Exploring the Brine Microbiota of a Traditional Norwegian Fermented Fish Product (Rakfisk) from Six Different Producers during Two Consecutive Seasonal Productions

The purpose of this study was to explore the microbiota of Norwegian fermented fish (rakfisk), a traditional product popular in the Norwegian market. Brine samples, collected from six producers during two subsequent years, were used. The producers applied different salt concentrations (between 3.8% and 7.2% NaCl), ripening temperatures (between 3.5 and 7.5 °C), fish species (trout or char), and fish upbringing (wild trout, on-shore farmed trout or char, and off-shore farmed char). The microbiota in the brine during the ripening process was mainly characterized by DNA-based, culture-independent methods. In total, 1710 samples were processed and of these 1342 were used for the final analysis. The microbiota was dominated by Gammaproteobacteria and Bacilli with the largest variance between samples associated with the genera Psychrobacter and Lactobacillus. The variance in the material was mainly determined by the origin of the samples, i.e., the different producers. The microbiota from the individual producers was to a large extent reproducible from one year to the next and appeared to be determined by the relatively small differences in the salinity and the ripening temperature. This is the first study exploring the microbiota in rakfisk brine and it provides insights into environmental factors affecting the rakfisk ecosystems.

Multispecies and Watershed Approaches to Freshwater Fish Conservation

<em>Abstract</em>.—The Blackfoot River restoration endeavor is an ongoing collaborative, comprehensive, and successful river conservation story in western North America. This chapter describes the restoration framework and process that shaped the first 30 years of this wild trout conservation story. The program began in the late 1980s when fish population surveys identified widespread habitat degradation and depleted numbers of wild trout throughout lower elevations of the Blackfoot River basin and the precarious status of migratory native trout. These initial findings triggered basinwide protective angling regulations for native trout, followed by fish population surveys in all streams. Fisheries data were then combined with basinwide aquatic habitat assessments to facilitate a collaborative multiscale restoration methodology to improve the ecological integrity of the river and its tributaries. Elements of the restoration framework included (1) basin-scale fish and habitat data collections that helped to identify human-induced limiting factors and promote landowner education/cooperation, (2) pilot restoration projects and prioritizations of tributary restoration work, (3) the site-specific integration of passive restoration (e.g. grazing and revegetation) and active restoration (e.g. fish screens, channel reconstruction) techniques, (4) the application of the reference reach concept within the restoration framework, and (5) the essential role of watershed groups in fundraising, implementation planning, and watershed-scale conservation easement protection, especially on private ranchlands. Finally, this chapter summarizes programmatic elements, specific case studies, and restoration techniques that preceded wild trout population expansion in the tributaries and main-stem Blackfoot River. The purpose of this chapter is to help others understand how we approached and implemented a major watershed restoration program.