Reports

Seasonal and geographical variation in chemical composition and lipid stability of Atlantic mackerel (Scomber scombrus) caught in Icelandic waters

Published:

01/12/2015

Authors:

Paulina E. Romotowska, Magnea G. Karlsdóttir, María Guðjónsdóttir, Sigurjón Arason, Hörður G. Kristinsson

Supported by:

AVS Fisheries Research Fund (R 040-12)

contact

Sigurjón Arason

Chief Engineer

sigurjon.arason@matis.is

Seasonal and geographical variation in chemical composition and lipid stability of Atlantic mackerel (Scomber scombrus) caught in Icelandic waters

During the time that mackerel is off the coast of Iceland, it is eaten a lot, which causes it to gain weight quickly, with the result that the meat becomes very sensitive to handling. In this study, mackerel caught in the summer seasons of 2012 and 2013 (July, August, September) and from different fishing areas (east, northeast, south and southeast) were examined. In order to assess how well the raw material is suitable for processing high-quality products for human consumption, the mackerel was measured in terms of water and fat content, fatty acid composition, color, coloration and free fatty acids. In general, the mackerel collected in the summer of 2012 was of better quality than mackerel from 2013. The results also indicated a variability between fishing months in terms of fat content and the progress of development. Mackerel caught in the middle of the season had the lowest developmental value, indicating that this mackerel is best suited for processing high-quality products for human consumption.

Atlantic mackerel (Scomber scombrus) appears in Icelandic waters during its heavy feeding period, resulting in variation in mackerel products quality. Fish caught at different season during the summers of 2012 and 2013 (July, August, September) and at different sites of the Icelandic fishing area (East, Northeast, South and Southeast) were analyzed. Measurements of lipid and water content, fatty acid composition, color changes, lipid hydroperoxide (PV), thiobarbituric reactive substances (TBARS) and free fatty acid (FFA) were studied with the aim of investigating whether this raw material was suitable for the production of high quality products for human consumption. In general, samples collected during the summer of 2012 showed a better condition than fish from 2013. The results indicated seasonal variation in lipid content and rancidity development. The lowest rancidity values were observed in the middle of the Icelandic catching season, indicating that this raw material was best suited for production of high quality products. Moreover, geographical variation of the mackerel catches had an impact on the saturation of the fatty acids, and appeared as follows: East> Southeast> Northeast> South.

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Reports

Lobster trap fishing

Published:

01/09/2013

Authors:

Heather Philp, Vigfús Þórarinn Ásbjörnsson, Ragnheiður Sveinþórsdóttir

Supported by:

AVS Reference Number R 043‐10

Lobster trap fishing

In the project, new fishing areas were defined for lobster trapping, they were tested and evaluated for feasibility. An optimal time was also found before the traps were visited after they had been laid. Data showing seasonal fluctuations, both in terms of catches and catch values, were reviewed, and new data were collected and defined. Markets for live lobsters were examined along with prices according to the seasons. The results of the project show that a large lobster is the most common catch in traps in Iceland, in fact the lobster is so large that traditional British packages are too small for it. It is also gratifying that the time of year that seems to be the biggest catch is the time when the highest price is obtained in the markets for live lobsters. New fishing areas that were defined proved to be good and promising for the future.

In the project, new fishing grounds were identified for the purpose of lobster trap fishing. They were explored and assessed. Also, the optimal “soak” time for the fishing was determined. A lot of historical data were explored to show how the catches varied during the year - both catches and the value of the catch - and new data were collected. Markets for live lobster were explored by value and time of year. The results of the project show that big lobsters are the most common catch in traps in Iceland. And in fact, the lobsters are so big that the packaging used for the lobster in the UK is too small. It's positive for Iceland that the time of year when catches are highest coincides with the time of year when prices are the highest too. New fishing grounds were identified which were both productive and promising for the future.

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Reports

Process control for fishing, processing and processing of salted fish. Impact of raw material variables on the utilization and quality of salted fish

Published:

01/08/2007

Authors:

Lárus Þorvaldsson, Þóra Valsdóttir, Sigurjón Arason, Kristín Anna Þórarinsdóttir

Supported by:

AVS, Rannís Technology Development Fund

contact

Þóra Valsdóttir

Project Manager

thora.valsdottir@matis.is

Process control for fishing, processing and processing of salted fish. Impact of raw material variables on the utilization and quality of salted fish

Data was collected from Vísir hf. and Þorbjörn hf. and the relationship between utilization and quality with fishing areas, fishing time, fishing vessels, cooling on board and changes in the processing process are assessed. It was found that fishing areas had a significant effect on processing utilization, but the difference in effect utilization and quality by fishing area was smaller. Fluctuations in efficiency and quality proved to be seasonal and there was also a difference between years. Changes in cooling on board, ie. the use of liquid ice instead of flake ice on board did not prove to have a significant effect in the aforementioned manner. On the other hand, changes in the mechanism of action, ie. injection, both utilization and quality. The content of the report was part of the project "Process management for fishing, processing and processing of salted fish".

Analysis of data collected by the fisheries companies Vísir and Thorfish revealed the effects of fishing grounds, season, fishing vessels, chilling methods on board and salting procedure on yield and quality of salted products. Effects of fishing grounds on processing yield were significant but curing yield and quality were less influenced. Variation in curing yield and quality were seasonal and differences between years were observed. Changes in chilling methods on-board, ie use of liquid ice instead of flake ice did not affect yield and quality of salted products. On the other hand, changes in the salting procedure did, when injection was added as the initial step in the process.

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