Blog post

Mackerel

Published on
July 13, 2012

Except for the eastern end at 5.45 east – with some young herring - it seemed that the 55.41N transect is just as empty as the the 56.11N transect.

Haul9.jpg

However, at Ingeborgs watch “light” schools at the bottom started to appear. At first we decided to wait a little and save time for more substantial recordings, but after lunch we had to satisfy our (fisheries-)scientific hunger. We shot the trawl at 11:00 UTC 55.44N – 0.26E. The catch consisted of 900 kg of mackerel. With hindsight this was not so surprising as the schools showed up relatively strong on the 200 kHz echogram (upper – right in the picture). Mackerel is a fish species without a gas filled swimbladder. Species with swimbladder like herring, show up relatively strong on the lower frequencies, like the 38 kHz (left in the picture).

A basket of mackerel
A basket of mackerel
There are some herrings (23) in the catch as well; here sampled by Marcel
There are some herrings (23) in the catch as well; here sampled by Marcel
Ingeborg checks the stomach contents
Ingeborg checks the stomach contents
All stomachs contain small crustaceans, including some Mysids (long white in the picture). Most specimens have some parasitic worms in their stomach
All stomachs contain small crustaceans, including some Mysids (long white in the picture). Most specimens have some parasitic worms in their stomach