take shape. After mere days, it is an embryo with eyes.
It becomes clear that there is a fish larvae inside the egg.
How long the process takes, depends on sea temperature. When the temperature is around 5 degrees, the larvae hatches after 20 days. An enzym will weaken the eggshell.
Very few survive
The newly hatched larvae have to find food while avoiding being eating by larger fish, krill or jellyfish. Few do.
"Fewer than one egg per million grow into fish that get to spawn during their lifespan."