ICELANDIC RESEARCH TRIP FINDS LOW DENSITIES OF MACKEREL

Icelandic research trip finds low densities of mackerel. The Icelandic research vessel Árni Friðriksson ended its participation on August 2nd in the annual international pelagic ecosystem expedition in the North Sea during the summer. During this 33-day expedition of Árna around Iceland, 65 tug stations were taken and about 6000 nautical miles or 11 thousand km were sailed. Sea measurements were then taken and baitfish taken at all surface towing stations. In addition, the mid-ocean layer was investigated by means of torques and echo sounders. Whale counting was also part of the expedition, see here. 

Distribution of mackerel inland the smallest ever recorded
The distribution and density of mackerel, herring and pollock in Icelandic territorial waters was studied. The preliminary results of measurements show that the spread of mackerel in Icelandic territorial waters is the smallest that has been measured since the expedition was first launched in the summer of 2010. Mackerel was measured at 5 of the 43 surface trawling stations, all but one of which were located off the south-east of the country. At three of the five stations only a few fish were caught, while the catch was 1.7 tons and 10.3 tons at the other two stations. The mackerel was large with an average length of 40 cm and an average weight of 550 g.

Fewer Icelandic summer spawning herrings were found
As in previous years, Norwegian-Icelandic spring spawning herrings were found at many trawl stations in the north and east of the country. Less was obtained from Icelandic summer spawning herring on the continental shelf to the south and west of the country, where only a few fish were caught at three stations. The lines of this expedition are too vague to give any information as to the size of that population.

Kolmunni was measured at the continental shelf edge to the south and west of the country in a similar density to last summers.

Preliminary results show that the temperature in the surface layer of the sea was similar to the summer of 2023 for the south and west of the country, but colder for the northeast and east of the country.

As in previous years, ships from Norway, the Faroe Islands and Denmark took part in the expedition. Data from the five ships will be compiled and analysed from the middle of August and the results will be presented towards the end of August.

Image: Árni Friðriksson on a wintery summer’s day off the Westfjords on July 4, 2024. The photo was taken by Anna Heiða Ólafsdóttir, expedition leader of the mackerel expedition.

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