Effects of different trawling time on freshness changes in icefish (Salangichthys microdon)

Abstract

Abstract In icefish ( Salangichthys microdon ) fishing in Lake Kasumigaura, trawling time is approximately 2 h. However, keeping icefish in the nets for about 2 h during the summer high water temperatures may degrade their quality. Therefore, this study compared the quality changes during refrigerated storage of icefish caught in August (summer), October (autumn), and December (winter), with trawling times set to 120 min and 30 min. After landing, samples were stored for 7 days at 5 °C, −1 °C, and −2 °C. The effects of trawling time were pronounced in K -value and free amino acid content. Immediately after harvest, K -values showed a significant difference between the 120-min and 30-min groups in August, whereas no significant difference was shown in October and December. For amino acids, taurine levels generally showed 120 min < 30 min in August and October, but not in December. For other amino acids, August and October showed a tendency of 30 min > 120 min, whereas December showed 120 min > 30 min. Based on these results, as high water temperatures increase K -value and lead to the consumption of taurine as part of the stress response, it is necessary to shorten fishing times in the summer.