The purpose of this paper is to look at how relationships between buyers and sellers are affected when on the supply side the most important resource is available only through a trading system created from a market perspective, whereas on the customer side the interaction resembles a network where relationships are long-term and complex. The empirical setting of the study is the pelagic industry, where this situation represents a challenge for the Norwegian herring exporters as they try to bridge these two types of interactions. In this industry, the purchasing of the herring is subject to a blind auction by law. At the same time, Norwegian exporters have customers in European seafood markets characterised by long-term relationships and close cooperation between importers, processors, producers and retailers. To analyse this situation, the study applies a qualitative research design including personal interviews with selected respondents in Norway and the three largest Norwegian herring export markets: Germany, Poland and Russia. The authors find that the interaction in these particular supplier–customer relationships is not extended to its full potential. It seems that the market-type transactions create “spillover-effects” to the other relationships, meaning that it is difficult to maintain high-involvement relationships when interaction in connected relationships is limited.