Season and sexual maturation - impact on roe and muscle quality in trout

Summary

There are established markets for roe from salmon and trout for human consumption, and there is still a growing demand for such roe, partly due to the "sushi wave". The goal of this project is production of rainbow trout that provides high quality products of both roe and muscle. The results from the 2015 season showed that the female rainbow trout, close to full sexual maturity, gets a visual quality reduction especially in meat color and external characteristics. The rainbow trout does not seem to have significant osmotic challenges in the maturation process in seawater. All samples of chloride are within normal concentration of rainbow trout, both in the 2015 and 2016 season. Based on the results, expected slaughtering and harvesting of roe should occur from mid-December, in order to maximize the production volume of roe. However, the level of maturation is the main factor determining the fish quality - flesh quality and skin pigment. Thus, the fish should be slaughtered during October / November to obtain better slaughter yield.